[instructions] Sync github-agentic-workflows.md with v0.66.1

[github-actions]

Instructions Update - Synchronized with v0.66.1

This PR updates github-agentic-workflows.md based on changes since the v0.66.1 release.

Changes Made

• add-comment — reply_to_id for discussion threading: Document the new reply_to_id agent output field that enables threaded replies within GitHub Discussions (shipped in v0.66.1).
• steps/post-steps — secrets restriction: Document the compiler check (added post-release in Add compiler check disallowing secrets expressions in custom steps #24450) that treats $\{\{ secrets.* }} expressions (excluding secrets.GITHUB_TOKEN) in custom steps as an error in strict mode and a warning otherwise.

Documentation Commits Reviewed

• e255fc7 Add compiler check disallowing secrets expressions in custom steps (Add compiler check disallowing secrets expressions in custom steps #24450)

Safe-Outputs Code Audit

Audited SafeOutputsConfig in compiler_types.go and safe_outputs_config.go against the instructions file. All operations currently defined in code (create-issue, add-comment, create-pull-request, create-pull-request-review-comment, submit-pull-request-review, reply-to-pull-request-review-comment, resolve-pull-request-review-thread, create-discussion, update-discussion, close-discussion, close-issue, close-pull-request, mark-pull-request-as-ready-for-review, update-issue, update-pull-request, push-to-pull-request-branch, upload-asset, update-release, add-labels, remove-labels, add-reviewer, assign-milestone, link-sub-issue, hide-comment, set-issue-type, dispatch-workflow, dispatch_repository, call-workflow, create-code-scanning-alerts, autofix-code-scanning-alert, create-agent-session, update-project, create-project, create-project-status-update, assign-to-agent, assign-to-user, unassign-from-user, missing-tool, missing-data, noop, threat-detection, jobs, scripts, actions) are documented in the instructions file. The auth field on HTTP MCP servers is also already documented.

Validation

• Followed prompting best practices (imperative mood, minimal examples)
• Maintained technical tone and brevity
• Updated only necessary sections
• Verified accuracy against current codebase
• Removed outdated or redundant content

Generated by Instructions Janitor · ● 312.3K · ◷

• expires on Apr 6, 2026, 10:54 AM UTC