diff --git a/README.md b/README.md
index 6f44a65..67af2e1 100644
--- a/README.md
+++ b/README.md
@@ -78,6 +78,7 @@ status and refs are printed to stderr.
 - Implementation clarifications: `docs/spec-clarifications.md`
 - Spec coverage matrix: `AUDITS.md` (Spec Coverage section)
 - Index/log API sketch: `docs/index-log-api-sketch.md`
+- Federation core API: `include/amduat/fed/` (registry, ingest, replay, view)
 
 ## PEL reference
 
diff --git a/include/amduat/fed/replay.h b/include/amduat/fed/replay.h
index 315feb1..2f59853 100644
--- a/include/amduat/fed/replay.h
+++ b/include/amduat/fed/replay.h
@@ -55,6 +55,7 @@ bool amduat_fed_replay_build(const amduat_fed_record_t *records,
                              amduat_fed_replay_view_t *out_view);
 
 /* Backwards-compatible alias for amduat_fed_replay_build. */
+/* Deprecated: use amduat_fed_replay_build. */
 bool amduat_fed_replay_domain(const amduat_fed_record_t *records,
                               size_t count,
                               uint32_t domain_id,