What problem does it solve? Turning a rough feature idea into an actionable plan usually means scattered notes, uninvestigated assumptions, and documents that ignore what the codebase already does. This Skill produces a structured, codebase-grounded plan document before any code is written, so downstream steps like hardening, issue filing, and implementation have a consistent input. ## Core Features & Use Cases - Codebase-grounded brainstorming: Reads the existing repo to find patterns and utilities the plan should reuse, then proposes genuinely distinct approaches (minimal, ideal, lateral) with a recommendation. - Canonical plan-doc format: Writes docs/plans/plan-<slug>-YYYY-MM-DD.md with Context, Design decisions, Approach, Open questions, and Non-goals sections that downstream skills (grillkit, issuekit, implementkit) read directly. - Workflow handoff: Records open questions for adversarial hardening and hands off to issue filing or phase-by-phase implementation without writing code or creating issues itself. - Use Case: You say "plan this feature" for a new SSO login flow. The Skill reads your auth code, proposes three approaches, settles the structural decisions with you, and writes docs/plans/plan-sso-login-2026-07-23.md ready for hardening. ## Quick Start Ask the agent to plan a feature, for example: "Use plankit to brainstorm and write a plan document for adding SSO login to the app."