hs:plan

Run the hs:plan skill with your feature or refactor description. It interviews you for scope and acceptance criteria, researches the codebase, scans ownership and policy constraints, then writes plan.md plus phase files under plans/<timestamp>-<slug>/ for human approval.

--fast is for small, low-risk tasks of 1-2 files and skips research and red-team gates. --hard is the default for real features and runs the full pipeline: constraint scan, red-team review, and validation before approval.

The red-team gate spawns a @red-teamer subagent that adversarially reviews the plan using 2-4 personas such as Security Adversary and Failure Mode Analyst. Every finding needs file:line evidence, is capped at 15 items, and gets an accept/reject disposition recorded in plan.md.

Yes, --tdd is an orthogonal flag that adds Tests Before, Implement, Tests After, and a Regression Gate section to each phase file. The regression gate records the exact test command so the execution step runs red-to-green in the correct order.

The plan-graph.yaml sidecar makes the phase dependency graph machine-checkable. The plan_graph.py tool uses it to detect dependency cycles, ordering hazards, and shared-file conflicts between parallel phases, and it hard-fails on any phase missing its post artifact declaration.

Skip it for trivial changes where planning overhead exceeds the work, such as a one-line fix with no logic change. The skill itself defaults to --fast for 1-2 file, low-risk tasks, and it never writes code or modifies files outside the plans/ directory.