diff --git a/docs/open-collection-gap-analysis/AGENT_PROGRESS.md b/docs/open-collection-gap-analysis/AGENT_PROGRESS.md
index 7017506..17d031a 100644
--- a/docs/open-collection-gap-analysis/AGENT_PROGRESS.md
+++ b/docs/open-collection-gap-analysis/AGENT_PROGRESS.md
@@ -20,7 +20,7 @@ Status values: `Unclaimed`, `Claimed`, `In Progress`, `Review Ready`, `Blocked`,
 
 | Role | Owner | Scope | Since | Current Focus |
 | --- | --- | --- | --- | --- |
-| Supervisor | Codex | Sanity-check completed tracks, run build/test/package/install verification, preserve GitButler branch hygiene, and append progress reports. | 2026-06-14 22:31 NZT | OC-160 queued as a focused gRPC demo server startup and live verification reliability follow-up. |
+| Supervisor | Codex | Sanity-check completed tracks, run build/test/package/install verification, preserve GitButler branch hygiene, and append progress reports. | 2026-06-14 22:31 NZT | OC-160 complete after gRPC demo server startup, diagnostics, live smoke, package, and install verification. |
 
 ## Test Coverage Rules
 
@@ -73,7 +73,7 @@ Use full branch names for stacking existing branches with `but move <child-branc
 | OC-130 | Protocol-native request editor first paint | Done | Codex | `feature/oc-130-protocol-layout-stability` (g0), stacked on `feature/oc-120-preview-media-controls`; implementation commit `a3d3251` | Satisfied by `test/protocolLayoutStability.test.ts` plus shared request editor/protocol regressions: neutral first-paint shell, host invalid-YAML fallback message, direct HTTP/GraphQL/WebSocket/gRPC hydration, no visible HTTP default or stale non-HTTP controls during hydration, layout-stability CSS assertions, no-op round-trip and protocol-aware validation coverage, and request type UX startup regression. | `npx vitest run test/protocolLayoutStability.test.ts` passed 9 tests; `npm run compile` passed; focused `npx vitest run test/protocolLayoutStability.test.ts test/requestTypeUx.test.ts test/runtimeAuthoringUx.test.ts test/schemaRoundTrip.test.ts test/validationService.test.ts` passed 5 files/34 tests; targeted protocol/editor matrix passed 9 files/89 tests; `node scripts\validate-collection.js examples\demo-api` passed 44/44 files; `npm test` passed 25 files/454 tests; `npm run build` passed. | 2026-06-15 12:03 NZT | OC-130 complete. Preserve parallel/unrelated unassigned OC-140 docs IDs `wp`/`tks`/`tkt`/`uxu` and PDF.js media churn IDs `qp`/`ko`; do not commit them to OC-130. |
 | OC-140 | First-class WebSocket lifecycle UX | Done | Codex | `feature/oc-140-websocket-lifecycle-ux` (g0 after restack), stacked on `supervisor/add-websocket-lifecycle-task`; implementation commit `ec0f014`; supervisor/user follow-up commits `d2b93d4`, `1c918d5`, `401a82e`, `3bfc234`, and `b3ff548` | Satisfied by `test/webSocketSupport.test.ts` plus shared command, CodeLens, Copilot, editor, validation, round-trip, and demo regressions: persistent WebSocket sessions now expose connect/disconnect lifecycle operations through one fixed-width stateful editor button plus a separate send-message flow; retain session state and message history; surface editor controls/history, bottom status bar management, command palette/tree/CodeLens actions, and `missio_websocket_session`; route live send-tool WebSocket execution to lifecycle diagnostics; disconnect on editor/session cleanup; prefer freshly posted WebSocket lifecycle requests over stale debounced YAML; extract send-message payloads from the same resolved lifecycle request; keep Send styled as the primary request action; hide the HTTP-style response placeholder/body pane so WebSocket history fills the response area; show millisecond-precision history timestamps; and add local connect-only, repeated-send, and server-push fixtures. | `npm run compile` passed; `npx vitest run test/webSocketSupport.test.ts test/protocolLayoutStability.test.ts` passed 2 files/35 tests; `node scripts/validate-collection.js examples/demo-api` passed 47/47 files; live local WebSocket lifecycle smoke returned `LIVE_WS_LIFECYCLE_SMOKE ok`; `npm test` passed 25 files/465 tests; `npm run build` passed. | 2026-06-15 14:32 NZT | OC-140 complete. WebSocket lifecycle sessions are file-path scoped for editor/command flows, persist for that request until disconnect/close/editor disposal, and are intentionally not shared across separate request files. Preserve unrelated PDF.js media churn IDs `qp`/`ko`. |
 | OC-150 | Runtime assertion variables and WebSocket runtime results UX | Done | Codex | feature/oc-150-runtime-assertion-variables, stacked on supervisor/add-runtime-assertion-variable-task; implementation commit `55dd694`; completion ledger commit `940a696`; acceptance rework commit `a2e63b4`; WebSocket runtime-tab follow-up commit `0cfc7f8`; lifecycle restyle follow-up commit `608eb19`; no-fill send follow-up commit `3e6cee0`; no-fill cancel follow-up commit `7f021ca` | Satisfied by `test/runtimeAuthoringUx.test.ts` for shared variable-aware assertion expression/value/description inputs and dynamic row overlays; `test/runtimeExecutionService.test.ts` for assertion expression/value/description interpolation, after-response script-produced assertion variables avoiding preflight prompts, deterministic unresolved assertion diagnostics, disabled assertions, and HTTP/GraphQL/WebSocket/gRPC runtime parity; `test/unresolvedVars.test.ts` for preserving request/auth preflight while deferring runtime assertion placeholders to runtime diagnostics; `test/webSocketSupport.test.ts` for WebSocket messages/history inside the existing response tab container plus visible runtime assertion/test/action results, theme-coloured no-fill lifecycle controls, blue no-fill Send controls, and red no-fill Cancel controls; `test/protocolLayoutStability.test.ts` for no HTTP response placeholder flash, no duplicate WebSocket response panel, Runtime tab visibility before WebSocket runtime results exist, and non-WebSocket response layout reset after WebSocket. | Rework verification passed: `npm run compile`; `npx vitest run test/runtimeAuthoringUx.test.ts test/runtimeExecutionService.test.ts test/unresolvedVars.test.ts test/webSocketSupport.test.ts test/protocolLayoutStability.test.ts test/responseProvider.test.ts test/sendRequestTool.test.ts` passed 7 files/91 tests; `node scripts/validate-collection.js examples/demo-api` passed 47/47 files; `npm test` passed 25 files/476 tests; `npm run build` passed. Follow-up verification passed: `npx vitest run test/protocolLayoutStability.test.ts test/webSocketSupport.test.ts` passed 2 files/40 tests; `npm run compile` passed; OC-150 matrix passed 7 files/92 tests; `node scripts/validate-collection.js examples/demo-api` passed 47/47 files; `npm run build` passed. Lifecycle restyle verification passed: `npx vitest run test/webSocketSupport.test.ts` passed 26 tests; `npm run compile` passed; `npx vitest run test/protocolLayoutStability.test.ts test/webSocketSupport.test.ts` passed 2 files/40 tests; `npm run build` passed. Send follow-up verification passed: `npx vitest run test/webSocketSupport.test.ts test/protocolLayoutStability.test.ts` passed 2 files/40 tests; `npm run compile` passed; `npm run build` passed. Cancel follow-up verification passed: `npx vitest run test/webSocketSupport.test.ts test/protocolLayoutStability.test.ts` passed 2 files/40 tests; `npm run compile` passed; `npm run build` passed. Supervisor install pass also packaged `C:\Users\chris\AppData\Local\Temp\missio-0.8.0-oc150-rework.vsix` and installed `missio.missio@0.8.0`. | 2026-06-15 16:43 NZT | OC-150 accepted after WebSocket runtime-tab, lifecycle style, send-button style, and cancel-button style follow-ups; no remaining OC-150 action. |
-| OC-160 | gRPC demo server reliability | Unclaimed | - | suggested branch `feature/oc-160-grpc-demo-server-reliability` | Reproduce or explain the failing gRPC demo requests; verify the local gRPC fixture binds the documented `localhost:50051`/`127.0.0.1:50051` endpoint; align `examples/demo-api/opencollection.yml`, gRPC request files, proto paths, and request descriptions; add automated fixture-start smoke coverage for representative or complete gRPC demo requests, including unary, streaming, runtime, and deterministic error demos; cover missing-fixture diagnostics and run shared gRPC/runtime/send-tool/response-provider/schema/validation regressions. | Not started. | 2026-06-15 16:54 NZT | Claim OC-160, reproduce the user-facing failure, then make the gRPC demo startup and smoke-test path reliable before packaging/installing for user verification. |
+| OC-160 | gRPC demo server reliability | Done | Codex | `feature/oc-160-grpc-demo-server-reliability` (h0), parent of `feature/oc-170-request-action-first-click`; implementation commits `839c15d` and supervisor rework commit `96b5040` | Satisfied by `test/grpcSupport.test.ts` and demo fixture docs: reproduced the failing closed-port behavior through Missio execution when only `node examples/demo-api/server.js` is running; documented that gRPC requires the separate deterministic fixture `node examples/demo-api/grpc-server.js`; preserved demo guidance only in request-scoped README/server-log/folder/request docs; removed Missio-demo-specific hints from generic gRPC transport errors; kept raw gRPC diagnostics generic with status code, status name, details/message; and added automated live fixture smoke coverage for unary, metadata/defaults, server-streaming, client-streaming, bidirectional-streaming, deterministic error streaming, and runtime lifecycle demos using an isolated port override so tests do not depend on `localhost:50051` being closed. | Reproduction showed port `127.0.0.1:50051` closed before and after starting only `examples/demo-api/server.js`; the pre-fix Missio execution error was `UNAVAILABLE`/`ECONNREFUSED` without demo guidance. Rework verification passed: source search found no `localDemoFixtureHint`, `Missio gRPC demo fixture`, `x-missio-error-hint`, or generic hint plumbing in gRPC/request-execution/tool paths; focused OC-160 reliability tests passed 3 tests; `npx vitest run test/grpcSupport.test.ts` passed 22 tests; `node scripts/validate-collection.js examples/demo-api` passed 47/47 files; `npm run compile`; `npm test` passed 25 files/490 tests; `npm run build`; `npm run install:local` packaged `C:\Users\chris\AppData\Local\Temp\missio-0.8.0-local.vsix` and installed `missio.missio@0.8.0`. | 2026-06-15 18:03 NZT | OC-160 rework complete. Generic gRPC errors no longer mention the Missio demo fixture; demo start guidance remains in demo docs/logs/request descriptions. |
 
 ## Dependency Map
 
@@ -109,6 +109,32 @@ Record cross-cutting decisions here so parallel agents do not rediscover them.
 
 ## Task Logs
 
+### OC-160 gRPC Demo Server Reliability
+
+- 2026-06-15 17:01 NZT - Codex: Claimed OC-160 and recorded the coverage plan before implementation.
+  GitButler: created `feature/oc-160-grpc-demo-server-reliability`; `but status -fv` showed no unassigned changes before the claim.
+  Coverage: reproduce or concretely explain the current gRPC demo-request failure; verify `localhost:50051`/`127.0.0.1:50051` fixture binding; align `examples/demo-api/opencollection.yml`, gRPC request endpoints, proto paths, folder/request descriptions, and local start guidance; add automated fixture-start smoke coverage for packaged unary, metadata, server-streaming, client-streaming, bidirectional-streaming, deterministic error-stream, and runtime gRPC demos where applicable; add missing-fixture diagnostics coverage; run demo collection validation, targeted gRPC/runtime/send-tool/response-provider/schema/validation regressions, compile, full test, build, package, and install verification.
+  Changed: `docs/open-collection-gap-analysis/AGENT_PROGRESS.md`.
+  Verified: `but status -fv`, OC-160 task page, OC-030 gRPC task page, demo server, gRPC fixture server, and demo collection reviewed; implementation tests not run yet.
+  Next: reproduce the closed-port behavior through Missio execution when only `node examples/demo-api/server.js` is running, then patch fixture guidance/diagnostics/tests.
+
+- 2026-06-15 17:14 NZT - Codex: Completed OC-160 after reproducing the current failure and adding deterministic gRPC fixture diagnostics, docs, and live smoke coverage.
+  GitButler: committed implementation/docs/tests as `839c15d` on `feature/oc-160-grpc-demo-server-reliability` after restacking above `supervisor/add-request-action-first-click-task`; AGENT_PROGRESS closeout committed separately to keep unrelated OC-170 ledger edits out of OC-160.
+  Reproduced: `Test-NetConnection 127.0.0.1 -Port 50051` returned false; hidden `node examples/demo-api/server.js` made HTTP health available on port 3456 but left 50051 closed; the pre-fix Missio execution path for `missio.demo.DemoService/EchoUnary` failed with `UNAVAILABLE`/`ECONNREFUSED 127.0.0.1:50051` and no `node examples/demo-api/grpc-server.js` hint.
+  Changed: `examples/demo-api/README.md`, all packaged `examples/demo-api/gRPC/*.yml` descriptions, `examples/demo-api/server.js`, `examples/demo-api/grpc-server.js`, `src/services/grpcClient.ts`, `src/services/requestExecutionService.ts`, `src/copilot/tools/sendRequestTool.ts`, and `test/grpcSupport.test.ts`.
+  Live smoke: the automated test starts `examples/demo-api/grpc-server.js` on `127.0.0.1:50051` and executes `echo-unary.yml`, `echo-metadata-defaults.yml`, `stream-users.yml`, `upload-users-client-streaming.yml`, `chat-users-bidi-streaming.yml`, `stream-users-error.yml`, and `runtime-unary-lifecycle.yml` through `RequestExecutionService`; the deterministic error stream retains the partial Ada response before the INTERNAL error, and runtime lifecycle reports 4 passed, 0 failed, 0 skipped.
+  Verified: missing-fixture diagnostic regression passed; live gRPC fixture smoke passed; `npx vitest run test/grpcSupport.test.ts` passed 21 tests; `npx vitest run test/grpcSupport.test.ts test/runtimeExecutionService.test.ts test/responseProvider.test.ts test/sendRequestTool.test.ts test/schemaRoundTrip.test.ts test/validationService.test.ts` passed 6 files/56 tests; `node scripts/validate-collection.js examples/demo-api` passed 47/47 files; `npm run compile` passed; `npm test` passed 25 files/479 tests; `npm run build` passed; `npm run install:local` packaged `C:\Users\chris\AppData\Local\Temp\missio-0.8.0-local.vsix`, confirmed `examples/` in the VSIX, and installed `missio.missio@0.8.0`.
+  Next: OC-160 is complete; only unrelated OC-170 ledger planning changes should remain unassigned if that task has not been claimed.
+
+- 2026-06-15 17:58 NZT - Codex: Addressed supervisor rework by removing Missio-demo-specific gRPC fixture hints from generic transport errors.
+  GitButler: committed implementation/test rework as `96b5040` (`Remove demo-specific gRPC transport hints`) on `feature/oc-160-grpc-demo-server-reliability`; the branch now sits under the completed OC-170 branch in the applied stack and `zz` was clean immediately after the implementation commit.
+  Rework: removed `_localDemoFixtureHint()` from `GrpcClient`, removed the `hint` field from gRPC error summaries/normalized errors, removed `x-missio-error-hint` and protocol-error body `hint` output, and removed Copilot send-tool propagation of arbitrary `err.hint`. gRPC errors now report the generic status code/name/details/message only.
+  Demo guidance: kept start guidance in `examples/demo-api/README.md`, `examples/demo-api/server.js` logs, `examples/demo-api/grpc-server.js` logs, and the gRPC folder/request docs. Did not add a runtime-script request-scoped hint because the current runtime cannot preflight connection refusal consistently before transport execution across unary, server-streaming, client-streaming, and bidirectional gRPC requests; post-response runtime only applies to unary runtime requests and would be partial.
+  Test hardening: changed the packaged demo fixture smoke to start `examples/demo-api/grpc-server.js` with `MISSIO_GRPC_PORT=0`, read the bound loopback port from readiness output, override `LOCAL.grpcBaseUrl` in the in-memory demo collection, and stop the child process after the smoke. The suite no longer requires `localhost:50051` to be closed and still covers all 7 packaged gRPC demo requests through Missio execution.
+  Changed: `examples/demo-api/grpc-server.js`, `src/services/grpcClient.ts`, `src/services/requestExecutionService.ts`, `src/copilot/tools/sendRequestTool.ts`, `test/grpcSupport.test.ts`, and this ledger.
+  Verified: `npx vitest run test/grpcSupport.test.ts -t "gRPC demo server reliability"` passed 3 tests; `npx vitest run test/grpcSupport.test.ts` passed 22 tests; `npm run compile` passed; `node scripts/validate-collection.js examples/demo-api` passed 47/47 files; `rg -n "localDemoFixtureHint|Missio gRPC demo fixture|x-missio-error-hint|hint" src/services/grpcClient.ts src/services/requestExecutionService.ts src/copilot/tools/sendRequestTool.ts` returned no matches; `npm test` passed 25 files/490 tests; `npm run build` passed; `npm run install:local` packaged `C:\Users\chris\AppData\Local\Temp\missio-0.8.0-local.vsix` and installed `missio.missio@0.8.0`.
+  Next: OC-160 rework is complete; generic transport diagnostics stay unbranded and demo guidance remains request-scoped.
+
 ### Supervisor Reports
 
 - 2026-06-15 16:54 NZT - Codex Supervisor: Added OC-160 as a focused follow-up for gRPC demo server reliability after user reported all gRPC demo requests failing, likely because no local fixture is listening on `localhost:50051`.
diff --git a/examples/demo-api/README.md b/examples/demo-api/README.md
new file mode 100644
index 0000000..bfca2e5
--- /dev/null
+++ b/examples/demo-api/README.md
@@ -0,0 +1,17 @@
+# Missio Demo API
+
+The demo collection is local-only and does not require internet access for protocol fixtures.
+
+Start the HTTP, GraphQL, WebSocket, runtime, auth, redirect, and binary upload fixture:
+
+```powershell
+node examples/demo-api/server.js
+```
+
+Start the gRPC fixture in a second terminal before sending requests under `examples/demo-api/gRPC/`:
+
+```powershell
+node examples/demo-api/grpc-server.js
+```
+
+The gRPC fixture binds `127.0.0.1:50051`, matching `LOCAL.grpcBaseUrl=localhost:50051` in `opencollection.yml`. If a gRPC demo request reports `UNAVAILABLE` or `ECONNREFUSED`, start or restart that fixture and retry with the LOCAL environment selected.
diff --git a/examples/demo-api/gRPC/chat-users-bidi-streaming.yml b/examples/demo-api/gRPC/chat-users-bidi-streaming.yml
index e1b3fa3..c2bffc1 100644
--- a/examples/demo-api/gRPC/chat-users-bidi-streaming.yml
+++ b/examples/demo-api/gRPC/chat-users-bidi-streaming.yml
@@ -25,4 +25,4 @@ grpc:
             "requestId": "{{grpcRequestId}}-chat-2"
           }
         }
-docs: Run `node examples/demo-api/grpc-server.js`, select the LOCAL environment, then send this bidirectional-streaming gRPC request.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, then send this bidirectional-streaming gRPC request to `LOCAL.grpcBaseUrl=localhost:50051`.
diff --git a/examples/demo-api/gRPC/echo-metadata-defaults.yml b/examples/demo-api/gRPC/echo-metadata-defaults.yml
index c213e31..ceabe04 100644
--- a/examples/demo-api/gRPC/echo-metadata-defaults.yml
+++ b/examples/demo-api/gRPC/echo-metadata-defaults.yml
@@ -17,4 +17,4 @@ grpc:
         "requestId": "{{grpcRequestId}}"
       }
     }
-docs: Run `node examples/demo-api/grpc-server.js` to verify collection, folder, and request metadata merging.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, then send this unary gRPC request to verify collection, folder, and request metadata merging at `localhost:50051`.
diff --git a/examples/demo-api/gRPC/echo-unary.yml b/examples/demo-api/gRPC/echo-unary.yml
index 37d41df..d8bd4a0 100644
--- a/examples/demo-api/gRPC/echo-unary.yml
+++ b/examples/demo-api/gRPC/echo-unary.yml
@@ -23,4 +23,4 @@ runtime:
   auth:
     type: bearer
     token: "{{grpcToken}}"
-docs: Run `node examples/demo-api/grpc-server.js`, select the LOCAL environment, then send this unary gRPC request.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, then send this unary gRPC request to `LOCAL.grpcBaseUrl=localhost:50051`.
diff --git a/examples/demo-api/gRPC/folder.yml b/examples/demo-api/gRPC/folder.yml
index a96e666..0bde27b 100644
--- a/examples/demo-api/gRPC/folder.yml
+++ b/examples/demo-api/gRPC/folder.yml
@@ -5,4 +5,4 @@ request:
   metadata:
     - name: x-demo-folder
       value: folder-{{grpcRequestId}}
-docs: Run `node examples/demo-api/grpc-server.js` before sending these local gRPC requests.
+docs: From the repository root, run `node examples/demo-api/grpc-server.js` before sending these local gRPC requests. The fixture binds `127.0.0.1:50051`, matching `LOCAL.grpcBaseUrl=localhost:50051`.
diff --git a/examples/demo-api/gRPC/runtime-unary-lifecycle.yml b/examples/demo-api/gRPC/runtime-unary-lifecycle.yml
index 0adc1c7..77f85ce 100644
--- a/examples/demo-api/gRPC/runtime-unary-lifecycle.yml
+++ b/examples/demo-api/gRPC/runtime-unary-lifecycle.yml
@@ -63,4 +63,4 @@ runtime:
       variable:
         scope: runtime
         name: grpcRuntimeRequestId
-docs: Run `node examples/demo-api/grpc-server.js`, select the LOCAL environment, optionally edit the request Runtime tab, then send to see unary gRPC metadata/message mutation plus runtime tests, assertions, logs, and set-variable actions.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, optionally edit the request Runtime tab, then send to `LOCAL.grpcBaseUrl=localhost:50051` to see unary gRPC metadata/message mutation plus runtime tests, assertions, logs, and set-variable actions.
diff --git a/examples/demo-api/gRPC/stream-users-error.yml b/examples/demo-api/gRPC/stream-users-error.yml
index 9300b0c..052f474 100644
--- a/examples/demo-api/gRPC/stream-users-error.yml
+++ b/examples/demo-api/gRPC/stream-users-error.yml
@@ -14,4 +14,4 @@ grpc:
         "requestId": "{{grpcRequestId}}-error"
       }
     }
-docs: Run `node examples/demo-api/grpc-server.js`; this server-streaming request emits one response and then a deterministic gRPC INTERNAL error for diagnostics testing.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, then send this server-streaming request. It emits one response from `localhost:50051` and then a deterministic gRPC INTERNAL error for diagnostics testing.
diff --git a/examples/demo-api/gRPC/stream-users.yml b/examples/demo-api/gRPC/stream-users.yml
index 0cf1bb3..de75faa 100644
--- a/examples/demo-api/gRPC/stream-users.yml
+++ b/examples/demo-api/gRPC/stream-users.yml
@@ -14,4 +14,4 @@ grpc:
         "requestId": "{{grpcRequestId}}"
       }
     }
-docs: Run `node examples/demo-api/grpc-server.js`, select the LOCAL environment, then send this server-streaming gRPC request.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, then send this server-streaming gRPC request to `LOCAL.grpcBaseUrl=localhost:50051`.
diff --git a/examples/demo-api/gRPC/upload-users-client-streaming.yml b/examples/demo-api/gRPC/upload-users-client-streaming.yml
index efc30bc..cffdf94 100644
--- a/examples/demo-api/gRPC/upload-users-client-streaming.yml
+++ b/examples/demo-api/gRPC/upload-users-client-streaming.yml
@@ -32,4 +32,4 @@ runtime:
   auth:
     type: bearer
     token: "{{grpcToken}}"
-docs: Run `node examples/demo-api/grpc-server.js`, select the LOCAL environment, then send this client-streaming gRPC request.
+docs: Run `node examples/demo-api/grpc-server.js` from the repository root, select the LOCAL environment, then send this client-streaming gRPC request to `LOCAL.grpcBaseUrl=localhost:50051`.
diff --git a/examples/demo-api/grpc-server.js b/examples/demo-api/grpc-server.js
index b8a1651..ed44385 100644
--- a/examples/demo-api/grpc-server.js
+++ b/examples/demo-api/grpc-server.js
@@ -5,7 +5,11 @@ const grpc = require('@grpc/grpc-js');
 const protoLoader = require('@grpc/proto-loader');
 
 const HOST = '127.0.0.1';
-const PORT = 50051;
+const PORT = Number(process.env.MISSIO_GRPC_PORT ?? '50051');
+if (!Number.isInteger(PORT) || PORT < 0 || PORT > 65535) {
+  console.error(`Invalid MISSIO_GRPC_PORT value: ${process.env.MISSIO_GRPC_PORT}`);
+  process.exit(1);
+}
 const ADDRESS = `${HOST}:${PORT}`;
 const PROTO_DIR = path.join(__dirname, 'proto');
 const PROTO_PATH = path.join(PROTO_DIR, 'services', 'missio_demo.proto');
@@ -98,13 +102,46 @@ server.addService(proto.DemoService.service, {
   streamUsersWithError,
 });
 
+let shutdownStarted = false;
+
+function shutdown(signal) {
+  if (shutdownStarted) return;
+  shutdownStarted = true;
+  console.log(`Received ${signal}; shutting down the gRPC demo server.`);
+
+  const forceTimer = setTimeout(() => {
+    console.error('Graceful gRPC shutdown timed out; forcing shutdown.');
+    server.forceShutdown();
+    process.exitCode = 1;
+  }, 2_000);
+  forceTimer.unref();
+
+  server.tryShutdown((error) => {
+    clearTimeout(forceTimer);
+    if (error) {
+      console.error(error);
+      server.forceShutdown();
+      process.exitCode = 1;
+      return;
+    }
+    console.log('Missio gRPC Demo Server stopped.');
+  });
+}
+
 server.bindAsync(ADDRESS, grpc.ServerCredentials.createInsecure(), (err, port) => {
   if (err) {
     console.error(err);
     process.exit(1);
   }
   server.start();
-  console.log(`Missio gRPC Demo Server -> ${ADDRESS}`);
+  process.once('SIGINT', () => shutdown('SIGINT'));
+  process.once('SIGTERM', () => shutdown('SIGTERM'));
+  const boundAddress = `${HOST}:${port}`;
+  console.log(`Missio gRPC Demo Server -> ${boundAddress}`);
+  console.log('Start command: node examples/demo-api/grpc-server.js');
+  console.log(port === 50051
+    ? 'OpenCollection LOCAL.grpcBaseUrl: localhost:50051'
+    : `OpenCollection LOCAL.grpcBaseUrl override for this process: ${boundAddress}`);
   console.log(`Proto: ${PROTO_PATH}`);
   console.log('Methods:');
   console.log('  missio.demo.DemoService/EchoUnary');
@@ -112,5 +149,5 @@ server.bindAsync(ADDRESS, grpc.ServerCredentials.createInsecure(), (err, port) =
   console.log('  missio.demo.DemoService/UploadUsers');
   console.log('  missio.demo.DemoService/ChatUsers');
   console.log('  missio.demo.DemoService/StreamUsersWithError');
-  console.log(`Listening on ${HOST}:${port}. Press Ctrl+C to stop.`);
+  console.log(`Listening on ${boundAddress}. Press Ctrl+C to stop.`);
 });
diff --git a/examples/demo-api/server.js b/examples/demo-api/server.js
index 7d0b48f..66a2343 100644
--- a/examples/demo-api/server.js
+++ b/examples/demo-api/server.js
@@ -6,6 +6,10 @@
  *
  * Runs on http://localhost:3456
  *
+ * gRPC demo requests use a separate local fixture:
+ *   node examples/demo-api/grpc-server.js
+ * It binds 127.0.0.1:50051, matching LOCAL.grpcBaseUrl in opencollection.yml.
+ *
  * Routes:
  *   GET  /health              – liveness check
  *   POST /upload              – accepts any binary body, returns upload info as JSON
@@ -496,6 +500,9 @@ server.listen(PORT, '127.0.0.1', () => {
   console.log(`  WS   ws://localhost:${PORT}/ws/push        (server push after connect)`);
   console.log(`  WS   ws://localhost:${PORT}/ws/close       (deterministic server close)`);
   console.log(`  WS   ws://localhost:${PORT}/ws/reject      (deterministic upgrade rejection)`);
+  console.log('\ngRPC demo requests:');
+  console.log('  Start the separate gRPC fixture: node examples/demo-api/grpc-server.js');
+  console.log('  It binds 127.0.0.1:50051, matching LOCAL.grpcBaseUrl=localhost:50051.');
   console.log('\nFixture files for demo requests:');
   console.log(`  ${path.join(FIXTURES_DIR, 'sample.png')}`);
   console.log(`  ${path.join(FIXTURES_DIR, 'sample.txt')}`);
diff --git a/test/grpcSupport.test.ts b/test/grpcSupport.test.ts
index 415eba9..095748e 100644
--- a/test/grpcSupport.test.ts
+++ b/test/grpcSupport.test.ts
@@ -1,7 +1,9 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import * as fs from 'fs';
+import * as net from 'net';
 import * as os from 'os';
 import * as path from 'path';
+import { spawn, type ChildProcessWithoutNullStreams } from 'child_process';
 import Ajv from 'ajv';
 import { parse as parseYaml, stringify as stringifyYaml } from 'yaml';
 import * as grpc from '@grpc/grpc-js';
@@ -38,6 +40,12 @@ function validateGrpcRequestData(data: unknown): void {
 let server: grpc.Server | undefined;
 let address = '';
 
+interface DemoGrpcServerProcess {
+  child: ChildProcessWithoutNullStreams;
+  target: string;
+  output: () => string;
+}
+
 function makeContext() {
   const state = new Map<string, unknown>();
   return {
@@ -91,6 +99,135 @@ function makeCollection(): MissioCollection {
   };
 }
 
+function makeDemoCollection(): MissioCollection {
+  const filePath = path.join(demoRoot, 'opencollection.yml');
+  return {
+    id: filePath,
+    filePath,
+    rootDir: demoRoot,
+    data: parseYaml(fs.readFileSync(filePath, 'utf-8')) as any,
+  };
+}
+
+function readDemoGrpcRequest(fileName: string) {
+  return parseYaml(fs.readFileSync(path.join(demoRoot, 'gRPC', fileName), 'utf-8'));
+}
+
+function readDemoGrpcFolderDefaults(): RequestDefaults | undefined {
+  return parseYaml(fs.readFileSync(path.join(demoRoot, 'gRPC', 'folder.yml'), 'utf-8')).request;
+}
+
+function setDemoGrpcBaseUrl(collection: MissioCollection, value: string): void {
+  const environments = collection.data.config?.environments ?? [];
+  const local = environments.find(env => env.name === 'LOCAL');
+  if (!local) throw new Error('Demo collection is missing LOCAL environment.');
+  local.variables ??= [];
+  const variable = local.variables.find(item => item.name === 'grpcBaseUrl');
+  if (variable) variable.value = value;
+  else local.variables.push({ name: 'grpcBaseUrl', value });
+}
+
+async function withUnavailableLocalGrpcTarget<T>(run: (target: string) => Promise<T>): Promise<T> {
+  const sockets = new Set<net.Socket>();
+  const server = net.createServer();
+  server.on('connection', socket => {
+    sockets.add(socket);
+    socket.once('close', () => sockets.delete(socket));
+    socket.destroy();
+  });
+  await new Promise<void>((resolve, reject) => {
+    server.once('error', reject);
+    server.listen(0, '127.0.0.1', () => resolve());
+  });
+  const bound = server.address();
+  if (!bound || typeof bound === 'string') {
+    throw new Error('Unable to create an unavailable local gRPC target.');
+  }
+
+  try {
+    return await run(`127.0.0.1:${bound.port}`);
+  } finally {
+    for (const socket of sockets) socket.destroy();
+    await new Promise<void>((resolve, reject) => {
+      server.close(error => error ? reject(error) : resolve());
+    });
+  }
+}
+
+function makeDemoGrpcExecution(environmentService: EnvironmentService): RequestExecutionService {
+  return new RequestExecutionService(
+    { send: vi.fn(), buildResolvedRequest: vi.fn(), cancelAll: vi.fn() } as any,
+    undefined,
+    new GrpcClient(environmentService),
+    new RuntimeExecutionService((runtimeCollection, folderDefaults, environmentName) =>
+      environmentService.resolveVariables(runtimeCollection, folderDefaults, environmentName),
+    ),
+  );
+}
+
+function startDemoGrpcServerProcess(): Promise<DemoGrpcServerProcess> {
+  const child = spawn(process.execPath, [path.join(demoRoot, 'grpc-server.js')], {
+    cwd: path.resolve(__dirname, '..'),
+    env: { ...process.env, MISSIO_GRPC_PORT: '0' },
+    stdio: 'pipe',
+    windowsHide: true,
+  });
+
+  return new Promise((resolve, reject) => {
+    let output = '';
+    let settled = false;
+    const cleanup = () => {
+      clearTimeout(timer);
+      child.off('exit', onExit);
+      child.off('error', onError);
+    };
+    const finish = (error?: Error, port?: string) => {
+      if (settled) return;
+      settled = true;
+      cleanup();
+      if (error) reject(error);
+      else resolve({ child, target: `127.0.0.1:${port}`, output: () => output });
+    };
+    const onData = (chunk: Buffer) => {
+      output += chunk.toString('utf-8');
+      const match = output.match(/Listening on 127\.0\.0\.1:(\d+)/i);
+      if (match) {
+        finish(undefined, match[1]);
+      }
+    };
+    const onExit = (code: number | null, signal: NodeJS.Signals | null) => {
+      finish(new Error(`gRPC demo server exited before readiness (code=${code}, signal=${signal}). Output:\n${output}`));
+    };
+    const onError = (error: Error) => finish(error);
+    const timer = setTimeout(() => {
+      finish(new Error(`Timed out waiting for gRPC demo server readiness. Output:\n${output}`));
+    }, 10_000);
+
+    child.stdout.on('data', onData);
+    child.stderr.on('data', onData);
+    child.once('exit', onExit);
+    child.once('error', onError);
+  });
+}
+
+async function stopDemoGrpcServerProcess(serverProcess: DemoGrpcServerProcess): Promise<void> {
+  if (serverProcess.child.exitCode !== null) return;
+  serverProcess.child.kill('SIGTERM');
+  await new Promise<void>((resolve, reject) => {
+    const timer = setTimeout(() => {
+      serverProcess.child.kill('SIGKILL');
+      reject(new Error(`Timed out stopping the gRPC demo server. Output:\n${serverProcess.output()}`));
+    }, 2_000);
+    serverProcess.child.once('close', () => {
+      clearTimeout(timer);
+      resolve();
+    });
+  });
+  if (process.platform !== 'win32' && !serverProcess.output().includes('Missio gRPC Demo Server stopped.')) {
+    throw new Error(`gRPC demo server did not report graceful shutdown. Output:\n${serverProcess.output()}`);
+  }
+}
+
 function makeUnaryRequest(url: string) {
   return {
     info: { name: 'Echo unary', type: 'grpc' as const },
@@ -752,3 +889,162 @@ describe('gRPC integration surfaces', () => {
     expect(response.runtime?.actions[0]).toMatchObject({ target: 'runtime.grpcRuntimeRequestId' });
   });
 });
+
+describe('gRPC demo server reliability', () => {
+  it('keeps unavailable local gRPC target diagnostics generic and unbranded', async () => {
+    await withUnavailableLocalGrpcTarget(async unavailableTarget => {
+      const environmentService = makeEnvironmentService();
+      const collection = makeDemoCollection();
+      const request = readDemoGrpcRequest('echo-unary.yml') as any;
+      request.grpc.url = unavailableTarget;
+      const execution = makeDemoGrpcExecution(environmentService);
+
+      let error: unknown;
+      try {
+        await execution.send(
+          request,
+          collection,
+          readDemoGrpcFolderDefaults(),
+          undefined,
+          undefined,
+          'LOCAL',
+        );
+      } catch (err) {
+        error = err;
+      }
+
+      expect(error).toBeInstanceOf(Error);
+      expect((error as any).code).toBe('GRPC_UNAVAILABLE');
+      expect((error as any).grpcStatus).toBe(grpc.status.UNAVAILABLE);
+      expect((error as any).grpcDetails).toEqual(expect.any(String));
+      expect((error as Error).message).toMatch(/UNAVAILABLE/i);
+      expect((error as Error).message).not.toMatch(/Missio gRPC demo fixture|node examples\/demo-api\/grpc-server\.js/i);
+      expect((error as any).hint).toBeUndefined();
+    });
+  });
+
+  it('keeps runtime-wrapped gRPC transport errors generic without hint headers', async () => {
+    await withUnavailableLocalGrpcTarget(async unavailableTarget => {
+      const environmentService = makeEnvironmentService();
+      const collection = makeDemoCollection();
+      setDemoGrpcBaseUrl(collection, unavailableTarget);
+      const request = readDemoGrpcRequest('runtime-unary-lifecycle.yml');
+      const execution = makeDemoGrpcExecution(environmentService);
+
+      const response = await execution.send(
+        request as any,
+        collection,
+        readDemoGrpcFolderDefaults(),
+        undefined,
+        undefined,
+        'LOCAL',
+      );
+      const body = JSON.parse(response.body);
+
+      expect(response.status).toBe(0);
+      expect(response.headers['x-missio-grpc-status']).toBe(String(grpc.status.UNAVAILABLE));
+      expect(response.headers['x-missio-error-hint']).toBeUndefined();
+      expect(body.error.hint).toBeUndefined();
+      expect(JSON.stringify(body)).not.toMatch(/Missio gRPC demo fixture|node examples\/demo-api\/grpc-server\.js/i);
+    });
+  });
+
+  it('starts the documented fixture and smokes every packaged gRPC demo request through Missio execution', async () => {
+    const demoServer = await startDemoGrpcServerProcess();
+    try {
+      const environmentService = makeEnvironmentService();
+      const collection = makeDemoCollection();
+      setDemoGrpcBaseUrl(collection, demoServer.target);
+      await environmentService.setActiveEnvironment(collection.id, 'LOCAL');
+      const execution = makeDemoGrpcExecution(environmentService);
+      const folderDefaults = readDemoGrpcFolderDefaults();
+      const send = (fileName: string) => execution.send(
+        readDemoGrpcRequest(fileName) as any,
+        collection,
+        folderDefaults,
+        undefined,
+        undefined,
+        'LOCAL',
+        undefined,
+        { requestId: path.join(demoRoot, 'gRPC', fileName) },
+      );
+
+      const unary = JSON.parse((await send('echo-unary.yml')).body);
+      expect(unary).toMatchObject({
+        message: 'Hello Ada',
+        name: 'Ada',
+        userId: 42,
+        requestId: 'demo-trace-001',
+        authorization: 'Bearer demo-token',
+        defaultMetadata: 'request-override-demo-trace-001',
+        folderMetadata: 'folder-demo-trace-001',
+        requestMetadata: 'request-demo-trace-001',
+      });
+
+      const metadata = JSON.parse((await send('echo-metadata-defaults.yml')).body);
+      expect(metadata).toMatchObject({
+        message: 'Hello Metadata Ada',
+        defaultMetadata: 'collection-demo-trace-001',
+        folderMetadata: 'folder-demo-trace-001',
+        requestMetadata: 'metadata-defaults-demo-trace-001',
+      });
+
+      const serverStream = JSON.parse((await send('stream-users.yml')).body);
+      expect(serverStream).toMatchObject({
+        methodType: 'server-streaming',
+        sentMessageCount: 1,
+        receivedMessageCount: 2,
+      });
+      expect(serverStream.receivedMessages.map((entry: any) => entry.message.name)).toEqual(['Ada', 'Grace']);
+
+      const clientStream = JSON.parse((await send('upload-users-client-streaming.yml')).body);
+      expect(clientStream).toMatchObject({
+        methodType: 'client-streaming',
+        sentMessageCount: 2,
+        receivedMessageCount: 1,
+      });
+      expect(clientStream.receivedMessages[0].message).toMatchObject({
+        count: 2,
+        names: 'Ada,Grace',
+        requestIds: 'demo-trace-001-1,demo-trace-001-2',
+        authorization: 'Bearer demo-token',
+        defaultMetadata: 'collection-demo-trace-001',
+      });
+
+      const bidiStream = JSON.parse((await send('chat-users-bidi-streaming.yml')).body);
+      expect(bidiStream).toMatchObject({
+        methodType: 'bidi-streaming',
+        sentMessageCount: 2,
+        receivedMessageCount: 2,
+      });
+      expect(bidiStream.receivedMessages.map((entry: any) => entry.message.name)).toEqual(['ack:Ada', 'ack:Grace']);
+
+      const errorResponse = await send('stream-users-error.yml');
+      const errorStream = JSON.parse(errorResponse.body);
+      expect(errorResponse.status).toBe(0);
+      expect(errorStream.receivedMessages[0].message).toMatchObject({
+        id: 42,
+        name: 'Ada',
+        requestId: 'demo-trace-001-error',
+      });
+      expect(errorStream.error).toMatchObject({
+        name: 'INTERNAL',
+        details: 'Demo stream failure after partial data',
+      });
+
+      const runtimeResponse = await send('runtime-unary-lifecycle.yml');
+      const runtimeBody = JSON.parse(runtimeResponse.body);
+      expect(runtimeBody).toMatchObject({
+        name: 'Ada Runtime',
+        userId: 77,
+        requestMetadata: 'script-demo-trace-001',
+        requestId: 'runtime-demo-trace-001',
+      });
+      expect(runtimeResponse.runtime?.success).toBe(true);
+      expect(runtimeResponse.runtime?.summary).toEqual({ passed: 4, failed: 0, skipped: 0 });
+      expect(runtimeResponse.runtime?.actions[0]).toMatchObject({ target: 'runtime.grpcRuntimeRequestId' });
+    } finally {
+      await stopDemoGrpcServerProcess(demoServer);
+    }
+  }, 20_000);
+});