diff --git a/.github/scripts/check-autofix-contracts.sh b/.github/scripts/check-autofix-contracts.sh
new file mode 100755
index 00000000000..ed4cc325bcd
--- /dev/null
+++ b/.github/scripts/check-autofix-contracts.sh
@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+fail() {
+  if [[ -n "${GITHUB_OUTPUT:-}" ]]; then
+    echo "outcome=failed" >> "${GITHUB_OUTPUT}"
+  fi
+  exit 1
+}
+
+changed_files="$(cat)"
+
+if ! npm run check-i18n; then
+  echo '❌ i18n verification failed.'
+  fail
+fi
+
+if grep -Fxq 'packages/core/src/tools/tool-names.ts' <<< "${changed_files}"; then
+  if ! npm run test --workspace packages/web-shell -- \
+    client/components/messages/toolFormatting.drift.test.ts; then
+    echo '❌ Web Shell tool-display contract verification failed.'
+    fail
+  fi
+fi
diff --git a/.github/workflows/qwen-autofix.yml b/.github/workflows/qwen-autofix.yml
index dc209d65ce8..4609f471b9a 100644
--- a/.github/workflows/qwen-autofix.yml
+++ b/.github/workflows/qwen-autofix.yml
@@ -644,6 +644,7 @@ jobs:
       - name: 'Stage trusted schema gate'
         run: |-
           cp .github/scripts/check-settings-schema.sh "${RUNNER_TEMP}/check-settings-schema.sh"
+          cp .github/scripts/check-autofix-contracts.sh "${RUNNER_TEMP}/check-autofix-contracts.sh"
           cp .github/scripts/resolve-owning-packages.sh "${RUNNER_TEMP}/resolve-owning-packages.sh"
 
       - name: 'Check bot credentials'
@@ -1151,6 +1152,8 @@ jobs:
           # and kill the gate with no outcome), and the gate logic must come
           # from the trusted base, not the branch under verification.
           bash "${RUNNER_TEMP}/check-settings-schema.sh"
+          git diff --name-only "origin/main...${BRANCH}" \
+            | bash "${RUNNER_TEMP}/check-autofix-contracts.sh"
 
           # Run changed/related tests for the packages this fix touches.
           # --changed follows the import graph so transitive breakage is caught.
@@ -2480,6 +2483,7 @@ jobs:
       - name: 'Stage trusted schema gate and agent runner'
         run: |-
           cp .github/scripts/check-settings-schema.sh "${RUNNER_TEMP}/check-settings-schema.sh"
+          cp .github/scripts/check-autofix-contracts.sh "${RUNNER_TEMP}/check-autofix-contracts.sh"
           cp .github/scripts/resolve-owning-packages.sh "${RUNNER_TEMP}/resolve-owning-packages.sh"
           # The agent step runs AFTER prepare checks out the PR branch, so
           # invoking the runner from the working tree would execute
@@ -3075,6 +3079,8 @@ jobs:
           # and kill the gate with no outcome), and the gate logic must come
           # from the trusted base, not the branch under verification.
           bash "${RUNNER_TEMP}/check-settings-schema.sh"
+          git diff --name-only "origin/main...${BRANCH}" \
+            | bash "${RUNNER_TEMP}/check-autofix-contracts.sh"
 
           if git diff --quiet "origin/${BRANCH}...${BRANCH}"; then
             # No new commit. That is only legitimate as a deliberate no-action.
diff --git a/scripts/tests/qwen-autofix-workflow.test.js b/scripts/tests/qwen-autofix-workflow.test.js
index 1948bf8cb58..67fbc05d951 100644
--- a/scripts/tests/qwen-autofix-workflow.test.js
+++ b/scripts/tests/qwen-autofix-workflow.test.js
@@ -25,6 +25,8 @@ const sandboxImageResolverScript = readFileSync(
   '.github/scripts/resolve-sandbox-image.mjs',
   'utf8',
 );
+const autofixContractsScriptPath = '.github/scripts/check-autofix-contracts.sh';
+const autofixContractsScript = readFileSync(autofixContractsScriptPath, 'utf8');
 const autofixRunnerScriptPath = '.qwen/skills/autofix/scripts/run-agent.mjs';
 const checkBotCredentialsStep =
   workflow.match(
@@ -4103,6 +4105,12 @@ describe('qwen-autofix workflow', () => {
       expect(step).not.toContain(
         'bash .github/scripts/check-settings-schema.sh',
       );
+      expect(step).toContain(
+        'bash "${RUNNER_TEMP}/check-autofix-contracts.sh"',
+      );
+      expect(step).not.toContain(
+        'bash .github/scripts/check-autofix-contracts.sh',
+      );
       // The owning-package resolver is likewise a shared script staged from the
       // trusted base, invoked (not inlined) so the two gates cannot drift into
       // resolving packages differently. The old inline detection must be gone.
@@ -4125,6 +4133,11 @@ describe('qwen-autofix workflow', () => {
         /cp \.github\/scripts\/check-settings-schema\.sh "\$\{RUNNER_TEMP\}\/check-settings-schema\.sh"/g,
       ) ?? [],
     ).toHaveLength(2);
+    expect(
+      workflow.match(
+        /cp \.github\/scripts\/check-autofix-contracts\.sh "\$\{RUNNER_TEMP\}\/check-autofix-contracts\.sh"/g,
+      ) ?? [],
+    ).toHaveLength(2);
     // The owning-package resolver is staged the same way, in the same steps.
     expect(
       workflow.match(
@@ -4201,6 +4214,88 @@ describe('qwen-autofix workflow', () => {
         'bash "${RUNNER_TEMP}/check-settings-schema.sh"',
       ),
     ).toBeLessThan(reviewVerifyGate.indexOf('outcome=noop'));
+    expect(
+      reviewVerifyGate.indexOf(
+        'bash "${RUNNER_TEMP}/check-autofix-contracts.sh"',
+      ),
+    ).toBeLessThan(reviewVerifyGate.indexOf('outcome=noop'));
+    expect(autofixContractsScript).toContain('npm run check-i18n');
+    expect(autofixContractsScript).toContain(
+      'packages/core/src/tools/tool-names.ts',
+    );
+    expect(autofixContractsScript).toContain(
+      'client/components/messages/toolFormatting.drift.test.ts',
+    );
+    expect(autofixContractsScript).toContain('outcome=failed');
+    expect(ciWorkflow).toContain("run: 'npm run check-i18n'");
+    expect(ciWorkflow).toContain('npm run test:ci');
+  });
+
+  it('runs cross-package autofix contracts only when their source changes', () => {
+    const dir = mkdtempSync(join(tmpdir(), 'autofix-contracts-'));
+    const npmLog = join(dir, 'npm.log');
+    try {
+      writeFileSync(
+        join(dir, 'npm'),
+        [
+          '#!/usr/bin/env bash',
+          'printf \'%s\\n\' "$*" >> "${NPM_LOG}"',
+          'if [[ "$*" == "run check-i18n" ]]; then',
+          '  exit "${I18N_EXIT:-0}"',
+          'fi',
+          'exit "${DRIFT_EXIT:-0}"',
+          '',
+        ].join('\n'),
+      );
+      chmodSync(join(dir, 'npm'), 0o755);
+
+      const run = (changedFiles, extraEnv = {}) =>
+        spawnSync('bash', [resolve(autofixContractsScriptPath)], {
+          input: changedFiles,
+          encoding: 'utf8',
+          env: {
+            ...process.env,
+            PATH: `${dir}:${process.env.PATH}`,
+            NPM_LOG: npmLog,
+            ...extraEnv,
+          },
+        });
+
+      expect(run('packages/core/src/config/config.ts\n').status).toBe(0);
+      expect(readFileSync(npmLog, 'utf8').trim().split('\n')).toEqual([
+        'run check-i18n',
+      ]);
+
+      writeFileSync(npmLog, '');
+      expect(run('packages/core/src/tools/tool-names.ts\n').status).toBe(0);
+      expect(readFileSync(npmLog, 'utf8').trim().split('\n')).toEqual([
+        'run check-i18n',
+        'run test --workspace packages/web-shell -- client/components/messages/toolFormatting.drift.test.ts',
+      ]);
+
+      writeFileSync(npmLog, '');
+      const output = join(dir, 'output');
+      expect(
+        run('packages/core/src/tools/tool-names.ts\n', {
+          GITHUB_OUTPUT: output,
+          I18N_EXIT: '1',
+        }).status,
+      ).toBe(1);
+      expect(readFileSync(npmLog, 'utf8').trim()).toBe('run check-i18n');
+      expect(readFileSync(output, 'utf8')).toContain('outcome=failed');
+
+      writeFileSync(npmLog, '');
+      writeFileSync(output, '');
+      expect(
+        run('packages/core/src/tools/tool-names.ts\n', {
+          GITHUB_OUTPUT: output,
+          DRIFT_EXIT: '1',
+        }).status,
+      ).toBe(1);
+      expect(readFileSync(output, 'utf8')).toContain('outcome=failed');
+    } finally {
+      rmSync(dir, { recursive: true, force: true });
+    }
   });
 
   it('passes model credentials directly to qwen subprocesses', () => {