security: pin package execution and vendor agent instructions

Summary

The official skills/react-doctor/SKILL.md executes react-doctor@latest and fetches the authoritative triage playbook and rule guidance at runtime. A skill invocation can therefore execute package code and follow instructions that were not present during installation or review.

This is a supply-chain hardening report. It contains no credential values or exploit payloads.

Recommended remediation

• Execute an exact, reviewed react-doctor package version rather than @latest.
• Vendor the triage playbook and rule guidance into the versioned skill source or release artifact.
• Treat prompt and package updates as reviewed source changes, not runtime authority.
• Do not execute packages or fetch authoritative instructions at skill load time.

Future upgrades can still be offered explicitly, but should identify the exact target version and require review before execution.

Duplicate check

No matching open security issue or visible draft repository security advisory was found. Open issues #781 and #1133 mention React Doctor invocation workflows but do not cover mutable package execution or runtime authoritative instructions.