diff --git a/tests/runner-e2e/STOCK-HARNESS.md b/tests/runner-e2e/STOCK-HARNESS.md
index 70ecfb1827..c5df1e385c 100644
--- a/tests/runner-e2e/STOCK-HARNESS.md
+++ b/tests/runner-e2e/STOCK-HARNESS.md
@@ -151,6 +151,11 @@ builds that daemon from the locked Rust source before TypeScript gates, retains
 The required daemon-frame test selects that built debug binary explicitly,
 without replacing staged product binaries. The receipt records its SHA-256;
 verification rejects a changed binary before provider admission.
+The [next cold pilot](https://github.com/paperclipai/paperclip/actions/runs/37040493183)
+at `ac6ddefb589c18fa9c30946db40e58499e9fb0e0` then found the required fake Codex
+protocol fixture absent. It also stopped before paid providers. Setup uses the
+package's ordinary locked workspace `--bins` build, covering both the daemon
+and its fixture; verification binds both binaries to the retained receipt.
 
 Dispatch the trusted workflow from `master`, with `target_branch` naming the
 same-repository candidate and an exact cell selector first. The workflow resolves
diff --git a/tests/runner-e2e/stock-harness-checks.mjs b/tests/runner-e2e/stock-harness-checks.mjs
index b818e4673b..7fcd16b364 100644
--- a/tests/runner-e2e/stock-harness-checks.mjs
+++ b/tests/runner-e2e/stock-harness-checks.mjs
@@ -74,6 +74,9 @@ export function sourceFingerprint() {
     "packages/paperclip-runner/src/live/runnerd-codex-transport.ts",
     "packages/paperclip-runner/src/live/live-session.ts",
     "packages/paperclip-runner/runner/crates/runner-core/src/codex_provider.rs",
+    "packages/paperclip-runner/runner/crates/runner-core/src/bin/fake-codex-app-server.rs",
+    "packages/paperclip-runner/runner/Cargo.toml", "packages/paperclip-runner/runner/Cargo.lock",
+    "packages/paperclip-runner/runner/crates/runner-core/Cargo.toml",
     "packages/paperclip-runner/runner/crates/runner-core/tests/codex_provider.rs",
   ]);
   const sourceErrors = [];
@@ -91,6 +94,7 @@ export function assertPreflightReceipt(report, current) {
       report.setup?.passed !== true || report.setup?.exitCode !== 0 ||
       report.setup?.sdkExitCode !== 0 || report.setup?.runnerdExitCode !== 0 ||
       report.setup?.runnerdSha256 !== current.runnerdSha256 ||
+      report.setup?.fakeCodexSha256 !== current.fakeCodexSha256 ||
       report.providerCalls !== 0 || report.sourceSha !== current.sha ||
       report.sourceFingerprint !== current.fingerprint || report.sourceErrors?.length !== 0 ||
       !Array.isArray(report.gates) || report.gates.length !== expected.length ||
@@ -116,6 +120,8 @@ export function main(args = process.argv.slice(2)) {
       sha: git.stdout.trim(), fingerprint: source.fingerprint,
       runnerdSha256: createHash("sha256").update(readFileSync(join(root,
         "packages/paperclip-runner/runner/target/debug", `paperclip-runnerd${process.platform === "win32" ? ".exe" : ""}`))).digest("hex"),
+      fakeCodexSha256: createHash("sha256").update(readFileSync(join(root,
+        "packages/paperclip-runner/runner/target/debug/fake-codex-app-server"))).digest("hex"),
     });
     const output = resolve(verify, "..");
     for (const gate of stockHarnessGates) {
@@ -144,7 +150,7 @@ export function main(args = process.argv.slice(2)) {
   // cells do not download native artifacts, so compile it before TS discovery.
   const runnerd = setupRun.status === 0 ? spawnSync("cargo", ["build", "--locked",
     ...(args.includes("--allow-rust-network") ? [] : ["--offline"]),
-    "-p", "paperclip-runner-core", "--bin", "paperclip-runnerd"], {
+    "--workspace", "--bins"], {
     cwd: join(root, "packages/paperclip-runner/runner"), env, encoding: "utf8", timeout: 10 * 60_000,
   }) : null;
   writeFileSync(join(output, "runnerd-build.txt"), `${runnerd?.stdout ?? ""}\n${runnerd?.stderr ?? ""}`);
@@ -164,6 +170,8 @@ export function main(args = process.argv.slice(2)) {
   const runnerdBinary = join(root, "packages/paperclip-runner/runner/target/debug",
     `paperclip-runnerd${process.platform === "win32" ? ".exe" : ""}`);
   setup.runnerdSha256 = createHash("sha256").update(readFileSync(runnerdBinary)).digest("hex");
+  setup.fakeCodexSha256 = createHash("sha256").update(readFileSync(join(root,
+    "packages/paperclip-runner/runner/target/debug/fake-codex-app-server"))).digest("hex");
   const results = [];
   for (const gate of stockHarnessGates) {
     console.log(`Checking ${gate.id}: ${gate.name}`);
diff --git a/tests/runner-e2e/stock-harness-checks.test.mjs b/tests/runner-e2e/stock-harness-checks.test.mjs
index 428cfa9ac0..92d34337e1 100644
--- a/tests/runner-e2e/stock-harness-checks.test.mjs
+++ b/tests/runner-e2e/stock-harness-checks.test.mjs
@@ -40,9 +40,10 @@ describe("stock harness prerequisite coverage", () => {
 });
 
 describe("stock harness prerequisite admission", () => {
-  const current = { sha: "a".repeat(40), fingerprint: "b".repeat(64), runnerdSha256: "c".repeat(64) };
+  const current = { sha: "a".repeat(40), fingerprint: "b".repeat(64), runnerdSha256: "c".repeat(64), fakeCodexSha256: "e".repeat(64) };
   const receipt = () => ({ schema: "paperclip.stock-harness-preflight.v3", passed: true,
-    setup: { passed: true, exitCode: 0, sdkExitCode: 0, runnerdExitCode: 0, runnerdSha256: current.runnerdSha256 },
+    setup: { passed: true, exitCode: 0, sdkExitCode: 0, runnerdExitCode: 0, runnerdSha256: current.runnerdSha256,
+      fakeCodexSha256: current.fakeCodexSha256 },
     providerCalls: 0, sourceSha: current.sha, sourceFingerprint: current.fingerprint,
     sourceErrors: [], gates: [...stockHarnessGates.map(g => g.id), "SH-1-rust"].map(id => ({ id, passed: true, exitCode: 0 })) });
   it("admits the same passing source revision", () => expect(assertPreflightReceipt(receipt(), current).passed).toBe(true));
@@ -58,6 +59,7 @@ describe("stock harness prerequisite admission", () => {
     ["failed cold setup", r => { r.setup.passed = false; r.setup.exitCode = 1; }],
     ["missing daemon build", r => { delete r.setup.runnerdExitCode; }],
     ["changed daemon binary", r => { r.setup.runnerdSha256 = "d".repeat(64); }],
+    ["changed protocol fixture", r => { r.setup.fakeCodexSha256 = "d".repeat(64); }],
   ])("rejects %s before providers", (_name, mutate) => {
     const r = receipt(); mutate(r); expect(() => assertPreflightReceipt(r, current)).toThrow("exact source SHA and fingerprint");
   });