[MarkusNeusinger]

Summary

• Security fix for feat(agents): Jules lane, delegation rules, secret-free Jules CI #12429. Google Jules names its own branch after the one it starts from (feature/head-metadata-dedup-<session id>), and ci-lint, ci-tests, ci-migrations, and ci-image also ran on every push to feature/**. A push run has no PR author, and Jules pushes with the owner's GitHub grant, so the PR-author checks from feat(agents): Jules lane, delegation rules, secret-free Jules CI #12429 treated unread Jules code as trusted. On both head-metadata pushes today, renderer-image reached its GCP login before Claude cancelled the runs; in both cases only files Jules had not touched ran with it, since the two diffs change app/ only.
• feature/** is removed from every push trigger, so feature branches and Jules's branches under them get CI only through pull requests. Run E2E Tests also refuses any ref under refs/heads/feature and any PR whose base is a feature branch; renderer-image refuses feature refs too. This also ends the doubled Lint/Tests runs on every Jules sub-PR.
• Skill, guardrails, and CLAUDE.md drop the "e2e on the push the merge makes" claim: e2e runs on the PR into main.

Plan

N/A. Follows the owner's decision of 2026-10-29 that Jules PRs run without secrets or an OIDC token.

Test plan

• actionlint on ci-lint.yml, ci-tests.yml, ci-migrations.yml, ci-image.yml
• tests/unit/test_agent_instructions.py and tests/unit/workflows: 1098 passed
• uv run python -m tools.changelog check --base origin/main
• Gemini 3.8 Flash pre-PR check: no remaining path where Jules code runs with secrets; its two findings (PR-into-feature guard, stale comment) fixed
• Workflow changes have no local verification loop. After merge: the next Jules push to a feature/…-<session id> branch starts no workflow run, and its PR into the feature branch shows Run E2E Tests skipped

[Copilot]

🟡 Changes recommended

Critical merge-group guard gaps could allow untrusted feature code to run in OIDC-enabled jobs with GCP access, and two documentation issues remain.

4 open issues

• Exclude feature merge groups from the OIDC-enabled job · New
• Block feature merge queues from the OIDC-enabled job · New
• Mirror the feature push rule in Copilot instructions · New
• Complete the security changelog sentence · New

What changed in this PR

This pull request hardens CI for Jules-managed feature/** branches by removing push-triggered workflows, restricting credentialed jobs, and updating the related documentation.

Changes:

• Removes feature/** from push triggers for lint, tests, migrations, and image workflows.
• Adds feature-ref and feature-base guards to E2E and renderer-image jobs.
• Updates Jules guidance, guardrails, and the changelog for PR-based validation.

File	Summary	Review notes
CLAUDE.md	Documents that feature-branch pushes no longer run CI.	Mirror the updated guidance in .github/copilot-instructions.md.
changelog.d/​ci-no-feature-push.md	Records the CI security change.	Clarify the incomplete final clause describing E2E behavior.
.github/​workflows/​ci-tests.yml	Removes feature push triggers and guards the E2E job.	Add a merge_group base-branch guard for feature branches. Add regression tests for feature push filters and ref/base guards.
.github/​workflows/​ci-migrations.yml	Removes feature push triggers.	No additional review comments.
.github/​workflows/​ci-lint.yml	Removes feature push triggers while retaining feature pull-request checks.	No additional review comments.
.github/​workflows/​ci-image.yml	Removes feature push triggers and guards the renderer-image job.	Add a merge_group base-branch guard so feature code cannot reach the OIDC-enabled job.
.claude/​skills/​jules-task/​SKILL.md	Updates Jules CI and merge guidance.	No additional review comments.
.claude/​guardrails.md	Documents the feature-push security incident and mitigation.	No additional review comments.

_{Review effort: Lite}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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