[plan] Add issue fields support to update-issue safe output

[github-actions]

Objective

Investigate and implement issue fields support in the update-issue safe output, similar to how labels can be added/removed.

Context

The create-issue safe output is being updated to support fields (see companion issue). The update-issue safe output should also allow setting or updating issue fields. Tracked in #30846.

Approach

1. Review the current update-issue safe output schema and implementation in actions/setup/js/
2. Determine the correct semantics: should updating fields be a replace (set) or merge (add/remove) operation?
3. Add an optional fields parameter to update-issue mirroring the create-issue approach
4. Implement field-update logic using the GitHub API (reference set_issue_fields in issues_granular.go)
5. Handle partial updates gracefully (only provided fields are modified)

Files to Modify

• actions/setup/js/ — safe output action source (update-issue handler)
• pkg/workflow/js/safe_outputs_tools.json — update tool definition
• schemas/ — JSON schema updates if applicable

Acceptance Criteria

• update-issue safe output accepts an optional fields parameter
• Fields are updated without affecting other issue properties
• Invalid field names/values produce actionable error messages
• Unit tests cover update success, partial update, and error cases
• Schema reference updated
  Related to Implement Issue Fields Support in Safe Outputs #30846

Generated by Plan Command for issue #30846 · ● 3.1M · ◷

• expires on May 9, 2026, 6:53 PM UTC