Feature: dry-run / plan-only mode (no Anthropic API key) #4
Description
Problem
The Action requires anthropic_api_key (Anthropic API key) to run, which blocks contributors/users who only want to try the workflow or help with OSS without paid keys.
Request
Add a "dry-run" / "plan-only" mode that:
- validates inputs and environment variables
- prints the intended plan/steps (or a stubbed plan)
- does NOT require
anthropic_api_key - never touches cloud provider APIs / never applies changes
Why it helps
- allows community contributions, CI checks, docs improvements
- safer onboarding for alpha users
- easier bug reports (repro without secrets)