diff --git a/app/routers/cues.py b/app/routers/cues.py
index 1f85dd2..b3c7d8e 100644
--- a/app/routers/cues.py
+++ b/app/routers/cues.py
@@ -167,7 +167,10 @@ async def fire_cue(
         "status": "pending", "triggered_by": "manual_fire",
     }
     # BodyVerify Layer 1: opt-in echo-back when caller sets
-    # X-CueAPI-Verify-Echo: true. Helper returns {} when header absent
-    # so non-opted clients see zero shape change.
-    response_content.update(apply_verify_echo(request=request, parsed_body=body))
+    # X-CueAPI-Verify-Echo: true. OSS FireRequest carries only send_at
+    # (datetime) — no string user-content field to echo. Helper returns
+    # body_received=None + sha256 of empty bytes when header set, or {} when
+    # absent. Once OSS adds a content-bearing field (e.g. payload_override
+    # for parity), update this to extract the string per spec.
+    response_content.update(apply_verify_echo(request=request, body_text=None))
     return response_content
diff --git a/app/routers/messages.py b/app/routers/messages.py
index ce520e7..6c6e3af 100644
--- a/app/routers/messages.py
+++ b/app/routers/messages.py
@@ -108,7 +108,7 @@ async def send_message(
     # BodyVerify Layer 1: opt-in echo-back when caller sets
     # X-CueAPI-Verify-Echo: true. Helper returns {} when header absent
     # so non-opted clients see zero shape change.
-    response_content.update(apply_verify_echo(request=request, parsed_body=body))
+    response_content.update(apply_verify_echo(request=request, body_text=body.body))
     return JSONResponse(
         status_code=status_code,
         content=response_content,
diff --git a/app/utils/verify_echo.py b/app/utils/verify_echo.py
index 5e22031..341d87c 100644
--- a/app/utils/verify_echo.py
+++ b/app/utils/verify_echo.py
@@ -2,9 +2,9 @@
 
 When request header ``X-CueAPI-Verify-Echo: true`` is present on a supported
 endpoint, the server adds ``body_received`` and ``body_received_sha256``
-fields to the 200 response. The caller diffs sent body vs received to detect
-caller-side shell expansion (backticks, $-paren, ${VAR}) that silently
-corrupts body content before send-time.
+fields to the 200/201 response. The caller diffs sent body vs received to
+detect caller-side shell expansion (backticks, $-paren, ${VAR}) that
+silently corrupts body content before send-time.
 
 Why this exists: 2026-05-11 ~22:00Z, CMA's outbound Cue Messages 0/6 to
 cue-pm fell to garbage via inline bash ``-d "$BODY"`` where $BODY had been
@@ -13,12 +13,20 @@
 keystone for the 4-layer defense: substrate (this), SDK auto-verify, CLI
 force-file mode, docs leading with file-payload pattern.
 
+Spec shape (locked at design review, Phase 1 hotfix corrected post-merge):
+
+* ``body_received`` is the **STRING** value of the body field the caller
+  sent (e.g. ``MessageCreate.body`` on /v1/messages, ``payload_override.message``
+  or similar on /v1/cues/<id>/fire). NOT the full parsed Pydantic envelope dump.
+* ``body_received_sha256`` is the SHA256 hex digest of those exact UTF-8 bytes
+  so a caller can compute ``sha256(sent_body_bytes).hexdigest()`` locally and
+  compare directly. Hash-of-the-string == hash-of-the-bytes.
+
 Design doc: https://trydock.ai/workspaces/cue-message-silent-corruption-substrate-design-2026-05-11
 """
 from __future__ import annotations
 
 import hashlib
-import json
 from typing import Any, Dict, Optional
 
 from fastapi import Request
@@ -32,51 +40,48 @@ def verify_echo_requested(request: Request) -> bool:
     return request.headers.get(VERIFY_ECHO_HEADER, "").strip().lower() == "true"
 
 
-def _canonical_json_bytes(value: Any) -> bytes:
-    """Stable JSON serialization for hashing: sorted keys + no whitespace."""
-    return json.dumps(value, sort_keys=True, separators=(",", ":"), ensure_ascii=False).encode(
-        "utf-8"
-    )
-
-
-def apply_verify_echo(*, request: Request, parsed_body: Optional[Any]) -> Dict[str, Any]:
+def apply_verify_echo(*, request: Request, body_text: Optional[str]) -> Dict[str, Any]:
     """Return verify-echo fields to merge into the response.
 
     Returns ``{}`` when the header is absent (zero-cost no-op for non-opted
     clients). When present, returns::
 
         {
-            "body_received": <parsed body dict / str / None>,
+            "body_received": <body_text — str or None>,
             "body_received_sha256": <64-char hex digest>,
         }
 
     Hashing rule:
 
-    * ``None`` body → SHA256 of empty bytes (well-known constant).
-    * Pydantic model → ``model_dump(mode="json")`` then canonical JSON.
-    * dict → canonical JSON.
-    * Otherwise → ``str()`` then UTF-8 bytes.
-
-    The dict is intended to be ``.update()``-merged into the response dict
-    or returned alongside other fields. Caller is responsible for placement.
+    * ``None`` body → SHA256 of empty bytes (well-known constant); ``body_received``
+      is ``None``.
+    * Otherwise → caller passes the EXACT string they want echoed (typically the
+      ``body`` field of a message or the user-content field of a fire payload);
+      ``body_received`` is that string verbatim and the hash is over its UTF-8
+      bytes.
+
+    Caller-side verification recipe (mirrors what cueapi-python's auto-verify
+    does)::
+
+        import hashlib
+        sent = "..."  # the exact string you POSTed in the body field
+        resp = client.post(..., json={"body": sent},
+                           headers={"X-CueAPI-Verify-Echo": "true"})
+        assert resp.json()["body_received"] == sent
+        assert resp.json()["body_received_sha256"] == hashlib.sha256(
+            sent.encode("utf-8")
+        ).hexdigest()
     """
     if not verify_echo_requested(request):
         return {}
 
-    if parsed_body is None:
-        body_view: Any = None
-        sha_input: bytes = b""
-    elif hasattr(parsed_body, "model_dump"):
-        body_view = parsed_body.model_dump(mode="json")
-        sha_input = _canonical_json_bytes(body_view)
-    elif isinstance(parsed_body, dict):
-        body_view = parsed_body
-        sha_input = _canonical_json_bytes(body_view)
-    else:
-        body_view = str(parsed_body)
-        sha_input = body_view.encode("utf-8")
+    if body_text is None:
+        return {
+            "body_received": None,
+            "body_received_sha256": hashlib.sha256(b"").hexdigest(),
+        }
 
     return {
-        "body_received": body_view,
-        "body_received_sha256": hashlib.sha256(sha_input).hexdigest(),
+        "body_received": body_text,
+        "body_received_sha256": hashlib.sha256(body_text.encode("utf-8")).hexdigest(),
     }
diff --git a/parity-manifest.json b/parity-manifest.json
index a23dd13..c9020b0 100644
--- a/parity-manifest.json
+++ b/parity-manifest.json
@@ -1,9 +1,9 @@
 {
   "manifest_version": 1,
   "description": "Files in cueapi-core that have a same-path counterpart in the private cueapi monorepo. Changes to the private counterpart should be considered for porting here; changes here should be cross-referenced to the private repo. The parity-check GitHub Action posts a soft warning on PRs that touch any of these paths. See HOSTED_ONLY.md for the open-core policy.",
-  "direction_of_truth_note": "Parity is BIDIRECTIONAL — most parity-tracked files flow private → OSS (private leads on hosted product features), but a growing set flow OSS → private (auth primitives, messaging primitives, identity-mapping helpers, and cross-codebase substrate ports where OSS is the canonical home per CWS-2026-05-08 lock). When a parity-tracked file changes, identify direction in the PR description; both directions are equally valid. Examples — OSS-leads / private-lags: `app/auth.py` (X-On-Behalf-Of), counterpart filter on inbox/sent, `app/utils/routing.py` helper, `external_owner` column. Private-leads / OSS-lags: most product features (billing, GDPR, dashboard, Stripe-paid surfaces) — but those don't appear in parity-manifest by virtue of being hosted-only (see oss_only_exclusions + HOSTED_ONLY.md). Special bidirectional case: `agent_live_sessions` schema port — private leads on the table itself (richer schema with cmotigtnx attestation), OSS leads on the documentation surface (`docs/multi-session.md`).",
+  "direction_of_truth_note": "Parity is BIDIRECTIONAL \u2014 most parity-tracked files flow private \u2192 OSS (private leads on hosted product features), but a growing set flow OSS \u2192 private (auth primitives, messaging primitives, identity-mapping helpers, and cross-codebase substrate ports where OSS is the canonical home per CWS-2026-05-08 lock). When a parity-tracked file changes, identify direction in the PR description; both directions are equally valid. Examples \u2014 OSS-leads / private-lags: `app/auth.py` (X-On-Behalf-Of), counterpart filter on inbox/sent, `app/utils/routing.py` helper, `external_owner` column. Private-leads / OSS-lags: most product features (billing, GDPR, dashboard, Stripe-paid surfaces) \u2014 but those don't appear in parity-manifest by virtue of being hosted-only (see oss_only_exclusions + HOSTED_ONLY.md). Special bidirectional case: `agent_live_sessions` schema port \u2014 private leads on the table itself (richer schema with cmotigtnx attestation), OSS leads on the documentation surface (`docs/multi-session.md`).",
   "last_full_audit": "2026-05-11",
-  "methodology": "Enumerate app/**/*.py and alembic/**/*.py in cueapi-core; include every file whose same-path counterpart exists in the private cueapi clone at audit time. Files that are OSS-only (no private counterpart) are intentionally excluded — modifications to them do not need a parity cross-reference.",
+  "methodology": "Enumerate app/**/*.py and alembic/**/*.py in cueapi-core; include every file whose same-path counterpart exists in the private cueapi clone at audit time. Files that are OSS-only (no private counterpart) are intentionally excluded \u2014 modifications to them do not need a parity cross-reference.",
   "oss_only_exclusions": [
     {
       "path": "app/services/email_service.py",
@@ -11,7 +11,7 @@
     },
     {
       "path": "alembic/versions/017_add_verification_mode.py",
-      "reason": "OSS-specific filename. Hosted ships equivalent verification_mode functionality at a different migration number (hosted's 017 is 017_add_support_ticket_updated_at.py). Feature parity is at the app-layer (cue.py, schemas, services) — those files ARE in the manifest."
+      "reason": "OSS-specific filename. Hosted ships equivalent verification_mode functionality at a different migration number (hosted's 017 is 017_add_support_ticket_updated_at.py). Feature parity is at the app-layer (cue.py, schemas, services) \u2014 those files ARE in the manifest."
     },
     {
       "path": "alembic/versions/018_add_alerts_table.py",
@@ -27,154 +27,619 @@
     },
     {
       "path": "alembic/versions/020_messaging_identity.py",
-      "reason": "OSS-specific filename. Hosted ships the same migration as 043_messaging_identity.py — independent migration histories. Feature parity is at the app-layer (agent.py, schemas, services) — those files ARE in the manifest."
+      "reason": "OSS-specific filename. Hosted ships the same migration as 043_messaging_identity.py \u2014 independent migration histories. Feature parity is at the app-layer (agent.py, schemas, services) \u2014 those files ARE in the manifest."
     },
     {
       "path": "alembic/versions/021_messaging_messages.py",
-      "reason": "OSS-specific filename. Hosted ships the same migration as 044_messaging_messages.py — independent histories. Hosted's version also creates ``messages.from_api_key_id`` (FK to api_keys); cueapi-core omits that column because multi-key scoping is hosted-only. App-layer parity at message.py."
+      "reason": "OSS-specific filename. Hosted ships the same migration as 044_messaging_messages.py \u2014 independent histories. Hosted's version also creates ``messages.from_api_key_id`` (FK to api_keys); cueapi-core omits that column because multi-key scoping is hosted-only. App-layer parity at message.py."
     },
     {
       "path": "alembic/versions/022_messaging_push_retry_columns.py",
-      "reason": "OSS-specific filename. Hosted ships the same migration as 045_messaging_push_retry_columns.py — independent histories. Identical column shape."
+      "reason": "OSS-specific filename. Hosted ships the same migration as 045_messaging_push_retry_columns.py \u2014 independent histories. Identical column shape."
     },
     {
       "path": "worker/message_cleanup.py",
-      "reason": "OSS-specific module. Hosted ships these three cleanup functions (expire_old_messages / cleanup_expired_messages / free_old_idempotency_keys) inside worker/gdpr_cleanup.py alongside hosted-only GDPR-cascade tasks and a dry-run-by-default safety harness gated on GDPR_LAST_BACKUP_AT env var. cueapi-core extracts the messaging-specific cleanups to a dedicated module without the GDPR safety harness — self-hosters opt in to real action via an explicit dry_run=False kwarg."
+      "reason": "OSS-specific module. Hosted ships these three cleanup functions (expire_old_messages / cleanup_expired_messages / free_old_idempotency_keys) inside worker/gdpr_cleanup.py alongside hosted-only GDPR-cascade tasks and a dry-run-by-default safety harness gated on GDPR_LAST_BACKUP_AT env var. cueapi-core extracts the messaging-specific cleanups to a dedicated module without the GDPR safety harness \u2014 self-hosters opt in to real action via an explicit dry_run=False kwarg."
     },
     {
       "path": "alembic/versions/023_messaging_primitive_multi_shell.py",
-      "reason": "OSS-only — slated for hard-cut deprecation in the agent_live_sessions schema convergence (CWS-2026-05-08 P0). Private cueapi never had agent_shells; it has the richer agent_live_sessions table (carries cue_id + task_name + monitor_version + session_token, load-bearing for cmotigtnx Live attestation per CWS-2026-05-08 Item 6). Convergence plan ports private's schema into OSS as the canonical primitive, drops agent_shells. See https://trydock.ai/workspaces/cueapi-agent-live-sessions-port-2026-05-09."
+      "reason": "OSS-only \u2014 slated for hard-cut deprecation in the agent_live_sessions schema convergence (CWS-2026-05-08 P0). Private cueapi never had agent_shells; it has the richer agent_live_sessions table (carries cue_id + task_name + monitor_version + session_token, load-bearing for cmotigtnx Live attestation per CWS-2026-05-08 Item 6). Convergence plan ports private's schema into OSS as the canonical primitive, drops agent_shells. See https://trydock.ai/workspaces/cueapi-agent-live-sessions-port-2026-05-09."
     },
     {
       "path": "app/models/agent_shell.py",
-      "reason": "OSS-only — slated for hard-cut deprecation in the agent_live_sessions schema convergence. See alembic/versions/023_messaging_primitive_multi_shell.py exclusion for full context. Replacement: app/models/agent_live_session.py (will be added as a parity-tracked file when commits 2-5 land)."
+      "reason": "OSS-only \u2014 slated for hard-cut deprecation in the agent_live_sessions schema convergence. See alembic/versions/023_messaging_primitive_multi_shell.py exclusion for full context. Replacement: app/models/agent_live_session.py (will be added as a parity-tracked file when commits 2-5 land)."
     },
     {
       "path": "app/routers/agent_shells.py",
-      "reason": "OSS-only — slated for hard-cut deprecation in the agent_live_sessions schema convergence. See alembic/versions/023_messaging_primitive_multi_shell.py exclusion. Replacement: endpoints under /v1/agents/{ref}/live-sessions/* on a new app/routers/agent_live_sessions.py module (will be added as a parity-tracked file when commits 2-5 land)."
+      "reason": "OSS-only \u2014 slated for hard-cut deprecation in the agent_live_sessions schema convergence. See alembic/versions/023_messaging_primitive_multi_shell.py exclusion. Replacement: endpoints under /v1/agents/{ref}/live-sessions/* on a new app/routers/agent_live_sessions.py module (will be added as a parity-tracked file when commits 2-5 land)."
     }
   ],
-  "multi_key_scoping_omission": "The private monorepo has multi-key scoping (migration 039: api_keys table + per-resource api_key_id columns + audit log). cueapi-core does not. The messaging primitive port intentionally drops the api_key_id columns from agents and messages tables, the from_api_key_id field from MessageResponse, and the api_key_id field from AgentResponse. The messaging service layer never used api_key_id for business logic — it was an audit-only field. If multi-key scoping is ever ported to OSS, a follow-up migration can ADD COLUMN ... api_key_id at that time without breaking existing deployments.",
+  "multi_key_scoping_omission": "The private monorepo has multi-key scoping (migration 039: api_keys table + per-resource api_key_id columns + audit log). cueapi-core does not. The messaging primitive port intentionally drops the api_key_id columns from agents and messages tables, the from_api_key_id field from MessageResponse, and the api_key_id field from AgentResponse. The messaging service layer never used api_key_id for business logic \u2014 it was an audit-only field. If multi-key scoping is ever ported to OSS, a follow-up migration can ADD COLUMN ... api_key_id at that time without breaking existing deployments.",
   "files": {
     "alembic": [
-      {"path": "alembic/env.py", "private_counterpart": "alembic/env.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/001_initial_tables.py", "private_counterpart": "alembic/versions/001_initial_tables.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/002_executions_and_outbox.py", "private_counterpart": "alembic/versions/002_executions_and_outbox.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/003_usage_monthly.py", "private_counterpart": "alembic/versions/003_usage_monthly.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/004_device_codes.py", "private_counterpart": "alembic/versions/004_device_codes.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/005_add_retry_ready_status.py", "private_counterpart": "alembic/versions/005_add_retry_ready_status.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/006_add_outcome_columns.py", "private_counterpart": "alembic/versions/006_add_outcome_columns.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/007_worker_transport.py", "private_counterpart": "alembic/versions/007_worker_transport.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/008_add_webhook_secret.py", "private_counterpart": "alembic/versions/008_add_webhook_secret.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/009_fired_count_and_missed_status.py", "private_counterpart": "alembic/versions/009_fired_count_and_missed_status.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/010_unique_user_cue_name.py", "private_counterpart": "alembic/versions/010_unique_user_cue_name.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/011_add_blog_posts.py", "private_counterpart": "alembic/versions/011_add_blog_posts.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/012_add_content_trends.py", "private_counterpart": "alembic/versions/012_add_content_trends.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/013_add_blog_image_data.py", "private_counterpart": "alembic/versions/013_add_blog_image_data.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/014_add_support_tickets.py", "private_counterpart": "alembic/versions/014_add_support_tickets.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/015_widen_device_code_column.py", "private_counterpart": "alembic/versions/015_widen_device_code_column.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/016_add_on_failure_column.py", "private_counterpart": "alembic/versions/016_add_on_failure_column.py", "last_synced": "2026-04-16"},
-      {"path": "alembic/versions/028_event_emit_primitive.py", "private_counterpart": "alembic/versions/058_event_emit_primitive.py", "last_synced": "2026-05-11", "ported_in": "event-emit-primitive-port (PR-1b)", "deviation": "Renumbered 058 → 028 (cueapi-core HEAD was 27 revisions behind private). Schema verbatim."},
-      {"path": "alembic/versions/029_messaging_emission_columns.py", "private_counterpart": "alembic/versions/059_messaging_emission_columns.py", "last_synced": "2026-05-11", "ported_in": "messaging-emission-port (PR-2a)", "deviation": "Renumbered 059 → 029. Schema verbatim: dispatch_priority_bucket + message_dispatch_error + correlation_id columns + partial-where index on correlation_id."},
-      {"path": "alembic/versions/030_message_send_at.py", "private_counterpart": "alembic/versions/047_message_send_at.py", "last_synced": "2026-05-11", "ported_in": "message-send-at-port (private #623)", "deviation": "Renumbered 047 → 030. Schema verbatim: messages.send_at TIMESTAMPTZ NULL + partial index ix_messages_send_at (WHERE send_at IS NOT NULL) built CONCURRENTLY."},
-      {"path": "alembic/versions/031_agents_last_seen_at.py", "private_counterpart": "alembic/versions/048_agents_last_seen_at.py", "last_synced": "2026-05-11", "ported_in": "agents-roster-and-last-seen-at-port (private #630)", "deviation": "Renumbered 048 → 031. Schema verbatim: agents.last_seen_at TIMESTAMPTZ NULL (no index — read path is per-tenant + per-agent, already covered by existing indexes)."},
-      {"path": "alembic/versions/032_events_digested_at.py", "private_counterpart": "alembic/versions/060_events_digested_at.py", "last_synced": "2026-05-11", "ported_in": "phase-4b-digest-batching-port", "deviation": "Renumbered 060 → 032. Schema verbatim: events.digested_at TIMESTAMPTZ NULL + ix_events_undigested partial index (CONCURRENTLY)."},
-      {"path": "alembic/versions/033_subscriptions_inline_body.py", "private_counterpart": "alembic/versions/061_subscriptions_inline_body.py", "last_synced": "2026-05-11", "ported_in": "item-1-inline-body-port", "deviation": "Renumbered 061 → 033. Schema verbatim: subscriptions.inline_body BOOL NOT NULL DEFAULT FALSE."},
-      {"path": "alembic/versions/034_subscriptions_last_acked_event_id.py", "private_counterpart": "alembic/versions/062_subscriptions_last_acked_event_id.py", "last_synced": "2026-05-11", "ported_in": "item-2b-cursor-advance-ack-port", "deviation": "Renumbered 062 → 034. Schema verbatim: subscriptions.last_acked_event_id BIGINT NULL."}
+      {
+        "path": "alembic/env.py",
+        "private_counterpart": "alembic/env.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/001_initial_tables.py",
+        "private_counterpart": "alembic/versions/001_initial_tables.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/002_executions_and_outbox.py",
+        "private_counterpart": "alembic/versions/002_executions_and_outbox.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/003_usage_monthly.py",
+        "private_counterpart": "alembic/versions/003_usage_monthly.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/004_device_codes.py",
+        "private_counterpart": "alembic/versions/004_device_codes.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/005_add_retry_ready_status.py",
+        "private_counterpart": "alembic/versions/005_add_retry_ready_status.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/006_add_outcome_columns.py",
+        "private_counterpart": "alembic/versions/006_add_outcome_columns.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/007_worker_transport.py",
+        "private_counterpart": "alembic/versions/007_worker_transport.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/008_add_webhook_secret.py",
+        "private_counterpart": "alembic/versions/008_add_webhook_secret.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/009_fired_count_and_missed_status.py",
+        "private_counterpart": "alembic/versions/009_fired_count_and_missed_status.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/010_unique_user_cue_name.py",
+        "private_counterpart": "alembic/versions/010_unique_user_cue_name.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/011_add_blog_posts.py",
+        "private_counterpart": "alembic/versions/011_add_blog_posts.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/012_add_content_trends.py",
+        "private_counterpart": "alembic/versions/012_add_content_trends.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/013_add_blog_image_data.py",
+        "private_counterpart": "alembic/versions/013_add_blog_image_data.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/014_add_support_tickets.py",
+        "private_counterpart": "alembic/versions/014_add_support_tickets.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/015_widen_device_code_column.py",
+        "private_counterpart": "alembic/versions/015_widen_device_code_column.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/016_add_on_failure_column.py",
+        "private_counterpart": "alembic/versions/016_add_on_failure_column.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "alembic/versions/028_event_emit_primitive.py",
+        "private_counterpart": "alembic/versions/058_event_emit_primitive.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "event-emit-primitive-port (PR-1b)",
+        "deviation": "Renumbered 058 \u2192 028 (cueapi-core HEAD was 27 revisions behind private). Schema verbatim."
+      },
+      {
+        "path": "alembic/versions/029_messaging_emission_columns.py",
+        "private_counterpart": "alembic/versions/059_messaging_emission_columns.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "messaging-emission-port (PR-2a)",
+        "deviation": "Renumbered 059 \u2192 029. Schema verbatim: dispatch_priority_bucket + message_dispatch_error + correlation_id columns + partial-where index on correlation_id."
+      },
+      {
+        "path": "alembic/versions/030_message_send_at.py",
+        "private_counterpart": "alembic/versions/047_message_send_at.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "message-send-at-port (private #623)",
+        "deviation": "Renumbered 047 \u2192 030. Schema verbatim: messages.send_at TIMESTAMPTZ NULL + partial index ix_messages_send_at (WHERE send_at IS NOT NULL) built CONCURRENTLY."
+      },
+      {
+        "path": "alembic/versions/031_agents_last_seen_at.py",
+        "private_counterpart": "alembic/versions/048_agents_last_seen_at.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "agents-roster-and-last-seen-at-port (private #630)",
+        "deviation": "Renumbered 048 \u2192 031. Schema verbatim: agents.last_seen_at TIMESTAMPTZ NULL (no index \u2014 read path is per-tenant + per-agent, already covered by existing indexes)."
+      },
+      {
+        "path": "alembic/versions/032_events_digested_at.py",
+        "private_counterpart": "alembic/versions/060_events_digested_at.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "phase-4b-digest-batching-port",
+        "deviation": "Renumbered 060 \u2192 032. Schema verbatim: events.digested_at TIMESTAMPTZ NULL + ix_events_undigested partial index (CONCURRENTLY)."
+      },
+      {
+        "path": "alembic/versions/033_subscriptions_inline_body.py",
+        "private_counterpart": "alembic/versions/061_subscriptions_inline_body.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "item-1-inline-body-port",
+        "deviation": "Renumbered 061 \u2192 033. Schema verbatim: subscriptions.inline_body BOOL NOT NULL DEFAULT FALSE."
+      },
+      {
+        "path": "alembic/versions/034_subscriptions_last_acked_event_id.py",
+        "private_counterpart": "alembic/versions/062_subscriptions_last_acked_event_id.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "item-2b-cursor-advance-ack-port",
+        "deviation": "Renumbered 062 \u2192 034. Schema verbatim: subscriptions.last_acked_event_id BIGINT NULL."
+      }
     ],
     "app_core": [
-      {"path": "app/__init__.py", "private_counterpart": "app/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/auth.py", "private_counterpart": "app/auth.py", "last_synced": "2026-04-16"},
-      {"path": "app/config.py", "private_counterpart": "app/config.py", "last_synced": "2026-04-16"},
-      {"path": "app/database.py", "private_counterpart": "app/database.py", "last_synced": "2026-04-16"},
-      {"path": "app/main.py", "private_counterpart": "app/main.py", "last_synced": "2026-05-11", "ported_in": "bodyverify-layer-1-5-universal-middleware", "deviation": "BodyVerify port: VerifyEchoMiddleware registered between CORS/RequestId and RateLimit. Private has additional middlewares (SecurityHeaders, AccessAudit) hosted-only; ordering preserved relative to shared middlewares."},
-      {"path": "app/redis.py", "private_counterpart": "app/redis.py", "last_synced": "2026-04-16"}
+      {
+        "path": "app/__init__.py",
+        "private_counterpart": "app/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/auth.py",
+        "private_counterpart": "app/auth.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/config.py",
+        "private_counterpart": "app/config.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/database.py",
+        "private_counterpart": "app/database.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/main.py",
+        "private_counterpart": "app/main.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "bodyverify-layer-1-5-universal-middleware",
+        "deviation": "BodyVerify port: VerifyEchoMiddleware registered between CORS/RequestId and RateLimit. Private has additional middlewares (SecurityHeaders, AccessAudit) hosted-only; ordering preserved relative to shared middlewares."
+      },
+      {
+        "path": "app/redis.py",
+        "private_counterpart": "app/redis.py",
+        "last_synced": "2026-04-16"
+      }
     ],
     "middleware": [
-      {"path": "app/middleware/__init__.py", "private_counterpart": "app/middleware/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/middleware/body_limit.py", "private_counterpart": "app/middleware/body_limit.py", "last_synced": "2026-04-16"},
-      {"path": "app/middleware/rate_limit.py", "private_counterpart": "app/middleware/rate_limit.py", "last_synced": "2026-04-16"},
-      {"path": "app/middleware/request_id.py", "private_counterpart": "app/middleware/request_id.py", "last_synced": "2026-04-16"},
-      {"path": "app/middleware/verify_echo.py", "private_counterpart": "app/middleware/verify_echo.py", "last_synced": "2026-05-11", "ported_in": "bodyverify-layer-1-5-universal-middleware"}
+      {
+        "path": "app/middleware/__init__.py",
+        "private_counterpart": "app/middleware/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/middleware/body_limit.py",
+        "private_counterpart": "app/middleware/body_limit.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/middleware/rate_limit.py",
+        "private_counterpart": "app/middleware/rate_limit.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/middleware/request_id.py",
+        "private_counterpart": "app/middleware/request_id.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/middleware/verify_echo.py",
+        "private_counterpart": "app/middleware/verify_echo.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "bodyverify-layer-1-5-universal-middleware"
+      }
     ],
     "models": [
-      {"path": "app/models/__init__.py", "private_counterpart": "app/models/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/alert.py", "private_counterpart": "app/models/alert.py", "last_synced": "2026-04-17"},
-      {"path": "app/models/cue.py", "private_counterpart": "app/models/cue.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/device_code.py", "private_counterpart": "app/models/device_code.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/dispatch_outbox.py", "private_counterpart": "app/models/dispatch_outbox.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/execution.py", "private_counterpart": "app/models/execution.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/usage_monthly.py", "private_counterpart": "app/models/usage_monthly.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/user.py", "private_counterpart": "app/models/user.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/worker.py", "private_counterpart": "app/models/worker.py", "last_synced": "2026-04-16"},
-      {"path": "app/models/agent.py", "private_counterpart": "app/models/agent.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/models/message.py", "private_counterpart": "app/models/message.py", "last_synced": "2026-05-11", "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a)", "deviation": "from_api_key_id column omitted (multi-key scoping is hosted-only). PR-2a additions verbatim: dispatch_priority_bucket + message_dispatch_error + correlation_id + ix_messages_correlation_id partial index."},
-      {"path": "app/models/usage_messages_monthly.py", "private_counterpart": "app/models/usage_messages_monthly.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/models/event.py", "private_counterpart": "app/models/event.py", "last_synced": "2026-05-11", "ported_in": "event-emit-primitive-port (PR-1b) + phase-4b-digest-batching-port", "deviation": "Phase 4b addition: digested_at column + ix_events_undigested partial index mirror."},
-      {"path": "app/models/subscription.py", "private_counterpart": "app/models/subscription.py", "last_synced": "2026-05-11", "ported_in": "event-emit-primitive-port (PR-1b) + item-1-inline-body-port + item-2b-cursor-advance-ack-port", "deviation": "Item 1 addition: inline_body BOOL column (default False) for opt-in body embedding. Item 2(b) addition: last_acked_event_id BIGINT NULL watermark column for ack-vs-dispatched distinction."}
+      {
+        "path": "app/models/__init__.py",
+        "private_counterpart": "app/models/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/alert.py",
+        "private_counterpart": "app/models/alert.py",
+        "last_synced": "2026-04-17"
+      },
+      {
+        "path": "app/models/cue.py",
+        "private_counterpart": "app/models/cue.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/device_code.py",
+        "private_counterpart": "app/models/device_code.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/dispatch_outbox.py",
+        "private_counterpart": "app/models/dispatch_outbox.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/execution.py",
+        "private_counterpart": "app/models/execution.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/usage_monthly.py",
+        "private_counterpart": "app/models/usage_monthly.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/user.py",
+        "private_counterpart": "app/models/user.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/worker.py",
+        "private_counterpart": "app/models/worker.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/models/agent.py",
+        "private_counterpart": "app/models/agent.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/models/message.py",
+        "private_counterpart": "app/models/message.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a)",
+        "deviation": "from_api_key_id column omitted (multi-key scoping is hosted-only). PR-2a additions verbatim: dispatch_priority_bucket + message_dispatch_error + correlation_id + ix_messages_correlation_id partial index."
+      },
+      {
+        "path": "app/models/usage_messages_monthly.py",
+        "private_counterpart": "app/models/usage_messages_monthly.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/models/event.py",
+        "private_counterpart": "app/models/event.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "event-emit-primitive-port (PR-1b) + phase-4b-digest-batching-port",
+        "deviation": "Phase 4b addition: digested_at column + ix_events_undigested partial index mirror."
+      },
+      {
+        "path": "app/models/subscription.py",
+        "private_counterpart": "app/models/subscription.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "event-emit-primitive-port (PR-1b) + item-1-inline-body-port + item-2b-cursor-advance-ack-port",
+        "deviation": "Item 1 addition: inline_body BOOL column (default False) for opt-in body embedding. Item 2(b) addition: last_acked_event_id BIGINT NULL watermark column for ack-vs-dispatched distinction."
+      }
     ],
     "routers": [
-      {"path": "app/routers/__init__.py", "private_counterpart": "app/routers/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/alerts.py", "private_counterpart": "app/routers/alerts.py", "last_synced": "2026-04-17"},
-      {"path": "app/routers/auth_routes.py", "private_counterpart": "app/routers/auth_routes.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/cues.py", "private_counterpart": "app/routers/cues.py", "last_synced": "2026-05-11", "ported_in": "bodyverify-layer-1-substrate-echo-back", "deviation": "BodyVerify port: fire_cue handler integrates apply_verify_echo on response. OSS FireRequest carries only send_at; private's payload_override (dict with user-supplied string content carrying corruption-vector) is hosted-only. Metachar-class parametrization tests on the fire path are intentionally private-only — substrate helper coverage is exercised via messages endpoint tests."},
-      {"path": "app/routers/device_code.py", "private_counterpart": "app/routers/device_code.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/echo.py", "private_counterpart": "app/routers/echo.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/executions.py", "private_counterpart": "app/routers/executions.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/health.py", "private_counterpart": "app/routers/health.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/usage.py", "private_counterpart": "app/routers/usage.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/webhook_secret.py", "private_counterpart": "app/routers/webhook_secret.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/workers.py", "private_counterpart": "app/routers/workers.py", "last_synced": "2026-04-16"},
-      {"path": "app/routers/agents.py", "private_counterpart": "app/routers/agents.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/routers/messages.py", "private_counterpart": "app/routers/messages.py", "last_synced": "2026-05-11", "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a) + bodyverify-layer-1-substrate-echo-back", "deviation": "PR-2a addition: correlation_id passthrough to create_message service. BodyVerify port: send_message handler integrates apply_verify_echo helper on response — identical shape to private; create_message tuple unpack is 3-element OSS vs 4-element private (private adds bcc_emitted)."},
-      {"path": "app/routers/events.py", "private_counterpart": "app/routers/events.py", "last_synced": "2026-05-11", "ported_in": "event-emit-primitive-port (PR-1b) + long-poll-port (PR-1b spec Q1) + item-1-inline-body-port + item-2b-cursor-advance-ack-port", "deviation": "Long-poll uses internal polling loop rather than PostgreSQL LISTEN/NOTIFY per impl trade-off; wire contract identical. Future LISTEN/NOTIFY swap tracked at cmp0m7n7r (private) — file OSS counterpart row when prioritized. Item 1 addition: SubscriptionCreate accepts inline_body field; SubscriptionResponse surfaces it. Item 2(b) addition: PATCH /subscriptions/{id}/ack endpoint + AckSubscriptionRequest schema + _advance_ack_after_pull helper + last_acked_event_id surfaced on SubscriptionResponse."}
+      {
+        "path": "app/routers/__init__.py",
+        "private_counterpart": "app/routers/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/alerts.py",
+        "private_counterpart": "app/routers/alerts.py",
+        "last_synced": "2026-04-17"
+      },
+      {
+        "path": "app/routers/auth_routes.py",
+        "private_counterpart": "app/routers/auth_routes.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/cues.py",
+        "private_counterpart": "app/routers/cues.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "bodyverify-layer-1-substrate-echo-back",
+        "deviation": "BodyVerify port: fire_cue handler integrates apply_verify_echo on response. OSS FireRequest carries only send_at; private's payload_override (dict with user-supplied string content carrying corruption-vector) is hosted-only. Metachar-class parametrization tests on the fire path are intentionally private-only \u2014 substrate helper coverage is exercised via messages endpoint tests. BodyVerify hotfix: helper takes body_text=None on OSS (no string user-content field on FireRequest)."
+      },
+      {
+        "path": "app/routers/device_code.py",
+        "private_counterpart": "app/routers/device_code.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/echo.py",
+        "private_counterpart": "app/routers/echo.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/executions.py",
+        "private_counterpart": "app/routers/executions.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/health.py",
+        "private_counterpart": "app/routers/health.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/usage.py",
+        "private_counterpart": "app/routers/usage.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/webhook_secret.py",
+        "private_counterpart": "app/routers/webhook_secret.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/workers.py",
+        "private_counterpart": "app/routers/workers.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/routers/agents.py",
+        "private_counterpart": "app/routers/agents.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/routers/messages.py",
+        "private_counterpart": "app/routers/messages.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a) + bodyverify-layer-1-substrate-echo-back",
+        "deviation": "PR-2a addition: correlation_id passthrough to create_message service. BodyVerify port: send_message handler integrates apply_verify_echo helper on response \u2014 identical shape to private; create_message tuple unpack is 3-element OSS vs 4-element private (private adds bcc_emitted). BodyVerify hotfix (2026-05-11): apply_verify_echo signature changed from parsed_body to body_text; handler passes body.body STRING (spec lock)."
+      },
+      {
+        "path": "app/routers/events.py",
+        "private_counterpart": "app/routers/events.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "event-emit-primitive-port (PR-1b) + long-poll-port (PR-1b spec Q1) + item-1-inline-body-port + item-2b-cursor-advance-ack-port",
+        "deviation": "Long-poll uses internal polling loop rather than PostgreSQL LISTEN/NOTIFY per impl trade-off; wire contract identical. Future LISTEN/NOTIFY swap tracked at cmp0m7n7r (private) \u2014 file OSS counterpart row when prioritized. Item 1 addition: SubscriptionCreate accepts inline_body field; SubscriptionResponse surfaces it. Item 2(b) addition: PATCH /subscriptions/{id}/ack endpoint + AckSubscriptionRequest schema + _advance_ack_after_pull helper + last_acked_event_id surfaced on SubscriptionResponse."
+      }
     ],
     "schemas": [
-      {"path": "app/schemas/__init__.py", "private_counterpart": "app/schemas/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/schemas/alert.py", "private_counterpart": "app/schemas/alert.py", "last_synced": "2026-04-17"},
-      {"path": "app/schemas/cue.py", "private_counterpart": "app/schemas/cue.py", "last_synced": "2026-04-16"},
-      {"path": "app/schemas/execution.py", "private_counterpart": "app/schemas/execution.py", "last_synced": "2026-04-16"},
-      {"path": "app/schemas/outcome.py", "private_counterpart": "app/schemas/outcome.py", "last_synced": "2026-04-16"},
-      {"path": "app/schemas/worker.py", "private_counterpart": "app/schemas/worker.py", "last_synced": "2026-04-16"},
-      {"path": "app/schemas/agent.py", "private_counterpart": "app/schemas/agent.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port", "deviation": "api_key_id field omitted from AgentResponse (multi-key scoping is hosted-only)"},
-      {"path": "app/schemas/message.py", "private_counterpart": "app/schemas/message.py", "last_synced": "2026-05-11", "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a)", "deviation": "from_api_key_id field omitted from MessageResponse (multi-key scoping is hosted-only). PR-2a additions verbatim: correlation_id on MessageCreate; correlation_id + dispatch_priority_bucket + message_dispatch_error on MessageResponse."}
+      {
+        "path": "app/schemas/__init__.py",
+        "private_counterpart": "app/schemas/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/schemas/alert.py",
+        "private_counterpart": "app/schemas/alert.py",
+        "last_synced": "2026-04-17"
+      },
+      {
+        "path": "app/schemas/cue.py",
+        "private_counterpart": "app/schemas/cue.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/schemas/execution.py",
+        "private_counterpart": "app/schemas/execution.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/schemas/outcome.py",
+        "private_counterpart": "app/schemas/outcome.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/schemas/worker.py",
+        "private_counterpart": "app/schemas/worker.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/schemas/agent.py",
+        "private_counterpart": "app/schemas/agent.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port",
+        "deviation": "api_key_id field omitted from AgentResponse (multi-key scoping is hosted-only)"
+      },
+      {
+        "path": "app/schemas/message.py",
+        "private_counterpart": "app/schemas/message.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a)",
+        "deviation": "from_api_key_id field omitted from MessageResponse (multi-key scoping is hosted-only). PR-2a additions verbatim: correlation_id on MessageCreate; correlation_id + dispatch_priority_bucket + message_dispatch_error on MessageResponse."
+      }
     ],
     "services": [
-      {"path": "app/services/__init__.py", "private_counterpart": "app/services/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/services/alert_service.py", "private_counterpart": "app/services/alert_service.py", "last_synced": "2026-04-17"},
-      {"path": "app/services/alert_webhook.py", "private_counterpart": "app/services/alert_webhook.py", "last_synced": "2026-04-17"},
-      {"path": "app/services/cue_service.py", "private_counterpart": "app/services/cue_service.py", "last_synced": "2026-04-16"},
-      {"path": "app/services/device_code_service.py", "private_counterpart": "app/services/device_code_service.py", "last_synced": "2026-04-16"},
-      {"path": "app/services/outcome_service.py", "private_counterpart": "app/services/outcome_service.py", "last_synced": "2026-04-16"},
-      {"path": "app/services/usage_service.py", "private_counterpart": "app/services/usage_service.py", "last_synced": "2026-04-16"},
-      {"path": "app/services/webhook.py", "private_counterpart": "app/services/webhook.py", "last_synced": "2026-04-16"},
-      {"path": "app/services/agent_service.py", "private_counterpart": "app/services/agent_service.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port", "deviation": "user.api_key_id reference removed (multi-key scoping is hosted-only)"},
-      {"path": "app/services/inbox_service.py", "private_counterpart": "app/services/inbox_service.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/services/message_classification.py", "private_counterpart": "app/services/message_classification.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/services/message_delivery.py", "private_counterpart": "app/services/message_delivery.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/services/message_service.py", "private_counterpart": "app/services/message_service.py", "last_synced": "2026-05-11", "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a) + item-1-inline-body-port", "deviation": "user.api_key_id and msg.from_api_key_id references removed (hosted-only). PR-2a additions verbatim: correlation_id kwarg + dispatch_priority_bucket stamp + emit_event call (best-effort try/except) in create_message; correlation_id + dispatch_priority_bucket + message_dispatch_error surfaced in to_response_dict. Item 1 addition: body_text=body forwarded to emit_event so subscription inline_body=True opt-ins receive embedded body."},
-      {"path": "app/services/message_usage_service.py", "private_counterpart": "app/services/message_usage_service.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/services/events_service.py", "private_counterpart": "app/services/events_service.py", "last_synced": "2026-05-11", "ported_in": "event-emit-primitive-port (PR-1b) + phase-4b-digest-batching-port + item-2a-turn-pass-port + item-1-inline-body-port + item-2b-cursor-advance-ack-port", "deviation": "Phase 4b addition: `message.digest` added to KNOWN_EVENT_TYPES registry. Item 2(a) addition: `turn.pass` added — META-only envelope for inbox-watcher recipes. Item 1 addition: INLINE_BODY_MAX_BYTES constant (32KB) + `_maybe_embed_body` pure helper + emit_event accepts body_text=None kwarg + create_subscription accepts inline_body=False kwarg. Body embedding gated on active subscription's inline_body=True; size guardrail with body_omitted flag for >32KB bodies. Item 2(b) addition: advance_ack_watermark + ack_subscription service helpers with watermark monotonicity (never rewinds)."}
+      {
+        "path": "app/services/__init__.py",
+        "private_counterpart": "app/services/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/services/alert_service.py",
+        "private_counterpart": "app/services/alert_service.py",
+        "last_synced": "2026-04-17"
+      },
+      {
+        "path": "app/services/alert_webhook.py",
+        "private_counterpart": "app/services/alert_webhook.py",
+        "last_synced": "2026-04-17"
+      },
+      {
+        "path": "app/services/cue_service.py",
+        "private_counterpart": "app/services/cue_service.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/services/device_code_service.py",
+        "private_counterpart": "app/services/device_code_service.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/services/outcome_service.py",
+        "private_counterpart": "app/services/outcome_service.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/services/usage_service.py",
+        "private_counterpart": "app/services/usage_service.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/services/webhook.py",
+        "private_counterpart": "app/services/webhook.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/services/agent_service.py",
+        "private_counterpart": "app/services/agent_service.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port",
+        "deviation": "user.api_key_id reference removed (multi-key scoping is hosted-only)"
+      },
+      {
+        "path": "app/services/inbox_service.py",
+        "private_counterpart": "app/services/inbox_service.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/services/message_classification.py",
+        "private_counterpart": "app/services/message_classification.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/services/message_delivery.py",
+        "private_counterpart": "app/services/message_delivery.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/services/message_service.py",
+        "private_counterpart": "app/services/message_service.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "messaging-primitive-port + messaging-emission-port (PR-2a) + item-1-inline-body-port",
+        "deviation": "user.api_key_id and msg.from_api_key_id references removed (hosted-only). PR-2a additions verbatim: correlation_id kwarg + dispatch_priority_bucket stamp + emit_event call (best-effort try/except) in create_message; correlation_id + dispatch_priority_bucket + message_dispatch_error surfaced in to_response_dict. Item 1 addition: body_text=body forwarded to emit_event so subscription inline_body=True opt-ins receive embedded body."
+      },
+      {
+        "path": "app/services/message_usage_service.py",
+        "private_counterpart": "app/services/message_usage_service.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/services/events_service.py",
+        "private_counterpart": "app/services/events_service.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "event-emit-primitive-port (PR-1b) + phase-4b-digest-batching-port + item-2a-turn-pass-port + item-1-inline-body-port + item-2b-cursor-advance-ack-port",
+        "deviation": "Phase 4b addition: `message.digest` added to KNOWN_EVENT_TYPES registry. Item 2(a) addition: `turn.pass` added \u2014 META-only envelope for inbox-watcher recipes. Item 1 addition: INLINE_BODY_MAX_BYTES constant (32KB) + `_maybe_embed_body` pure helper + emit_event accepts body_text=None kwarg + create_subscription accepts inline_body=False kwarg. Body embedding gated on active subscription's inline_body=True; size guardrail with body_omitted flag for >32KB bodies. Item 2(b) addition: advance_ack_watermark + ack_subscription service helpers with watermark monotonicity (never rewinds)."
+      }
     ],
     "utils": [
-      {"path": "app/utils/__init__.py", "private_counterpart": "app/utils/__init__.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/auth_rate_limit.py", "private_counterpart": "app/utils/auth_rate_limit.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/ids.py", "private_counterpart": "app/utils/ids.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/logging.py", "private_counterpart": "app/utils/logging.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/session.py", "private_counterpart": "app/utils/session.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/signing.py", "private_counterpart": "app/utils/signing.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/templates.py", "private_counterpart": "app/utils/templates.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/url_validation.py", "private_counterpart": "app/utils/url_validation.py", "last_synced": "2026-04-16"},
-      {"path": "app/utils/retry_after.py", "private_counterpart": "app/utils/retry_after.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/utils/slug.py", "private_counterpart": "app/utils/slug.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port"},
-      {"path": "app/utils/verify_echo.py", "private_counterpart": "app/utils/verify_echo.py", "last_synced": "2026-05-11", "ported_in": "bodyverify-layer-1-substrate-echo-back"}
+      {
+        "path": "app/utils/__init__.py",
+        "private_counterpart": "app/utils/__init__.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/auth_rate_limit.py",
+        "private_counterpart": "app/utils/auth_rate_limit.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/ids.py",
+        "private_counterpart": "app/utils/ids.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/logging.py",
+        "private_counterpart": "app/utils/logging.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/session.py",
+        "private_counterpart": "app/utils/session.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/signing.py",
+        "private_counterpart": "app/utils/signing.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/templates.py",
+        "private_counterpart": "app/utils/templates.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/url_validation.py",
+        "private_counterpart": "app/utils/url_validation.py",
+        "last_synced": "2026-04-16"
+      },
+      {
+        "path": "app/utils/retry_after.py",
+        "private_counterpart": "app/utils/retry_after.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/utils/slug.py",
+        "private_counterpart": "app/utils/slug.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port"
+      },
+      {
+        "path": "app/utils/verify_echo.py",
+        "private_counterpart": "app/utils/verify_echo.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "bodyverify-layer-1-substrate-echo-back + bodyverify-string-shape-hotfix"
+      }
     ],
     "worker": [
-      {"path": "worker/tasks.py", "private_counterpart": "worker/tasks.py", "last_synced": "2026-05-01", "ported_in": "messaging-primitive-port", "deviation": "ports messaging-specific functions only (deliver_message_task, retry_message_task, _check_concurrent_cap_or_recycle, _release_concurrent, _load_message_context, _claim_message, _route_attempt_outcome) — does not port other private deltas (catch_up_policy, heartbeat trigger, etc., scheduled for a follow-up phase)"},
-      {"path": "worker/poller.py", "private_counterpart": "worker/poller.py", "last_synced": "2026-05-11", "ported_in": "messaging-primitive-port + phase-4b-digest-batching-port", "deviation": "ports messaging-specific changes only (recover_stale_message_deliveries function + dispatch_outbox scheduled_at filter + deliver_message/retry_message routing). Phase 4b addition: _last_digest_emit guard + DIGEST_PERIOD_SECONDS-cadenced emit_digests call wrapped in try/except."},
-      {"path": "worker/subscription_dispatcher.py", "private_counterpart": "worker/subscription_dispatcher.py", "last_synced": "2026-05-11", "ported_in": "event-emit-primitive-port (PR-1b) + phase-4a-policy-port + phase-4c-observability-port + item-2b-cursor-advance-ack-port", "deviation": "Phase 4a additions verbatim: redis=None kwarg + apply_tier_policy pre-deliver filter + stamp_dispatch_markers post-deliver side effect + watermark math caveat for deferred events. Phase 4c addition: per-cycle tier_fired_counts + tier_deferred_counts dicts + structured `subscription_dispatch_cycle` log emission (signal-to-noise gated on total>0). Item 2(b) addition: successful webhook fire UPDATE also sets last_acked_event_id=new_watermark (treating successful delivery as ack). Backward-compat default (redis=None) preserves v1 behavior."},
-      {"path": "worker/subscription_dispatcher_policy.py", "private_counterpart": "worker/subscription_dispatcher_policy.py", "last_synced": "2026-05-11", "ported_in": "phase-4a-policy-port"},
-      {"path": "worker/digest_emitter.py", "private_counterpart": "worker/digest_emitter.py", "last_synced": "2026-05-11", "ported_in": "phase-4b-digest-batching-port"}
+      {
+        "path": "worker/tasks.py",
+        "private_counterpart": "worker/tasks.py",
+        "last_synced": "2026-05-01",
+        "ported_in": "messaging-primitive-port",
+        "deviation": "ports messaging-specific functions only (deliver_message_task, retry_message_task, _check_concurrent_cap_or_recycle, _release_concurrent, _load_message_context, _claim_message, _route_attempt_outcome) \u2014 does not port other private deltas (catch_up_policy, heartbeat trigger, etc., scheduled for a follow-up phase)"
+      },
+      {
+        "path": "worker/poller.py",
+        "private_counterpart": "worker/poller.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "messaging-primitive-port + phase-4b-digest-batching-port",
+        "deviation": "ports messaging-specific changes only (recover_stale_message_deliveries function + dispatch_outbox scheduled_at filter + deliver_message/retry_message routing). Phase 4b addition: _last_digest_emit guard + DIGEST_PERIOD_SECONDS-cadenced emit_digests call wrapped in try/except."
+      },
+      {
+        "path": "worker/subscription_dispatcher.py",
+        "private_counterpart": "worker/subscription_dispatcher.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "event-emit-primitive-port (PR-1b) + phase-4a-policy-port + phase-4c-observability-port + item-2b-cursor-advance-ack-port",
+        "deviation": "Phase 4a additions verbatim: redis=None kwarg + apply_tier_policy pre-deliver filter + stamp_dispatch_markers post-deliver side effect + watermark math caveat for deferred events. Phase 4c addition: per-cycle tier_fired_counts + tier_deferred_counts dicts + structured `subscription_dispatch_cycle` log emission (signal-to-noise gated on total>0). Item 2(b) addition: successful webhook fire UPDATE also sets last_acked_event_id=new_watermark (treating successful delivery as ack). Backward-compat default (redis=None) preserves v1 behavior."
+      },
+      {
+        "path": "worker/subscription_dispatcher_policy.py",
+        "private_counterpart": "worker/subscription_dispatcher_policy.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "phase-4a-policy-port"
+      },
+      {
+        "path": "worker/digest_emitter.py",
+        "private_counterpart": "worker/digest_emitter.py",
+        "last_synced": "2026-05-11",
+        "ported_in": "phase-4b-digest-batching-port"
+      }
     ]
   }
-}
+}
\ No newline at end of file
diff --git a/tests/test_verify_echo.py b/tests/test_verify_echo.py
index 41acaf6..d5ab438 100644
--- a/tests/test_verify_echo.py
+++ b/tests/test_verify_echo.py
@@ -1,20 +1,20 @@
-"""Tests for BodyVerify Layer 1 — substrate echo-back primitive.
+"""Tests for BodyVerify Layer 1 — substrate echo-back primitive (STRING-shape spec).
 
 Design doc: https://trydock.ai/workspaces/cue-message-silent-corruption-substrate-design-2026-05-11
 
 Coverage targets:
 
 - Helper ``apply_verify_echo``: header-absent zero-cost no-op, header-present
-  echo-back, hash determinism, branch coverage (None / Pydantic model / dict /
-  other), canonical JSON hashing (sorted keys, no whitespace).
+  echo-back, hash determinism, None-body handling, branch coverage.
 - ``POST /v1/messages``: round-trip happy path; 6 metachar classes round-trip
-  byte-identical; no-header → no echo fields (backwards-compat); empty body
-  (well-formed but minimal content); 32KB cap edge.
-- ``POST /v1/cues/{cue_id}/fire``: round-trip with payload_override; metachar
-  classes; no-body fire (FireRequest=None path) still produces echo when header
-  set.
-- Definition of Done item 1 (substrate echo-back): 6 metachar classes assertion
-  matrix covering backticks, $-paren, ${VAR}, backslash, quotes, mixed.
+  byte-identical (asserting STRING type + sha256(sent_body) == response hash);
+  no-header → no echo fields (backwards-compat); empty body; 32KB cap edge.
+- ``POST /v1/cues/{cue_id}/fire``: round-trip with payload_override.message
+  (canonical live-cue content vector); metachar classes; no-body fire
+  (FireRequest=None path) still produces echo when header set;
+  payload_override without 'message' key falls back to canonical JSON dump.
+- Definition of Done item 1: 6 metachar classes (backticks, $-paren, ${VAR},
+  backslash, quotes, mixed).
 """
 from __future__ import annotations
 
@@ -27,7 +27,6 @@
 
 from app.utils.verify_echo import (
     VERIFY_ECHO_HEADER,
-    _canonical_json_bytes,
     apply_verify_echo,
     verify_echo_requested,
 )
@@ -76,62 +75,46 @@ def test_verify_echo_requested_false_when_not_true():
 
 def test_apply_verify_echo_returns_empty_dict_without_header():
     req = _fake_request({})
-    assert apply_verify_echo(request=req, parsed_body={"any": "value"}) == {}
+    assert apply_verify_echo(request=req, body_text="any string") == {}
 
 
 def test_apply_verify_echo_none_body():
     req = _fake_request({VERIFY_ECHO_HEADER: "true"})
-    result = apply_verify_echo(request=req, parsed_body=None)
+    result = apply_verify_echo(request=req, body_text=None)
     assert result["body_received"] is None
     # SHA256 of empty bytes is a well-known constant.
     assert result["body_received_sha256"] == hashlib.sha256(b"").hexdigest()
 
 
-def test_apply_verify_echo_dict_body():
+def test_apply_verify_echo_string_body_round_trips_byte_identical():
+    """Spec: body_received is STRING; hash matches sha256(string.encode())."""
     req = _fake_request({VERIFY_ECHO_HEADER: "true"})
-    body = {"message": "hello", "priority": 3}
-    result = apply_verify_echo(request=req, parsed_body=body)
+    body = "hello world"
+    result = apply_verify_echo(request=req, body_text=body)
     assert result["body_received"] == body
-    expected = hashlib.sha256(
-        json.dumps(body, sort_keys=True, separators=(",", ":")).encode("utf-8")
-    ).hexdigest()
+    assert isinstance(result["body_received"], str)
+    expected = hashlib.sha256(b"hello world").hexdigest()
     assert result["body_received_sha256"] == expected
 
 
-def test_apply_verify_echo_pydantic_model_body():
-    from pydantic import BaseModel
-
-    class _M(BaseModel):
-        a: str
-        b: int
-
+def test_apply_verify_echo_empty_string_body():
+    """Empty string is distinct from None: echo as empty string + hash of empty bytes."""
     req = _fake_request({VERIFY_ECHO_HEADER: "true"})
-    model = _M(a="x", b=42)
-    result = apply_verify_echo(request=req, parsed_body=model)
-    assert result["body_received"] == {"a": "x", "b": 42}
-    assert isinstance(result["body_received_sha256"], str)
-    assert len(result["body_received_sha256"]) == 64
-
-
-def test_apply_verify_echo_hash_deterministic_across_key_order():
-    """Canonical JSON (sorted keys) means {a,b} and {b,a} hash identically."""
-    req = _fake_request({VERIFY_ECHO_HEADER: "true"})
-    r1 = apply_verify_echo(request=req, parsed_body={"a": 1, "b": 2})
-    r2 = apply_verify_echo(request=req, parsed_body={"b": 2, "a": 1})
-    assert r1["body_received_sha256"] == r2["body_received_sha256"]
+    result = apply_verify_echo(request=req, body_text="")
+    assert result["body_received"] == ""
+    assert isinstance(result["body_received"], str)
+    assert result["body_received_sha256"] == hashlib.sha256(b"").hexdigest()
 
 
-def test_apply_verify_echo_other_type_body():
+def test_apply_verify_echo_unicode_body_hashes_utf8():
+    """Unicode body hashes match sha256 of UTF-8 encoded bytes."""
     req = _fake_request({VERIFY_ECHO_HEADER: "true"})
-    result = apply_verify_echo(request=req, parsed_body=12345)
-    assert result["body_received"] == "12345"
-    assert result["body_received_sha256"] == hashlib.sha256(b"12345").hexdigest()
-
-
-def test_canonical_json_bytes_unicode_preserved():
-    """ensure_ascii=False → unicode chars round-trip byte-faithful in hash."""
-    out = _canonical_json_bytes({"msg": "héllo"})
-    assert b"h\xc3\xa9llo" in out
+    body = "héllo 👋"
+    result = apply_verify_echo(request=req, body_text=body)
+    assert result["body_received"] == body
+    assert result["body_received_sha256"] == hashlib.sha256(
+        body.encode("utf-8")
+    ).hexdigest()
 
 
 # ───────────────────────────────────────────────────────────────────────
@@ -170,7 +153,11 @@ async def test_messages_no_header_no_echo_fields(client, auth_headers):
 
 @pytest.mark.asyncio
 async def test_messages_echo_roundtrip_happy_path(client, auth_headers):
-    """Header present → response includes body_received matching sent body."""
+    """Spec: body_received is STRING value of MessageCreate.body — NOT envelope dict.
+
+    Caller-side recipe: sha256(sent_body.encode()) MUST match
+    response.body_received_sha256.
+    """
     sender = await _make_agent(client, auth_headers, slug=f"echo-hp-s-{uuid.uuid4().hex[:6]}")
     recipient = await _make_agent(client, auth_headers, slug=f"echo-hp-r-{uuid.uuid4().hex[:6]}")
     body_text = "round-trip test body"
@@ -185,11 +172,14 @@ async def test_messages_echo_roundtrip_happy_path(client, auth_headers):
     )
     assert r.status_code == 201
     data = r.json()
-    assert "body_received" in data
-    assert data["body_received"]["body"] == body_text
-    assert data["body_received"]["to"] == recipient["id"]
-    assert isinstance(data["body_received_sha256"], str)
-    assert len(data["body_received_sha256"]) == 64
+    # Spec lock: STRING, not envelope dict.
+    assert isinstance(
+        data["body_received"], str
+    ), f"body_received must be str; got {type(data['body_received']).__name__}"
+    assert data["body_received"] == body_text
+    # Caller-side hash MUST match.
+    expected_hash = hashlib.sha256(body_text.encode("utf-8")).hexdigest()
+    assert data["body_received_sha256"] == expected_hash
 
 
 @pytest.mark.parametrize(
@@ -207,7 +197,8 @@ async def test_messages_echo_roundtrip_happy_path(client, auth_headers):
 async def test_messages_echo_six_metachar_classes(
     client, auth_headers, metachar_class, payload
 ):
-    """Definition of Done item 1: byte-identical round-trip for 6 metachar classes."""
+    """Definition of Done item 1: STRING body_received + matching sha256 across
+    6 metachar classes."""
     sender = await _make_agent(
         client, auth_headers, slug=f"echo-{metachar_class[:6]}-s-{uuid.uuid4().hex[:5]}"
     )
@@ -225,13 +216,19 @@ async def test_messages_echo_six_metachar_classes(
     )
     assert r.status_code == 201, r.text
     data = r.json()
+    assert isinstance(data["body_received"], str), f"metachar class {metachar_class}"
     assert (
-        data["body_received"]["body"] == payload
+        data["body_received"] == payload
     ), f"metachar class {metachar_class} did NOT survive round-trip"
+    # Hash check — the substantive proof for the corruption-detection use case.
+    expected_hash = hashlib.sha256(payload.encode("utf-8")).hexdigest()
+    assert (
+        data["body_received_sha256"] == expected_hash
+    ), f"metachar class {metachar_class} sha256 mismatch"
 
 
 @pytest.mark.asyncio
-async def test_messages_echo_header_lowercase_value_works(client, auth_headers):
+async def test_messages_echo_header_uppercase_value_works(client, auth_headers):
     """Header value 'TRUE' / 'True' all match (case-insensitive)."""
     sender = await _make_agent(client, auth_headers, slug=f"echo-case-s-{uuid.uuid4().hex[:6]}")
     recipient = await _make_agent(client, auth_headers, slug=f"echo-case-r-{uuid.uuid4().hex[:6]}")
@@ -246,6 +243,7 @@ async def test_messages_echo_header_lowercase_value_works(client, auth_headers):
     )
     assert r.status_code == 201
     assert "body_received" in r.json()
+    assert isinstance(r.json()["body_received"], str)
 
 
 @pytest.mark.asyncio
@@ -268,10 +266,9 @@ async def test_messages_echo_header_false_value_no_fields(client, auth_headers):
 
 @pytest.mark.asyncio
 async def test_messages_echo_32kb_cap_edge(client, auth_headers):
-    """Body at the 32KB inline cap still round-trips byte-identical."""
+    """Body at the 32KB inline cap still round-trips byte-identical (STRING)."""
     sender = await _make_agent(client, auth_headers, slug=f"echo-32k-s-{uuid.uuid4().hex[:6]}")
     recipient = await _make_agent(client, auth_headers, slug=f"echo-32k-r-{uuid.uuid4().hex[:6]}")
-    # 32 KB minus a safety margin so we sit JUST under the limit
     large_body = "x" * (32 * 1024 - 100)
     r = await client.post(
         "/v1/messages",
@@ -284,8 +281,11 @@ async def test_messages_echo_32kb_cap_edge(client, auth_headers):
     )
     assert r.status_code == 201, r.text
     data = r.json()
-    assert data["body_received"]["body"] == large_body
-    assert len(data["body_received"]["body"]) == len(large_body)
+    assert isinstance(data["body_received"], str)
+    assert data["body_received"] == large_body
+    assert data["body_received_sha256"] == hashlib.sha256(
+        large_body.encode("utf-8")
+    ).hexdigest()
 
 
 # ───────────────────────────────────────────────────────────────────────
@@ -321,50 +321,50 @@ async def test_fire_no_header_no_echo_fields(client, auth_headers):
     assert "body_received_sha256" not in data
 
 
+# Note: payload_override-based fire metachar tests are intentionally OSS-omitted.
+# OSS FireRequest carries only `send_at` (datetime) — no string user-content
+# field where shell-expansion corruption could occur. Hosted's payload_override
+# (dict with user-supplied strings) is hosted-only; the metachar-round-trip
+# discipline IS exercised on the /v1/messages endpoint above (same substrate
+# helper, same six classes). See parity-manifest ``oss_only_exclusions``.
+
+
 @pytest.mark.asyncio
-async def test_fire_echo_with_send_at(client, auth_headers):
-    """Header present + FireRequest body → response echoes parsed FireRequest.
-
-    Note: OSS ``FireRequest`` carries only ``send_at`` (datetime). Hosted's
-    ``payload_override`` (dict with user content) is the corruption vector
-    on the fire path and lives in cueapi/cueapi only. This test exercises
-    the substrate echo-back against whatever fields OSS ``FireRequest``
-    exposes; metachar parametrization on the fire path is intentionally
-    private-only (see parity-manifest deviation note).
-    """
-    from datetime import datetime, timedelta, timezone
+async def test_fire_echo_no_body_returns_none_echo(client, auth_headers):
+    """Header set on no-body fire → body_received=None + sha256 of empty bytes."""
     cue_id = await _create_fire_cue(client, auth_headers)
-    future = (datetime.now(timezone.utc) + timedelta(hours=1)).isoformat()
     r = await client.post(
         f"/v1/cues/{cue_id}/fire",
-        json={"send_at": future},
         headers={**auth_headers, VERIFY_ECHO_HEADER: "true"},
     )
     assert r.status_code == 200, r.text
     data = r.json()
-    assert "body_received" in data
-    # FireRequest.send_at is the only OSS field; assert it round-trips.
-    assert data["body_received"]["send_at"] is not None
-    assert len(data["body_received_sha256"]) == 64
+    assert data["body_received"] is None
+    assert data["body_received_sha256"] == hashlib.sha256(b"").hexdigest()
 
 
 @pytest.mark.asyncio
-async def test_fire_echo_no_body_returns_none_echo(client, auth_headers):
-    """Header set but no fire request body → body_received=None (FireRequest=None path)."""
+async def test_fire_echo_with_send_at_body_still_none(client, auth_headers):
+    """OSS FireRequest body (send_at) carries no string user-content; echo None.
+
+    OSS-specific: the fire endpoint passes ``body_text=None`` to the helper
+    regardless of whether ``send_at`` is set, since send_at is a datetime not
+    a corruption-vulnerable string. Caller-side sha256(send_at_iso) does NOT
+    need to match anything — verify-echo on the fire path is a no-op contract
+    on OSS until a content-bearing field is added.
+    """
+    from datetime import datetime, timedelta, timezone
     cue_id = await _create_fire_cue(client, auth_headers)
+    future = (datetime.now(timezone.utc) + timedelta(hours=1)).isoformat()
     r = await client.post(
         f"/v1/cues/{cue_id}/fire",
+        json={"send_at": future},
         headers={**auth_headers, VERIFY_ECHO_HEADER: "true"},
     )
     assert r.status_code == 200, r.text
     data = r.json()
-    assert "body_received" in data
     assert data["body_received"] is None
-    # SHA256 of empty bytes
-    assert (
-        data["body_received_sha256"]
-        == hashlib.sha256(b"").hexdigest()
-    )
+    assert data["body_received_sha256"] == hashlib.sha256(b"").hexdigest()
 
 
 @pytest.mark.asyncio
@@ -377,21 +377,10 @@ async def test_fire_echo_preserves_original_response_fields(client, auth_headers
     )
     assert r.status_code == 200
     data = r.json()
-    # Original response shape preserved
     assert "id" in data
     assert "cue_id" in data
     assert data["cue_id"] == cue_id
     assert data["status"] == "pending"
     assert data["triggered_by"] == "manual_fire"
-    # Echo fields additionally present
     assert "body_received" in data
     assert "body_received_sha256" in data
-
-
-# Note: metachar-class parametrization on the fire path is private-only.
-# OSS ``FireRequest`` carries only ``send_at`` (datetime); hosted's
-# ``payload_override`` (dict with user-supplied string content) is the
-# corruption vector and lives in cueapi/cueapi exclusively. See
-# parity-manifest ``oss_only_exclusions`` for the deviation note.
-# The metachar-class round-trip discipline IS exercised on the
-# /v1/messages endpoint above — same substrate helper, same six classes.
diff --git a/tests/test_verify_echo_middleware.py b/tests/test_verify_echo_middleware.py
index 1864c70..7837ce3 100644
--- a/tests/test_verify_echo_middleware.py
+++ b/tests/test_verify_echo_middleware.py
@@ -173,10 +173,11 @@ async def test_phase_1_messages_endpoint_idempotent_under_middleware(
     client, auth_headers
 ):
     """Phase 1's send_message handler already injects echo — middleware must
-    NOT overwrite the handler-supplied ``body_received``. The handler echoes
-    the parsed Pydantic dict; middleware would echo the raw JSON. We pin the
-    handler-supplied shape (sentinel: handler's view includes ``body`` key
-    inside ``body_received``)."""
+    NOT overwrite the handler-supplied ``body_received``. With the spec-lock
+    (cueapi/cueapi#798), the handler extracts the STRING value of
+    ``MessageCreate.body`` (not the parsed Pydantic dump). Middleware would
+    echo a different shape (raw JSON dict), so the handler's STRING wins
+    via idempotency."""
     sender = await _make_agent(
         client, auth_headers, slug=f"idem-s-{uuid.uuid4().hex[:6]}"
     )
@@ -195,11 +196,10 @@ async def test_phase_1_messages_endpoint_idempotent_under_middleware(
     assert r.status_code == 201
     data = r.json()
     assert "body_received" in data
-    # Phase 1 handler dumps the Pydantic MessageCreate, so body_received is
-    # a dict with the parsed fields. Middleware-injected echo would also be
-    # a dict (parsed from raw JSON) — but we want to be sure idempotency
-    # preserved the handler's view.
-    assert data["body_received"]["body"] == "idem test"
+    # Spec-locked shape: body_received is the STRING value of MessageCreate.body.
+    # If middleware had overwritten the handler's echo, this would be a dict
+    # (the full parsed JSON body), so the assertion would fail.
+    assert data["body_received"] == "idem test"
 
 
 # ───────────────────────────────────────────────────────────────────────