docs(runtime): clarify queue adapter staging

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Documentation
+
+- **PR #TBD** by @Michaelyklam (refs #1925) — Clarify the RuntimeAdapter Slice 3c state after #2544 shipped. The RFC now distinguishes shipped `/api/goal` routing through `RuntimeAdapter.update_goal(...)` from the still-staged `queue_message(...)` protocol method, and explicitly warns not to add a new server-side queue endpoint or queue scheduler merely for adapter symmetry while `/queue` remains browser-side queue/drain behavior.
+
 ## [v0.51.91] — 2026-05-18 — Release BO (stage-384 — 5-PR full sweep batch — reasoning-replay history fix + archive-extract per-session inbox + fallback streaming warnings + sanitized custom-provider env hints + Slice 3c queue/goal adapter routing)
 
 ### Fixed

docs/rfcs/hermes-run-adapter-contract.md

@@ -52,7 +52,7 @@ The immediate goal is not to build a sidecar. The immediate goal is to define th
 browser contract, classify current runtime state, and gate the first reversible
 journal slice.
 
-## Current Gate State — 2026-05-17
+## Current Gate State — 2026-05-18
 
 Slice 1 is now past the first active validation gate:
 
@@ -85,11 +85,19 @@ adapter-seam work:
 - #2487 shipped the Slice 3b approval/clarify gate, and #2496 shipped approval /
   clarify response routing through the adapter seam in v0.51.89.
 - #2509 shipped the Slice 3c queue/continue + goal gate in v0.51.90.
-
-The next gate is not the runner/sidecar yet. It is the Slice 3c implementation:
-add the queue/goal adapter methods and route accepted legacy control paths
-through them without moving goal evaluation, continuation scheduling, or
-execution ownership out of the existing agent loop.
+- #2544 shipped the first Slice 3c implementation in v0.51.91. The goal
+  route now uses `RuntimeAdapter.update_goal(...)` only when
+  `HERMES_WEBUI_RUNTIME_ADAPTER=legacy-journal` is enabled, while preserving the
+  legacy-direct response shape and leaving post-turn goal evaluation in the
+  existing agent loop.
+
+The next gate is still not the runner/sidecar by default. Slice 3c's goal route
+is shipped, and `queue_message(...)` remains a staged protocol method. Queue /
+continue routing needs an explicit follow-up contract because the legacy `/queue`
+path is browser-side queue/drain behavior today; no new server-side queue endpoint
+or queue scheduler should be added just for adapter symmetry. If maintainers want
+queue/continue to move before Slice 4, that follow-up should specify the exact
+legacy entry point, response shape, and ordering/idempotency contract first.
 
 ## Goals
 
@@ -354,12 +362,12 @@ class RuntimeAdapter:
     ) -> ControlResult: ...
 ```
 
-`queue_message` is named for the legacy `/api/session/queue` payload: it
-accepts follow-up chat text rather than arbitrary runtime input. The method name
-does not require the HTTP route to change; it documents the adapter-level control
-semantics that a later Slice 3c implementation should preserve. The method enters
-the protocol before route wiring so queue/continue can land as a separate, small
-control-routing follow-up instead of being coupled to goal routing.
+`queue_message` is named for the legacy queued-message payload shape: it accepts
+follow-up chat text rather than arbitrary runtime input. The method name does not
+require a new HTTP route. Today `/queue` is primarily browser-side queue/drain
+behavior; the adapter method enters the protocol so a later queue/continue slice
+has a typed control surface, but route wiring remains deliberately staged until
+the exact legacy entry point and ordering/idempotency contract are explicit.
 
 For `update_goal`, the `action` argument is the bounded adapter capability label.
 During the legacy-journal slice, the legacy goal parser still receives the full

tests/test_runtime_adapter_seam.py

@@ -302,3 +302,14 @@ def test_chat_start_adapter_path_preserves_legacy_response_shape():
     assert 'response.setdefault("run_id", result.run_id)' not in adapter_branch
     assert 'response.setdefault("status", result.status)' not in adapter_branch
     assert 'response.setdefault("active_controls", result.active_controls)' not in adapter_branch
+
+
+def test_rfc_distinguishes_goal_routing_from_queue_route_staging():
+    routes = importlib.import_module("api.routes")
+    rfc = (routes.Path(__file__).parent.parent / "docs" / "rfcs" / "hermes-run-adapter-contract.md").read_text(encoding="utf-8")
+
+    assert "#2544 shipped the first Slice 3c implementation" in rfc
+    assert "route now uses `RuntimeAdapter.update_goal(...)`" in rfc
+    assert "`queue_message(...)` remains a staged protocol method" in rfc
+    assert "no new server-side queue endpoint" in rfc
+    assert "or queue scheduler should be added just for adapter symmetry" in rfc