diff --git a/CMakeLists.txt b/CMakeLists.txt
index 42541c6..c63cc3c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -66,6 +66,7 @@ set(AMDUAT_ASL_SRCS
   src/near_core/asl/collection_view.c
   src/near_core/asl/none.c
   src/near_core/asl/artifact_io.c
+  src/near_core/asl/identity.c
   src/near_core/asl/io.c
   src/near_core/asl/index_accel.c
   src/near_core/asl/index_bloom.c
@@ -78,6 +79,8 @@ set(AMDUAT_ASL_SRCS
   src/near_core/asl/store.c
   src/near_core/asl/ref_text.c
   src/near_core/asl/registry.c
+  src/near_core/bytestore.c
+  src/near_core/fps.c
 )
 
 set(AMDUAT_ASL_LOG_STORE_SRCS
@@ -106,6 +109,8 @@ set(AMDUAT_ENC_SRCS
   src/near_core/enc/asl_log.c
   src/near_core/enc/asl_core_index.c
   src/near_core/enc/asl_tgk_exec_plan.c
+  src/near_core/enc/pcb1.c
+  src/near_core/enc/fcs1.c
   src/near_core/enc/pel_program_dag.c
   src/near_core/enc/pel_program_dag_desc.c
   src/near_core/enc/pel_trace_dag.c
@@ -441,6 +446,26 @@ target_link_libraries(amduat_test_asl_tgk_exec_plan
 )
 add_test(NAME asl_tgk_exec_plan COMMAND amduat_test_asl_tgk_exec_plan)
 
+add_executable(amduat_test_fps tests/enc/test_fps.c)
+target_include_directories(amduat_test_fps
+  PRIVATE ${AMDUAT_INTERNAL_DIR}
+  PRIVATE ${AMDUAT_INCLUDE_DIR}
+)
+target_link_libraries(amduat_test_fps
+  PRIVATE amduat_enc amduat_hash_asl1 amduat_asl amduat_util
+)
+add_test(NAME fps COMMAND amduat_test_fps)
+
+add_executable(amduat_test_fcs_pcb1 tests/enc/test_fcs_pcb1.c)
+target_include_directories(amduat_test_fcs_pcb1
+  PRIVATE ${AMDUAT_INTERNAL_DIR}
+  PRIVATE ${AMDUAT_INCLUDE_DIR}
+)
+target_link_libraries(amduat_test_fcs_pcb1
+  PRIVATE amduat_enc amduat_hash_asl1 amduat_asl amduat_util
+)
+add_test(NAME fcs_pcb1 COMMAND amduat_test_fcs_pcb1)
+
 add_executable(amduat_test_tgk1_edge tests/enc/test_tgk1_edge.c)
 target_include_directories(amduat_test_tgk1_edge
   PRIVATE ${AMDUAT_INTERNAL_DIR}
@@ -471,6 +496,17 @@ target_link_libraries(amduat_test_tgk_store_mem
 )
 add_test(NAME tgk_store_mem COMMAND amduat_test_tgk_store_mem)
 
+add_executable(amduat_test_tgk_error_taxonomy
+  tests/tgk/test_tgk_error_taxonomy.c)
+target_include_directories(amduat_test_tgk_error_taxonomy
+  PRIVATE ${AMDUAT_INTERNAL_DIR}
+  PRIVATE ${AMDUAT_INCLUDE_DIR}
+)
+target_link_libraries(amduat_test_tgk_error_taxonomy
+  PRIVATE amduat_tgk
+)
+add_test(NAME tgk_error_taxonomy COMMAND amduat_test_tgk_error_taxonomy)
+
 add_executable(amduat_test_tgk_store_fs tests/tgk/test_tgk_store_fs.c)
 target_include_directories(amduat_test_tgk_store_fs
   PRIVATE ${AMDUAT_INTERNAL_DIR}
@@ -598,6 +634,28 @@ target_link_libraries(amduat_test_asl_index_accel
 )
 add_test(NAME asl_index_accel COMMAND amduat_test_asl_index_accel)
 
+add_executable(amduat_test_asl_log_encoding
+  tests/asl/test_asl_log_encoding.c)
+target_include_directories(amduat_test_asl_log_encoding
+  PRIVATE ${AMDUAT_INTERNAL_DIR}
+  PRIVATE ${AMDUAT_INCLUDE_DIR}
+)
+target_link_libraries(amduat_test_asl_log_encoding
+  PRIVATE amduat_asl
+)
+add_test(NAME asl_log_encoding COMMAND amduat_test_asl_log_encoding)
+
+add_executable(amduat_test_asl_error_taxonomy
+  tests/asl/test_asl_error_taxonomy.c)
+target_include_directories(amduat_test_asl_error_taxonomy
+  PRIVATE ${AMDUAT_INTERNAL_DIR}
+  PRIVATE ${AMDUAT_INCLUDE_DIR}
+)
+target_link_libraries(amduat_test_asl_error_taxonomy
+  PRIVATE amduat_asl
+)
+add_test(NAME asl_error_taxonomy COMMAND amduat_test_asl_error_taxonomy)
+
 add_executable(amduat_test_asl_derivation_index_fs
   tests/asl/test_asl_derivation_index_fs.c)
 target_include_directories(amduat_test_asl_derivation_index_fs
diff --git a/docs/SUBSTRATE_CONTRACT_V0_1.md b/docs/SUBSTRATE_CONTRACT_V0_1.md
index e3cc7dd..86747c8 100644
--- a/docs/SUBSTRATE_CONTRACT_V0_1.md
+++ b/docs/SUBSTRATE_CONTRACT_V0_1.md
@@ -17,11 +17,14 @@ it is introduced in this change and implemented in code (referenced below).
 2. **Reference** = `(hash_id, digest)`; equality is hash-id + digest equality.
    Sources: `tier1/asl-1-core.md`, `include/amduat/asl/core.h`.
 
-3. **Reference derivation** is based on canonical encoding + hash family; the API
-   exposes this via `amduat_asl_ref_derive`.
-   Sources: `tier1/asl-1-core.md`, `include/amduat/asl/ref_derive.h`.
+3. **Reference derivation** uses canonical encoding plus the ASL1 domain
+   separator (`"AMDUAT:ASL1:ART\0"`) and hash family; the API exposes this via
+   `amduat_asl_ref_derive`.
+   Sources: `tier1/asl-1-core.md`, `include/amduat/asl/ref_derive.h`,
+   `include/amduat/asl/identity.h`.
 
-4. **Hash family** in use for the stack is HASH/ASL1 (e.g., SHA-256).
+4. **Hash family** in use for the stack is HASH/ASL1 (e.g., SHA-256), with
+   registry/version metadata exposed in the core API.
    Sources: `tier1/hash-asl1.md`, `include/amduat/hash/asl1.h`.
 
 ---
diff --git a/docs/adr-031-asl-tgk-index-separation.md b/docs/adr-031-asl-tgk-index-separation.md
new file mode 100644
index 0000000..2544059
--- /dev/null
+++ b/docs/adr-031-asl-tgk-index-separation.md
@@ -0,0 +1,50 @@
+# ADR-031 — ASL + TGK Index Separation
+
+Status: Accepted
+Date: 2026-02-21
+Decision Owner: Architecture
+
+## Context
+
+ASL index/log provide artifact visibility, replay, and tombstone semantics.
+TGK store provides graph query semantics over TGK edge artifacts. We must decide
+whether to **merge** ASL and TGK indexes into one unified index structure, or
+keep them separated with explicit cross-layer invariants.
+
+## Decision
+
+We **reject** a merged ASL+TGK index.
+
+ASL index/log and TGK index remain **separate layers** with strict invariants
+that keep them consistent.
+
+## Rationale
+
+* ASL index is about **artifact visibility and replay**; TGK index is about
+  **graph query acceleration**. Their update streams and invariants differ.
+* Keeping them separate preserves clean layering and deterministic replay.
+* TGK indexes can be rebuilt or swapped without changing ASL semantics.
+* A merged index risks coupling graph query policies with storage visibility,
+  complicating federation and policy enforcement.
+
+## Invariants (Normative)
+
+1. **Visibility alignment:** TGK indexes MUST only index artifacts visible under
+   ASL log replay at the same `(snapshot_id, log_position)`.
+2. **Tombstone enforcement:** TGK indexes MUST respect ASL tombstones and
+   tombstone lifts at their `logseq`.
+3. **No new identity:** TGK nodes/edges MUST use ASL `Reference` identities;
+   TGK MUST NOT introduce a distinct object identity scheme.
+4. **Deterministic derivation:** TGK index updates MUST be deterministically
+   derived from ASL-admitted records (segments/log). No side-channel writes.
+5. **Replay equivalence:** Replaying ASL log + sealed segments MUST yield the
+   same TGK index state (up to encoding) as an online build.
+6. **Snapshot consistency:** TGK queries at a snapshot MUST be consistent with
+   ASL `IndexState` for that snapshot.
+
+## Consequences
+
+* ASL and TGK index encodings remain separate specs.
+* Conformance tests for ASL and TGK can evolve independently, with explicit
+  cross-layer checks for the invariants above.
+* TGK index rebuilds remain possible without touching ASL log/segment formats.
diff --git a/include/amduat/asl/identity.h b/include/amduat/asl/identity.h
new file mode 100644
index 0000000..976dee3
--- /dev/null
+++ b/include/amduat/asl/identity.h
@@ -0,0 +1,28 @@
+#ifndef AMDUAT_ASL_IDENTITY_H
+#define AMDUAT_ASL_IDENTITY_H
+
+#include "amduat/asl/core.h"
+#include "amduat/hash/asl1.h"
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+  const char *hash_registry;
+  uint16_t hash_registry_version;
+  amduat_octets_t domain_separator;
+} amduat_asl_identity_rules_t;
+
+/* Domain separator for ASL/1 artifact identity hashing. */
+amduat_octets_t amduat_asl_identity_domain_separator(void);
+
+const amduat_asl_identity_rules_t *amduat_asl_identity_rules(void);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* AMDUAT_ASL_IDENTITY_H */
diff --git a/include/amduat/bytestore.h b/include/amduat/bytestore.h
new file mode 100644
index 0000000..7afac89
--- /dev/null
+++ b/include/amduat/bytestore.h
@@ -0,0 +1,137 @@
+#ifndef AMDUAT_BYTESTORE_H
+#define AMDUAT_BYTESTORE_H
+
+#include "amduat/asl/core.h"
+#include "amduat/hash/asl1.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  AMDUAT_BYTESTORE_OK = 0,
+  AMDUAT_BYTESTORE_ERR_POLICY_SIZE = 1,
+  AMDUAT_BYTESTORE_ERR_IDENTITY_MISMATCH = 2,
+  AMDUAT_BYTESTORE_ERR_STREAM_ORDER = 3,
+  AMDUAT_BYTESTORE_ERR_STREAM_TRUNCATED = 4,
+  AMDUAT_BYTESTORE_ERR_AREA_VIOLATION = 5,
+  AMDUAT_BYTESTORE_ERR_CRASH_SIMULATION = 6,
+  AMDUAT_BYTESTORE_ERR_STORE_MISSING = 7,
+  AMDUAT_BYTESTORE_ERR_UNSUPPORTED = 8,
+  AMDUAT_BYTESTORE_ERR_IO = 9,
+  AMDUAT_BYTESTORE_ERR_INVALID = 10
+} amduat_bytestore_error_t;
+
+typedef struct {
+  amduat_hash_id_t hash_id;
+  size_t max_object_size;
+  const char *public_root;
+  const char *secure_root;
+} amduat_bytestore_config_t;
+
+typedef struct {
+  bool present;
+  size_t size;
+} amduat_bytestore_stat_t;
+
+typedef struct {
+  /* Return 1 for a chunk, 0 for end-of-stream, -1 on error. */
+  int (*next)(void *ctx, amduat_octets_t *out_chunk);
+  void *ctx;
+} amduat_bytestore_stream_t;
+
+typedef struct {
+  amduat_bytestore_error_t (*put)(void *ctx,
+                                  amduat_octets_t payload,
+                                  amduat_reference_t *out_cid);
+  amduat_bytestore_error_t (*put_stream)(void *ctx,
+                                         amduat_bytestore_stream_t stream,
+                                         amduat_reference_t *out_cid);
+  amduat_bytestore_error_t (*import_cor)(void *ctx,
+                                         amduat_octets_t envelope,
+                                         amduat_reference_t *out_cid);
+  amduat_bytestore_error_t (*export_cor)(void *ctx,
+                                         amduat_reference_t cid,
+                                         amduat_octets_t *out_envelope);
+  amduat_bytestore_error_t (*get)(void *ctx,
+                                  amduat_reference_t cid,
+                                  amduat_octets_t *out_bytes);
+  amduat_bytestore_error_t (*stat)(void *ctx,
+                                   amduat_reference_t cid,
+                                   amduat_bytestore_stat_t *out_stat);
+  amduat_bytestore_error_t (*assert_area_isolation)(void *ctx,
+                                                    const char *public_root,
+                                                    const char *secure_root);
+  amduat_bytestore_error_t (*validate_config)(void *ctx,
+                                              amduat_bytestore_config_t config);
+} amduat_bytestore_ops_t;
+
+static inline void amduat_bytestore_ops_init(amduat_bytestore_ops_t *ops) {
+  if (ops == NULL) {
+    return;
+  }
+  ops->put = NULL;
+  ops->put_stream = NULL;
+  ops->import_cor = NULL;
+  ops->export_cor = NULL;
+  ops->get = NULL;
+  ops->stat = NULL;
+  ops->assert_area_isolation = NULL;
+  ops->validate_config = NULL;
+}
+
+typedef struct {
+  amduat_bytestore_config_t config;
+  amduat_bytestore_ops_t ops;
+  void *ctx;
+} amduat_bytestore_t;
+
+void amduat_bytestore_init(amduat_bytestore_t *store,
+                           amduat_bytestore_config_t config,
+                           amduat_bytestore_ops_t ops,
+                           void *ctx);
+
+amduat_bytestore_error_t amduat_bytestore_put(amduat_bytestore_t *store,
+                                              amduat_octets_t payload,
+                                              amduat_reference_t *out_cid);
+amduat_bytestore_error_t amduat_bytestore_put_stream(
+    amduat_bytestore_t *store,
+    amduat_bytestore_stream_t stream,
+    amduat_reference_t *out_cid);
+amduat_bytestore_error_t amduat_bytestore_import_cor(
+    amduat_bytestore_t *store,
+    amduat_octets_t envelope,
+    amduat_reference_t *out_cid);
+amduat_bytestore_error_t amduat_bytestore_export_cor(
+    amduat_bytestore_t *store,
+    amduat_reference_t cid,
+    amduat_octets_t *out_envelope);
+amduat_bytestore_error_t amduat_bytestore_get(amduat_bytestore_t *store,
+                                              amduat_reference_t cid,
+                                              amduat_octets_t *out_bytes);
+amduat_bytestore_error_t amduat_bytestore_stat(
+    amduat_bytestore_t *store,
+    amduat_reference_t cid,
+    amduat_bytestore_stat_t *out_stat);
+amduat_bytestore_error_t amduat_bytestore_assert_area_isolation(
+    amduat_bytestore_t *store,
+    const char *public_root,
+    const char *secure_root);
+
+bool amduat_bytestore_cid_for_payload(amduat_hash_id_t hash_id,
+                                      amduat_octets_t payload,
+                                      amduat_reference_t *out_cid);
+
+bool amduat_bytestore_cid_for_stream(amduat_hash_id_t hash_id,
+                                     amduat_bytestore_stream_t stream,
+                                     amduat_reference_t *out_cid);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* AMDUAT_BYTESTORE_H */
diff --git a/include/amduat/enc/fcs1.h b/include/amduat/enc/fcs1.h
new file mode 100644
index 0000000..f35dc36
--- /dev/null
+++ b/include/amduat/enc/fcs1.h
@@ -0,0 +1,52 @@
+#ifndef AMDUAT_ENC_FCS1_H
+#define AMDUAT_ENC_FCS1_H
+
+#include "amduat/asl/core.h"
+#include "amduat/enc/pcb1.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  AMDUAT_FCS1_OK = 0,
+  AMDUAT_FCS1_ERR_HEADER_INVALID = 1,
+  AMDUAT_FCS1_ERR_TAG_ORDER = 2,
+  AMDUAT_FCS1_ERR_UNKNOWN_TAG = 3,
+  AMDUAT_FCS1_ERR_PARAMETER_FORMAT = 4,
+  AMDUAT_FCS1_ERR_PCB_ARITY_MISMATCH = 5,
+  AMDUAT_FCS1_ERR_CYCLE_DETECTED = 6,
+  AMDUAT_FCS1_ERR_VARINT_NON_MINIMAL = 7,
+  AMDUAT_FCS1_ERR_TRAILING_BYTES = 8,
+  AMDUAT_FCS1_ERR_INVALID = 9
+} amduat_fcs1_error_t;
+
+typedef struct {
+  amduat_reference_t function_ptr;
+  amduat_reference_t parameter_block;
+  uint32_t arity;
+} amduat_fcs1_descriptor_t;
+
+typedef bool (*amduat_fcs1_resolve_fn)(void *ctx,
+                                       amduat_reference_t ref,
+                                       amduat_octets_t *out_bytes);
+
+amduat_fcs1_error_t amduat_fcs1_decode_v1(amduat_octets_t bytes,
+                                          amduat_fcs1_descriptor_t *out_desc);
+
+amduat_fcs1_error_t amduat_fcs1_validate_v1(
+    amduat_octets_t bytes,
+    amduat_fcs1_resolve_fn resolver,
+    void *resolver_ctx);
+
+void amduat_fcs1_descriptor_free(amduat_fcs1_descriptor_t *desc);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* AMDUAT_ENC_FCS1_H */
diff --git a/include/amduat/enc/pcb1.h b/include/amduat/enc/pcb1.h
new file mode 100644
index 0000000..8567341
--- /dev/null
+++ b/include/amduat/enc/pcb1.h
@@ -0,0 +1,38 @@
+#ifndef AMDUAT_ENC_PCB1_H
+#define AMDUAT_ENC_PCB1_H
+
+#include "amduat/asl/core.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  AMDUAT_PCB1_OK = 0,
+  AMDUAT_PCB1_ERR_HEADER_INVALID = 1,
+  AMDUAT_PCB1_ERR_TAG_ORDER = 2,
+  AMDUAT_PCB1_ERR_UNKNOWN_TAG = 3,
+  AMDUAT_PCB1_ERR_MANIFEST_ORDER = 4,
+  AMDUAT_PCB1_ERR_DIGEST_MISMATCH = 5,
+  AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL = 6,
+  AMDUAT_PCB1_ERR_TRAILING_BYTES = 7,
+  AMDUAT_PCB1_ERR_INVALID = 8
+} amduat_pcb1_error_t;
+
+typedef struct {
+  uint32_t slot_count;
+} amduat_pcb1_manifest_t;
+
+amduat_pcb1_error_t amduat_pcb1_decode_v1(amduat_octets_t bytes,
+                                          amduat_pcb1_manifest_t *out_manifest,
+                                          amduat_octets_t *out_slot_data);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* AMDUAT_ENC_PCB1_H */
diff --git a/include/amduat/fps.h b/include/amduat/fps.h
new file mode 100644
index 0000000..516e93e
--- /dev/null
+++ b/include/amduat/fps.h
@@ -0,0 +1,61 @@
+#ifndef AMDUAT_FPS_H
+#define AMDUAT_FPS_H
+
+#include "amduat/asl/core.h"
+#include "amduat/hash/asl1.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef enum {
+  AMDUAT_FPS_OK = 0,
+  AMDUAT_FPS_ERR_IO_FAILURE = 1,
+  AMDUAT_FPS_ERR_NORMALIZATION = 2,
+  AMDUAT_FPS_ERR_CID_NOT_FOUND = 3,
+  AMDUAT_FPS_ERR_SLICE_RANGE = 4,
+  AMDUAT_FPS_ERR_EMPTY_INPUTS = 5,
+  AMDUAT_FPS_ERR_REV_ALIGNMENT = 6,
+  AMDUAT_FPS_ERR_INVALID_LEVEL = 7,
+  AMDUAT_FPS_ERR_SPLICE_RANGE = 8,
+  AMDUAT_FPS_ERR_INVALID = 9
+} amduat_fps_error_t;
+
+typedef enum {
+  AMDUAT_FPS_REVERSE_BITS = 0,
+  AMDUAT_FPS_REVERSE_BYTES = 1,
+  AMDUAT_FPS_REVERSE_WORDS = 2,
+  AMDUAT_FPS_REVERSE_LONGS = 3
+} amduat_fps_reverse_level_t;
+
+amduat_fps_error_t amduat_fps_slice(amduat_octets_t input,
+                                    size_t offset,
+                                    size_t length,
+                                    amduat_octets_t *out);
+
+amduat_fps_error_t amduat_fps_concat(const amduat_octets_t *inputs,
+                                     size_t input_count,
+                                     amduat_octets_t *out);
+
+amduat_fps_error_t amduat_fps_reverse(amduat_octets_t input,
+                                      amduat_fps_reverse_level_t level,
+                                      amduat_octets_t *out);
+
+amduat_fps_error_t amduat_fps_splice(amduat_octets_t a,
+                                     size_t offset,
+                                     amduat_octets_t b,
+                                     amduat_octets_t *out);
+
+bool amduat_fps_cid_for_payload(amduat_hash_id_t hash_id,
+                                amduat_octets_t payload,
+                                amduat_reference_t *out_cid);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* AMDUAT_FPS_H */
diff --git a/include/amduat/hash/asl1.h b/include/amduat/hash/asl1.h
index 7af61e4..70958d6 100644
--- a/include/amduat/hash/asl1.h
+++ b/include/amduat/hash/asl1.h
@@ -34,6 +34,15 @@ typedef struct {
 } amduat_hash_asl1_stream_t;
 
 enum { AMDUAT_HASH_ASL1_ID_SHA256 = 0x0001 };
+enum {
+  AMDUAT_HASH_ASL1_VERSION_MAJOR = 0,
+  AMDUAT_HASH_ASL1_VERSION_MINOR = 2,
+  AMDUAT_HASH_ASL1_VERSION_PATCH = 5,
+  AMDUAT_HASH_ASL1_VERSION = 0x0205
+};
+
+#define AMDUAT_HASH_ASL1_FAMILY "ASL1"
+#define AMDUAT_HASH_ASL1_REGISTRY "HASH/ASL1"
 
 amduat_octets_t amduat_hash_asl1_key(amduat_hash_id_t hash_id, uint8_t out[2]);
 
@@ -49,6 +58,11 @@ bool amduat_hash_asl1_digest(amduat_hash_id_t hash_id,
                              amduat_octets_t input,
                              uint8_t *out,
                              size_t out_len);
+bool amduat_hash_asl1_digest_domain(amduat_hash_id_t hash_id,
+                                    amduat_octets_t domain_separator,
+                                    amduat_octets_t input,
+                                    uint8_t *out,
+                                    size_t out_len);
 
 bool amduat_hash_asl1_stream_init(amduat_hash_id_t hash_id,
                                   amduat_hash_asl1_stream_t *out);
diff --git a/registry/README.md b/registry/README.md
index d405c18..9d6619c 100644
--- a/registry/README.md
+++ b/registry/README.md
@@ -24,6 +24,9 @@ are data nodes that can be hashed and referenced.
 
 ## JSONL manifests
 
+Common conventions for all registry manifests are captured in
+`registry/manifest.schema.md`.
+
 Each registry has a `registry/<name>.jsonl` manifest. Each line is one entry.
 The manifest is the source of truth for codegen and documentation tables.
 
diff --git a/registry/enc-asl1-core.jsonl b/registry/enc-asl1-core.jsonl
index b09c2fd..24a9a6f 100644
--- a/registry/enc-asl1-core.jsonl
+++ b/registry/enc-asl1-core.jsonl
@@ -1 +1 @@
-{"registry":"ENC/ASL1-CORE","profile_id":"0x0001","handle":"amduat.enc.asl1.core.profile.0001@1","name":"ASL_ENC_CORE_V1","version":"0x0105","status":"mandatory","spec_ref":"ENC/ASL1-CORE v1.0.5","notes":"Canonical encoding profile for ASL/1-CORE artifacts and references.","descriptor_sha256":"ed4ce5f50d4cb62d5e420da377ffcc0a767939f795b2c9ea00e57d79e12d93c2"}
+{"registry":"ENC/ASL1-CORE","profile_id":"0x0001","handle":"amduat.enc.asl1.core.profile.0001@1","name":"ASL_ENC_CORE_V1","version":"0x0106","status":"mandatory","spec_ref":"ENC/ASL1-CORE v1.0.6","notes":"Canonical encoding profile for ASL/1-CORE artifacts and references.","descriptor_sha256":"2d86c1367149e37d076a63fc91673dbc56fe08df83c94a11e323a0185948a87b"}
diff --git a/registry/manifest.schema.md b/registry/manifest.schema.md
new file mode 100644
index 0000000..fc24e7f
--- /dev/null
+++ b/registry/manifest.schema.md
@@ -0,0 +1,43 @@
+# Registry Manifest Schema (core)
+
+This file defines the common conventions for registry JSONL manifests in
+`vendor/amduat/registry/`. Each registry then supplies a registry-specific
+schema that fixes the key field(s) and the descriptor field ordering used for
+`descriptor_sha256`.
+
+## JSONL rules
+
+- Each line is one JSON object (JSONL).
+- Fields must match the registry-specific schema.
+- Required fields must be present even if the value is `null`.
+
+## Handle naming
+
+Handles are stable identifiers in the `amduat` namespace:
+
+```
+amduat.<domain>.<registry>.<kind>.<id>@<version>
+```
+
+`id` is the canonical key for the registry (usually lowercase, zero-padded hex).
+`version` increments only if the meaning of the key changes.
+
+## Canonical descriptor digest
+
+Each entry includes `descriptor_sha256`, the SHA-256 digest (lowercase hex) of
+its canonical descriptor JSON object. The canonical descriptor object:
+
+- Includes the descriptor fields defined by the registry-specific schema.
+- Uses the exact field ordering specified by the registry-specific schema.
+- Excludes the `descriptor_sha256` field itself.
+- Uses standard JSON encoding with no extra whitespace.
+- Is hashed over its UTF-8 byte sequence.
+
+Registry-specific schema files define the precise field ordering and any
+additional constraints on descriptor fields.
+
+## Canonical key encoding
+
+Each registry defines the byte encoding of its key. The encoding is used when
+constructing ASL registry artifacts. See the registry-specific schema for the
+exact key encoding (e.g., big-endian `u16` for `HASH/ASL1`).
diff --git a/src/near_core/asl/identity.c b/src/near_core/asl/identity.c
new file mode 100644
index 0000000..c98b17f
--- /dev/null
+++ b/src/near_core/asl/identity.c
@@ -0,0 +1,18 @@
+#include "amduat/asl/identity.h"
+
+static const uint8_t k_asl_identity_domain_sep[] = {
+    'A', 'M', 'D', 'U', 'A', 'T', ':', 'A',
+    'S', 'L', '1', ':', 'A', 'R', 'T', 0x00};
+
+amduat_octets_t amduat_asl_identity_domain_separator(void) {
+  return amduat_octets(k_asl_identity_domain_sep,
+                       sizeof(k_asl_identity_domain_sep));
+}
+
+const amduat_asl_identity_rules_t *amduat_asl_identity_rules(void) {
+  static const amduat_asl_identity_rules_t k_rules = {
+      AMDUAT_HASH_ASL1_REGISTRY,
+      AMDUAT_HASH_ASL1_VERSION,
+      {k_asl_identity_domain_sep, sizeof(k_asl_identity_domain_sep)}};
+  return &k_rules;
+}
diff --git a/src/near_core/asl/ref_derive.c b/src/near_core/asl/ref_derive.c
index 9e37cac..4179151 100644
--- a/src/near_core/asl/ref_derive.c
+++ b/src/near_core/asl/ref_derive.c
@@ -1,5 +1,6 @@
 #include "amduat/asl/ref_derive.h"
 
+#include "amduat/asl/identity.h"
 #include "amduat/enc/asl1_core.h"
 #include "amduat/enc/asl1_core_codec.h"
 #include "amduat/hash/asl1.h"
@@ -53,10 +54,11 @@ bool amduat_asl_ref_derive(amduat_artifact_t artifact,
     return false;
   }
 
-  if (!amduat_hash_asl1_digest(hash_id,
-                               artifact_bytes,
-                               digest,
-                               hash_desc->digest_len)) {
+  if (!amduat_hash_asl1_digest_domain(hash_id,
+                                      amduat_asl_identity_domain_separator(),
+                                      artifact_bytes,
+                                      digest,
+                                      hash_desc->digest_len)) {
     amduat_octets_free(&artifact_bytes);
     free(digest);
     return false;
diff --git a/src/near_core/bytestore.c b/src/near_core/bytestore.c
new file mode 100644
index 0000000..a650ff0
--- /dev/null
+++ b/src/near_core/bytestore.c
@@ -0,0 +1,235 @@
+#include "amduat/bytestore.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static const char k_amduat_bytestore_domain_sep[] = "CAS:OBJ\0";
+
+static bool amduat_bytestore_trim_trailing_slash(const char *input,
+                                                 size_t *out_len) {
+  size_t len;
+
+  if (input == NULL || out_len == NULL) {
+    return false;
+  }
+  len = strlen(input);
+  while (len > 1u && input[len - 1u] == '/') {
+    len--;
+  }
+  *out_len = len;
+  return true;
+}
+
+static bool amduat_bytestore_path_is_prefix(const char *parent,
+                                            size_t parent_len,
+                                            const char *child,
+                                            size_t child_len) {
+  if (parent_len == 0u || child_len == 0u) {
+    return false;
+  }
+  if (child_len < parent_len) {
+    return false;
+  }
+  if (memcmp(parent, child, parent_len) != 0) {
+    return false;
+  }
+  if (child_len == parent_len) {
+    return true;
+  }
+  return child[parent_len] == '/';
+}
+
+void amduat_bytestore_init(amduat_bytestore_t *store,
+                           amduat_bytestore_config_t config,
+                           amduat_bytestore_ops_t ops,
+                           void *ctx) {
+  if (store == NULL) {
+    return;
+  }
+  store->config = config;
+  store->ops = ops;
+  store->ctx = ctx;
+}
+
+amduat_bytestore_error_t amduat_bytestore_put(amduat_bytestore_t *store,
+                                              amduat_octets_t payload,
+                                              amduat_reference_t *out_cid) {
+  if (store == NULL || store->ops.put == NULL) {
+    return AMDUAT_BYTESTORE_ERR_UNSUPPORTED;
+  }
+  return store->ops.put(store->ctx, payload, out_cid);
+}
+
+amduat_bytestore_error_t amduat_bytestore_put_stream(
+    amduat_bytestore_t *store,
+    amduat_bytestore_stream_t stream,
+    amduat_reference_t *out_cid) {
+  if (store == NULL || store->ops.put_stream == NULL) {
+    return AMDUAT_BYTESTORE_ERR_UNSUPPORTED;
+  }
+  return store->ops.put_stream(store->ctx, stream, out_cid);
+}
+
+amduat_bytestore_error_t amduat_bytestore_import_cor(
+    amduat_bytestore_t *store,
+    amduat_octets_t envelope,
+    amduat_reference_t *out_cid) {
+  if (store == NULL || store->ops.import_cor == NULL) {
+    return AMDUAT_BYTESTORE_ERR_UNSUPPORTED;
+  }
+  return store->ops.import_cor(store->ctx, envelope, out_cid);
+}
+
+amduat_bytestore_error_t amduat_bytestore_export_cor(
+    amduat_bytestore_t *store,
+    amduat_reference_t cid,
+    amduat_octets_t *out_envelope) {
+  if (store == NULL || store->ops.export_cor == NULL) {
+    return AMDUAT_BYTESTORE_ERR_UNSUPPORTED;
+  }
+  return store->ops.export_cor(store->ctx, cid, out_envelope);
+}
+
+amduat_bytestore_error_t amduat_bytestore_get(amduat_bytestore_t *store,
+                                              amduat_reference_t cid,
+                                              amduat_octets_t *out_bytes) {
+  if (store == NULL || store->ops.get == NULL) {
+    return AMDUAT_BYTESTORE_ERR_UNSUPPORTED;
+  }
+  return store->ops.get(store->ctx, cid, out_bytes);
+}
+
+amduat_bytestore_error_t amduat_bytestore_stat(
+    amduat_bytestore_t *store,
+    amduat_reference_t cid,
+    amduat_bytestore_stat_t *out_stat) {
+  if (store == NULL || store->ops.stat == NULL) {
+    return AMDUAT_BYTESTORE_ERR_UNSUPPORTED;
+  }
+  return store->ops.stat(store->ctx, cid, out_stat);
+}
+
+amduat_bytestore_error_t amduat_bytestore_assert_area_isolation(
+    amduat_bytestore_t *store,
+    const char *public_root,
+    const char *secure_root) {
+  size_t public_len;
+  size_t secure_len;
+
+  if (store != NULL && store->ops.assert_area_isolation != NULL) {
+    return store->ops.assert_area_isolation(store->ctx, public_root,
+                                            secure_root);
+  }
+  if (!amduat_bytestore_trim_trailing_slash(public_root, &public_len) ||
+      !amduat_bytestore_trim_trailing_slash(secure_root, &secure_len)) {
+    return AMDUAT_BYTESTORE_ERR_INVALID;
+  }
+  if (public_len == 0u || secure_len == 0u) {
+    return AMDUAT_BYTESTORE_ERR_INVALID;
+  }
+  if (public_len == secure_len &&
+      memcmp(public_root, secure_root, public_len) == 0) {
+    return AMDUAT_BYTESTORE_ERR_AREA_VIOLATION;
+  }
+  if (amduat_bytestore_path_is_prefix(public_root, public_len, secure_root,
+                                      secure_len)) {
+    return AMDUAT_BYTESTORE_ERR_AREA_VIOLATION;
+  }
+  if (amduat_bytestore_path_is_prefix(secure_root, secure_len, public_root,
+                                      public_len)) {
+    return AMDUAT_BYTESTORE_ERR_AREA_VIOLATION;
+  }
+  return AMDUAT_BYTESTORE_OK;
+}
+
+bool amduat_bytestore_cid_for_payload(amduat_hash_id_t hash_id,
+                                      amduat_octets_t payload,
+                                      amduat_reference_t *out_cid) {
+  const amduat_hash_asl1_desc_t *desc;
+  uint8_t *digest;
+  amduat_octets_t domain_sep;
+
+  if (out_cid == NULL) {
+    return false;
+  }
+  *out_cid = amduat_reference(0, amduat_octets(NULL, 0u));
+  desc = amduat_hash_asl1_desc_lookup(hash_id);
+  if (desc == NULL || desc->digest_len == 0u) {
+    return false;
+  }
+  digest = (uint8_t *)malloc(desc->digest_len);
+  if (digest == NULL) {
+    return false;
+  }
+  domain_sep = amduat_octets(k_amduat_bytestore_domain_sep,
+                             sizeof(k_amduat_bytestore_domain_sep) - 1u);
+  if (!amduat_hash_asl1_digest_domain(hash_id, domain_sep, payload, digest,
+                                      desc->digest_len)) {
+    free(digest);
+    return false;
+  }
+  *out_cid = amduat_reference(hash_id, amduat_octets(digest, desc->digest_len));
+  return true;
+}
+
+bool amduat_bytestore_cid_for_stream(amduat_hash_id_t hash_id,
+                                     amduat_bytestore_stream_t stream,
+                                     amduat_reference_t *out_cid) {
+  amduat_hash_asl1_stream_t hasher;
+  const amduat_hash_asl1_desc_t *desc;
+  uint8_t *digest;
+  amduat_octets_t domain_sep;
+  amduat_octets_t chunk;
+  int next_status;
+
+  if (out_cid == NULL || stream.next == NULL) {
+    return false;
+  }
+  *out_cid = amduat_reference(0, amduat_octets(NULL, 0u));
+  desc = amduat_hash_asl1_desc_lookup(hash_id);
+  if (desc == NULL || desc->digest_len == 0u) {
+    return false;
+  }
+  if (!amduat_hash_asl1_stream_init(hash_id, &hasher)) {
+    return false;
+  }
+  domain_sep = amduat_octets(k_amduat_bytestore_domain_sep,
+                             sizeof(k_amduat_bytestore_domain_sep) - 1u);
+  if (!amduat_hash_asl1_stream_update(&hasher, domain_sep)) {
+    amduat_hash_asl1_stream_destroy(&hasher);
+    return false;
+  }
+  while (true) {
+    chunk = amduat_octets(NULL, 0u);
+    next_status = stream.next(stream.ctx, &chunk);
+    if (next_status == 0) {
+      break;
+    }
+    if (next_status < 0) {
+      amduat_hash_asl1_stream_destroy(&hasher);
+      return false;
+    }
+    if (chunk.len != 0u && chunk.data == NULL) {
+      amduat_hash_asl1_stream_destroy(&hasher);
+      return false;
+    }
+    if (chunk.len != 0u &&
+        !amduat_hash_asl1_stream_update(&hasher, chunk)) {
+      amduat_hash_asl1_stream_destroy(&hasher);
+      return false;
+    }
+  }
+  digest = (uint8_t *)malloc(desc->digest_len);
+  if (digest == NULL) {
+    amduat_hash_asl1_stream_destroy(&hasher);
+    return false;
+  }
+  if (!amduat_hash_asl1_stream_final(&hasher, digest, desc->digest_len)) {
+    free(digest);
+    amduat_hash_asl1_stream_destroy(&hasher);
+    return false;
+  }
+  amduat_hash_asl1_stream_destroy(&hasher);
+  *out_cid = amduat_reference(hash_id, amduat_octets(digest, desc->digest_len));
+  return true;
+}
diff --git a/src/near_core/enc/asl1_core.c b/src/near_core/enc/asl1_core.c
index 1b563c5..266e162 100644
--- a/src/near_core/enc/asl1_core.c
+++ b/src/near_core/enc/asl1_core.c
@@ -1,7 +1,7 @@
 #include "amduat/enc/asl1_core.h"
 
 static amduat_enc_asl1_core_profile_desc_t g_enc_asl1_core_profiles[] = {
-    {AMDUAT_ENC_ASL1_CORE_V1, "ASL_ENC_CORE_V1", 0x0105, NULL}};
+    {AMDUAT_ENC_ASL1_CORE_V1, "ASL_ENC_CORE_V1", 0x0106, NULL}};
 
 amduat_octets_t amduat_enc_asl1_core_key(
     amduat_asl_encoding_profile_id_t profile_id,
diff --git a/src/near_core/enc/asl_tgk_exec_plan.c b/src/near_core/enc/asl_tgk_exec_plan.c
index 4a99b69..33e2972 100644
--- a/src/near_core/enc/asl_tgk_exec_plan.c
+++ b/src/near_core/enc/asl_tgk_exec_plan.c
@@ -166,6 +166,9 @@ static bool amduat_asl_tgk_exec_plan_validate_operator(
   if (((uint32_t)op->flags & ~AMDUAT_ASL_TGK_EXEC_PLAN_OP_FLAG_MASK) != 0u) {
     return false;
   }
+  if (op->snapshot.logseq_min > op->snapshot.logseq_max) {
+    return false;
+  }
   if (op->input_count > AMDUAT_ASL_TGK_EXEC_PLAN_INPUT_CAP) {
     return false;
   }
diff --git a/src/near_core/enc/fcs1.c b/src/near_core/enc/fcs1.c
new file mode 100644
index 0000000..26f0a55
--- /dev/null
+++ b/src/near_core/enc/fcs1.c
@@ -0,0 +1,294 @@
+#include "amduat/enc/fcs1.h"
+
+#include "amduat/enc/asl1_core_codec.h"
+
+#include <string.h>
+
+enum {
+  AMDUAT_FCS1_HEADER_LEN = 7,
+  AMDUAT_FCS1_TAG_FUNCTION = 0x30,
+  AMDUAT_FCS1_TAG_PARAMS = 0x31,
+  AMDUAT_FCS1_TAG_ARITY = 0x32,
+  AMDUAT_FCS1_TAG_LEGACY_MIN = 0x33,
+  AMDUAT_FCS1_TAG_LEGACY_MAX = 0x36
+};
+
+typedef struct {
+  const uint8_t *data;
+  size_t len;
+  size_t offset;
+} amduat_fcs1_cursor_t;
+
+static bool amduat_fcs1_read_varint(amduat_fcs1_cursor_t *cur,
+                                    uint64_t *out,
+                                    bool *out_minimal) {
+  uint64_t value = 0u;
+  uint32_t shift = 0u;
+  size_t bytes = 0u;
+
+  if (cur == NULL || out == NULL || out_minimal == NULL) {
+    return false;
+  }
+  while (cur->offset < cur->len) {
+    uint8_t byte = cur->data[cur->offset++];
+    value |= ((uint64_t)(byte & 0x7fu)) << shift;
+    bytes++;
+    if ((byte & 0x80u) == 0u) {
+      break;
+    }
+    shift += 7u;
+    if (shift >= 64u) {
+      return false;
+    }
+  }
+  if (bytes == 0u || cur->offset > cur->len) {
+    return false;
+  }
+  {
+    size_t minimal_len = 1u;
+    uint64_t tmp = value;
+    while (tmp >= 0x80u) {
+      tmp >>= 7u;
+      minimal_len++;
+    }
+    *out_minimal = (minimal_len == bytes);
+  }
+  *out = value;
+  return true;
+}
+
+static bool amduat_fcs1_read_bytes(amduat_fcs1_cursor_t *cur,
+                                   amduat_octets_t *out,
+                                   bool *out_minimal) {
+  uint64_t len;
+  bool minimal;
+
+  if (!amduat_fcs1_read_varint(cur, &len, &minimal)) {
+    return false;
+  }
+  if (len > SIZE_MAX || cur->len - cur->offset < (size_t)len) {
+    return false;
+  }
+  *out = amduat_octets(cur->data + cur->offset, (size_t)len);
+  cur->offset += (size_t)len;
+  *out_minimal = minimal;
+  return true;
+}
+
+static bool amduat_fcs1_has_header(amduat_octets_t bytes) {
+  static const uint8_t magic[4] = {'F', 'C', 'S', '1'};
+
+  if (bytes.len < AMDUAT_FCS1_HEADER_LEN || bytes.data == NULL) {
+    return false;
+  }
+  if (memcmp(bytes.data, magic, sizeof(magic)) != 0) {
+    return false;
+  }
+  if (bytes.data[4] != 0x01u || bytes.data[5] != 0x00u ||
+      bytes.data[6] != 0x00u) {
+    return false;
+  }
+  return true;
+}
+
+void amduat_fcs1_descriptor_free(amduat_fcs1_descriptor_t *desc) {
+  if (desc == NULL) {
+    return;
+  }
+  amduat_reference_free(&desc->function_ptr);
+  amduat_reference_free(&desc->parameter_block);
+  desc->arity = 0u;
+}
+
+amduat_fcs1_error_t amduat_fcs1_decode_v1(amduat_octets_t bytes,
+                                          amduat_fcs1_descriptor_t *out_desc) {
+  amduat_fcs1_cursor_t cur;
+  uint8_t last_tag = 0u;
+  bool seen_function = false;
+  bool seen_params = false;
+  bool seen_arity = false;
+
+  if (out_desc == NULL) {
+    return AMDUAT_FCS1_ERR_INVALID;
+  }
+  out_desc->function_ptr = amduat_reference(0, amduat_octets(NULL, 0u));
+  out_desc->parameter_block = amduat_reference(0, amduat_octets(NULL, 0u));
+  out_desc->arity = 0u;
+
+  if (!amduat_fcs1_has_header(bytes)) {
+    return AMDUAT_FCS1_ERR_HEADER_INVALID;
+  }
+
+  cur.data = bytes.data;
+  cur.len = bytes.len;
+  cur.offset = AMDUAT_FCS1_HEADER_LEN;
+
+  while (cur.offset < cur.len) {
+    uint8_t tag = cur.data[cur.offset++];
+    bool minimal = true;
+
+    if (tag <= last_tag) {
+      return AMDUAT_FCS1_ERR_TAG_ORDER;
+    }
+    last_tag = tag;
+
+    if (tag == AMDUAT_FCS1_TAG_FUNCTION ||
+        tag == AMDUAT_FCS1_TAG_PARAMS) {
+      amduat_octets_t cid_bytes;
+      if (!amduat_fcs1_read_bytes(&cur, &cid_bytes, &minimal)) {
+        return AMDUAT_FCS1_ERR_INVALID;
+      }
+      if (!minimal) {
+        return AMDUAT_FCS1_ERR_VARINT_NON_MINIMAL;
+      }
+      if (tag == AMDUAT_FCS1_TAG_FUNCTION) {
+        if (seen_function) {
+          return AMDUAT_FCS1_ERR_TAG_ORDER;
+        }
+        if (!amduat_enc_asl1_core_decode_reference_v1(cid_bytes,
+                                                      &out_desc->function_ptr)) {
+          return AMDUAT_FCS1_ERR_INVALID;
+        }
+        seen_function = true;
+      } else {
+        if (seen_params) {
+          return AMDUAT_FCS1_ERR_TAG_ORDER;
+        }
+        if (!amduat_enc_asl1_core_decode_reference_v1(cid_bytes,
+                                                      &out_desc->parameter_block)) {
+          return AMDUAT_FCS1_ERR_INVALID;
+        }
+        seen_params = true;
+      }
+    } else if (tag == AMDUAT_FCS1_TAG_ARITY) {
+      uint64_t arity_raw = 0u;
+      if (seen_arity) {
+        return AMDUAT_FCS1_ERR_TAG_ORDER;
+      }
+      if (!amduat_fcs1_read_varint(&cur, &arity_raw, &minimal)) {
+        return AMDUAT_FCS1_ERR_INVALID;
+      }
+      if (!minimal) {
+        return AMDUAT_FCS1_ERR_VARINT_NON_MINIMAL;
+      }
+      if (arity_raw > UINT32_MAX) {
+        return AMDUAT_FCS1_ERR_INVALID;
+      }
+      out_desc->arity = (uint32_t)arity_raw;
+      seen_arity = true;
+    } else if (tag >= AMDUAT_FCS1_TAG_LEGACY_MIN &&
+               tag <= AMDUAT_FCS1_TAG_LEGACY_MAX) {
+      return AMDUAT_FCS1_ERR_UNKNOWN_TAG;
+    } else {
+      return AMDUAT_FCS1_ERR_UNKNOWN_TAG;
+    }
+  }
+
+  if (!seen_function || !seen_params || !seen_arity) {
+    return AMDUAT_FCS1_ERR_TAG_ORDER;
+  }
+  if (cur.offset != cur.len) {
+    return AMDUAT_FCS1_ERR_TRAILING_BYTES;
+  }
+  return AMDUAT_FCS1_OK;
+}
+
+static amduat_fcs1_error_t amduat_fcs1_validate_cycle(
+    amduat_reference_t ref,
+    amduat_fcs1_resolve_fn resolver,
+    void *resolver_ctx,
+    amduat_reference_t *stack,
+    size_t stack_len,
+    size_t stack_cap) {
+  amduat_octets_t bytes = amduat_octets(NULL, 0u);
+  amduat_fcs1_descriptor_t desc;
+  amduat_fcs1_error_t err;
+
+  if (resolver == NULL) {
+    return AMDUAT_FCS1_ERR_INVALID;
+  }
+  if (!resolver(resolver_ctx, ref, &bytes)) {
+    return AMDUAT_FCS1_OK;
+  }
+  if (!amduat_fcs1_has_header(bytes)) {
+    amduat_octets_free(&bytes);
+    return AMDUAT_FCS1_OK;
+  }
+
+  for (size_t i = 0u; i < stack_len; ++i) {
+    if (amduat_reference_eq(stack[i], ref)) {
+      amduat_octets_free(&bytes);
+      return AMDUAT_FCS1_ERR_CYCLE_DETECTED;
+    }
+  }
+
+  memset(&desc, 0, sizeof(desc));
+  err = amduat_fcs1_decode_v1(bytes, &desc);
+  amduat_octets_free(&bytes);
+  if (err != AMDUAT_FCS1_OK) {
+    amduat_fcs1_descriptor_free(&desc);
+    return err;
+  }
+
+  if (stack_len >= stack_cap) {
+    amduat_fcs1_descriptor_free(&desc);
+    return AMDUAT_FCS1_ERR_INVALID;
+  }
+  stack[stack_len] = desc.function_ptr;
+  err = amduat_fcs1_validate_cycle(desc.function_ptr,
+                                   resolver,
+                                   resolver_ctx,
+                                   stack,
+                                   stack_len + 1u,
+                                   stack_cap);
+  amduat_fcs1_descriptor_free(&desc);
+  return err;
+}
+
+amduat_fcs1_error_t amduat_fcs1_validate_v1(
+    amduat_octets_t bytes,
+    amduat_fcs1_resolve_fn resolver,
+    void *resolver_ctx) {
+  amduat_fcs1_descriptor_t desc;
+  amduat_octets_t pcb_bytes = amduat_octets(NULL, 0u);
+  amduat_pcb1_manifest_t manifest;
+  amduat_octets_t slot_data;
+  amduat_fcs1_error_t err;
+  amduat_pcb1_error_t pcb_err;
+  amduat_reference_t stack[16];
+
+  memset(&desc, 0, sizeof(desc));
+  err = amduat_fcs1_decode_v1(bytes, &desc);
+  if (err != AMDUAT_FCS1_OK) {
+    return err;
+  }
+
+  if (resolver == NULL ||
+      !resolver(resolver_ctx, desc.parameter_block, &pcb_bytes)) {
+    amduat_fcs1_descriptor_free(&desc);
+    return AMDUAT_FCS1_ERR_PARAMETER_FORMAT;
+  }
+
+  pcb_err = amduat_pcb1_decode_v1(pcb_bytes, &manifest, &slot_data);
+  amduat_octets_free(&pcb_bytes);
+  if (pcb_err != AMDUAT_PCB1_OK) {
+    amduat_fcs1_descriptor_free(&desc);
+    return AMDUAT_FCS1_ERR_PARAMETER_FORMAT;
+  }
+  (void)slot_data;
+
+  if (desc.arity != manifest.slot_count) {
+    amduat_fcs1_descriptor_free(&desc);
+    return AMDUAT_FCS1_ERR_PCB_ARITY_MISMATCH;
+  }
+
+  stack[0] = desc.function_ptr;
+  err = amduat_fcs1_validate_cycle(desc.function_ptr,
+                                   resolver,
+                                   resolver_ctx,
+                                   stack,
+                                   1u,
+                                   sizeof(stack) / sizeof(stack[0]));
+  amduat_fcs1_descriptor_free(&desc);
+  return err;
+}
diff --git a/src/near_core/enc/pcb1.c b/src/near_core/enc/pcb1.c
new file mode 100644
index 0000000..b2361fa
--- /dev/null
+++ b/src/near_core/enc/pcb1.c
@@ -0,0 +1,256 @@
+#include "amduat/enc/pcb1.h"
+
+#include <string.h>
+
+enum {
+  AMDUAT_PCB1_HEADER_LEN = 7,
+  AMDUAT_PCB1_TAG_MANIFEST = 0x50,
+  AMDUAT_PCB1_TAG_DATA = 0x51,
+  AMDUAT_PCB1_DIGEST_LEN = 32
+};
+
+typedef struct {
+  const uint8_t *data;
+  size_t len;
+  size_t offset;
+} amduat_pcb1_cursor_t;
+
+static bool amduat_pcb1_read_varint(amduat_pcb1_cursor_t *cur,
+                                    uint64_t *out,
+                                    bool *out_minimal) {
+  uint64_t value = 0u;
+  uint32_t shift = 0u;
+  size_t start;
+  size_t bytes = 0u;
+
+  if (cur == NULL || out == NULL || out_minimal == NULL) {
+    return false;
+  }
+  start = cur->offset;
+  while (cur->offset < cur->len) {
+    uint8_t byte = cur->data[cur->offset++];
+    value |= ((uint64_t)(byte & 0x7fu)) << shift;
+    bytes++;
+    if ((byte & 0x80u) == 0u) {
+      break;
+    }
+    shift += 7u;
+    if (shift >= 64u) {
+      return false;
+    }
+  }
+  if (bytes == 0u || cur->offset > cur->len) {
+    return false;
+  }
+  {
+    size_t minimal_len = 1u;
+    uint64_t tmp = value;
+    while (tmp >= 0x80u) {
+      tmp >>= 7u;
+      minimal_len++;
+    }
+    *out_minimal = (minimal_len == bytes);
+  }
+  *out = value;
+  return true;
+}
+
+static bool amduat_pcb1_read_bytes(amduat_pcb1_cursor_t *cur,
+                                   amduat_octets_t *out,
+                                   bool *out_minimal) {
+  uint64_t len;
+  bool minimal;
+
+  if (!amduat_pcb1_read_varint(cur, &len, &minimal)) {
+    return false;
+  }
+  if (len > SIZE_MAX || cur->len - cur->offset < (size_t)len) {
+    return false;
+  }
+  *out = amduat_octets(cur->data + cur->offset, (size_t)len);
+  cur->offset += (size_t)len;
+  *out_minimal = minimal;
+  return true;
+}
+
+static amduat_pcb1_error_t amduat_pcb1_parse_manifest(
+    amduat_octets_t bytes,
+    amduat_pcb1_manifest_t *out_manifest) {
+  amduat_pcb1_cursor_t cur;
+  uint64_t slot_count = 0u;
+  uint64_t last_index = 0u;
+  bool minimal;
+
+  if (out_manifest == NULL) {
+    return AMDUAT_PCB1_ERR_INVALID;
+  }
+  out_manifest->slot_count = 0u;
+  cur.data = bytes.data;
+  cur.len = bytes.len;
+  cur.offset = 0u;
+
+  if (!amduat_pcb1_read_varint(&cur, &slot_count, &minimal)) {
+    return AMDUAT_PCB1_ERR_INVALID;
+  }
+  if (!minimal) {
+    return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+  }
+  if (slot_count > UINT32_MAX) {
+    return AMDUAT_PCB1_ERR_INVALID;
+  }
+
+  for (uint64_t i = 0u; i < slot_count; ++i) {
+    uint64_t index;
+    uint64_t name_len;
+    uint64_t type;
+    uint64_t digest_len;
+    amduat_octets_t name;
+    amduat_octets_t digest;
+
+    if (!amduat_pcb1_read_varint(&cur, &index, &minimal)) {
+      return AMDUAT_PCB1_ERR_INVALID;
+    }
+    if (!minimal) {
+      return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+    }
+    if (i > 0u && index <= last_index) {
+      return AMDUAT_PCB1_ERR_MANIFEST_ORDER;
+    }
+    last_index = index;
+
+    if (!amduat_pcb1_read_varint(&cur, &name_len, &minimal)) {
+      return AMDUAT_PCB1_ERR_INVALID;
+    }
+    if (!minimal) {
+      return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+    }
+    if (name_len > SIZE_MAX || cur.len - cur.offset < (size_t)name_len) {
+      return AMDUAT_PCB1_ERR_INVALID;
+    }
+    name = amduat_octets(cur.data + cur.offset, (size_t)name_len);
+    (void)name;
+    cur.offset += (size_t)name_len;
+
+    if (!amduat_pcb1_read_varint(&cur, &type, &minimal)) {
+      return AMDUAT_PCB1_ERR_INVALID;
+    }
+    if (!minimal) {
+      return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+    }
+    (void)type;
+
+    if (!amduat_pcb1_read_varint(&cur, &digest_len, &minimal)) {
+      return AMDUAT_PCB1_ERR_INVALID;
+    }
+    if (!minimal) {
+      return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+    }
+    if (digest_len != AMDUAT_PCB1_DIGEST_LEN) {
+      return AMDUAT_PCB1_ERR_DIGEST_MISMATCH;
+    }
+    if (cur.len - cur.offset < AMDUAT_PCB1_DIGEST_LEN) {
+      return AMDUAT_PCB1_ERR_INVALID;
+    }
+    digest = amduat_octets(cur.data + cur.offset, AMDUAT_PCB1_DIGEST_LEN);
+    (void)digest;
+    cur.offset += AMDUAT_PCB1_DIGEST_LEN;
+  }
+
+  if (cur.offset != cur.len) {
+    return AMDUAT_PCB1_ERR_TRAILING_BYTES;
+  }
+
+  out_manifest->slot_count = (uint32_t)slot_count;
+  return AMDUAT_PCB1_OK;
+}
+
+amduat_pcb1_error_t amduat_pcb1_decode_v1(amduat_octets_t bytes,
+                                          amduat_pcb1_manifest_t *out_manifest,
+                                          amduat_octets_t *out_slot_data) {
+  static const uint8_t magic[4] = {'P', 'C', 'B', '1'};
+  amduat_pcb1_cursor_t cur;
+  uint8_t version;
+  uint8_t flags;
+  uint8_t rsv;
+  uint8_t tag;
+  uint8_t last_tag = 0u;
+  bool minimal;
+  bool seen_manifest = false;
+  bool seen_data = false;
+  amduat_octets_t manifest_bytes = amduat_octets(NULL, 0u);
+  amduat_octets_t slot_data = amduat_octets(NULL, 0u);
+
+  if (out_manifest == NULL || out_slot_data == NULL) {
+    return AMDUAT_PCB1_ERR_INVALID;
+  }
+  out_manifest->slot_count = 0u;
+  *out_slot_data = amduat_octets(NULL, 0u);
+
+  if (bytes.len < AMDUAT_PCB1_HEADER_LEN || bytes.data == NULL) {
+    return AMDUAT_PCB1_ERR_HEADER_INVALID;
+  }
+  if (memcmp(bytes.data, magic, sizeof(magic)) != 0) {
+    return AMDUAT_PCB1_ERR_HEADER_INVALID;
+  }
+  version = bytes.data[4];
+  flags = bytes.data[5];
+  rsv = bytes.data[6];
+  if (version != 0x01u || flags != 0x00u || rsv != 0x00u) {
+    return AMDUAT_PCB1_ERR_HEADER_INVALID;
+  }
+
+  cur.data = bytes.data;
+  cur.len = bytes.len;
+  cur.offset = AMDUAT_PCB1_HEADER_LEN;
+
+  while (cur.offset < cur.len) {
+    tag = cur.data[cur.offset++];
+    if (tag <= last_tag) {
+      return AMDUAT_PCB1_ERR_TAG_ORDER;
+    }
+    last_tag = tag;
+    if (tag == AMDUAT_PCB1_TAG_MANIFEST) {
+      if (seen_manifest) {
+        return AMDUAT_PCB1_ERR_TAG_ORDER;
+      }
+      if (!amduat_pcb1_read_bytes(&cur, &manifest_bytes, &minimal)) {
+        return AMDUAT_PCB1_ERR_INVALID;
+      }
+      if (!minimal) {
+        return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+      }
+      seen_manifest = true;
+    } else if (tag == AMDUAT_PCB1_TAG_DATA) {
+      if (seen_data) {
+        return AMDUAT_PCB1_ERR_TAG_ORDER;
+      }
+      if (!amduat_pcb1_read_bytes(&cur, &slot_data, &minimal)) {
+        return AMDUAT_PCB1_ERR_INVALID;
+      }
+      if (!minimal) {
+        return AMDUAT_PCB1_ERR_VARINT_NON_MINIMAL;
+      }
+      seen_data = true;
+    } else {
+      return AMDUAT_PCB1_ERR_UNKNOWN_TAG;
+    }
+  }
+
+  if (!seen_manifest || !seen_data) {
+    return AMDUAT_PCB1_ERR_TAG_ORDER;
+  }
+  if (cur.offset != cur.len) {
+    return AMDUAT_PCB1_ERR_TRAILING_BYTES;
+  }
+
+  {
+    amduat_pcb1_error_t err =
+        amduat_pcb1_parse_manifest(manifest_bytes, out_manifest);
+    if (err != AMDUAT_PCB1_OK) {
+      return err;
+    }
+  }
+
+  *out_slot_data = slot_data;
+  return AMDUAT_PCB1_OK;
+}
diff --git a/src/near_core/fps.c b/src/near_core/fps.c
new file mode 100644
index 0000000..cb6b96f
--- /dev/null
+++ b/src/near_core/fps.c
@@ -0,0 +1,202 @@
+#include "amduat/fps.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+static const char k_amduat_fps_domain_sep[] = "CAS:OBJ\0";
+
+static uint8_t amduat_fps_reverse_bits8(uint8_t value) {
+  value = (uint8_t)(((value & 0xf0u) >> 4) | ((value & 0x0fu) << 4));
+  value = (uint8_t)(((value & 0xccu) >> 2) | ((value & 0x33u) << 2));
+  value = (uint8_t)(((value & 0xaau) >> 1) | ((value & 0x55u) << 1));
+  return value;
+}
+
+static bool amduat_fps_alloc_output(size_t len, amduat_octets_t *out) {
+  uint8_t *buf;
+
+  if (out == NULL) {
+    return false;
+  }
+  *out = amduat_octets(NULL, 0u);
+  if (len == 0u) {
+    return true;
+  }
+  buf = (uint8_t *)malloc(len);
+  if (buf == NULL) {
+    return false;
+  }
+  *out = amduat_octets(buf, len);
+  return true;
+}
+
+amduat_fps_error_t amduat_fps_slice(amduat_octets_t input,
+                                    size_t offset,
+                                    size_t length,
+                                    amduat_octets_t *out) {
+  if (out == NULL || (input.len != 0u && input.data == NULL)) {
+    return AMDUAT_FPS_ERR_INVALID;
+  }
+  if (offset > input.len || length > input.len - offset) {
+    return AMDUAT_FPS_ERR_SLICE_RANGE;
+  }
+  if (!amduat_fps_alloc_output(length, out)) {
+    return AMDUAT_FPS_ERR_IO_FAILURE;
+  }
+  if (length != 0u) {
+    memcpy((void *)out->data, input.data + offset, length);
+  }
+  return AMDUAT_FPS_OK;
+}
+
+amduat_fps_error_t amduat_fps_concat(const amduat_octets_t *inputs,
+                                     size_t input_count,
+                                     amduat_octets_t *out) {
+  size_t total = 0u;
+  size_t i;
+  uint8_t *cursor;
+
+  if (out == NULL) {
+    return AMDUAT_FPS_ERR_INVALID;
+  }
+  if (input_count == 0u) {
+    return AMDUAT_FPS_ERR_EMPTY_INPUTS;
+  }
+  if (inputs == NULL) {
+    return AMDUAT_FPS_ERR_INVALID;
+  }
+  for (i = 0u; i < input_count; ++i) {
+    if (inputs[i].len != 0u && inputs[i].data == NULL) {
+      return AMDUAT_FPS_ERR_INVALID;
+    }
+    if (SIZE_MAX - total < inputs[i].len) {
+      return AMDUAT_FPS_ERR_IO_FAILURE;
+    }
+    total += inputs[i].len;
+  }
+  if (!amduat_fps_alloc_output(total, out)) {
+    return AMDUAT_FPS_ERR_IO_FAILURE;
+  }
+  cursor = (uint8_t *)out->data;
+  for (i = 0u; i < input_count; ++i) {
+    if (inputs[i].len != 0u) {
+      memcpy(cursor, inputs[i].data, inputs[i].len);
+      cursor += inputs[i].len;
+    }
+  }
+  return AMDUAT_FPS_OK;
+}
+
+amduat_fps_error_t amduat_fps_reverse(amduat_octets_t input,
+                                      amduat_fps_reverse_level_t level,
+                                      amduat_octets_t *out) {
+  size_t unit_size;
+  size_t i;
+  size_t unit_count;
+
+  if (out == NULL || (input.len != 0u && input.data == NULL)) {
+    return AMDUAT_FPS_ERR_INVALID;
+  }
+
+  if (level == AMDUAT_FPS_REVERSE_BITS) {
+    if (!amduat_fps_alloc_output(input.len, out)) {
+      return AMDUAT_FPS_ERR_IO_FAILURE;
+    }
+    for (i = 0u; i < input.len; ++i) {
+      size_t dst = input.len - 1u - i;
+      ((uint8_t *)out->data)[dst] = amduat_fps_reverse_bits8(input.data[i]);
+    }
+    return AMDUAT_FPS_OK;
+  }
+
+  if (level == AMDUAT_FPS_REVERSE_BYTES) {
+    unit_size = 1u;
+  } else if (level == AMDUAT_FPS_REVERSE_WORDS) {
+    unit_size = 2u;
+  } else if (level == AMDUAT_FPS_REVERSE_LONGS) {
+    unit_size = 4u;
+  } else {
+    return AMDUAT_FPS_ERR_INVALID_LEVEL;
+  }
+
+  if (unit_size != 0u && input.len % unit_size != 0u) {
+    return AMDUAT_FPS_ERR_REV_ALIGNMENT;
+  }
+  if (!amduat_fps_alloc_output(input.len, out)) {
+    return AMDUAT_FPS_ERR_IO_FAILURE;
+  }
+  unit_count = unit_size == 0u ? 0u : input.len / unit_size;
+  for (i = 0u; i < unit_count; ++i) {
+    size_t src_offset = i * unit_size;
+    size_t dst_offset = (unit_count - 1u - i) * unit_size;
+    memcpy((uint8_t *)out->data + dst_offset,
+           input.data + src_offset,
+           unit_size);
+  }
+  return AMDUAT_FPS_OK;
+}
+
+amduat_fps_error_t amduat_fps_splice(amduat_octets_t a,
+                                     size_t offset,
+                                     amduat_octets_t b,
+                                     amduat_octets_t *out) {
+  size_t total;
+
+  if (out == NULL ||
+      (a.len != 0u && a.data == NULL) ||
+      (b.len != 0u && b.data == NULL)) {
+    return AMDUAT_FPS_ERR_INVALID;
+  }
+  if (offset > a.len) {
+    return AMDUAT_FPS_ERR_SPLICE_RANGE;
+  }
+  if (SIZE_MAX - a.len < b.len) {
+    return AMDUAT_FPS_ERR_IO_FAILURE;
+  }
+  total = a.len + b.len;
+  if (!amduat_fps_alloc_output(total, out)) {
+    return AMDUAT_FPS_ERR_IO_FAILURE;
+  }
+  if (offset != 0u) {
+    memcpy((uint8_t *)out->data, a.data, offset);
+  }
+  if (b.len != 0u) {
+    memcpy((uint8_t *)out->data + offset, b.data, b.len);
+  }
+  if (a.len > offset) {
+    memcpy((uint8_t *)out->data + offset + b.len,
+           a.data + offset,
+           a.len - offset);
+  }
+  return AMDUAT_FPS_OK;
+}
+
+bool amduat_fps_cid_for_payload(amduat_hash_id_t hash_id,
+                                amduat_octets_t payload,
+                                amduat_reference_t *out_cid) {
+  const amduat_hash_asl1_desc_t *desc;
+  amduat_octets_t domain_sep;
+  uint8_t *digest;
+
+  if (out_cid == NULL) {
+    return false;
+  }
+  *out_cid = amduat_reference(0, amduat_octets(NULL, 0u));
+  desc = amduat_hash_asl1_desc_lookup(hash_id);
+  if (desc == NULL || desc->digest_len == 0u) {
+    return false;
+  }
+  digest = (uint8_t *)malloc(desc->digest_len);
+  if (digest == NULL) {
+    return false;
+  }
+  domain_sep = amduat_octets(k_amduat_fps_domain_sep,
+                             sizeof(k_amduat_fps_domain_sep) - 1u);
+  if (!amduat_hash_asl1_digest_domain(hash_id, domain_sep, payload, digest,
+                                      desc->digest_len)) {
+    free(digest);
+    return false;
+  }
+  *out_cid = amduat_reference(hash_id, amduat_octets(digest, desc->digest_len));
+  return true;
+}
diff --git a/src/near_core/hash/asl1.c b/src/near_core/hash/asl1.c
index ee4c314..3d02520 100644
--- a/src/near_core/hash/asl1.c
+++ b/src/near_core/hash/asl1.c
@@ -125,6 +125,58 @@ bool amduat_hash_asl1_digest(amduat_hash_id_t hash_id,
   return desc->impl.digest(desc->impl.ctx, input, out, desc->digest_len);
 }
 
+bool amduat_hash_asl1_digest_domain(amduat_hash_id_t hash_id,
+                                    amduat_octets_t domain_separator,
+                                    amduat_octets_t input,
+                                    uint8_t *out,
+                                    size_t out_len) {
+  amduat_hash_asl1_stream_t stream;
+  uint8_t *buffer;
+  size_t total_len;
+
+  if (out == NULL) {
+    return false;
+  }
+  if ((domain_separator.len != 0 && domain_separator.data == NULL) ||
+      (input.len != 0 && input.data == NULL)) {
+    return false;
+  }
+
+  if (amduat_hash_asl1_stream_init(hash_id, &stream)) {
+    bool ok = amduat_hash_asl1_stream_update(&stream, domain_separator) &&
+              amduat_hash_asl1_stream_update(&stream, input) &&
+              amduat_hash_asl1_stream_final(&stream, out, out_len);
+    amduat_hash_asl1_stream_destroy(&stream);
+    return ok;
+  }
+
+  if (domain_separator.len > SIZE_MAX - input.len) {
+    return false;
+  }
+  total_len = domain_separator.len + input.len;
+  buffer = (uint8_t *)malloc(total_len);
+  if (buffer == NULL) {
+    return false;
+  }
+  if (domain_separator.len != 0) {
+    memcpy(buffer, domain_separator.data, domain_separator.len);
+  }
+  if (input.len != 0) {
+    memcpy(buffer + domain_separator.len, input.data, input.len);
+  }
+
+  if (!amduat_hash_asl1_digest(hash_id,
+                               amduat_octets(buffer, total_len),
+                               out,
+                               out_len)) {
+    free(buffer);
+    return false;
+  }
+
+  free(buffer);
+  return true;
+}
+
 static bool amduat_hash_asl1_sha256_stream_update(void *ctx,
                                                   amduat_octets_t input) {
   if (input.len != 0 && input.data == NULL) {
diff --git a/src/tools/amduat_conformance_run.c b/src/tools/amduat_conformance_run.c
index 997c2ae..d36b304 100644
--- a/src/tools/amduat_conformance_run.c
+++ b/src/tools/amduat_conformance_run.c
@@ -17,6 +17,8 @@ static void usage(FILE *out) {
           "  --backend <name|all>      Backend to run (repeatable)\n"
           "  --workdir <path>          Workdir for backend state\n"
           "  --fixtures <path>         Fixtures root (default: tests/fixtures/conformance)\n"
+          "  --json                    Emit machine-readable JSON summary\n"
+          "  --json-out <path>          Write JSON summary to a file\n"
           "  --help                    Show this help\n");
 }
 
@@ -85,6 +87,68 @@ static int print_results(const char *suite,
   return rc;
 }
 
+static void json_escape(FILE *out, const char *value) {
+  const unsigned char *p = (const unsigned char *)value;
+  fputc('"', out);
+  while (*p != '\0') {
+    switch (*p) {
+      case '\\':
+      case '"':
+        fputc('\\', out);
+        fputc(*p, out);
+        break;
+      case '\n':
+        fputs("\\n", out);
+        break;
+      case '\r':
+        fputs("\\r", out);
+        break;
+      case '\t':
+        fputs("\\t", out);
+        break;
+      default:
+        if (*p < 0x20) {
+          fprintf(out, "\\u%04x", (unsigned int)*p);
+        } else {
+          fputc(*p, out);
+        }
+        break;
+    }
+    p++;
+  }
+  fputc('"', out);
+}
+
+static const char *status_string(amduat_conformance_status_t status) {
+  switch (status) {
+    case AMDUAT_CONFORMANCE_STATUS_PASS:
+      return "PASS";
+    case AMDUAT_CONFORMANCE_STATUS_SKIP:
+      return "SKIPPED";
+    case AMDUAT_CONFORMANCE_STATUS_FAIL:
+    default:
+      return "FAIL";
+  }
+}
+
+static void json_write_results(FILE *out,
+                               const amduat_conformance_backend_result_t *results,
+                               size_t results_len) {
+  size_t i;
+  fputc('[', out);
+  for (i = 0; i < results_len; ++i) {
+    if (i != 0) {
+      fputc(',', out);
+    }
+    fputs("{\"backend\":", out);
+    json_escape(out, results[i].backend);
+    fputs(",\"status\":", out);
+    json_escape(out, status_string(results[i].status));
+    fputc('}', out);
+  }
+  fputc(']', out);
+}
+
 static const char *fallback_fixtures_root(const char *path) {
   struct stat st;
 
@@ -106,10 +170,16 @@ int main(int argc, char **argv) {
   const char *suite = "all";
   const char *fixtures = "tests/fixtures/conformance";
   const char *workdir = "/tmp/amduat_conformance";
+  const char *json_out_path = NULL;
   char *backend_selection = NULL;
   bool include_optional = env_truthy(getenv("AMDUAT_CONFORMANCE_INCLUDE_OPTIONAL"));
+  bool json_out = false;
   int i;
   int rc = 0;
+  amduat_conformance_backend_result_t *asl_results = NULL;
+  size_t asl_results_len = 0u;
+  amduat_conformance_backend_result_t *tgk_results = NULL;
+  size_t tgk_results_len = 0u;
 
   for (i = 1; i < argc; ++i) {
     if (strcmp(argv[i], "--help") == 0) {
@@ -149,6 +219,15 @@ int main(int argc, char **argv) {
       fixtures = argv[++i];
       continue;
     }
+    if (strcmp(argv[i], "--json") == 0) {
+      json_out = true;
+      continue;
+    }
+    if (strcmp(argv[i], "--json-out") == 0 && i + 1 < argc) {
+      json_out = true;
+      json_out_path = argv[++i];
+      continue;
+    }
 
     fprintf(stderr, "unknown argument: %s\n", argv[i]);
     usage(stderr);
@@ -167,33 +246,31 @@ int main(int argc, char **argv) {
   }
 
   if (strcmp(suite, "asl") == 0 || strcmp(suite, "all") == 0) {
-    amduat_conformance_backend_result_t *results = NULL;
-    size_t results_len = 0u;
     int suite_rc = amduat_asl_store_conformance_run(
         backend_selection, fixtures, workdir, include_optional, true,
-        &results, &results_len);
+        &asl_results, &asl_results_len);
     if (suite_rc != 0) {
       rc = 1;
     }
-    if (print_results("asl", results, results_len) != 0) {
-      rc = 1;
+    if (!json_out) {
+      if (print_results("asl", asl_results, asl_results_len) != 0) {
+        rc = 1;
+      }
     }
-    free(results);
   }
 
   if (strcmp(suite, "tgk") == 0 || strcmp(suite, "all") == 0) {
-    amduat_conformance_backend_result_t *results = NULL;
-    size_t results_len = 0u;
     int suite_rc = amduat_tgk_store_conformance_run(
         backend_selection, fixtures, workdir, include_optional, true,
-        &results, &results_len);
+        &tgk_results, &tgk_results_len);
     if (suite_rc != 0) {
       rc = 1;
     }
-    if (print_results("tgk", results, results_len) != 0) {
-      rc = 1;
+    if (!json_out) {
+      if (print_results("tgk", tgk_results, tgk_results_len) != 0) {
+        rc = 1;
+      }
     }
-    free(results);
   }
 
   if (strcmp(suite, "asl") != 0 && strcmp(suite, "tgk") != 0 &&
@@ -203,6 +280,40 @@ int main(int argc, char **argv) {
     rc = 1;
   }
 
+  if (json_out) {
+    FILE *out = stdout;
+    if (json_out_path != NULL) {
+      out = fopen(json_out_path, "w");
+      if (out == NULL) {
+        fprintf(stderr, "failed to open json output: %s\n", json_out_path);
+        rc = 1;
+      }
+    }
+    if (out != NULL) {
+      fputs("{\"suite\":", out);
+      json_escape(out, suite);
+      fputs(",\"fixtures\":", out);
+      json_escape(out, fixtures);
+      fputs(",\"workdir\":", out);
+      json_escape(out, workdir);
+      fputs(",\"include_optional\":", out);
+      fputs(include_optional ? "true" : "false", out);
+      fputs(",\"results\":{", out);
+      fputs("\"asl\":", out);
+      json_write_results(out, asl_results, asl_results_len);
+      fputs(",\"tgk\":", out);
+      json_write_results(out, tgk_results, tgk_results_len);
+      fputs("},\"status\":", out);
+      json_escape(out, rc == 0 ? "PASS" : "FAIL");
+      fputs("}\n", out);
+      if (out != stdout) {
+        fclose(out);
+      }
+    }
+  }
+
+  free(asl_results);
+  free(tgk_results);
   free(backend_selection);
   return rc;
 }
diff --git a/tests/asl/test_asl_error_taxonomy.c b/tests/asl/test_asl_error_taxonomy.c
new file mode 100644
index 0000000..dc87b10
--- /dev/null
+++ b/tests/asl/test_asl_error_taxonomy.c
@@ -0,0 +1,139 @@
+#include "amduat/asl/store.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static amduat_asl_store_error_t stub_put(void *ctx,
+                                         amduat_artifact_t artifact,
+                                         amduat_reference_t *out_ref) {
+  amduat_hash_id_t *hash_id = (amduat_hash_id_t *)ctx;
+  if (out_ref != NULL) {
+    uint8_t digest = 0xaa;
+    *out_ref = amduat_reference(*hash_id,
+                                amduat_octets(&digest, sizeof(digest)));
+  }
+  (void)artifact;
+  return AMDUAT_ASL_STORE_OK;
+}
+
+static amduat_asl_store_error_t stub_get_not_found(void *ctx,
+                                                   amduat_reference_t ref,
+                                                   amduat_artifact_t *out_artifact) {
+  (void)ctx;
+  (void)ref;
+  (void)out_artifact;
+  return AMDUAT_ASL_STORE_ERR_NOT_FOUND;
+}
+
+static amduat_asl_store_error_t stub_get_io(void *ctx,
+                                            amduat_reference_t ref,
+                                            amduat_artifact_t *out_artifact) {
+  (void)ctx;
+  (void)ref;
+  (void)out_artifact;
+  return AMDUAT_ASL_STORE_ERR_IO;
+}
+
+static int test_not_found_mapping(void) {
+  amduat_asl_store_ops_t ops;
+  amduat_asl_store_t store;
+  amduat_asl_store_config_t cfg = {0};
+  amduat_reference_t ref;
+  amduat_artifact_t artifact;
+  amduat_asl_store_error_t err;
+
+  amduat_asl_store_ops_init(&ops);
+  ops.get = stub_get_not_found;
+  cfg.hash_id = 0x0001u;
+  amduat_asl_store_init(&store, cfg, ops, NULL);
+
+  ref = amduat_reference(cfg.hash_id, amduat_octets(NULL, 0u));
+  memset(&artifact, 0, sizeof(artifact));
+  err = amduat_asl_store_get(&store, ref, &artifact);
+  return err == AMDUAT_ASL_STORE_ERR_NOT_FOUND ? 0 : 1;
+}
+
+static int test_io_mapping(void) {
+  amduat_asl_store_ops_t ops;
+  amduat_asl_store_t store;
+  amduat_asl_store_config_t cfg = {0};
+  amduat_reference_t ref;
+  amduat_artifact_t artifact;
+  amduat_asl_store_error_t err;
+
+  amduat_asl_store_ops_init(&ops);
+  ops.get = stub_get_io;
+  cfg.hash_id = 0x0001u;
+  amduat_asl_store_init(&store, cfg, ops, NULL);
+
+  ref = amduat_reference(cfg.hash_id, amduat_octets(NULL, 0u));
+  memset(&artifact, 0, sizeof(artifact));
+  err = amduat_asl_store_get(&store, ref, &artifact);
+  return err == AMDUAT_ASL_STORE_ERR_IO ? 0 : 1;
+}
+
+static int test_integrity_mapping(void) {
+  amduat_asl_store_ops_t ops;
+  amduat_asl_store_t store;
+  amduat_asl_store_config_t cfg = {0};
+  amduat_artifact_t artifact;
+  amduat_reference_t ref;
+  amduat_hash_id_t wrong_hash = 0x00ffu;
+  amduat_asl_store_error_t err;
+
+  amduat_asl_store_ops_init(&ops);
+  ops.put = stub_put;
+  cfg.hash_id = 0x0001u;
+  amduat_asl_store_init(&store, cfg, ops, &wrong_hash);
+
+  memset(&artifact, 0, sizeof(artifact));
+  err = amduat_asl_store_put(&store, artifact, &ref);
+  if (err != AMDUAT_ASL_STORE_ERR_INTEGRITY) {
+    return 1;
+  }
+  amduat_reference_free(&ref);
+  return 0;
+}
+
+static int test_unsupported_mapping(void) {
+  amduat_asl_store_ops_t ops;
+  amduat_asl_store_t store;
+  amduat_asl_store_config_t cfg = {0};
+  amduat_reference_t ref;
+  amduat_artifact_t artifact;
+  amduat_asl_store_error_t err;
+
+  amduat_asl_store_ops_init(&ops);
+  cfg.hash_id = 0x0001u;
+  amduat_asl_store_init(&store, cfg, ops, NULL);
+
+  ref = amduat_reference(cfg.hash_id, amduat_octets(NULL, 0u));
+  memset(&artifact, 0, sizeof(artifact));
+  err = amduat_asl_store_get(&store, ref, &artifact);
+  if (err != AMDUAT_ASL_STORE_ERR_UNSUPPORTED) {
+    return 1;
+  }
+
+  err = amduat_asl_store_put(&store, artifact, &ref);
+  return err == AMDUAT_ASL_STORE_ERR_UNSUPPORTED ? 0 : 1;
+}
+
+int main(void) {
+  if (test_not_found_mapping() != 0) {
+    fprintf(stderr, "not_found mapping failed\n");
+    return 1;
+  }
+  if (test_io_mapping() != 0) {
+    fprintf(stderr, "io mapping failed\n");
+    return 1;
+  }
+  if (test_integrity_mapping() != 0) {
+    fprintf(stderr, "integrity mapping failed\n");
+    return 1;
+  }
+  if (test_unsupported_mapping() != 0) {
+    fprintf(stderr, "unsupported mapping failed\n");
+    return 1;
+  }
+  return 0;
+}
diff --git a/tests/asl/test_asl_log_encoding.c b/tests/asl/test_asl_log_encoding.c
new file mode 100644
index 0000000..731f55a
--- /dev/null
+++ b/tests/asl/test_asl_log_encoding.c
@@ -0,0 +1,86 @@
+#include "amduat/enc/asl_log.h"
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+static void fill_hash(uint8_t *out, uint8_t seed) {
+  for (size_t i = 0; i < 32u; ++i) {
+    out[i] = (uint8_t)(seed + i);
+  }
+}
+
+static bool records_equal(const amduat_asl_log_record_t *lhs,
+                          const amduat_asl_log_record_t *rhs) {
+  if (lhs->logseq != rhs->logseq || lhs->record_type != rhs->record_type ||
+      lhs->payload.len != rhs->payload.len) {
+    return false;
+  }
+  if (lhs->payload.len != 0 &&
+      memcmp(lhs->payload.data, rhs->payload.data, lhs->payload.len) != 0) {
+    return false;
+  }
+  if (memcmp(lhs->record_hash, rhs->record_hash, sizeof(lhs->record_hash)) != 0) {
+    return false;
+  }
+  return true;
+}
+
+int main(void) {
+  uint8_t payload_a[4] = {0x01, 0x02, 0x03, 0x04};
+  uint8_t payload_b[8] = {0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17};
+  uint8_t payload_c[2] = {0xaa, 0xbb};
+  amduat_asl_log_record_t records[3];
+  amduat_asl_log_record_t *decoded = NULL;
+  size_t decoded_len = 0u;
+  amduat_octets_t bytes;
+
+  memset(records, 0, sizeof(records));
+
+  records[0].logseq = 1u;
+  records[0].record_type = AMDUAT_ASL_LOG_RECORD_SEGMENT_SEAL;
+  records[0].payload = amduat_octets(payload_a, sizeof(payload_a));
+  fill_hash(records[0].record_hash, 0x10);
+
+  records[1].logseq = 2u;
+  records[1].record_type = AMDUAT_ASL_LOG_RECORD_TOMBSTONE;
+  records[1].payload = amduat_octets(payload_b, sizeof(payload_b));
+  fill_hash(records[1].record_hash, 0x20);
+
+  records[2].logseq = 3u;
+  records[2].record_type = AMDUAT_ASL_LOG_RECORD_SNAPSHOT_ANCHOR;
+  records[2].payload = amduat_octets(payload_c, sizeof(payload_c));
+  fill_hash(records[2].record_hash, 0x30);
+
+  if (!amduat_enc_asl_log_encode_v1(records, 3u, &bytes)) {
+    fprintf(stderr, "encode failed\n");
+    return 1;
+  }
+
+  if (!amduat_enc_asl_log_decode_v1(bytes, &decoded, &decoded_len)) {
+    fprintf(stderr, "decode failed\n");
+    amduat_octets_free(&bytes);
+    return 1;
+  }
+
+  if (decoded_len != 3u) {
+    fprintf(stderr, "decoded length mismatch\n");
+    amduat_octets_free(&bytes);
+    amduat_enc_asl_log_free(decoded, decoded_len);
+    return 1;
+  }
+
+  for (size_t i = 0; i < decoded_len; ++i) {
+    if (!records_equal(&records[i], &decoded[i])) {
+      fprintf(stderr, "record mismatch at %zu\n", i);
+      amduat_octets_free(&bytes);
+      amduat_enc_asl_log_free(decoded, decoded_len);
+      return 1;
+    }
+  }
+
+  amduat_octets_free(&bytes);
+  amduat_enc_asl_log_free(decoded, decoded_len);
+  return 0;
+}
diff --git a/tests/asl/test_asl_ref_derive.c b/tests/asl/test_asl_ref_derive.c
index b43e96e..1b8e8de 100644
--- a/tests/asl/test_asl_ref_derive.c
+++ b/tests/asl/test_asl_ref_derive.c
@@ -1,3 +1,4 @@
+#include "amduat/asl/identity.h"
 #include "amduat/asl/ref_derive.h"
 #include "amduat/enc/asl1_core.h"
 #include "amduat/enc/asl1_core_codec.h"
@@ -39,10 +40,11 @@ static int test_ref_derive_roundtrip(void) {
     fprintf(stderr, "digest buffer too small\n");
     goto cleanup;
   }
-  if (!amduat_hash_asl1_digest(ref.hash_id,
-                               artifact_bytes,
-                               digest,
-                               hash_desc->digest_len)) {
+  if (!amduat_hash_asl1_digest_domain(ref.hash_id,
+                                      amduat_asl_identity_domain_separator(),
+                                      artifact_bytes,
+                                      digest,
+                                      hash_desc->digest_len)) {
     fprintf(stderr, "hash digest failed\n");
     goto cleanup;
   }
diff --git a/tests/enc/test_asl_tgk_exec_plan.c b/tests/enc/test_asl_tgk_exec_plan.c
index 6798b3f..0bcd242 100644
--- a/tests/enc/test_asl_tgk_exec_plan.c
+++ b/tests/enc/test_asl_tgk_exec_plan.c
@@ -13,6 +13,77 @@ enum {
   k_input_offset = 97
 };
 
+static bool read_file(const char *path, uint8_t **out_bytes, size_t *out_len) {
+  FILE *fp;
+  long size;
+  uint8_t *buffer;
+  size_t read_len;
+
+  if (path == NULL || out_bytes == NULL || out_len == NULL) {
+    return false;
+  }
+  *out_bytes = NULL;
+  *out_len = 0u;
+
+  fp = fopen(path, "rb");
+  if (fp == NULL) {
+    return false;
+  }
+  if (fseek(fp, 0, SEEK_END) != 0) {
+    fclose(fp);
+    return false;
+  }
+  size = ftell(fp);
+  if (size < 0) {
+    fclose(fp);
+    return false;
+  }
+  if (fseek(fp, 0, SEEK_SET) != 0) {
+    fclose(fp);
+    return false;
+  }
+
+  buffer = (uint8_t *)malloc((size_t)size + 1u);
+  if (buffer == NULL) {
+    fclose(fp);
+    return false;
+  }
+  read_len = fread(buffer, 1u, (size_t)size, fp);
+  fclose(fp);
+  if (read_len != (size_t)size) {
+    free(buffer);
+    return false;
+  }
+  buffer[size] = '\0';
+
+  *out_bytes = buffer;
+  *out_len = (size_t)size;
+  return true;
+}
+
+static bool build_fixture_path(char *out, size_t out_len) {
+  const char *needle = "/tests/enc/";
+  const char *path = __FILE__;
+  const char *pos = strstr(path, needle);
+  size_t prefix_len;
+
+  if (pos == NULL) {
+    return false;
+  }
+  prefix_len = (size_t)(pos - path);
+  if (prefix_len + strlen("/tests/fixtures/conformance/"
+                          "asl_tgk_exec_plan/artifacts/plan0.bin") + 1u >
+      out_len) {
+    return false;
+  }
+
+  memcpy(out, path, prefix_len);
+  out[prefix_len] = '\0';
+  strcat(out, "/tests/fixtures/conformance/"
+              "asl_tgk_exec_plan/artifacts/plan0.bin");
+  return true;
+}
+
 static void store_u32_le(uint8_t *out, uint32_t value) {
   out[0] = (uint8_t)(value & 0xffu);
   out[1] = (uint8_t)((value >> 8) & 0xffu);
@@ -217,6 +288,68 @@ cleanup:
   return exit_code;
 }
 
+static int test_invalid_snapshot_range(void) {
+  amduat_asl_tgk_exec_operator_def_t operators[1];
+  amduat_asl_tgk_exec_plan_t plan;
+
+  memset(operators, 0, sizeof(operators));
+  fill_default_params(&operators[0].params);
+  operators[0].op_id = 1u;
+  operators[0].op_type = AMDUAT_ASL_TGK_EXEC_OP_SEGMENT_SCAN;
+  operators[0].snapshot.logseq_min = 10u;
+  operators[0].snapshot.logseq_max = 1u;
+
+  plan.plan_version = AMDUAT_ASL_TGK_EXEC_PLAN_VERSION;
+  plan.operator_count = 1u;
+  plan.operators = operators;
+
+  if (amduat_enc_asl_tgk_exec_plan_encode_v1(&plan,
+                                             &(amduat_octets_t){0})) {
+    fprintf(stderr, "encode unexpectedly succeeded\n");
+    return 1;
+  }
+  return 0;
+}
+
+static int test_fixture_plan0(void) {
+  char path[512];
+  uint8_t *bytes = NULL;
+  size_t len = 0u;
+  amduat_asl_tgk_exec_plan_t plan;
+  int exit_code = 1;
+
+  if (!build_fixture_path(path, sizeof(path))) {
+    fprintf(stderr, "fixture path build failed\n");
+    return exit_code;
+  }
+  if (!read_file(path, &bytes, &len)) {
+    fprintf(stderr, "fixture read failed: %s\n", path);
+    return exit_code;
+  }
+
+  if (!amduat_enc_asl_tgk_exec_plan_decode_v1(amduat_octets(bytes, len),
+                                              &plan)) {
+    fprintf(stderr, "fixture decode failed\n");
+    goto cleanup;
+  }
+
+  if (plan.plan_version != AMDUAT_ASL_TGK_EXEC_PLAN_VERSION ||
+      plan.operator_count != 1u ||
+      plan.operators[0].op_type != AMDUAT_ASL_TGK_EXEC_OP_SEGMENT_SCAN ||
+      plan.operators[0].snapshot.logseq_max != 10u) {
+    fprintf(stderr, "fixture contents mismatch\n");
+    goto cleanup_plan;
+  }
+
+  exit_code = 0;
+
+cleanup_plan:
+  amduat_enc_asl_tgk_exec_plan_free(&plan);
+cleanup:
+  free(bytes);
+  return exit_code;
+}
+
 int main(void) {
   if (test_round_trip() != 0) {
     return 1;
@@ -227,5 +360,11 @@ int main(void) {
   if (test_truncated_decode() != 0) {
     return 1;
   }
-  return test_invalid_input_count();
+  if (test_invalid_input_count() != 0) {
+    return 1;
+  }
+  if (test_invalid_snapshot_range() != 0) {
+    return 1;
+  }
+  return test_fixture_plan0();
 }
diff --git a/tests/enc/test_fcs_pcb1.c b/tests/enc/test_fcs_pcb1.c
new file mode 100644
index 0000000..f9c41bc
--- /dev/null
+++ b/tests/enc/test_fcs_pcb1.c
@@ -0,0 +1,236 @@
+#include "amduat/enc/fcs1.h"
+#include "amduat/enc/asl1_core_codec.h"
+#include "amduat/fps.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static bool encode_varint(uint64_t value, uint8_t **out, size_t *out_len) {
+  uint8_t buf[10];
+  size_t len = 0u;
+
+  do {
+    uint8_t byte = (uint8_t)(value & 0x7fu);
+    value >>= 7u;
+    if (value != 0u) {
+      byte |= 0x80u;
+    }
+    buf[len++] = byte;
+  } while (value != 0u);
+
+  *out = (uint8_t *)malloc(len);
+  if (*out == NULL) {
+    return false;
+  }
+  memcpy(*out, buf, len);
+  *out_len = len;
+  return true;
+}
+
+static bool append_bytes(uint8_t **buf, size_t *len, size_t *cap,
+                         const void *data, size_t data_len) {
+  if (*len + data_len > *cap) {
+    size_t next = *cap == 0u ? 64u : *cap * 2u;
+    while (next < *len + data_len) {
+      next *= 2u;
+    }
+    uint8_t *next_buf = (uint8_t *)realloc(*buf, next);
+    if (next_buf == NULL) {
+      return false;
+    }
+    *buf = next_buf;
+    *cap = next;
+  }
+  memcpy(*buf + *len, data, data_len);
+  *len += data_len;
+  return true;
+}
+
+static bool append_varint(uint8_t **buf, size_t *len, size_t *cap,
+                          uint64_t value) {
+  uint8_t *enc = NULL;
+  size_t enc_len = 0u;
+  bool ok = encode_varint(value, &enc, &enc_len) &&
+            append_bytes(buf, len, cap, enc, enc_len);
+  free(enc);
+  return ok;
+}
+
+static bool build_pcb1_bytes(amduat_octets_t *out_bytes,
+                             amduat_reference_t *out_cid) {
+  uint8_t *buf = NULL;
+  size_t len = 0u;
+  size_t cap = 0u;
+  uint8_t manifest[1 + 1 + 1 + 1 + 32];
+  size_t manifest_len = 0u;
+  uint8_t slot_data[] = {0x01, 0x02, 0x03};
+  amduat_octets_t payload;
+  amduat_octets_t cid_bytes;
+
+  manifest[manifest_len++] = 0x01; /* slot count */
+  manifest[manifest_len++] = 0x01; /* index */
+  manifest[manifest_len++] = 0x00; /* name len */
+  manifest[manifest_len++] = 0x00; /* type */
+  manifest[manifest_len++] = 0x20; /* digest len */
+  memset(manifest + manifest_len, 0, 32);
+  manifest_len += 32;
+
+  if (!append_bytes(&buf, &len, &cap, "PCB1", 4u)) {
+    return false;
+  }
+  {
+    uint8_t header[3] = {0x01, 0x00, 0x00};
+    if (!append_bytes(&buf, &len, &cap, header, sizeof(header))) {
+      free(buf);
+      return false;
+    }
+  }
+
+  if (!append_bytes(&buf, &len, &cap, (uint8_t[]){0x50}, 1u) ||
+      !append_varint(&buf, &len, &cap, manifest_len) ||
+      !append_bytes(&buf, &len, &cap, manifest, manifest_len)) {
+    free(buf);
+    return false;
+  }
+
+  if (!append_bytes(&buf, &len, &cap, (uint8_t[]){0x51}, 1u) ||
+      !append_varint(&buf, &len, &cap, sizeof(slot_data)) ||
+      !append_bytes(&buf, &len, &cap, slot_data, sizeof(slot_data))) {
+    free(buf);
+    return false;
+  }
+
+  payload = amduat_octets(buf, len);
+  if (!amduat_fps_cid_for_payload(AMDUAT_HASH_ASL1_ID_SHA256,
+                                  payload,
+                                  out_cid)) {
+    free(buf);
+    return false;
+  }
+  if (!amduat_enc_asl1_core_encode_reference_v1(*out_cid, &cid_bytes)) {
+    amduat_reference_free(out_cid);
+    free(buf);
+    return false;
+  }
+  amduat_octets_free(&cid_bytes);
+
+  *out_bytes = payload;
+  return true;
+}
+
+static bool build_fcs1_bytes(amduat_octets_t *out_bytes,
+                             amduat_reference_t function_ref,
+                             amduat_reference_t pcb_ref,
+                             uint32_t arity) {
+  uint8_t *buf = NULL;
+  size_t len = 0u;
+  size_t cap = 0u;
+  amduat_octets_t func_bytes;
+  amduat_octets_t pcb_bytes;
+
+  if (!amduat_enc_asl1_core_encode_reference_v1(function_ref, &func_bytes) ||
+      !amduat_enc_asl1_core_encode_reference_v1(pcb_ref, &pcb_bytes)) {
+    return false;
+  }
+
+  if (!append_bytes(&buf, &len, &cap, "FCS1", 4u)) {
+    return false;
+  }
+  {
+    uint8_t header[3] = {0x01, 0x00, 0x00};
+    if (!append_bytes(&buf, &len, &cap, header, sizeof(header))) {
+      free(buf);
+      return false;
+    }
+  }
+
+  if (!append_bytes(&buf, &len, &cap, (uint8_t[]){0x30}, 1u) ||
+      !append_varint(&buf, &len, &cap, func_bytes.len) ||
+      !append_bytes(&buf, &len, &cap, func_bytes.data, func_bytes.len)) {
+    free(buf);
+    amduat_octets_free(&func_bytes);
+    amduat_octets_free(&pcb_bytes);
+    return false;
+  }
+
+  if (!append_bytes(&buf, &len, &cap, (uint8_t[]){0x31}, 1u) ||
+      !append_varint(&buf, &len, &cap, pcb_bytes.len) ||
+      !append_bytes(&buf, &len, &cap, pcb_bytes.data, pcb_bytes.len)) {
+    free(buf);
+    amduat_octets_free(&func_bytes);
+    amduat_octets_free(&pcb_bytes);
+    return false;
+  }
+
+  if (!append_bytes(&buf, &len, &cap, (uint8_t[]){0x32}, 1u) ||
+      !append_varint(&buf, &len, &cap, arity)) {
+    free(buf);
+    amduat_octets_free(&func_bytes);
+    amduat_octets_free(&pcb_bytes);
+    return false;
+  }
+
+  amduat_octets_free(&func_bytes);
+  amduat_octets_free(&pcb_bytes);
+  *out_bytes = amduat_octets(buf, len);
+  return true;
+}
+
+typedef struct {
+  amduat_reference_t pcb_ref;
+  amduat_octets_t pcb_bytes;
+} resolver_ctx_t;
+
+static bool resolve_ref(void *ctx,
+                        amduat_reference_t ref,
+                        amduat_octets_t *out_bytes) {
+  resolver_ctx_t *state = (resolver_ctx_t *)ctx;
+
+  if (state == NULL || out_bytes == NULL) {
+    return false;
+  }
+  if (!amduat_reference_eq(ref, state->pcb_ref)) {
+    return false;
+  }
+  return amduat_octets_clone(state->pcb_bytes, out_bytes);
+}
+
+int main(void) {
+  amduat_octets_t pcb_bytes;
+  amduat_reference_t pcb_ref;
+  amduat_octets_t fcs_bytes;
+  amduat_reference_t func_ref;
+  uint8_t func_digest[32];
+  resolver_ctx_t ctx;
+  amduat_fcs1_error_t err;
+
+  if (!build_pcb1_bytes(&pcb_bytes, &pcb_ref)) {
+    return 1;
+  }
+  memset(func_digest, 0x11, sizeof(func_digest));
+  func_ref = amduat_reference(AMDUAT_HASH_ASL1_ID_SHA256,
+                              amduat_octets(func_digest,
+                                            sizeof(func_digest)));
+  if (!build_fcs1_bytes(&fcs_bytes, func_ref, pcb_ref, 1u)) {
+    amduat_reference_free(&pcb_ref);
+    amduat_octets_free(&pcb_bytes);
+    return 1;
+  }
+
+  ctx.pcb_ref = pcb_ref;
+  ctx.pcb_bytes = pcb_bytes;
+  err = amduat_fcs1_validate_v1(fcs_bytes, resolve_ref, &ctx);
+  if (err != AMDUAT_FCS1_OK) {
+  amduat_reference_free(&pcb_ref);
+  amduat_octets_free(&pcb_bytes);
+  amduat_octets_free(&fcs_bytes);
+  return 1;
+}
+
+  amduat_reference_free(&pcb_ref);
+  amduat_octets_free(&pcb_bytes);
+  amduat_octets_free(&fcs_bytes);
+  return 0;
+}
diff --git a/tests/enc/test_fps.c b/tests/enc/test_fps.c
new file mode 100644
index 0000000..895bfc6
--- /dev/null
+++ b/tests/enc/test_fps.c
@@ -0,0 +1,626 @@
+#include "amduat/fps.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+  const uint8_t *data;
+  size_t len;
+  size_t offset;
+} cursor_t;
+
+static bool read_file(const char *path, uint8_t **out_bytes, size_t *out_len) {
+  FILE *fp;
+  long size;
+  uint8_t *buffer;
+  size_t read_len;
+
+  if (path == NULL || out_bytes == NULL || out_len == NULL) {
+    return false;
+  }
+  *out_bytes = NULL;
+  *out_len = 0u;
+
+  fp = fopen(path, "rb");
+  if (fp == NULL) {
+    return false;
+  }
+  if (fseek(fp, 0, SEEK_END) != 0) {
+    fclose(fp);
+    return false;
+  }
+  size = ftell(fp);
+  if (size < 0) {
+    fclose(fp);
+    return false;
+  }
+  if (fseek(fp, 0, SEEK_SET) != 0) {
+    fclose(fp);
+    return false;
+  }
+
+  buffer = (uint8_t *)malloc((size_t)size + 1u);
+  if (buffer == NULL) {
+    fclose(fp);
+    return false;
+  }
+  read_len = fread(buffer, 1u, (size_t)size, fp);
+  fclose(fp);
+  if (read_len != (size_t)size) {
+    free(buffer);
+    return false;
+  }
+  buffer[size] = '\0';
+
+  *out_bytes = buffer;
+  *out_len = (size_t)size;
+  return true;
+}
+
+static bool build_fixture_path(char *out, size_t out_len) {
+  const char *needle = "/tests/enc/";
+  const char *path = __FILE__;
+  const char *pos = strstr(path, needle);
+  size_t prefix_len;
+
+  if (pos == NULL) {
+    return false;
+  }
+  prefix_len = (size_t)(pos - path);
+  if (prefix_len + strlen("/tests/fixtures/conformance/"
+                          "fps_1/manifest.json") + 1u >
+      out_len) {
+    return false;
+  }
+
+  memcpy(out, path, prefix_len);
+  out[prefix_len] = '\0';
+  strcat(out, "/tests/fixtures/conformance/fps_1/manifest.json");
+  return true;
+}
+
+static bool cursor_expect(cursor_t *cur, const char *literal) {
+  size_t len = strlen(literal);
+  if (cur->len - cur->offset < len) {
+    return false;
+  }
+  if (memcmp(cur->data + cur->offset, literal, len) != 0) {
+    return false;
+  }
+  cur->offset += len;
+  return true;
+}
+
+static bool cursor_skip_ws(cursor_t *cur) {
+  while (cur->offset < cur->len) {
+    char c = (char)cur->data[cur->offset];
+    if (c != ' ' && c != '\n' && c != '\r' && c != '\t') {
+      break;
+    }
+    cur->offset++;
+  }
+  return true;
+}
+
+static bool cursor_read_string(cursor_t *cur, char **out) {
+  size_t start;
+  size_t end;
+  char *buf;
+
+  if (!cursor_skip_ws(cur) || cur->offset >= cur->len ||
+      cur->data[cur->offset] != '"') {
+    return false;
+  }
+  cur->offset++;
+  start = cur->offset;
+  while (cur->offset < cur->len && cur->data[cur->offset] != '"') {
+    cur->offset++;
+  }
+  if (cur->offset >= cur->len) {
+    return false;
+  }
+  end = cur->offset;
+  cur->offset++;
+
+  buf = (char *)malloc(end - start + 1u);
+  if (buf == NULL) {
+    return false;
+  }
+  memcpy(buf, cur->data + start, end - start);
+  buf[end - start] = '\0';
+  *out = buf;
+  return true;
+}
+
+static bool cursor_read_number(cursor_t *cur, size_t *out) {
+  size_t start;
+  size_t value = 0u;
+  bool has_digit = false;
+
+  if (!cursor_skip_ws(cur)) {
+    return false;
+  }
+  start = cur->offset;
+  while (cur->offset < cur->len) {
+    char c = (char)cur->data[cur->offset];
+    if (c < '0' || c > '9') {
+      break;
+    }
+    has_digit = true;
+    value = value * 10u + (size_t)(c - '0');
+    cur->offset++;
+  }
+  if (!has_digit || start == cur->offset) {
+    return false;
+  }
+  *out = value;
+  return true;
+}
+
+static bool hex_decode(const char *hex, uint8_t **out, size_t *out_len) {
+  size_t len;
+  size_t i;
+  uint8_t *buf;
+
+  if (hex == NULL || out == NULL || out_len == NULL) {
+    return false;
+  }
+  len = strlen(hex);
+  if (len % 2u != 0u) {
+    return false;
+  }
+  buf = (uint8_t *)malloc(len / 2u);
+  if (buf == NULL) {
+    return false;
+  }
+  for (i = 0u; i < len; i += 2u) {
+    unsigned int byte;
+    if (sscanf(hex + i, "%2x", &byte) != 1) {
+      free(buf);
+      return false;
+    }
+    buf[i / 2u] = (uint8_t)byte;
+  }
+  *out = buf;
+  *out_len = len / 2u;
+  return true;
+}
+
+static bool hex_eq(const char *hex, amduat_octets_t bytes) {
+  uint8_t *decoded = NULL;
+  size_t decoded_len = 0u;
+  bool ok = false;
+
+  if (!hex_decode(hex, &decoded, &decoded_len)) {
+    return false;
+  }
+  ok = decoded_len == bytes.len &&
+       (decoded_len == 0u ||
+        memcmp(decoded, bytes.data, decoded_len) == 0);
+  free(decoded);
+  return ok;
+}
+
+static bool cid_matches(const char *hex, amduat_octets_t output) {
+  amduat_reference_t cid;
+  size_t hex_len = strlen(hex);
+  char *lower = NULL;
+  char *scratch = NULL;
+  bool ok = false;
+
+  if (!amduat_fps_cid_for_payload(AMDUAT_HASH_ASL1_ID_SHA256, output, &cid)) {
+    return false;
+  }
+  lower = (char *)malloc(hex_len + 1u);
+  if (lower == NULL) {
+    amduat_reference_free(&cid);
+    return false;
+  }
+  scratch = (char *)malloc(cid.digest.len * 2u + 1u);
+  if (scratch == NULL) {
+    free(lower);
+    amduat_reference_free(&cid);
+    return false;
+  }
+  for (size_t i = 0u; i < hex_len; ++i) {
+    char c = hex[i];
+    if (c >= 'A' && c <= 'F') {
+      c = (char)(c - 'A' + 'a');
+    }
+    lower[i] = c;
+  }
+  lower[hex_len] = '\0';
+  for (size_t i = 0u; i < cid.digest.len; ++i) {
+    sprintf(scratch + i * 2u, "%02x", cid.digest.data[i]);
+  }
+  ok = strcmp(lower, scratch) == 0;
+  free(lower);
+  free(scratch);
+  amduat_reference_free(&cid);
+  return ok;
+}
+
+static bool parse_manifest_cases(cursor_t *cur) {
+  if (!cursor_skip_ws(cur) || cur->offset >= cur->len ||
+      cur->data[cur->offset] != '[') {
+    return false;
+  }
+  cur->offset++;
+  while (true) {
+    char *field = NULL;
+    char *value = NULL;
+    char *op = NULL;
+    char *input = NULL;
+    char *insert = NULL;
+    char *output = NULL;
+    char *cid_hex = NULL;
+    char *level = NULL;
+    char *inputs[4] = {0};
+    size_t inputs_len = 0u;
+    size_t offset = 0u;
+    size_t length = 0u;
+    bool has_offset = false;
+    bool has_length = false;
+    bool has_inputs = false;
+    bool has_input = false;
+    bool has_insert = false;
+    bool has_level = false;
+    bool has_output = false;
+    bool has_cid = false;
+    bool ok = true;
+
+    if (!cursor_skip_ws(cur)) {
+      return false;
+    }
+    if (cur->offset < cur->len && cur->data[cur->offset] == ']') {
+      cur->offset++;
+      return true;
+    }
+    if (cur->offset >= cur->len || cur->data[cur->offset] != '{') {
+      return false;
+    }
+    cur->offset++;
+    while (true) {
+      if (!cursor_read_string(cur, &field)) {
+        ok = false;
+        break;
+      }
+      if (!cursor_skip_ws(cur) || cur->offset >= cur->len ||
+          cur->data[cur->offset] != ':') {
+        ok = false;
+        break;
+      }
+      cur->offset++;
+      if (strcmp(field, "id") == 0 ||
+          strcmp(field, "op") == 0 || strcmp(field, "input") == 0 ||
+          strcmp(field, "insert") == 0 || strcmp(field, "output") == 0 ||
+          strcmp(field, "cid_sha256") == 0 || strcmp(field, "level") == 0) {
+        if (!cursor_read_string(cur, &value)) {
+          ok = false;
+          break;
+        }
+        if (strcmp(field, "id") == 0) {
+          free(value);
+          value = NULL;
+        } else if (strcmp(field, "op") == 0) {
+          op = value;
+        } else if (strcmp(field, "input") == 0) {
+          input = value;
+          has_input = true;
+        } else if (strcmp(field, "insert") == 0) {
+          insert = value;
+          has_insert = true;
+        } else if (strcmp(field, "output") == 0) {
+          output = value;
+          has_output = true;
+        } else if (strcmp(field, "cid_sha256") == 0) {
+          cid_hex = value;
+          has_cid = true;
+        } else {
+          level = value;
+          has_level = true;
+        }
+      } else if (strcmp(field, "offset") == 0 ||
+                 strcmp(field, "length") == 0) {
+        size_t num = 0u;
+        if (!cursor_read_number(cur, &num)) {
+          ok = false;
+          break;
+        }
+        if (strcmp(field, "offset") == 0) {
+          offset = num;
+          has_offset = true;
+        } else {
+          length = num;
+          has_length = true;
+        }
+      } else if (strcmp(field, "inputs") == 0) {
+        if (!cursor_skip_ws(cur) || cur->offset >= cur->len ||
+            cur->data[cur->offset] != '[') {
+          ok = false;
+          break;
+        }
+        cur->offset++;
+        while (true) {
+          if (!cursor_skip_ws(cur)) {
+            ok = false;
+            break;
+          }
+          if (cur->offset < cur->len && cur->data[cur->offset] == ']') {
+            cur->offset++;
+            break;
+          }
+          if (inputs_len >= 4u) {
+            ok = false;
+            break;
+          }
+          if (!cursor_read_string(cur, &inputs[inputs_len++])) {
+            ok = false;
+            break;
+          }
+          if (!cursor_skip_ws(cur)) {
+            ok = false;
+            break;
+          }
+          if (cur->offset < cur->len && cur->data[cur->offset] == ',') {
+            cur->offset++;
+            continue;
+          }
+        }
+        has_inputs = true;
+      } else {
+        ok = false;
+        break;
+      }
+
+      free(field);
+      field = NULL;
+      if (!cursor_skip_ws(cur)) {
+        ok = false;
+        break;
+      }
+      if (cur->offset < cur->len && cur->data[cur->offset] == ',') {
+        cur->offset++;
+        continue;
+      }
+      if (cur->offset < cur->len && cur->data[cur->offset] == '}') {
+        cur->offset++;
+        break;
+      }
+    }
+
+    if (!ok || op == NULL || !has_output || !has_cid) {
+      ok = false;
+    }
+
+    if (ok) {
+      amduat_octets_t output_bytes = amduat_octets(NULL, 0u);
+      amduat_octets_t out = amduat_octets(NULL, 0u);
+      amduat_octets_t input_bytes = amduat_octets(NULL, 0u);
+      amduat_octets_t insert_bytes = amduat_octets(NULL, 0u);
+      uint8_t *decoded = NULL;
+      size_t decoded_len = 0u;
+      uint8_t *insert_decoded = NULL;
+      size_t insert_len = 0u;
+
+      if (!hex_decode(output, &decoded, &decoded_len)) {
+        ok = false;
+      } else {
+        output_bytes = amduat_octets(decoded, decoded_len);
+      }
+
+      if (ok && !cid_matches(cid_hex, output_bytes)) {
+        ok = false;
+      }
+
+      if (ok && strcmp(op, "slice") == 0) {
+        if (!has_input || !has_offset || !has_length) {
+          ok = false;
+        } else if (!hex_decode(input, &decoded, &decoded_len)) {
+          ok = false;
+        } else {
+          input_bytes = amduat_octets(decoded, decoded_len);
+          if (amduat_fps_slice(input_bytes, offset, length, &out) !=
+              AMDUAT_FPS_OK) {
+            ok = false;
+          } else if (!hex_eq(output, out)) {
+            ok = false;
+          }
+        }
+      } else if (ok && strcmp(op, "concat") == 0) {
+        if (!has_inputs) {
+          ok = false;
+        } else {
+          amduat_octets_t in_octets[4];
+          for (size_t i = 0u; i < inputs_len; ++i) {
+            if (!hex_decode(inputs[i], &decoded, &decoded_len)) {
+              ok = false;
+              break;
+            }
+            in_octets[i] = amduat_octets(decoded, decoded_len);
+          }
+          if (ok) {
+            if (amduat_fps_concat(in_octets, inputs_len, &out) !=
+                AMDUAT_FPS_OK) {
+              ok = false;
+            } else if (!hex_eq(output, out)) {
+              ok = false;
+            }
+          }
+          for (size_t i = 0u; i < inputs_len; ++i) {
+            free((void *)in_octets[i].data);
+          }
+        }
+      } else if (ok && strcmp(op, "reverse") == 0) {
+        amduat_fps_reverse_level_t lvl = AMDUAT_FPS_REVERSE_BYTES;
+        if (!has_input || !has_level) {
+          ok = false;
+        } else if (strcmp(level, "bit") == 0) {
+          lvl = AMDUAT_FPS_REVERSE_BITS;
+        } else if (strcmp(level, "byte") == 0) {
+          lvl = AMDUAT_FPS_REVERSE_BYTES;
+        } else if (strcmp(level, "word") == 0) {
+          lvl = AMDUAT_FPS_REVERSE_WORDS;
+        } else if (strcmp(level, "long") == 0) {
+          lvl = AMDUAT_FPS_REVERSE_LONGS;
+        } else {
+          ok = false;
+        }
+        if (ok && !hex_decode(input, &decoded, &decoded_len)) {
+          ok = false;
+        }
+        if (ok) {
+          input_bytes = amduat_octets(decoded, decoded_len);
+          if (amduat_fps_reverse(input_bytes, lvl, &out) != AMDUAT_FPS_OK) {
+            ok = false;
+          } else if (!hex_eq(output, out)) {
+            ok = false;
+          }
+        }
+      } else if (ok && strcmp(op, "splice") == 0) {
+        if (!has_input || !has_insert || !has_offset) {
+          ok = false;
+        } else if (!hex_decode(input, &decoded, &decoded_len) ||
+                   !hex_decode(insert, &insert_decoded, &insert_len)) {
+          ok = false;
+        } else {
+          input_bytes = amduat_octets(decoded, decoded_len);
+          insert_bytes = amduat_octets(insert_decoded, insert_len);
+          if (amduat_fps_splice(input_bytes, offset, insert_bytes, &out) !=
+              AMDUAT_FPS_OK) {
+            ok = false;
+          } else if (!hex_eq(output, out)) {
+            ok = false;
+          }
+        }
+      } else if (ok) {
+        ok = false;
+      }
+
+      amduat_octets_free(&out);
+      free((void *)output_bytes.data);
+      if (input_bytes.data != NULL) {
+        free((void *)input_bytes.data);
+      }
+      if (insert_bytes.data != NULL) {
+        free((void *)insert_bytes.data);
+      }
+    }
+
+    free(op);
+    free(input);
+    free(insert);
+    free(output);
+    free(cid_hex);
+    free(level);
+    for (size_t i = 0u; i < inputs_len; ++i) {
+      free(inputs[i]);
+    }
+
+    if (!ok) {
+      return false;
+    }
+
+    if (!cursor_skip_ws(cur)) {
+      return false;
+    }
+    if (cur->offset < cur->len && cur->data[cur->offset] == ',') {
+      cur->offset++;
+      continue;
+    }
+    if (cur->offset < cur->len && cur->data[cur->offset] == ']') {
+      cur->offset++;
+      return true;
+    }
+  }
+}
+
+static bool parse_manifest(uint8_t *bytes, size_t len) {
+  cursor_t cur;
+  char *field = NULL;
+  char *schema = NULL;
+  bool ok = false;
+
+  cur.data = bytes;
+  cur.len = len;
+  cur.offset = 0u;
+
+  if (!cursor_skip_ws(&cur) || cur.offset >= cur.len ||
+      cur.data[cur.offset] != '{') {
+    return false;
+  }
+  cur.offset++;
+
+  while (true) {
+    if (!cursor_read_string(&cur, &field)) {
+      break;
+    }
+    if (!cursor_skip_ws(&cur) || cur.offset >= cur.len ||
+        cur.data[cur.offset] != ':') {
+      break;
+    }
+    cur.offset++;
+    if (strcmp(field, "schema") == 0) {
+      if (!cursor_read_string(&cur, &schema)) {
+        break;
+      }
+    } else if (strcmp(field, "cases") == 0) {
+      if (!parse_manifest_cases(&cur)) {
+        break;
+      }
+    } else {
+      break;
+    }
+
+    free(field);
+    field = NULL;
+    if (!cursor_skip_ws(&cur)) {
+      break;
+    }
+    if (cur.offset < cur.len && cur.data[cur.offset] == ',') {
+      cur.offset++;
+      continue;
+    }
+    if (cur.offset < cur.len && cur.data[cur.offset] == '}') {
+      cur.offset++;
+      break;
+    }
+  }
+
+  if (schema != NULL &&
+      strcmp(schema, "amduat.conformance.fps.v0") == 0) {
+    ok = true;
+  }
+
+  free(field);
+  free(schema);
+  return ok;
+}
+
+int main(void) {
+  char path[512];
+  uint8_t *bytes = NULL;
+  size_t len = 0u;
+  int exit_code = 1;
+
+  if (!build_fixture_path(path, sizeof(path))) {
+    fprintf(stderr, "fixture path build failed\n");
+    return exit_code;
+  }
+  if (!read_file(path, &bytes, &len)) {
+    fprintf(stderr, "fixture read failed: %s\n", path);
+    return exit_code;
+  }
+  if (!parse_manifest(bytes, len)) {
+    fprintf(stderr, "fixture parse failed\n");
+    goto cleanup;
+  }
+
+  exit_code = 0;
+
+cleanup:
+  free(bytes);
+  return exit_code;
+}
diff --git a/tests/fixtures/conformance/README.md b/tests/fixtures/conformance/README.md
new file mode 100644
index 0000000..23cb9e2
--- /dev/null
+++ b/tests/fixtures/conformance/README.md
@@ -0,0 +1,22 @@
+# Conformance Fixtures
+
+This directory holds small, canonical fixture sets and manifests used by the
+core conformance harness.
+
+## ASL/1-STORE fixtures
+
+- `asl_put_get/manifest.json` — byte fixtures for PUT/GET idempotency.
+
+## TGK/STORE/1 fixtures
+
+- `tgk_edges/manifest.json` — canonical edge payload fixtures.
+
+## PEL trace TGK vectors
+
+- `../../vectors/pel_trace_tgk_test_vectors_v0.json`
+- `../../vectors/pel_trace_tgk_test_vectors_v1.json`
+
+## Generator
+
+`generate_manifest.py` can (re)generate the ASL/1-STORE fixture manifest with
+canonical ordering and file digests.
diff --git a/tests/fixtures/conformance/asl_put_get/manifest.json b/tests/fixtures/conformance/asl_put_get/manifest.json
index 6760b6c..c1bb79e 100644
--- a/tests/fixtures/conformance/asl_put_get/manifest.json
+++ b/tests/fixtures/conformance/asl_put_get/manifest.json
@@ -1,8 +1,23 @@
 {
   "schema": "amduat.conformance.fixtures.v0",
   "fixtures": [
-    {"id": "empty", "artifact": "a0.bin", "notes": "empty payload"},
-    {"id": "hello", "artifact": "a1.bin", "notes": "ascii payload"},
-    {"id": "binary", "artifact": "a2.bin", "notes": "0..255"}
+    {
+      "id": "a0",
+      "artifact": "artifacts/a0.bin",
+      "size": "0",
+      "sha256": "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
+    },
+    {
+      "id": "a1",
+      "artifact": "artifacts/a1.bin",
+      "size": "12",
+      "sha256": "29e86b2096b77c51796e607cbac976bf507c443c2efd14ab343a5c07f9978644"
+    },
+    {
+      "id": "a2",
+      "artifact": "artifacts/a2.bin",
+      "size": "256",
+      "sha256": "40aff2e9d2d8922e47afd4648e6967497158785fbd1da870e7110266bf944880"
+    }
   ]
 }
diff --git a/tests/fixtures/conformance/asl_tgk_exec_plan/artifacts/plan0.bin b/tests/fixtures/conformance/asl_tgk_exec_plan/artifacts/plan0.bin
new file mode 100644
index 0000000..5c77959
Binary files /dev/null and b/tests/fixtures/conformance/asl_tgk_exec_plan/artifacts/plan0.bin differ
diff --git a/tests/fixtures/conformance/asl_tgk_exec_plan/manifest.json b/tests/fixtures/conformance/asl_tgk_exec_plan/manifest.json
new file mode 100644
index 0000000..54a9bca
--- /dev/null
+++ b/tests/fixtures/conformance/asl_tgk_exec_plan/manifest.json
@@ -0,0 +1,12 @@
+{
+  "schema": "amduat.conformance.fixtures.v0",
+  "fixtures": [
+    {
+      "id": "plan0",
+      "artifact": "artifacts/plan0.bin",
+      "size": "137",
+      "sha256": "3633b7a6ca915bb4be8837648890ed91a2a67781b837edd6c00a09a7a2d3cc7b",
+      "notes": "ASL/TGK exec plan v1 fixture"
+    }
+  ]
+}
diff --git a/tests/fixtures/conformance/fps_1/manifest.json b/tests/fixtures/conformance/fps_1/manifest.json
new file mode 100644
index 0000000..c1f0cba
--- /dev/null
+++ b/tests/fixtures/conformance/fps_1/manifest.json
@@ -0,0 +1,65 @@
+{
+  "schema": "amduat.conformance.fps.v0",
+  "cases": [
+    {
+      "id": "concat0",
+      "op": "concat",
+      "inputs": [
+        "dead",
+        "beef"
+      ],
+      "output": "deadbeef",
+      "cid_sha256": "42f90312198cb86ae022fd58e8dd825cc0fea31bf17685040f40a6a49bf55330"
+    },
+    {
+      "id": "reverse_bits0",
+      "op": "reverse",
+      "level": "bit",
+      "input": "01f0",
+      "output": "0f80",
+      "cid_sha256": "3a26c2b229a79ed7337cacc1d68e5aa34c3cb12c6027a5bdfb6ae87c9433390e"
+    },
+    {
+      "id": "reverse_bytes0",
+      "op": "reverse",
+      "level": "byte",
+      "input": "01020304",
+      "output": "04030201",
+      "cid_sha256": "56f83c32ac7262d4aff0e766e8f3ddbaa325f928ddfb7764aeb1143ed3417d4e"
+    },
+    {
+      "id": "reverse_longs0",
+      "op": "reverse",
+      "level": "long",
+      "input": "0102030405060708",
+      "output": "0506070801020304",
+      "cid_sha256": "f720714eb46590c97470c8970768c0162322feb7cfd85a3e3f9af85653729eca"
+    },
+    {
+      "id": "reverse_words0",
+      "op": "reverse",
+      "level": "word",
+      "input": "0102030405060708",
+      "output": "0708050603040102",
+      "cid_sha256": "ae08a370a31a4dccd5ce7f86629e0823087f1ac8f29aa52c7fc9a0b515e38389"
+    },
+    {
+      "id": "slice0",
+      "op": "slice",
+      "input": "000102030405",
+      "offset": 2,
+      "length": 3,
+      "output": "020304",
+      "cid_sha256": "8d81247326859e1abafaf9cbf25cdb8c088c778b3ec109cdf9085bd8f2787fac"
+    },
+    {
+      "id": "splice0",
+      "op": "splice",
+      "input": "010203",
+      "offset": 1,
+      "insert": "ff",
+      "output": "01ff0203",
+      "cid_sha256": "a82fb8838858d19c3c258205d6de59dcb8d0f97d3898cfbbe848098aaedec6a7"
+    }
+  ]
+}
diff --git a/tests/fixtures/conformance/generate_manifest.py b/tests/fixtures/conformance/generate_manifest.py
new file mode 100755
index 0000000..1f629af
--- /dev/null
+++ b/tests/fixtures/conformance/generate_manifest.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+import argparse
+import hashlib
+import json
+import os
+from pathlib import Path
+
+
+def sha256_file(path: Path) -> str:
+    h = hashlib.sha256()
+    with path.open("rb") as f:
+        for chunk in iter(lambda: f.read(1024 * 1024), b""):
+            h.update(chunk)
+    return h.hexdigest()
+
+
+def build_asl_manifest(root: Path) -> dict:
+    artifacts_dir = root / "artifacts"
+    fixtures = []
+    for entry in sorted(artifacts_dir.iterdir()):
+        if not entry.is_file() or entry.suffix != ".bin":
+            continue
+        artifact_rel = f"artifacts/{entry.name}"
+        fixtures.append(
+            {
+                "id": entry.stem,
+                "artifact": artifact_rel,
+                "size": str(entry.stat().st_size),
+                "sha256": sha256_file(entry),
+            }
+        )
+    return {"schema": "amduat.conformance.fixtures.v0", "fixtures": fixtures}
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(
+        description="Generate conformance fixture manifests."
+    )
+    parser.add_argument(
+        "root",
+        type=Path,
+        help="Fixture directory containing artifacts/",
+    )
+    parser.add_argument(
+        "--out",
+        type=Path,
+        default=None,
+        help="Output manifest path (defaults to <root>/manifest.json)",
+    )
+    args = parser.parse_args()
+
+    manifest = build_asl_manifest(args.root)
+    out_path = args.out or (args.root / "manifest.json")
+    out_path.parent.mkdir(parents=True, exist_ok=True)
+    with out_path.open("w", encoding="utf-8") as f:
+        json.dump(manifest, f, indent=2, sort_keys=False)
+        f.write("\n")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/tests/fixtures/conformance/manifest.schema.md b/tests/fixtures/conformance/manifest.schema.md
new file mode 100644
index 0000000..870f3a4
--- /dev/null
+++ b/tests/fixtures/conformance/manifest.schema.md
@@ -0,0 +1,99 @@
+# Conformance Fixture Manifests
+
+This directory contains small, canonical fixture sets used by conformance tests.
+Each fixture set publishes a JSON manifest with deterministic ordering.
+
+## Common rules
+
+- JSON must be UTF-8, no comments.
+- Arrays are ordered and MUST be in canonical order as specified by the schema.
+- Artifact references use the canonical `ReferenceBytes` hex encoding when
+  present (lowercase hex, no `0x` prefix).
+- `sha256` fields are lowercase hex of the raw bytes.
+
+## Schema: `amduat.conformance.fixtures.v0`
+
+Used by simple ASL/1-STORE byte fixtures (e.g. `asl_put_get`).
+
+```
+{
+  "schema": "amduat.conformance.fixtures.v0",
+  "fixtures": [
+    {
+      "id": "string",
+      "artifact": "relative/path.bin",
+      "size": "0",
+      "sha256": "hex",
+      "notes": "optional string"
+    }
+  ]
+}
+```
+
+Rules:
+
+- `fixtures` MUST be sorted by ascending `id`.
+- `artifact` is a path relative to the manifest file.
+- `size` is the byte length of the artifact file encoded as a decimal string.
+- `sha256` is the digest of the artifact file contents.
+
+## Schema: `amduat.conformance.tgk_edges.v0`
+
+Used by TGK edge fixture sets.
+
+```
+{
+  "schema": "amduat.conformance.tgk_edges.v0",
+  "edges": [
+    {
+      "id": "string",
+      "type": 0,
+      "from": ["refhex"],
+      "to": ["refhex"],
+      "payload": "hex",
+      "notes": "optional string"
+    }
+  ]
+}
+```
+
+Rules:
+
+- `edges` MUST be sorted by ascending `id`.
+- `from`/`to` are lists of `ReferenceBytes` hex (lowercase).
+- `payload` is hex-encoded edge payload bytes (lowercase).
+
+## Schema: `amduat.conformance.fps.v0`
+
+Used by FPS/1 primitive conformance vectors.
+
+```
+{
+  "schema": "amduat.conformance.fps.v0",
+  "cases": [
+    {
+      "id": "string",
+      "op": "slice|concat|reverse|splice",
+      "input": "hex",
+      "inputs": ["hex"],
+      "insert": "hex",
+      "offset": 0,
+      "length": 0,
+      "level": "bit|byte|word|long",
+      "output": "hex",
+      "cid_sha256": "hex"
+    }
+  ]
+}
+```
+
+Rules:
+
+- `cases` MUST be sorted by ascending `id`.
+- `input` is used for unary operations.
+- `inputs` is used for `concat`.
+- `insert` is used for `splice`.
+- `offset` and `length` are required for `slice` and `splice`.
+- `level` is required for `reverse`.
+- `output` is the expected output payload bytes.
+- `cid_sha256` is `SHA-256("CAS:OBJ\\0" || output)` in lowercase hex.
diff --git a/tests/tgk/test_tgk_error_taxonomy.c b/tests/tgk/test_tgk_error_taxonomy.c
new file mode 100644
index 0000000..dae9a44
--- /dev/null
+++ b/tests/tgk/test_tgk_error_taxonomy.c
@@ -0,0 +1,103 @@
+#include "amduat/tgk/store.h"
+
+#include <stdio.h>
+#include <string.h>
+
+static amduat_tgk_graph_error_t stub_resolve_edge(void *ctx,
+                                                  amduat_reference_t ref,
+                                                  amduat_tgk_edge_body_t *out_body) {
+  amduat_tgk_graph_error_t *err = (amduat_tgk_graph_error_t *)ctx;
+  (void)ref;
+  (void)out_body;
+  return *err;
+}
+
+static int test_not_edge_mapping(void) {
+  amduat_tgk_store_ops_t ops;
+  amduat_tgk_store_t store;
+  amduat_tgk_store_config_t cfg;
+  amduat_tgk_graph_error_t err = GS_ERR_NOT_EDGE;
+
+  memset(&cfg, 0, sizeof(cfg));
+  memset(&ops, 0, sizeof(ops));
+  ops.resolve_edge = stub_resolve_edge;
+  amduat_tgk_store_init(&store, cfg, ops, &err);
+
+  if (amduat_tgk_store_resolve_edge(&store, amduat_reference(0, amduat_octets(NULL, 0u)), NULL) !=
+      GS_ERR_NOT_EDGE) {
+    return 1;
+  }
+  return 0;
+}
+
+static int test_artifact_error_mapping(void) {
+  amduat_tgk_store_ops_t ops;
+  amduat_tgk_store_t store;
+  amduat_tgk_store_config_t cfg;
+  amduat_tgk_graph_error_t err = GS_ERR_ARTIFACT_ERROR;
+
+  memset(&cfg, 0, sizeof(cfg));
+  memset(&ops, 0, sizeof(ops));
+  ops.resolve_edge = stub_resolve_edge;
+  amduat_tgk_store_init(&store, cfg, ops, &err);
+
+  if (amduat_tgk_store_resolve_edge(&store, amduat_reference(0, amduat_octets(NULL, 0u)), NULL) !=
+      GS_ERR_ARTIFACT_ERROR) {
+    return 1;
+  }
+  return 0;
+}
+
+static int test_unsupported_mapping(void) {
+  amduat_tgk_store_ops_t ops;
+  amduat_tgk_store_t store;
+  amduat_tgk_store_config_t cfg;
+
+  memset(&cfg, 0, sizeof(cfg));
+  memset(&ops, 0, sizeof(ops));
+  amduat_tgk_store_init(&store, cfg, ops, NULL);
+
+  if (amduat_tgk_store_resolve_edge(&store, amduat_reference(0, amduat_octets(NULL, 0u)), NULL) !=
+      GS_ERR_UNSUPPORTED) {
+    return 1;
+  }
+  return 0;
+}
+
+static int test_integrity_mapping(void) {
+  amduat_tgk_store_ops_t ops;
+  amduat_tgk_store_t store;
+  amduat_tgk_store_config_t cfg;
+  amduat_tgk_graph_error_t err = GS_ERR_INTEGRITY;
+
+  memset(&cfg, 0, sizeof(cfg));
+  memset(&ops, 0, sizeof(ops));
+  ops.resolve_edge = stub_resolve_edge;
+  amduat_tgk_store_init(&store, cfg, ops, &err);
+
+  if (amduat_tgk_store_resolve_edge(&store, amduat_reference(0, amduat_octets(NULL, 0u)), NULL) !=
+      GS_ERR_INTEGRITY) {
+    return 1;
+  }
+  return 0;
+}
+
+int main(void) {
+  if (test_not_edge_mapping() != 0) {
+    fprintf(stderr, "not edge mapping failed\n");
+    return 1;
+  }
+  if (test_artifact_error_mapping() != 0) {
+    fprintf(stderr, "artifact error mapping failed\n");
+    return 1;
+  }
+  if (test_unsupported_mapping() != 0) {
+    fprintf(stderr, "unsupported mapping failed\n");
+    return 1;
+  }
+  if (test_integrity_mapping() != 0) {
+    fprintf(stderr, "integrity mapping failed\n");
+    return 1;
+  }
+  return 0;
+}
diff --git a/tier1/asl-1-core.md b/tier1/asl-1-core.md
index f0b55d0..f3e4809 100644
--- a/tier1/asl-1-core.md
+++ b/tier1/asl-1-core.md
@@ -2,9 +2,9 @@
 
 Status: Approved
 Owner: Niklas Rydberg
-Version: 0.4.1
+Version: 0.4.2
 SoT: Yes
-Last Updated: 2025-11-16
+Last Updated: 2026-02-21
 Linked Phase Pack: N/A
 Tags: [deterministic, binary-minimalism]
 
@@ -20,7 +20,7 @@ Tags: [deterministic, binary-minimalism]
 **Informative references:**
 
 * `ENC/ASL1-CORE v1.x` — canonical encoding profile (`ASL_ENC_CORE_V1`)
-* `HASH/ASL1 v0.2.2` — ASL1 hash family and `HashId` assignments
+* `HASH/ASL1 v0.2.5` — ASL1 hash family and `HashId` assignments
 * `ASL/1-STORE v0.4.0` — content-addressable store over ASL/1-CORE
 * `TGK/1-CORE v0.7.0` — trace graph kernel over `Reference`
 * `PEL/1` — execution substrate
@@ -289,12 +289,16 @@ then the Reference `R` for `A` under `(P, H)` is:
 
 ```text
 ArtifactBytes = encode_P(A)
-digest        = H(ArtifactBytes)
+digest        = H("AMDUAT:ASL1:ART\0" || ArtifactBytes)
 Reference     = { hash_id = HID, digest = digest }
 ```
 
+The domain separator is the ASCII byte sequence `AMDUAT:ASL1:ART` followed by a
+single `0x00` terminator (16 bytes total). The separator MUST be present
+verbatim and MUST NOT be modified or omitted.
+
 > **ASL/CORE-REF-DERIVE/1**
-> Any component that claims to derive References from Artifacts for a given `(EncodingProfileId, HashId)` **MUST** use this exact procedure.
+> Any component that claims to derive References from Artifacts for a given `(EncodingProfileId, HashId)` **MUST** use this exact procedure, including the domain separator.
 
 ### 4.3 Deterministic agreement lemma (informative)
 
@@ -306,7 +310,7 @@ For any two conformant implementations that share:
 then for any Artifact `A`:
 
 * both will compute identical `ArtifactBytes`,
-* both will compute identical `digest = H(ArtifactBytes)`,
+* both will compute identical `digest = H("AMDUAT:ASL1:ART\0" || ArtifactBytes)`,
 * both will form identical `Reference {hash_id = HID, digest = digest}`.
 
 This is the basis for cross-Store and cross-domain determinism in Amduat.
@@ -316,6 +320,7 @@ This is the basis for cross-Store and cross-domain determinism in Amduat.
 While ASL/1-CORE is conceptually family-agnostic, the **Amduat 2.0 substrate** standardizes:
 
 * `ASL_ENC_CORE_V1` as the canonical Artifact encoding profile;
+* `HASH/ASL1` as the canonical hash namespace for `Reference.hash_id` values;
 * `HASH-ASL1-256` (`HashId = 0x0001`) as the canonical default hash algorithm for identity-critical surfaces.
 
 Other `(EncodingProfileId, HashId)` pairs are allowed but must be explicitly declared by the consuming profile or implementation.
@@ -495,4 +500,5 @@ Everything else — API design, transport formats, performance characteristics,
 
 ## Document History
 
+* **0.4.2 (2026-02-21):** Added ASL/1 identity domain separation and clarified hash namespace usage.
 * **0.4.1 (2025-11-16):** Registered as Tier-1 spec and aligned to the Amduat 2.0 substrate baseline.
diff --git a/tier1/asl-core-index-1.md b/tier1/asl-core-index-1.md
index e8dde9f..e594270 100644
--- a/tier1/asl-core-index-1.md
+++ b/tier1/asl-core-index-1.md
@@ -1,10 +1,10 @@
 # ASL/1-CORE-INDEX — Semantic Index Model
 
-Status: Draft
+Status: Approved
 Owner: Niklas Rydberg
-Version: 0.1.0
-SoT: No
-Last Updated: 2025-11-16
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
 Linked Phase Pack: N/A
 Tags: [deterministic, index, semantics]
 
diff --git a/tier1/asl-indexes-1.md b/tier1/asl-indexes-1.md
index fe53f6d..ec6aeb6 100644
--- a/tier1/asl-indexes-1.md
+++ b/tier1/asl-indexes-1.md
@@ -1,10 +1,10 @@
 # ASL/INDEXES/1 -- Index Taxonomy and Relationships
 
-Status: Draft
+Status: Approved
 Owner: Architecture
-Version: 0.1.0
-SoT: No
-Last Updated: 2025-01-17
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
 Linked Phase Pack: N/A
 Tags: [indexes, content, structural, materialization]
 
diff --git a/tier1/asl-log-1.md b/tier1/asl-log-1.md
index 333b313..3fff102 100644
--- a/tier1/asl-log-1.md
+++ b/tier1/asl-log-1.md
@@ -115,6 +115,22 @@ in `ENC-ASL-LOG`. The envelope MUST include:
 * `payload` (type-specific bytes)
 * `record_hash` (hash-chained integrity)
 
+### 3.4 Log Segment Identity (Optional)
+
+Implementations MAY store the log as **multiple segments** (e.g., rotated files).
+If segmented storage is used, each segment MUST be assigned a **store-local**
+`segment_id` (opaque `uint64_t`) and MUST carry a **segment hash** computed over
+the exact bytes of the segment as defined in `ENC/ASL-LOG/1`.
+
+A log segment identity is the tuple:
+
+```
+(segment_id, logseq_min, logseq_max, segment_hash)
+```
+
+This identity is used only for storage metadata and audit; it does not change
+the ASL/LOG/1 semantics or record ordering.
+
 ---
 
 ## 4. Record Types (Normative)
@@ -152,6 +168,8 @@ Semantics:
 * Segment MUST be immutable.
 * All referenced blocks MUST already be sealed.
 * Segment contents are not re-logged.
+* `segment_hash` MUST be the SHA-256 hash of the exact segment bytes as encoded
+  by `ENC/ASL-CORE-INDEX/1`, including the finalized footer.
 
 ### 4.2 TOMBSTONE
 
@@ -211,6 +229,9 @@ typedef struct {
 
 Semantics:
 
+* `snapshot_id` is an opaque, store-assigned `uint64_t` identifier persisted in
+  the anchor payload.
+* The anchor's `logseq` is the snapshot's log position.
 * Defines a replay checkpoint.
 * Enables log truncation below anchor with care.
 
@@ -249,7 +270,8 @@ typedef struct {
 
 To reconstruct CURRENT:
 
-1. Load latest snapshot anchor (if any).
+1. Load latest snapshot anchor (if any). If absent, treat
+   `snapshot_id = 0` and `snapshot.logseq = 0`.
 2. Initialize visible segments from that snapshot.
 3. Replay all log records with `logseq > snapshot.logseq`.
 4. Apply records in order:
diff --git a/tier1/asl-store-index-1.md b/tier1/asl-store-index-1.md
index 473561d..7bd9bec 100644
--- a/tier1/asl-store-index-1.md
+++ b/tier1/asl-store-index-1.md
@@ -87,6 +87,10 @@ Excludes:
 * Memory residency or caching
 * Federation, PEL, or TGK semantics (see `TGK/1` and `TGK/1-CORE`)
 
+**ByteStore boundary:** raw byte persistence, COR/1 import/export, and SA/PA
+isolation are defined in `BYTESTORE/1` (DDS §11). ASL/STORE-INDEX/1 assumes a
+conformant ByteStore beneath the index layer.
+
 ---
 
 ## 3. Core Concepts
@@ -144,6 +148,10 @@ as the inclusive `logseq` upper bound defined by `ASL/LOG/1`, not a byte offset
 into the log file. Snapshot anchors use their record `logseq` as the snapshot's
 log position.
 
+**Implementation note (identity):** SnapshotID values are store-assigned
+`uint64_t` identifiers persisted in `SNAPSHOT_ANCHOR` records. If no snapshot
+anchor exists, `SnapshotID` is treated as `0`.
+
 ### 3.5 Artifact Location
 
 * **ArtifactExtent**: `(BlockID, offset, length)` identifying a byte slice within a block.
diff --git a/tier1/asl-tgk-execution-plan-1.md b/tier1/asl-tgk-execution-plan-1.md
index e5b3c36..ba2823c 100644
--- a/tier1/asl-tgk-execution-plan-1.md
+++ b/tier1/asl-tgk-execution-plan-1.md
@@ -1,10 +1,10 @@
 # ASL/TGK-EXEC-PLAN/1 -- Unified Execution Plan Semantics
 
-Status: Draft
+Status: Approved
 Owner: Architecture
-Version: 0.1.0
-SoT: No
-Last Updated: 2025-01-17
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
 Linked Phase Pack: N/A
 Tags: [execution, query, tgk, determinism]
 
@@ -82,6 +82,10 @@ Each operator includes:
 * `traversal`: optional traversal parameters
 * `aggregation`: optional aggregation parameters
 
+Snapshot bounds MUST satisfy:
+
+* `logseq_min <= logseq_max`
+
 ---
 
 ## 2.1 Query Abstraction (Informative)
diff --git a/tier1/bytestore-1.md b/tier1/bytestore-1.md
new file mode 100644
index 0000000..c3c2809
--- /dev/null
+++ b/tier1/bytestore-1.md
@@ -0,0 +1,83 @@
+# BYTESTORE/1 — ByteStore API and Persistence Boundary
+
+Status: Draft
+Owner: Architecture
+Version: 0.1.0
+SoT: No
+Last Updated: 2026-02-21
+Tags: [bytestore, persistence, determinism]
+
+**Document ID:** `BYTESTORE/1`
+**Layer:** L0 — Persistence boundary (bytes only)
+
+**Depends on (normative):**
+
+* `DDS` §11 — ByteStore API & Persistence Discipline
+* `SRS` FR-BS-001…005 — determinism + durability requirements
+* `COR/1` — canonical envelope bytes
+* `ICD/1` — `max_object_size` policy
+
+**Informative references:**
+
+* `ADR-030` — ByteStore Persistence Contract
+* `AMDUAT_BYTESTORE` header — `vendor/amduat/include/amduat/bytestore.h`
+
+---
+
+## 1. Purpose
+
+BYTESTORE/1 defines the **code-level API surface** for ByteStore and maps it to
+the behavioural requirements already specified in DDS and SRS.
+
+It does not define new semantics; DDS §11 remains the source of truth.
+
+---
+
+## 2. API Surface (Normative)
+
+The following API signatures are required (see `amduat/bytestore.h`):
+
+* `put(payload) -> cid`
+* `put_stream(stream) -> cid`
+* `import_cor(envelope) -> cid`
+* `export_cor(cid) -> envelope`
+* `get(cid) -> bytes`
+* `stat(cid) -> {present, size}`
+* `assert_area_isolation(public_root, secure_root)`
+
+The error codes exposed by the header MUST map to ADR-006 lanes as specified in
+DDS §11.7.
+
+---
+
+## 3. Deterministic Identity (Normative)
+
+The CID derivation is fixed:
+
+```
+cid = algo_id || H("CAS:OBJ\0" || payload)
+```
+
+Implementations MUST use the exact domain separator and hash rules defined in
+DDS §11.2 and SRS FR-BS-001.
+
+---
+
+## 4. Persistence Discipline (Normative)
+
+All ByteStore writes MUST follow the fsync ladder from DDS §11.4 and enforce:
+
+* `ICD/1 max_object_size`
+* COR/1 import/export byte identity
+* SA/PA isolation
+* Streaming determinism
+
+---
+
+## 5. Non-Goals
+
+BYTESTORE/1 does not define:
+
+* Physical storage layout
+* Replication protocols
+* Transport or API gateways
diff --git a/tier1/dds.md b/tier1/dds.md
index 902bd33..62bf1b0 100644
--- a/tier1/dds.md
+++ b/tier1/dds.md
@@ -453,6 +453,104 @@ Phase 04 establishes deterministic linkage between FLS/1 envelopes and CRS/1 con
 * CRS payload headers MUST match `CRS1` (concept) or `CRR1` (relation) when linkage metadata declares the type ⇒ `ERR_FLS_PAYLOAD_KIND`.
 * Payloads MAY be CRS/1 concepts or CRR/1 relations; FLS/1 envelopes never mutate CRS graphs.
 
+##### 7.8.1.1 Session Envelope (Normative)
+
+Session envelopes bind a linkage session to its channel catalog and termination ledger.
+
+**Header:** `MAGIC="FLS1"`, `VERSION=0x01`, `FLAGS=0x00`, `RSV=0x00`.
+
+**TLVs (strict order; no padding):**
+
+| Tag    | Field                  | Type   | Card. | Notes |
+| ------ | ---------------------- | ------ | ----- | ----- |
+| `0x60` | `source_cid`           | CID    | 1     | Sender surface identity. |
+| `0x61` | `target_cid`           | CID    | 1     | Recipient surface identity. |
+| `0x66` | `session_id`           | BYTES  | 1     | 16-byte opaque session ID. |
+| `0x67` | `channel_catalog_cid`  | CID    | 1     | CID of `FLSC` channel catalog. |
+| `0x68` | `termination_ledger_cid` | CID  | 0-1   | CID of `FLSL` termination ledger. |
+| `0x64` | `timestamp`            | UINT64 | 0-1   | Optional bounded timing evidence. |
+| `0x65` | `signature`            | BYTES  | 0-1   | Ed25519 signature over `"AMDUAT:FLS\0" || canonical bytes`. |
+
+**Validation:**
+
+* `session_id` MUST be exactly 16 bytes ⇒ `ERR_FLS_SESSION_ID_LENGTH`.
+* `channel_catalog_cid` MUST resolve to an `FLSC` header ⇒ `ERR_FLS_CATALOG_KIND`.
+* `termination_ledger_cid` (if present) MUST resolve to an `FLSL` header ⇒ `ERR_FLS_LEDGER_KIND`.
+
+##### 7.8.1.2 Channel Catalog (Normative)
+
+Channel catalogs enumerate message channels and their ordering bounds.
+
+**Header:** `MAGIC="FLSC"`, `VERSION=0x01`, `FLAGS=0x00`, `RSV=0x00`.
+
+**Payload layout:**
+
+```
+channel_count : U32
+entries       : ChannelEntry[channel_count]
+
+ChannelEntry =
+  channel_id  : U32
+  kind        : U16
+  flags       : U16
+  first_seq   : U64
+  last_seq    : U64
+```
+
+**Rules:**
+
+* `entries` MUST be sorted by ascending `channel_id` ⇒ `ERR_FLS_CHANNEL_ORDER`.
+* `first_seq <= last_seq` for each entry ⇒ `ERR_FLS_CHANNEL_RANGE`.
+* `channel_id` MUST be unique ⇒ `ERR_FLS_CHANNEL_DUPLICATE`.
+
+##### 7.8.1.3 Message Envelope (Normative)
+
+Message envelopes bind a payload to a channel and sequence position.
+
+**Header:** `MAGIC="FLSM"`, `VERSION=0x01`, `FLAGS=0x00`, `RSV=0x00`.
+
+**TLVs (strict order; no padding):**
+
+| Tag    | Field        | Type   | Card. | Notes |
+| ------ | ------------ | ------ | ----- | ----- |
+| `0x66` | `session_id` | BYTES  | 1     | 16-byte session ID. |
+| `0x69` | `channel_id` | U32    | 1     | Channel identifier. |
+| `0x6A` | `seq`        | U64    | 1     | Monotonic sequence number within channel. |
+| `0x62` | `payload_cid`| CID    | 1     | Content payload CID. |
+| `0x64` | `timestamp`  | UINT64 | 0-1   | Optional bounded timing evidence. |
+| `0x65` | `signature`  | BYTES  | 0-1   | Optional Ed25519 signature. |
+
+**Rules:**
+
+* `session_id` MUST be exactly 16 bytes ⇒ `ERR_FLS_SESSION_ID_LENGTH`.
+* `seq` MUST be within the bounds declared in the channel catalog ⇒ `ERR_FLS_SEQ_RANGE`.
+
+##### 7.8.1.4 Termination Ledger (Normative)
+
+Termination ledgers declare channel completion bounds.
+
+**Header:** `MAGIC="FLSL"`, `VERSION=0x01`, `FLAGS=0x00`, `RSV=0x00`.
+
+**Payload layout:**
+
+```
+channel_count : U32
+entries       : TerminationEntry[channel_count]
+
+TerminationEntry =
+  channel_id  : U32
+  final_seq   : U64
+  reason_code : U16
+  rsv         : U16
+  closed_at   : U64
+```
+
+**Rules:**
+
+* `entries` MUST be sorted by ascending `channel_id` ⇒ `ERR_FLS_CHANNEL_ORDER`.
+* `final_seq` MUST be ≥ the channel’s `last_seq` from the catalog ⇒ `ERR_FLS_SEQ_RANGE`.
+* `closed_at` MUST be non-zero when a termination entry is present.
+
 #### 7.8.2 CRS/1 Concept & Relation TLVs (Normative)
 
 > **Scope:** Deterministic CRS/1 byte layout as ratified by ADR-020 v1.1.0. All TLVs
diff --git a/tier1/enc-asl-core-index-1.md b/tier1/enc-asl-core-index-1.md
index d2aa1c2..84ed2c8 100644
--- a/tier1/enc-asl-core-index-1.md
+++ b/tier1/enc-asl-core-index-1.md
@@ -1,10 +1,10 @@
 # ENC/ASL-CORE-INDEX/1 — Encoding Specification for ASL Core Index
 
-Status: Draft
+Status: Approved
 Owner: Niklas Rydberg
-Version: 0.1.0
-SoT: No
-Last Updated: 2025-11-16
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
 Linked Phase Pack: N/A
 Tags: [encoding, index, deterministic]
 
diff --git a/tier1/enc-asl-log-1.md b/tier1/enc-asl-log-1.md
index e8be67f..32bb5d4 100644
--- a/tier1/enc-asl-log-1.md
+++ b/tier1/enc-asl-log-1.md
@@ -141,6 +141,21 @@ continue replay without failure.
 * Unknown `record_type` values are the only exception: they MUST be skipped
   using `payload_len` and MUST NOT break replay determinism.
 
+### 5.1 Log Segment Hashing (Optional)
+
+If a store persists the log in **segments** (multiple files), the following
+rules apply:
+
+* **Segment hash:** `segment_hash = SHA-256(segment_bytes)` where
+  `segment_bytes` are the exact on-disk bytes of that segment, starting at the
+  `LogHeader` and ending at the final `record_hash`.
+* **Hash-chain continuity:** the `prev_record_hash` for the first record in a
+  segment MUST be:
+  * all-zeroes for the first segment in a domain, or
+  * the last record hash of the immediately preceding segment.
+* **Segment identity:** `(segment_id, logseq_min, logseq_max, segment_hash)`
+  is the canonical identity tuple for storage metadata and audit.
+
 ---
 
 ## 6. Record Type IDs (v1)
diff --git a/tier1/enc-asl1-core.md b/tier1/enc-asl1-core.md
index 7e4c4d9..f870da3 100644
--- a/tier1/enc-asl1-core.md
+++ b/tier1/enc-asl1-core.md
@@ -2,9 +2,9 @@
 
 Status: Approved
 Owner: Niklas Rydberg
-Version: 1.0.5
+Version: 1.0.6
 SoT: Yes
-Last Updated: 2025-11-16
+Last Updated: 2026-02-21
 Linked Phase Pack: N/A
 Tags: [deterministic, binary-minimalism]
 
@@ -16,11 +16,11 @@ Tags: [deterministic, binary-minimalism]
 
 **Depends on (normative):**
 
-* **ASL/1-CORE v0.4.1** (value model: `Artifact`, `TypeTag`, `Reference`, `HashId`)
+* **ASL/1-CORE v0.4.2** (value model: `Artifact`, `TypeTag`, `Reference`, `HashId`)
 
 **Integrates with (cross-profile rules):**
 
-* **HASH/ASL1 v0.2.4** (ASL1 hash family: registry of `HashId → algorithm, digest length`)
+* **HASH/ASL1 v0.2.5** (ASL1 hash family: registry of `HashId → algorithm, digest length`)
 
   * This profile does **not** depend on HASH/ASL1 to define its layouts.
   * When both profiles are implemented, additional cross-checks apply (see §4.4, §5).
@@ -424,10 +424,14 @@ For encoding profile `ASL_ENC_CORE_V1`, the canonical rule for constructing `Ref
 
 ```text
 ArtifactBytes = encode_artifact_core_v1(A)
-digest        = H(ArtifactBytes)
+digest        = H("AMDUAT:ASL1:ART\0" || ArtifactBytes)
 Reference     = { hash_id = HID, digest = digest }
 ```
 
+The domain separator is the ASCII byte sequence `AMDUAT:ASL1:ART` followed by a
+single `0x00` terminator (16 bytes total). The separator MUST be present
+verbatim and MUST NOT be modified or omitted.
+
 where:
 
 * `A` is an `Artifact` (ASL/1-CORE),
@@ -461,7 +465,7 @@ If two implementations:
 then for any `Artifact A` they MUST:
 
 * produce identical `ArtifactBytes = encode_artifact_core_v1(A)`,
-* produce identical `digest = H(ArtifactBytes)`,
+* produce identical `digest = H("AMDUAT:ASL1:ART\0" || ArtifactBytes)`,
 * produce identical `Reference` and `ReferenceBytes = encode_reference_core_v1(Reference)`.
 
 This is the determinism foundation used by ASL/1-STORE, PEL/1, FER/1, and FCT/1.
@@ -506,10 +510,10 @@ Canonical `ArtifactBytes`:
 00 0000000000000002 DEAD
 ```
 
-Digest with `HASH-ASL1-256` (SHA-256):
+Digest with `HASH-ASL1-256` (SHA-256) and domain separation:
 
 ```text
-digest = SHA-256(00 0000000000000002 DEAD)
+digest = SHA-256("AMDUAT:ASL1:ART\0" || 00 0000000000000002 DEAD)
 ```
 
 Assuming `HashId = 0001` for `HASH-ASL1-256`, the `ReferenceBytes` are:
@@ -555,7 +559,7 @@ Hashing and `ReferenceBytes` proceed as in §6.1.
 
 ## 7. Conformance
 
-An implementation conforms to `ENC/ASL1-CORE v1.0.5` if and only if it:
+An implementation conforms to `ENC/ASL1-CORE v1.0.6` if and only if it:
 
 1. **Correctly encodes and decodes Artifacts**
 
@@ -573,7 +577,7 @@ An implementation conforms to `ENC/ASL1-CORE v1.0.5` if and only if it:
 
 3. **Implements canonical hashing correctly**
 
-   * Uses `ArtifactBytes` from `encode_artifact_core_v1` as the **only** input to ASL1 hash functions when deriving `Reference`s under this profile.
+  * Uses the ASL/1-CORE domain separator (`"AMDUAT:ASL1:ART\0"`) plus `ArtifactBytes` from `encode_artifact_core_v1` as the **only** input to ASL1 hash functions when deriving `Reference`s under this profile.
    * Computes `Reference` via the canonical rule in §5.1.
    * Does not derive `Reference`s from non-canonical or alternative encodings in contexts that claim to use `ASL_ENC_CORE_V1`.
 
@@ -595,4 +599,5 @@ Everything else — transport, storage layout, replication, indexing, overlays,
 
 ## Document History
 
+* **1.0.6 (2026-02-21):** Added ASL/1-CORE identity domain separation to the reference derivation rule and updated registry metadata.
 * **1.0.5 (2025-11-16):** Registered as Tier-1 spec and aligned to the Amduat 2.0 substrate baseline.
diff --git a/tier1/fcs-1.md b/tier1/fcs-1.md
new file mode 100644
index 0000000..775195b
--- /dev/null
+++ b/tier1/fcs-1.md
@@ -0,0 +1,95 @@
+# FCS/1 — Function Composition Schema (Execution-Only)
+
+Status: Approved
+Owner: Architecture
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
+Linked Phase Pack: PH07
+Tags: [execution, descriptor, deterministic]
+
+**Document ID:** `FCS/1`
+**Layer:** L2 — Function descriptor schema for deterministic execution
+
+**Depends on (normative):**
+
+* `DDS` — canonical FCS/1 v1-min TLV layout and validation rules
+* `PCB1` — parameter block encoding rules (DDS §7.3)
+* `ASL/1-CORE v0.4.x` — logical value model (`Artifact`, `Reference`)
+
+---
+
+## 0. Purpose & Scope
+
+`FCS/1` defines the **execution-only** descriptor schema for composite and
+custom functions. It explicitly excludes policy, intent, scope, authority, and
+other governance metadata (those belong in `FCT/1`).
+
+`FCS/1` descriptors are immutable and content-addressed; identical descriptors
+MUST hash to identical CIDs.
+
+---
+
+## 1. Descriptor Model (logical)
+
+An `FCS/1` descriptor captures the deterministic execution recipe:
+
+```
+FCSDescriptor {
+  function_ptr     : CID   // FPS/1 primitive or nested FCS/1 descriptor
+  parameter_block  : CID   // PCB1 parameter block
+  arity            : uint32
+}
+```
+
+* `function_ptr` MAY reference another `FCS/1` descriptor (composition), or a
+  primitive function descriptor (e.g., `FPS/1`).
+* `parameter_block` MUST reference a valid PCB1 payload.
+* `arity` defines the expected number of input slots (must match PCB1).
+
+---
+
+## 2. Canonical Encoding (v1-min)
+
+The canonical byte encoding for `FCS/1` descriptors is defined by DDS §7.2:
+
+* COR/1 framing with strict TLV order.
+* Required TLVs only: `function_ptr (0x30)`, `parameter_block (0x31)`,
+  `arity (0x32)`.
+
+No other TLVs are permitted in v1-min.
+
+---
+
+## 3. Validation Rules
+
+Implementations MUST reject descriptors that violate any of the following:
+
+1. TLVs are not in strict ascending order, or appear more than once.
+2. `parameter_block` does not decode as a valid PCB1 envelope.
+3. `arity` does not match PCB1 slot manifest length.
+4. The descriptor graph (following nested `function_ptr` references) is cyclic.
+5. Any legacy or unknown governance TLV appears.
+
+Error mapping follows DDS (e.g., `ERR_FCS_TAG_ORDER`, `ERR_FCS_PARAMETER_FORMAT`,
+`ERR_PCB_ARITY_MISMATCH`, `ERR_FCS_CYCLE_DETECTED`, `ERR_FCS_UNKNOWN_TAG`).
+
+---
+
+## 4. Composition Semantics
+
+* Composition is **pure**: a descriptor that references another `FCS/1`
+  descriptor inherits its deterministic execution recipe.
+* The composed descriptor graph MUST be acyclic.
+* Registries MUST admit only canonical, validated `FCS/1` descriptors.
+
+---
+
+## 5. Conformance
+
+An implementation is **FCS/1–conformant** if it:
+
+* Accepts only v1-min canonical encodings.
+* Enforces the validation rules in §3.
+* Treats descriptors as immutable and content-addressed.
+* Rejects any descriptor with policy/intent metadata embedded.
diff --git a/tier1/fer-1.md b/tier1/fer-1.md
new file mode 100644
index 0000000..3998f62
--- /dev/null
+++ b/tier1/fer-1.md
@@ -0,0 +1,183 @@
+# FER/1 — Execution Receipts and Evidence (Core Semantics)
+
+Status: Draft
+Owner: Architecture
+Version: 0.1.0
+SoT: Yes
+Last Updated: 2026-02-21
+Linked Phase Pack: PH07
+Tags: [evidence, receipt, deterministic, execution]
+
+**Document ID:** `FER/1`
+**Layer:** L2 — Evidence receipts over PEL/1 execution
+
+**Depends on (normative):**
+
+* `ASL/1-CORE v0.4.x` — value model (`Artifact`, `Reference`)
+* `PEL/1-SURF v0.2.x` — surface execution results
+* `TGK/1-CORE v0.7.x` — trace graph kernel
+* `ENC/FER1-RECEIPT/1` — canonical receipt encoding
+* `DDS` (FER/1 layout and validation rules)
+
+---
+
+## 0. Purpose & Scope
+
+`FER/1` defines **receipt semantics** for deterministic execution evidence. It
+standardizes the logical fields of execution receipts and the minimal execution
+artifacts that higher layers can rely on, while delegating concrete encodings to
+`ENC/FER1-RECEIPT/1` and DDS.
+
+`FER/1` does **not** define policy, intent, authority, or certification rules
+(those belong to `FCT/1` and higher layers).
+
+---
+
+## 1. Core Concepts
+
+### 1.1 Execution Artifacts (logical schemas)
+
+`FER/1` uses four logical artifact shapes. Each is an ASL/1 `Artifact` whose
+encoding is profile-defined (not specified here).
+
+**ExecutionIntent** — records the inputs and environment for a run:
+
+```
+ExecutionIntent {
+  function_ref          : Reference   // FCS/1 descriptor or equivalent
+  program_ref           : Reference   // program artifact (scheme-specific)
+  input_manifest_ref    : Reference   // GS/1 manifest (ordered, deduped)
+  params_ref            : optional Reference
+  snapshot_id           : uint64      // snapshot identity (0 if absent)
+  execution_config_ref  : optional Reference // snapshot-scoped config
+  environment_ref       : Reference   // environment capsule (ICD/1 / PH03)
+}
+```
+
+**ExecutionOutput** — binds outputs to a run (used when outputs are multiple or
+need explicit naming):
+
+```
+ExecutionOutput {
+  output_refs     : list<Reference>   // ordered
+  result_ref      : Reference         // surface ExecutionResult artifact
+  trace_ref       : optional Reference
+}
+```
+
+**ExecutionReceipt** — evidence of a run (canonical encoding in
+`ENC/FER1-RECEIPT/1`):
+
+```
+ExecutionReceipt {
+  function_ref         : Reference
+  input_manifest_ref   : Reference
+  environment_ref      : Reference
+  evaluator_id         : bytes
+  output_ref           : Reference
+  executor_refs        : list<Reference>
+  parity_entries       : list<ParityEntry>
+  started_at           : uint64
+  completed_at         : uint64
+  // optional fields per FER/1 v1.1 (DDS): executor_fingerprint, logs,
+  // determinism_level, rng_seed, limits, parent, context, witnesses, run_id,
+  // signature, signature_ext
+}
+```
+
+**ExecutionObservation** — optional, typed evidence produced alongside a run:
+
+```
+ExecutionObservation {
+  kind        : enum        // e.g. stderr, stdout, metrics, trace
+  payload_ref : Reference   // artifact containing the observation payload
+  payload_sha256 : bytes[32]
+}
+```
+
+### 1.2 Program and input conventions
+
+* `function_ref` MUST reference the **function descriptor** used for evaluation
+  (e.g., FCS/1 descriptor).
+* `program_ref` MUST reference the program artifact used by that descriptor.
+* `input_manifest_ref` MUST reference a **canonical manifest artifact** that
+  enumerates inputs in deterministic order.
+* `params_ref`, when present, MUST be an immutable artifact included in the
+  input manifest.
+
+### 1.3 Snapshot binding
+
+All receipts are **snapshot-bound**:
+
+* `snapshot_id` in the intent MUST be the snapshot identity used for input
+  resolution (0 when absent).
+* Receipts and outputs are interpreted relative to that snapshot.
+
+---
+
+## 2. Output Reference Fallback
+
+`ExecutionReceipt.output_ref` is a single reference. The value MUST resolve as:
+
+1. The sole output artifact, **if the run produces exactly one output**; or
+2. An `ExecutionOutput` artifact when there are multiple outputs; or
+3. The surface `ExecutionResult` artifact, **only** if outputs are empty and
+   the result is the only durable artifact.
+
+This rule keeps receipts stable while supporting multi-output runs and
+zero-output executions.
+
+---
+
+## 3. TGK Traceability Edges (FER/1 profile)
+
+When ingesting receipts, a `TGK/FER/1` profile SHOULD emit traceability edges
+using TGK edge artifacts. Edge type assignments are defined by the profile; the
+semantics are:
+
+* `EDGE_EXECUTION`: `program_ref -> output_ref`
+* `EDGE_CONSUMED_BY`: `input_ref -> output_ref`
+* `EDGE_PRODUCED_BY`: `output_ref -> receipt_ref`
+* `EDGE_REALIZES`: `receipt_ref -> function_ref`
+* `EDGE_OBSERVED_BY`: `output_ref -> observation_ref` (optional)
+
+Edges MUST be derivable solely from receipt content and referenced artifacts.
+
+---
+
+## 4. Determinism & Validation (FER/1 v1.1)
+
+`FER/1` v1.1 receipts are **parity-first** and deterministic. Implementations
+MUST enforce the DDS validation rules, including:
+
+* Strict TLV order and no unknown tags.
+* `executor_set` and `parity_vector` ordered byte-lexicographically and aligned.
+* `parity_entries[i].output_ref` equals the top-level `output_ref`.
+* `started_at <= completed_at` and monotonic time envelope.
+* Determinism level defaults to `D1_bit_exact`; any other level requires an
+  explicit `rng_seed`.
+* `run_id`, when present, MUST equal the deterministic hash over
+  `{function_ref, input_manifest_ref, environment_ref, executor_fingerprint}`.
+* Receipts MUST NOT encode policy, intent, or authority metadata.
+
+The canonical binary layout for receipts is defined in
+`ENC/FER1-RECEIPT/1` and DDS.
+
+---
+
+## 5. Interactions
+
+* `PEL/1-SURF` provides the surface `ExecutionResult` artifact referenced by
+  `ExecutionOutput.result_ref`.
+* `FCT/1` binds policy, authority, and certification to one or more FER/1
+  receipts.
+
+---
+
+## 6. Conformance
+
+An implementation is **FER/1–conformant** if it:
+
+* Produces receipts that validate under `ENC/FER1-RECEIPT/1` and DDS rules.
+* Uses the output reference fallback rules in §2.
+* Emits TGK edges (when enabled) that are derivable from receipt content.
diff --git a/tier1/fps-1.md b/tier1/fps-1.md
new file mode 100644
index 0000000..916c766
--- /dev/null
+++ b/tier1/fps-1.md
@@ -0,0 +1,137 @@
+# FPS/1 — Functional Primitive Surface
+
+Status: Approved
+Owner: Architecture
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
+Tags: [primitives, determinism, bytes]
+
+**Document ID:** `FPS/1`
+**Layer:** L1 — Deterministic functional primitives over payload bytes
+
+**Depends on (normative):**
+
+* `ASL/1-CORE` — `Artifact`, `Reference`, hash identity
+* `HASH/ASL1` — hash family registry
+* `ADR-006` — deterministic error semantics
+* `ADR-015` — CAS rejection governance (alignment)
+
+**Informative references:**
+
+* `SRS` §12 — Functional Primitive Surface summary
+
+---
+
+## 0. Conventions
+
+The key words **MUST**, **MUST NOT**, **REQUIRED**, **SHOULD**, and **MAY** are
+to be interpreted as in RFC 2119.
+
+FPS/1 defines **pure, deterministic** operations over canonical byte payloads.
+The primitives are functional: identical inputs MUST produce identical outputs.
+
+---
+
+## 1. CID Derivation
+
+All primitives produce exactly one output payload and one CID.
+
+The CID for a payload is derived as:
+
+```
+cid = algo_id || H("CAS:OBJ\0" || payload)
+```
+
+* `algo_id` is an `ASL/1-CORE` hash identifier.
+* For v1, `algo_id` defaults to `HASH/ASL1` SHA-256.
+* The domain separator **MUST** be exactly `"CAS:OBJ\0"`.
+
+---
+
+## 2. Primitives (Normative)
+
+### 2.1 put
+
+```
+put(payload_bytes) -> CID
+```
+
+Canonical write; identity only. Storage durability is out of scope here.
+
+Errors: `ERR_IO_FAILURE`, `ERR_NORMALIZATION`
+
+### 2.2 get
+
+```
+get(CID) -> payload_bytes
+```
+
+Fetch canonical bytes from a conformant store.
+
+Errors: `ERR_CID_NOT_FOUND`
+
+### 2.3 slice
+
+```
+slice(CID, offset, length) -> CID
+```
+
+Extract a contiguous byte range.
+
+Errors: `ERR_SLICE_RANGE`
+
+### 2.4 concatenate
+
+```
+concatenate([CID1, ..., CIDn]) -> CID
+```
+
+Join payloads in order.
+
+Errors: `ERR_EMPTY_INPUTS`
+
+### 2.5 reverse
+
+```
+reverse(CID, level) -> CID
+```
+
+Reverse payload order at a specified granularity:
+
+* `bit` — reverse all bits in the payload
+* `byte` — reverse byte order
+* `word` — reverse 2-byte units
+* `long` — reverse 4-byte units
+
+Errors: `ERR_REV_ALIGNMENT`, `ERR_INVALID_LEVEL`
+
+### 2.6 splice
+
+```
+splice(CID_a, offset, CID_b) -> CID
+```
+
+Insert payload `b` into `a` at `offset`.
+
+Errors: `ERR_SPLICE_RANGE`
+
+---
+
+## 3. Determinism & Closure
+
+* Identical inputs MUST produce identical outputs.
+* Inputs are immutable.
+* Outputs MUST be valid inputs to any FPS/1 primitive.
+
+---
+
+## 4. Conformance Vectors
+
+The canonical vectors live in:
+
+```
+/amduat/tests/fixtures/conformance/fps_1/
+```
+
+Vectors are required for each primitive and include output bytes and CID.
diff --git a/tier1/ms-1.md b/tier1/ms-1.md
new file mode 100644
index 0000000..eb564c5
--- /dev/null
+++ b/tier1/ms-1.md
@@ -0,0 +1,203 @@
+# MS/1 — Concept Mapping Surface
+
+Status: Draft
+Owner: Architecture
+Version: 0.1.0
+SoT: No
+Last Updated: 2026-02-21
+Tags: [mapping, concepts, determinism]
+
+**Document ID:** `MS/1`
+**Layer:** L2 — Deterministic concept-to-data mapping surface
+
+**Depends on (normative):**
+
+* `ASL/1-CORE` — `Artifact`, `Reference`, TypeTag identity
+* `TGK/1` — concept nodes and predicate edges
+* `ADR-003` — canonical encoding discipline (BCF/1)
+* `ADR-006` — deterministic error semantics
+
+**Informative references:**
+
+* `amduatd-api-endpoint-spec.target.md` §4.12 (MS/1 mapping surface target)
+
+---
+
+## 0. Conventions
+
+The key words **MUST**, **MUST NOT**, **REQUIRED**, **SHOULD**, and **MAY** are
+to be interpreted as in RFC 2119.
+
+MS/1 defines the **deterministic mapping** from `(Concept, ContextFrame)` to
+outputs. It does not define transport or API endpoints.
+
+---
+
+## 1. Core Concepts
+
+### 1.1 Concept
+
+Concepts are graph nodes (TGK) with stable references.
+
+### 1.2 Context Frame
+
+A **Context Frame** is a canonical, content-addressed artifact encoding the
+bindings needed to execute a concept mapping.
+
+Logical model:
+
+```
+ContextFrame = {
+  bindings: Map<ConceptRef, Value>
+  predicates: Map<PredicateRef, Value>   // optional
+}
+```
+
+`Value` is one of:
+
+* `DataRef` — an `ASL/1-CORE` reference to data bytes
+* `Scalar` — a canonical scalar (`bool`, `int`, `float`, `string`, `null`)
+
+### 1.3 Mapping Result
+
+`ms_map` returns exactly one of:
+
+* `produced` — a canonical output artifact
+* `gap` — missing required bindings
+* `ambiguity` — multiple admissible bindings
+
+---
+
+## 2. Context Frame Canonical Encoding (Normative)
+
+Context Frames MUST be encoded deterministically as a canonical BCF/1 map:
+
+```
+{
+  "bindings": { <RefBytesHex> : <Value> ... },
+  "predicates": { <RefBytesHex> : <Value> ... }   // optional
+}
+```
+
+Rules:
+
+1. Keys are `ReferenceBytes` hex (lowercase, no `0x`), sorted
+   byte-lexicographically by raw `ReferenceBytes`.
+2. `Value` encoding is canonical BCF/1:
+   * `DataRef` is encoded as `{"ref": <RefBytesHex>}`.
+   * `Scalar` is encoded as the canonical scalar value.
+3. No duplicate keys.
+4. Missing `predicates` is equivalent to an empty map.
+
+The resulting bytes are content-addressed; the `ContextFrame` CID is the
+identity of the canonical bytes.
+
+Context Frame artifacts MUST use `type_tag=amduat.context_frame`.
+
+---
+
+## 3. Mapping Entrypoint (Normative)
+
+```
+ms_map(concept_ref, context_frame, attachments?, concept_inputs?) -> Result
+```
+
+### 3.1 Effective Frame
+
+The **effective** Context Frame is the canonical merge of:
+
+1. `context_frame` bindings
+2. `attachments` (data refs)
+3. `concept_inputs` (concept refs)
+
+Rules:
+
+* `attachments` are added as bindings under their declared concept keys.
+* `concept_inputs` are added as bindings where the value is a concept ref.
+* Conflicts (same key, different value) MUST yield `ambiguity`.
+
+### 3.2 Required Keys
+
+A concept MAY declare required bindings via TGK edges:
+
+* `ms.requires_key` — `concept_ref -> key_concept_ref`
+* `ms.requires_predicate` — `concept_ref -> predicate_concept_ref`
+
+Rules:
+
+* Missing required `ms.requires_key` bindings MUST yield `gap`.
+* Missing required `ms.requires_predicate` bindings MUST yield `gap`.
+
+### 3.3 Result Determination
+
+Given a concept and effective frame:
+
+1. If any required binding is missing ⇒ return `gap`.
+2. If any required binding is present with multiple admissible values ⇒ return
+   `ambiguity`.
+3. Otherwise, execute deterministically and return `produced`.
+
+All outcomes MUST be deterministic for identical inputs.
+
+---
+
+## 4. Gap & Ambiguity Artifacts (Normative)
+
+Gap and Ambiguity are **first-class artifacts** stored for audit.
+
+Canonical payloads (BCF/1 map, deterministic ordering):
+
+### 4.1 Gap
+
+```
+{
+  "concept_ref": <RefBytesHex>,
+  "context_ref": <RefBytesHex>,
+  "missing_keys": [<RefBytesHex>...],
+  "missing_predicates": [<RefBytesHex>...]
+}
+```
+
+### 4.2 Ambiguity
+
+```
+{
+  "concept_ref": <RefBytesHex>,
+  "context_ref": <RefBytesHex>,
+  "ambiguous_keys": [
+    { "key": <RefBytesHex>, "candidates": [<RefBytesHex>...] }
+  ]
+}
+```
+
+* Lists are sorted by key, then candidate bytes.
+* Missing arrays are encoded as empty arrays.
+
+Type tags:
+
+* Gap: `amduat.ms.gap`
+* Ambiguity: `amduat.ms.ambiguity`
+
+---
+
+## 5. Deterministic Error Codes (ADR-006)
+
+Errors MUST be mapped to deterministic codes:
+
+* `ERR_MS_INVALID_FRAME` — non-canonical or malformed Context Frame.
+* `ERR_MS_KEY_MISSING` — required key absent (Gap).
+* `ERR_MS_PREDICATE_MISSING` — required predicate absent (Gap).
+* `ERR_MS_AMBIGUOUS` — multiple admissible bindings (Ambiguity).
+* `ERR_MS_UNSUPPORTED` — unsupported scalar or value kind.
+
+These errors MUST NOT depend on runtime ordering or external state.
+
+---
+
+## 6. Non-Goals
+
+MS/1 does not define:
+
+* Transport or HTTP APIs
+* Execution engines or optimizers
+* Concept graph schemas beyond required key/predicate edges
diff --git a/tier1/pcb1.md b/tier1/pcb1.md
new file mode 100644
index 0000000..4cc43b4
--- /dev/null
+++ b/tier1/pcb1.md
@@ -0,0 +1,82 @@
+# PCB1 — Parameter Block Encoding (FCS/1)
+
+Status: Approved
+Owner: Architecture
+Version: 1.0.0
+SoT: Yes
+Last Updated: 2026-02-21
+Linked Phase Pack: PH07
+Tags: [execution, parameters, deterministic]
+
+**Document ID:** `PCB1`
+**Layer:** L2 — Parameter block encoding for FCS/1 descriptors
+
+**Depends on (normative):**
+
+* `DDS` — PCB1 envelope and TLV layout (DDS §7.3)
+* `ASL/1-CORE v0.4.x` — logical value model
+
+---
+
+## 0. Purpose & Scope
+
+`PCB1` defines a **deterministic, canonical** encoding for parameter blocks used
+by `FCS/1` descriptors. It standardizes slot manifests, slot data ordering, and
+arity validation.
+
+---
+
+## 1. Logical Model
+
+A PCB1 parameter block is a two-part payload:
+
+```
+PCB1 {
+  slot_manifest : list<Slot>
+  slot_data     : bytes
+}
+
+Slot {
+  index  : uint32
+  name   : string
+  type   : enum
+  digest : bytes[32]
+}
+```
+
+Slots MUST appear in ascending `index` order. The `slot_data` is a packed byte
+sequence that respects the manifest ordering.
+
+---
+
+## 2. Canonical Encoding
+
+The canonical byte encoding is defined by DDS §7.3:
+
+* COR/1 envelope with `MAGIC="PCB1"`, `VERSION=0x01`, `FLAGS=0x00`.
+* Strict TLV order; no padding.
+* Required TLVs:
+  * `slot_manifest (0x50)` — BCF/1 list of slot descriptors.
+  * `slot_data (0x51)` — packed bytes aligned with the manifest.
+
+---
+
+## 3. Validation Rules
+
+Implementations MUST reject PCB1 payloads that violate any of the following:
+
+1. TLVs are not in strict ascending order, or appear more than once.
+2. `slot_manifest` entries are not sorted by `index`.
+3. Slot digest mismatches (`ERR_PCB_DIGEST_MISMATCH`).
+4. Non-deterministic or duplicated manifest ordering (`ERR_PCB_MANIFEST_ORDER`).
+5. Arity mismatch between PCB1 slot count and the enclosing FCS/1 descriptor
+   (`ERR_PCB_ARITY_MISMATCH`).
+
+---
+
+## 4. Conformance
+
+An implementation is **PCB1–conformant** if it:
+
+* Emits the exact canonical encoding in DDS §7.3.
+* Enforces the validation rules in §3.
diff --git a/tier1/pel-1-surf.md b/tier1/pel-1-surf.md
index 1165f57..9fe5384 100644
--- a/tier1/pel-1-surf.md
+++ b/tier1/pel-1-surf.md
@@ -186,6 +186,27 @@ as defined in `ASL/1-STORE`. The store MAY expose more operations, but `PEL/1-SU
 
 All `program_ref`, `input_refs`, `params_ref`, and `result_ref` values are interpreted relative to the `StoreConfig` used by the StoreInstance.
 
+### 2.3 ExecutionContext (metadata surface)
+
+`PEL/1-SURF` execution is snapshot-bound. The **execution context metadata**
+surface is intentionally minimal to preserve determinism:
+
+```text
+ExecutionContext {
+  snapshot_id          : uint64             // opaque store-assigned snapshot ID
+  execution_config_ref : optional Reference // immutable config artifact
+}
+```
+
+Rules:
+
+* `snapshot_id` is the snapshot identity associated with the execution. If no
+  snapshot exists, callers MUST use `0`.
+* `execution_config_ref`, when present, MUST refer to an immutable Artifact that
+  is **snapshot-scoped** (its meaning is fixed for the snapshot) and **deterministic**.
+* The context is **metadata only** and MUST NOT change the semantics of `Exec_s`
+  beyond selecting deterministic, snapshot-scoped configuration.
+
 ---
 
 ## 3. Surface Execution Model
@@ -209,7 +230,22 @@ run(
 
 All references are interpreted relative to `store`’s `StoreConfig`.
 
-### 3.2 Relationship to PEL/1-CORE
+### 3.2 Determinism and context constraints
+
+To preserve determinism across replay and federation:
+
+* PEL execution MUST depend only on:
+  * the resolved Artifacts for `program_ref`, `input_refs`, and `params_ref`,
+  * the `ExecutionContext.snapshot_id`, and
+  * the Artifact referenced by `execution_config_ref` (if provided).
+* PEL execution MUST NOT read storage or layout metadata, including but not
+  limited to: block IDs, segment IDs, physical offsets, storage stats, GC state,
+  or backend-specific layout details.
+* Implementations MUST NOT call store APIs beyond `get` and `put` to derive
+  execution semantics. Index scans, log reads, or layout introspection are
+  forbidden for `PEL/1-SURF` determinism.
+
+### 3.3 Relationship to PEL/1-CORE
 
 For a supported scheme identified by `scheme_ref`, there exists a pure function `Exec_s` per `PEL/1-CORE`:
 
diff --git a/tier1/pel-output-policy-1.md b/tier1/pel-output-policy-1.md
new file mode 100644
index 0000000..c69bab5
--- /dev/null
+++ b/tier1/pel-output-policy-1.md
@@ -0,0 +1,99 @@
+# PEL/OUTPUT-POLICY/1 — Materialization & Promotion Policy
+
+Status: Draft
+Owner: Architecture
+Version: 0.1.0
+SoT: No
+Last Updated: 2026-02-21
+Tags: [pel, outputs, promotion, retention]
+
+**Document ID:** `PEL/OUTPUT-POLICY/1`
+**Layer:** L2 — Output handling policy (no execution semantics)
+
+**Depends on (normative):**
+
+* `PEL/1-CORE` — execution semantics
+* `ASL/LOG/1` — visibility and log ordering
+* `ASL/1-CORE-INDEX` — visibility and tombstone semantics
+
+**Informative references:**
+
+* `ASL/SYSTEM/1` — promotion/publication/retention separation
+
+---
+
+## 0. Conventions
+
+The key words **MUST**, **MUST NOT**, **REQUIRED**, **SHOULD**, and **MAY** are
+to be interpreted as in RFC 2119.
+
+This document defines **policy** for handling PEL outputs. It does not change
+PEL execution semantics.
+
+---
+
+## 1. Policy Dimensions
+
+Each output produced by PEL is subject to three independent policy decisions:
+
+### 1.1 Materialization
+
+Controls whether output bytes are stored, cached, or virtualized.
+
+* `store` — persist in the content index (authoritative).
+* `cache` — persist in materialization cache only (performance hint).
+* `virtualize` — compute in-memory only; do not persist.
+
+### 1.2 Promotion
+
+Controls whether an output is promoted from a derived view to **truth**.
+
+* `promote` — output becomes eligible for truth/published workflows.
+* `no_promote` — output remains derived and must not be treated as truth.
+
+Promotion is **explicit**; it MUST NOT be inferred from execution.
+
+### 1.3 Publication
+
+Controls visibility (internal vs published) encoded in index metadata.
+
+* `internal` — visible only to the local domain.
+* `published` — visible to federation/replay.
+
+Publication is distinct from promotion; a promoted output may still be internal.
+
+---
+
+## 2. Policy Hooks (Normative)
+
+Core implementations MUST expose a policy hook that can be invoked **per
+output** to decide the three dimensions above.
+
+The hook MUST be deterministic and MUST depend only on:
+
+* the execution inputs (program, params, inputs, snapshot state)
+* explicit policy configuration supplied by the caller
+
+The hook MUST NOT read storage layout or non-snapshot metadata.
+
+---
+
+## 3. Default Policy
+
+If no hook is supplied, the default policy is:
+
+* `materialization = store`
+* `promotion = no_promote`
+* `publication = internal`
+
+---
+
+## 4. API Layer Mapping (Informative)
+
+API layers should expose explicit controls for:
+
+* promotion (`publish` / `promote` flags)
+* visibility (`internal` vs `published`)
+* materialization (`store` vs `cache` vs `virtualize`)
+
+The API MUST NOT implicitly promote outputs without an explicit policy choice.
diff --git a/tier1/pel-program-dag-1.md b/tier1/pel-program-dag-1.md
index 8321564..17cdb45 100644
--- a/tier1/pel-program-dag-1.md
+++ b/tier1/pel-program-dag-1.md
@@ -364,6 +364,23 @@ At the ASL/1 layer:
 
 This scheme assumes such an encoding exists and is canonical; it does not define the layout itself.
 
+### 2.8 ProgramDescriptor (explicit executable artifacts)
+
+To prevent **implicit execution** of non-program artifacts (including receipts),
+this scheme defines **ProgramDescriptor** semantics:
+
+* Only **explicitly tagged Program Artifacts** are executable.
+* An artifact is executable **only if** its `type_tag` equals
+  `TYPE_TAG_PEL_PROGRAM_DAG_1` and its `bytes` decode as a `Program` under
+  `ENC/PEL-PROGRAM-DAG/1`.
+* Artifacts with any other `type_tag` (including receipt or evidence tags such
+  as `TYPE_TAG_FER1_RECEIPT_1`) **MUST NOT** be interpreted as programs, even if
+  their bytes happen to be decodable as a `Program`.
+* Artifacts with **no** `type_tag` are **not** executable.
+
+These rules ensure that only explicitly designated program artifacts can be
+executed, eliminating accidental execution of receipt payloads or other data.
+
 ---
 
 ## 3. Structural Validity
diff --git a/tier1/srs.md b/tier1/srs.md
index 561336c..9a8fd44 100644
--- a/tier1/srs.md
+++ b/tier1/srs.md
@@ -326,6 +326,28 @@ coverage `TV-MPR-001…003` (hash triple, missing weights, signature domain) and
 `TV-IER-001…004` (ok, missing seed, fingerprint mismatch, log digest mismatch)
 respectively with scenario summaries in accompanying `summary.md` files.
 
+### FR-031A FLS/1 Ordering & Error Semantics
+
+FLS/1 envelopes and payloads MUST follow deterministic ordering and reject
+malformed linkage metadata. Implementations SHALL:
+
+* Enforce strict TLV ordering and reject duplicates per DDS §7.8.1.
+* Enforce channel catalog ordering (`channel_id` ascending) and uniqueness.
+* Enforce message sequence bounds against the channel catalog.
+* Enforce termination ledger ordering and bounds.
+
+Violations MUST map to ADR-006 error codes (non-exhaustive):
+
+* `ERR_FLS_TAG_ORDER`, `ERR_FLS_DUPLICATE_TAG`, `ERR_FLS_UNKNOWN_TAG`
+* `ERR_FLS_CID_LENGTH`, `ERR_FLS_TIMESTAMP_LENGTH`
+* `ERR_FLS_SESSION_ID_LENGTH`, `ERR_FLS_CHANNEL_ORDER`, `ERR_FLS_CHANNEL_DUPLICATE`
+* `ERR_FLS_CHANNEL_RANGE`, `ERR_FLS_SEQ_RANGE`
+* `ERR_FLS_SIGNATURE_DOMAIN`, `ERR_FLS_SIGNATURE_LENGTH`, `ERR_FLS_SIGNATURE`
+* `ERR_FLS_PAYLOAD_CID_MISMATCH`, `ERR_FLS_PAYLOAD_KIND`
+
+Deterministic ordering and error mapping are required for replay stability and
+federated transport interoperability.
+
 ### FR-032 CT/1 Deterministic Replay (D1)
 
 Given identical AC/1 + DTF/1 + topology inputs, executing the runtime twice in
@@ -475,6 +497,15 @@ Errors MUST be emitted as stable symbolic codes including but not limited to:
 * Requirements link to tests/defects in Phase Packs
 * ADRs reference affected FR/NFR IDs
 
+### 10.1 Traceability Register (PH04)
+
+Traceability register entries anchor evidence and lineage tracking for Phase 04
+surfaces.
+
+| Entry ID | Surface | Phase | Evidence Path | Notes |
+| --- | --- | --- | --- | --- |
+| PH04-TR-FLS-001 | FLS/1 | PH04 | `/amduat/logs/ph04/evidence/fls1/PH04-EV-FLS-001/` | FLS/1 linkage envelopes + session/message ordering + error mapping coverage. |
+
 ---
 
 ## 11. Future Phases
diff --git a/tier1/tgk-store-1.md b/tier1/tgk-store-1.md
index 559d464..68177c8 100644
--- a/tier1/tgk-store-1.md
+++ b/tier1/tgk-store-1.md
@@ -28,10 +28,15 @@ Tags: [traceability, execution]
 * `PEL/1-SURF v0.2.x` — store-backed execution surface (producer of many EdgeArtifacts)
 * `CIL/1`, `FER/1`, `FCT/1`, `OI/1` — provenance and fact profiles that consume graph queries
 * (future) `TGK/PROV/1` — provenance / trace operators over `ProvenanceGraph`
+* `ADR-031` — ASL + TGK index separation boundary
 
 > **Normativity note**  
 > `TGK/STORE/1` is a near-core **graph store profile**, not a kernel surface. It introduces no new identity scheme. It defines how to expose and query the `ProvenanceGraph` from `TGK/1-CORE` over Artifacts reachable via `ASL/1-STORE` or equivalent feeds, and constrains graph indexes and query semantics.
 
+> **Index separation note**  
+> `TGK/STORE/1` assumes **separate** ASL and TGK indexes with explicit
+> cross-layer invariants (ADR-031). A merged index is intentionally rejected.
+
 © 2025 Niklas Rydberg.
 
 ## License
@@ -115,6 +120,23 @@ In this document:
 * **ArtifactRef**, **Node**, and **EdgeRef** are all ASL/1 `Reference` values.
 * **ExecutionEnvironment** is as in `TGK/1-CORE`: an abstract context with a finite Artifact set and a fixed TGK profile set “in effect” at a snapshot.
 
+---
+
+## 0.1 ASL + TGK Index Boundary (Normative)
+
+TGK indexes are **derived** from ASL visibility and MUST respect the following
+invariants (see ADR-031):
+
+1. TGK indexes MUST only include artifacts visible under ASL replay at the
+   same `(snapshot_id, log_position)`.
+2. TGK indexes MUST enforce ASL tombstones and tombstone lifts by `logseq`.
+3. TGK indexes MUST NOT introduce new identity schemes; all nodes/edges are
+   ASL `Reference` values.
+4. TGK index updates MUST be deterministically derived from ASL-admitted
+   segments and log records. No side-channel writes.
+5. Replaying ASL log + sealed segments MUST yield the same TGK index state
+   (up to encoding) as an online build.
+
 Additional terms introduced here:
 
 ```text