diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
new file mode 100644
index 0000000..1cc5f1a
--- /dev/null
+++ b/.github/CODEOWNERS
@@ -0,0 +1,15 @@
+# TriTRPC transport and agent-sandbox control-plane ownership.
+# This file protects workflow, transport-profile, schema, fixture, and verifier surfaces.
+
+.github/workflows/* @mdheller
+.github/CODEOWNERS @mdheller
+.github/copilot-instructions.md @mdheller
+
+README.md @mdheller
+Makefile @mdheller
+
+docs/CAPABILITY_FABRIC_SEMANTIC_SOURCE.md @mdheller
+docs/AGENT_SANDBOX_TRANSPORT_PROFILE.md @mdheller
+schemas/jsonschema/agent-sandbox-transport.v0.schema.json @mdheller
+fixtures/agent_sandbox_transport/* @mdheller
+tools/verify_agent_sandbox_transport.py @mdheller
diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
new file mode 100644
index 0000000..6e43e39
--- /dev/null
+++ b/.github/copilot-instructions.md
@@ -0,0 +1,17 @@
+# Copilot instructions for TriTRPC
+
+TriTRPC is the transport authority for deterministic ternary-native RPC framing, fixtures, canonical byte encoding, envelope ordering, AEAD/AAD boundaries, and transport-level verifier behavior.
+
+Do not redefine Capability Fabric semantic objects in this repository. Canonical semantics live in `SocioProphet/socioprophet-standards-knowledge`.
+
+When working on agent sandbox lifecycle artifacts:
+
+1. Treat this repository as the transport and fixture layer only.
+2. Reference the standards objects instead of redefining them.
+3. Preserve no-push failure invariants for infrastructure/model/tool failures.
+4. Do not modify `.github/workflows/**`, `.github/CODEOWNERS`, or transport verifier scripts without explicit maintainer review.
+5. Do not convert rate-limit, MCP, model, tool, attestation, or runner-bootstrap failures into successful writes.
+6. Prefer deterministic fixtures, canonical JSON, digest binding, and cross-language verifier behavior.
+7. Keep runtime implementation concerns in AgentPlane, Prophet Platform, or workspace-controller repositories rather than in TriTRPC transport docs.
+
+For ordinary code changes, keep `make verify` passing.
diff --git a/.github/workflows/agent-sandbox-transport.yml b/.github/workflows/agent-sandbox-transport.yml
new file mode 100644
index 0000000..3c3363e
--- /dev/null
+++ b/.github/workflows/agent-sandbox-transport.yml
@@ -0,0 +1,23 @@
+name: agent-sandbox-transport
+
+on:
+  pull_request:
+    paths:
+      - 'docs/AGENT_SANDBOX_TRANSPORT_PROFILE.md'
+      - 'schemas/jsonschema/agent-sandbox-transport.v0.schema.json'
+      - 'fixtures/agent_sandbox_transport/**'
+      - 'tools/verify_agent_sandbox_transport.py'
+      - '.github/workflows/agent-sandbox-transport.yml'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  verify-agent-sandbox-transport:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
+      - name: Verify agent sandbox transport fixtures
+        run: python tools/verify_agent_sandbox_transport.py
diff --git a/docs/AGENT_SANDBOX_TRANSPORT_PROFILE.md b/docs/AGENT_SANDBOX_TRANSPORT_PROFILE.md
new file mode 100644
index 0000000..83ab318
--- /dev/null
+++ b/docs/AGENT_SANDBOX_TRANSPORT_PROFILE.md
@@ -0,0 +1,145 @@
+# Agent Sandbox Transport Profile for TriTRPC (v0.1 draft)
+
+## Status
+
+Draft transport profile. This document is intentionally scoped to TriTRPC carriage, serialization, digest binding, fixture behavior, and verifier behavior.
+
+Canonical lifecycle semantics live in `SocioProphet/socioprophet-standards-knowledge`:
+
+- `docs/standards/044-agent-sandbox-lifecycle.md`
+- `schemas/jsonschema/capability-fabric/agent-sandbox-lifecycle.v0.schema.json`
+
+TriTRPC MUST NOT redefine the semantic meaning of `AgentSandboxSpec`, `AgentGenesisManifest`, `AgentFailureBundle`, or `AgentSandboxReceipt`.
+
+## Purpose
+
+This profile defines how agent sandbox lifecycle artifacts are carried over deterministic TriTRPC-style transport surfaces.
+
+It covers:
+- typed artifact carriage;
+- canonical JSON serialization for examples and fixtures;
+- digest and reference binding;
+- failure-bundle transport invariants;
+- deterministic verification expectations.
+
+It does not define:
+- actor trust semantics;
+- controllability class semantics;
+- proof-strength semantics;
+- admission policy meaning;
+- runtime placement policy.
+
+Those belong to the Capability Fabric standards source.
+
+## Transport object classes
+
+TriTRPC MAY carry the following lifecycle object classes as typed payloads or typed attachments:
+
+- `application/vnd.socioprophet.agent-sandbox-spec+json;v=0`
+- `application/vnd.socioprophet.agent-genesis-manifest+json;v=0`
+- `application/vnd.socioprophet.agent-failure-bundle+json;v=0`
+- `application/vnd.socioprophet.agent-sandbox-receipt+json;v=0`
+
+A TriTRPC frame carrying one of these objects SHOULD bind:
+- object media type;
+- canonical payload digest;
+- semantic schema reference;
+- producer identity or attestation reference;
+- parent sandbox or phase reference.
+
+## Canonical JSON profile
+
+For JSON fixtures and transport examples, canonicalization MUST use:
+- UTF-8 encoding;
+- sorted object keys;
+- no insignificant whitespace;
+- exact string values for enum-like fields;
+- SHA-256 digest over the canonical byte string.
+
+Digest strings use:
+
+```text
+sha256:<lowercase-hex-digest>
+```
+
+## Typed blob envelope
+
+A transport-facing lifecycle blob SHOULD use this shape:
+
+```json
+{
+  "schema_version": "tritrpc-agent-sandbox-transport.v0",
+  "blob_id": "blob_agent_sandbox_spec_0001",
+  "media_type": "application/vnd.socioprophet.agent-sandbox-spec+json;v=0",
+  "semantic_schema_ref": "capability-fabric:agent-sandbox-lifecycle.v0#/AgentSandboxSpec",
+  "payload_digest": "sha256:...",
+  "payload": { "...": "..." },
+  "attestation_ref": "github-attestation://..."
+}
+```
+
+TriTRPC implementations MAY carry `payload` inline for fixtures and small objects, or replace it with a `payload_ref` for large artifacts.
+
+## Failure-bundle no-push invariant
+
+A transport profile MUST preserve the failure-policy invariant from the canonical standard:
+
+- infrastructure/model/tool failures MUST NOT be represented as write-authorized outcomes;
+- `allow_partial_push` MUST be false for infrastructure failure bundles;
+- `allow_push_after_infra_failure` MUST be false for infrastructure failure bundles;
+- failure bundles SHOULD be sealed as artifacts or receipts, not converted into branch mutations.
+
+This is specifically intended to prevent the observed coding-agent failure mode where a model quota error enters a commit/push path during teardown.
+
+## Inception and genesis carriage
+
+An inception phase SHOULD emit an `AgentSandboxSpec` typed blob.
+
+A genesis phase SHOULD emit an `AgentGenesisManifest` typed blob.
+
+The genesis manifest SHOULD reference:
+- the exact control-plane revision;
+- the target workspace revision;
+- tool policy;
+- egress policy;
+- credential policy;
+- failure policy;
+- receipt policy.
+
+TriTRPC transport fixtures SHOULD prove that these references and digests are stable under canonical serialization.
+
+## Receipt carriage
+
+Every phase receipt carried by TriTRPC SHOULD include:
+- phase;
+- outcome;
+- payload digest;
+- signature or attestation reference;
+- parent sandbox identifier.
+
+Receipts MAY be carried as standalone typed blobs or bundled with the corresponding object.
+
+## Verification expectations
+
+A TriTRPC transport verifier SHOULD check:
+1. media type is recognized;
+2. semantic schema reference points to the standards source;
+3. canonical JSON digest matches payload;
+4. failure bundles preserve no-push invariants;
+5. phase receipt digest references are internally consistent;
+6. protected-path or write-policy semantics are referenced, not redefined.
+
+## Repository placement
+
+This repository owns:
+- this transport profile;
+- example typed lifecycle blobs;
+- transport verifier scripts;
+- deterministic fixtures proving digest/reference behavior.
+
+The standards repository owns:
+- lifecycle object semantics;
+- field meaning;
+- controllability classes;
+- proof-strength constraints;
+- receipt obligations.
diff --git a/fixtures/agent_sandbox_transport/failure_bundle.transport.example.json b/fixtures/agent_sandbox_transport/failure_bundle.transport.example.json
new file mode 100644
index 0000000..96e8703
--- /dev/null
+++ b/fixtures/agent_sandbox_transport/failure_bundle.transport.example.json
@@ -0,0 +1,22 @@
+{
+  "schema_version": "tritrpc-agent-sandbox-transport.v0",
+  "blob_id": "blob_agent_failure_bundle_0001",
+  "media_type": "application/vnd.socioprophet.agent-failure-bundle+json;v=0",
+  "semantic_schema_ref": "capability-fabric:agent-sandbox-lifecycle.v0#/AgentFailureBundle",
+  "payload_digest": "sha256:bc7bf0ac87b530c1c64543511fd07ede7509684a0cc2fb18cda9c64e2c72351b",
+  "payload": {
+    "schema_version": "agent-sandbox-lifecycle.v0",
+    "sandbox_id": "sandbox_tritrpc_pr_comment_0001",
+    "failure_kind": "model_rate_limited",
+    "failure_class": "INFRASTRUCTURE",
+    "retry_after_seconds": 1094,
+    "allow_partial_push": false,
+    "allow_push_after_infra_failure": false,
+    "evidence_refs": [
+      "github-actions-log://SocioProphet/TriTRPC/actions/runs/copilot-example#user_model_rate_limited"
+    ],
+    "sealed_at": "2026-05-04T00:00:00Z"
+  },
+  "attestation_ref": "github-attestation://example/failure-bundle/0001",
+  "parent_ref": "sandbox_tritrpc_pr_comment_0001"
+}
diff --git a/rust/tritrpc_v1/src/lib.rs b/rust/tritrpc_v1/src/lib.rs
index 4abbfc1..d578ace 100644
--- a/rust/tritrpc_v1/src/lib.rs
+++ b/rust/tritrpc_v1/src/lib.rs
@@ -434,7 +434,7 @@ pub mod avroenc {
         out.extend(enc_string(comp));
         out
     }
-    pub fn enc_Error(code: i32, msg: &str, details: Option<&[u8]>) -> Vec<u8> {
+    pub fn enc_error(code: i32, msg: &str, details: Option<&[u8]>) -> Vec<u8> {
         let mut out = Vec::new();
         out.extend(enc_int(code));
         out.extend(enc_string(msg));
diff --git a/schemas/jsonschema/agent-sandbox-transport.v0.schema.json b/schemas/jsonschema/agent-sandbox-transport.v0.schema.json
new file mode 100644
index 0000000..8ea7428
--- /dev/null
+++ b/schemas/jsonschema/agent-sandbox-transport.v0.schema.json
@@ -0,0 +1,37 @@
+{
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "$id": "https://schemas.socioprophet.example/tritrpc/agent-sandbox-transport.v0.schema.json",
+  "title": "TriTRPC Agent Sandbox Transport Blob v0",
+  "type": "object",
+  "additionalProperties": false,
+  "required": [
+    "schema_version",
+    "blob_id",
+    "media_type",
+    "semantic_schema_ref",
+    "payload_digest"
+  ],
+  "properties": {
+    "schema_version": { "type": "string", "const": "tritrpc-agent-sandbox-transport.v0" },
+    "blob_id": { "type": "string", "minLength": 1 },
+    "media_type": {
+      "type": "string",
+      "enum": [
+        "application/vnd.socioprophet.agent-sandbox-spec+json;v=0",
+        "application/vnd.socioprophet.agent-genesis-manifest+json;v=0",
+        "application/vnd.socioprophet.agent-failure-bundle+json;v=0",
+        "application/vnd.socioprophet.agent-sandbox-receipt+json;v=0"
+      ]
+    },
+    "semantic_schema_ref": { "type": "string", "pattern": "^capability-fabric:agent-sandbox-lifecycle\\.v0#/.+" },
+    "payload_digest": { "type": "string", "pattern": "^sha256:[0-9a-f]{64}$" },
+    "payload": { "type": "object" },
+    "payload_ref": { "type": "string" },
+    "attestation_ref": { "type": "string" },
+    "parent_ref": { "type": "string" }
+  },
+  "oneOf": [
+    { "required": ["payload"] },
+    { "required": ["payload_ref"] }
+  ]
+}
diff --git a/spec/drafts/path_h_semantic_wire/README.md b/spec/drafts/path_h_semantic_wire/README.md
new file mode 100644
index 0000000..4cbf64a
--- /dev/null
+++ b/spec/drafts/path_h_semantic_wire/README.md
@@ -0,0 +1,95 @@
+# Path-H Semantic Wire Fixtures
+
+Status: draft fixture slice  
+Scope: TritRPC Path-H hot-path control frames bound to Semantic SerDes projections
+
+## Purpose
+
+This slice adds executable fixture coverage for the Path-H semantic-wire contract.
+It complements the Path-H qutrit / hybrid control annex by binding the hot
+control frame to Semantic SerDes objects without placing full semantic payloads
+or quantum states on the hot path.
+
+The contract is:
+
+```text
+SemanticCell / SHIR assertion
+  -> SemanticControlCodebook
+  -> WireSemanticProjection
+  -> RouteProjectionBundle
+  -> Path-H hot frame
+  -> receipt / replay / projection-loss report
+```
+
+## Hot-path rule
+
+Path-H semantic frames carry only compact handles and ternary coordinates:
+
+- `CTRL243`
+- `route_h`
+- `projection_id`
+- `sem243_ref`
+- `state243_ref`
+- `schema_h`
+- `context_h`
+- `bundle_h`
+- replay epoch and sequence coordinates
+
+They must not carry:
+
+- full semantic payloads
+- sensitive policy objects
+- n-ary assertion graphs
+- trainable semantic tensors
+- quantum states
+
+## Required invariants
+
+The validator in `tools/verify_path_h_semantic_wire.py` enforces these draft
+invariants:
+
+1. `CTRL243.profile` must be `2` for Path-H.
+2. Path-H semantic control must use quantum or hybrid lane, never classical.
+3. Every semantic frame must include `route_h` and `projection_id`.
+4. Every semantic frame must include `sem243_ref` and `state243_ref`.
+5. Sensitive or full semantic payloads must remain off the hot path.
+6. Strict codebook epoch fixtures must not drift from the frame epoch.
+7. Lossy semantic lowering must cite a projection-loss report.
+8. BSM3 frames must use one of the nine canonical qutrit BSM3 codes.
+
+## Fixtures
+
+Positive fixtures live under:
+
+```text
+spec/drafts/path_h_semantic_wire/fixtures/valid/
+```
+
+Negative fixtures live under:
+
+```text
+spec/drafts/path_h_semantic_wire/fixtures/invalid/
+```
+
+Negative fixtures include `expected_error` so they act as regression tests for
+specific failure modes, not only generic failure.
+
+## Validation
+
+Run:
+
+```bash
+python tools/verify_path_h_semantic_wire.py
+```
+
+or through the repository verification surface:
+
+```bash
+make path-h-semantic-wire
+```
+
+## Boundary with Semantic SerDes
+
+Semantic SerDes owns the source meaning, codebook, projection, route bundle,
+receipts, and projection-loss reports. This repository owns the Path-H hot-frame
+invariants that make those handles safe to move over TritRPC.
diff --git a/spec/drafts/path_h_semantic_wire/fixtures/valid/bsm3_semantic_witness_frame.json b/spec/drafts/path_h_semantic_wire/fixtures/valid/bsm3_semantic_witness_frame.json
new file mode 100644
index 0000000..6a2fbff
--- /dev/null
+++ b/spec/drafts/path_h_semantic_wire/fixtures/valid/bsm3_semantic_witness_frame.json
@@ -0,0 +1,38 @@
+{
+  "fixture_name": "valid_path_h_bsm3_semantic_witness_frame",
+  "kind": "TELEPORT.BSM3",
+  "epoch_id": "epoch:path-h-semantic-wire:2026-05-12T00:00:00Z",
+  "codebook_version": "sem243-control-path-h-v0.1.0",
+  "ctrl243": {
+    "profile": 2,
+    "lane": 1,
+    "evidence": 1,
+    "fallback": 1,
+    "routefmt": 1
+  },
+  "route_h": "handle:route-path-h-bsm3-semantic-witness-v1",
+  "payload": {
+    "seq": 1843,
+    "ttl_ms": 1000,
+    "ts_ns": 1778709000100000000,
+    "pair_id": "pair:path-h-qutrit-001",
+    "basis_id": 3,
+    "bsm3_code": "12",
+    "projection_id": "wire-projection-path-h-bsm3-witness-001",
+    "sem243_ref": "sem243:qutrit.teleport.witness",
+    "state243_ref": "state243:qutrit-bsm3:v0.1",
+    "schema_h": "handle:schema-path-h-bsm3-v0.1",
+    "context_h": "handle:context-qutrit-link-001",
+    "bundle_h": "handle:bundle-bsm3-witness-001",
+    "semantic_projection_mode": "OPAQUE_HANDLE_ONLY",
+    "truth_class": "OBSERVED",
+    "control_evidence": "sampled",
+    "sensitive_off_hot_path": true,
+    "defer_ok": true
+  },
+  "receipt": {
+    "semantic_receipt_h": "handle:receipt-path-h-bsm3-witness-001",
+    "replay_required": true,
+    "projection_loss_report_ref": null
+  }
+}
diff --git a/spec/drafts/path_h_semantic_wire/fixtures/valid/permission_claim_frame.json b/spec/drafts/path_h_semantic_wire/fixtures/valid/permission_claim_frame.json
new file mode 100644
index 0000000..954d1a4
--- /dev/null
+++ b/spec/drafts/path_h_semantic_wire/fixtures/valid/permission_claim_frame.json
@@ -0,0 +1,35 @@
+{
+  "fixture_name": "valid_path_h_permission_claim_frame",
+  "kind": "SEMANTIC.CONTROL",
+  "epoch_id": "epoch:path-h-semantic-wire:2026-05-12T00:00:00Z",
+  "codebook_version": "sem243-control-path-h-v0.1.0",
+  "ctrl243": {
+    "profile": 2,
+    "lane": 2,
+    "evidence": 2,
+    "fallback": 1,
+    "routefmt": 1
+  },
+  "route_h": "handle:route-path-h-permission-claim-v1",
+  "payload": {
+    "seq": 1842,
+    "ttl_ms": 5000,
+    "ts_ns": 1778709000000000000,
+    "basis_id": 7,
+    "projection_id": "wire-projection-path-h-permission-claim-001",
+    "sem243_ref": "sem243:policy.permission.claim",
+    "state243_ref": "state243:allow-mid-deny:v0.1",
+    "schema_h": "handle:schema-shir-assertion-v0.1",
+    "context_h": "handle:context-actor-action-resource-condition",
+    "bundle_h": "handle:bundle-permission-claim-001",
+    "semantic_projection_mode": "OPAQUE_HANDLE_ONLY",
+    "truth_class": "ASSERTED",
+    "control_evidence": "verified",
+    "sensitive_off_hot_path": true
+  },
+  "receipt": {
+    "semantic_receipt_h": "handle:receipt-path-h-permission-claim-001",
+    "replay_required": true,
+    "projection_loss_report_ref": null
+  }
+}
diff --git a/spec/slices/scoped_disclosure_v0/README.md b/spec/slices/scoped_disclosure_v0/README.md
new file mode 100644
index 0000000..932b607
--- /dev/null
+++ b/spec/slices/scoped_disclosure_v0/README.md
@@ -0,0 +1,59 @@
+# Scoped Disclosure Slice v0
+
+## Purpose
+
+This slice defines the first transport-facing method pack for governed disclosure rooms.
+
+It does **not** attempt to make TriTRPC the canonical home of social doctrine. The doctrine layer belongs in the shared governance standards repository. This slice instead freezes the method surface that a deterministic transport layer needs in order to carry room creation, disclosure append, relay governance, moderation, reveal, and replay materialization.
+
+## Status
+
+This slice is a **composition-level design pack** for TriTRPC.
+
+It is not yet part of the stable TritRPC v1 normative wire canon. It is a reviewable slice pack that can later be bound to deterministic fixtures and cross-language pack/unpack tests.
+
+## Slice goals
+
+The slice exists to prove that disclosure governance can travel over the same deterministic transport discipline already used for policy, evidence, and replay flows.
+
+Minimum goals:
+
+- typed room-open request and response shapes
+- typed disclosure append request and response shapes
+- explicit relay authorization and denial flows
+- explicit moderation decision flows
+- explicit reveal request and reveal decision flows
+- first-class evidence append and room materialization
+
+## Method catalog
+
+1. `room.v1.Room/Open`
+2. `room.v1.Disclosure/Append`
+3. `room.v1.Relay/Authorize`
+4. `room.v1.Moderation/Decide`
+5. `room.v1.Reveal/Request`
+6. `room.v1.Reveal/Decide`
+7. `room.v1.Room/Materialize`
+
+See `methods.md` for request/response requirements.
+
+## Cross-repo relationship
+
+- `identity-is-prime-reference` owns root actor and projection semantics.
+- `sociosphere` owns local-first room realization and local relay/storage precedence.
+- `agentplane` owns tenant-side adjudication and evidence-bearing remote moderation or reveal execution.
+- `cairnpath-mesh` owns replay lineage and cairn materialization schemas.
+- `socioprophet-standards-storage` owns the canonical governance doctrine.
+- `TriTRPC` owns the typed transport-facing slice and its eventual deterministic fixtures.
+
+## Constraints
+
+- no viral default fan-out semantics
+- no implicit reveal by transport operator
+- no unconstrained public-provider egress by default
+- no mutation without evidence-bearing follow-up
+- no room materialization without versioned room-contract reference
+
+## Immediate next step
+
+Bind this slice to deterministic fixture vectors once the initial payload schemas stabilize across the standards, identity, and cairn repositories.
diff --git a/spec/slices/scoped_disclosure_v0/methods.md b/spec/slices/scoped_disclosure_v0/methods.md
new file mode 100644
index 0000000..5749568
--- /dev/null
+++ b/spec/slices/scoped_disclosure_v0/methods.md
@@ -0,0 +1,160 @@
+# Scoped Disclosure Slice v0 — Method Catalog
+
+This document defines the transport-facing methods for governed disclosure rooms.
+
+The request and response fields below are conceptual v0 shapes meant to guide shared schema work. They are not yet declared as stable TritRPC v1 canonical payload contracts.
+
+## 1. `room.v1.Room/Open`
+
+### Request
+
+- `room_contract_ref` — versioned reference to the governing room contract
+- `room_id` — deterministic room identifier or proposed identifier
+- `membership_snapshot_ref` — reference to the opening membership set
+- `projection_policy` — attributable / scoped pseudonymous / masked rules
+- `minimum_anonymity_set`
+- `retention_policy_ref`
+
+### Response
+
+- `room_id`
+- `room_contract_version`
+- `room_state_ref`
+- `decision` — accepted / rejected
+- `reason_code`
+
+## 2. `room.v1.Disclosure/Append`
+
+### Request
+
+- `room_id`
+- `event_id`
+- `actor_projection_ref`
+- `discourse_class`
+- `payload_ref` or `payload_inline`
+- `attachment_refs[]`
+- `requested_relay_mode`
+- `client_risk_flags[]`
+
+### Response
+
+- `event_id`
+- `accepted_projection_mode`
+- `accepted_relay_mode`
+- `moderation_state`
+- `evidence_append_ref`
+- `reason_code`
+
+## 3. `room.v1.Relay/Authorize`
+
+### Request
+
+- `room_id`
+- `event_id`
+- `requested_relay_mode`
+- `target_scope_ref`
+- `policy_basis_ref`
+- `requester_role`
+
+### Response
+
+- `event_id`
+- `relay_decision` — allow / deny / escalate
+- `granted_scope_ref`
+- `relay_receipt_ref`
+- `reason_code`
+
+## 4. `room.v1.Moderation/Decide`
+
+### Request
+
+- `room_id`
+- `event_id`
+- `moderation_action`
+- `policy_basis_ref`
+- `evidence_refs[]`
+- `requester_role`
+
+### Response
+
+- `event_id`
+- `moderation_decision_ref`
+- `effective_visibility`
+- `effective_relay_mode`
+- `appeal_path_ref`
+- `reason_code`
+
+## 5. `room.v1.Reveal/Request`
+
+### Request
+
+- `room_id`
+- `target_event_id`
+- `requester_identity_ref`
+- `requester_role`
+- `reason_code`
+- `policy_basis_ref`
+- `requested_reveal_scope`
+
+### Response
+
+- `reveal_request_ref`
+- `submission_state` — accepted / rejected / requires_quorum
+- `reason_code`
+
+## 6. `room.v1.Reveal/Decide`
+
+### Request
+
+- `reveal_request_ref`
+- `deciding_authority_ref` or `quorum_ref`
+- `decision`
+- `authorized_scope`
+- `rationale_ref`
+
+### Response
+
+- `reveal_decision_ref`
+- `decision`
+- `effective_scope`
+- `evidence_append_ref`
+- `reason_code`
+
+## 7. `room.v1.Room/Materialize`
+
+### Request
+
+- `room_id`
+- `materialization_point` — latest / as_of_event / as_of_time
+- `include_withdrawn`
+- `include_moderation_history`
+- `include_reveal_history`
+
+### Response
+
+- `room_state_ref`
+- `cairnline_ref`
+- `room_contract_version`
+- `membership_snapshot_ref`
+- `event_sequence_refs[]`
+
+## Deterministic fixture priorities
+
+The first fixture pass SHOULD prioritize:
+
+1. room open with contract version binding
+2. masked confessional append accepted under minimum anonymity set
+3. allegation append forced into moderator-only relay
+4. reveal request denied without sufficient authority
+5. reveal request approved with explicit decision artifact
+6. room materialization including moderation and reveal lineage
+
+## Invariants
+
+A conforming implementation of this slice MUST preserve these invariants:
+
+- no disclosure append without room-contract reference
+- no reveal decision without reveal request lineage
+- no relay widening without explicit relay receipt
+- no room materialization that hides contract version
+- no mutation of visibility or relay posture without evidence-bearing artifact emission
diff --git a/tools/verify_agent_sandbox_transport.py b/tools/verify_agent_sandbox_transport.py
new file mode 100644
index 0000000..2fd103d
--- /dev/null
+++ b/tools/verify_agent_sandbox_transport.py
@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+
+import hashlib
+import json
+import pathlib
+import sys
+
+ROOT = pathlib.Path(__file__).resolve().parents[1]
+FIXTURE_DIR = ROOT / "fixtures" / "agent_sandbox_transport"
+
+KNOWN_MEDIA_TYPES = {
+    "application/vnd.socioprophet.agent-sandbox-spec+json;v=0",
+    "application/vnd.socioprophet.agent-genesis-manifest+json;v=0",
+    "application/vnd.socioprophet.agent-failure-bundle+json;v=0",
+    "application/vnd.socioprophet.agent-sandbox-receipt+json;v=0",
+}
+
+
+def canonical_digest(payload: object) -> str:
+    data = json.dumps(payload, sort_keys=True, separators=(",", ":"), ensure_ascii=False).encode("utf-8")
+    return "sha256:" + hashlib.sha256(data).hexdigest()
+
+
+def verify_blob(path: pathlib.Path) -> None:
+    blob = json.loads(path.read_text(encoding="utf-8"))
+    assert blob["schema_version"] == "tritrpc-agent-sandbox-transport.v0", path
+    assert blob["media_type"] in KNOWN_MEDIA_TYPES, path
+    assert blob["semantic_schema_ref"].startswith("capability-fabric:agent-sandbox-lifecycle.v0#/"), path
+    assert "payload" in blob or "payload_ref" in blob, path
+    if "payload" in blob:
+        got = canonical_digest(blob["payload"])
+        assert got == blob["payload_digest"], f"{path}: digest mismatch {got} != {blob['payload_digest']}"
+        payload = blob["payload"]
+        if blob["media_type"] == "application/vnd.socioprophet.agent-failure-bundle+json;v=0":
+            assert payload.get("failure_class") in {"INFRASTRUCTURE", "CONTROL_PLANE", "VALIDATION", "POLICY", "USER_INPUT", "REPOSITORY", "UNKNOWN"}, path
+            assert payload.get("allow_partial_push") is False, f"{path}: failure bundle must not allow partial push"
+            assert payload.get("allow_push_after_infra_failure") is False, f"{path}: infra failure must not allow push"
+
+
+def main() -> int:
+    fixtures = sorted(FIXTURE_DIR.glob("*.json"))
+    if not fixtures:
+        raise SystemExit("no agent sandbox transport fixtures found")
+    for fixture in fixtures:
+        verify_blob(fixture)
+    print(f"verified {len(fixtures)} agent sandbox transport fixture(s)")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())