What problem does it solve? Planning sessions often stall on ambiguity, produce bloated multi-file design docs, or pad option lists with artificial alternatives. This Skill converts a change request into exactly one durable decision capsule, keeping the brainstorming step of a change pipeline focused and auditable. ## Core Features & Use Cases - Autonomous and interactive modes: In autonomous mode it resolves ambiguity by inspecting the repository and records assumptions with cited evidence; in interactive mode it asks only questions whose answers would change the decision, scope, or a contract. - Single-capsule output: Writes exactly one Markdown file (e.g. openspec/changes/<change-id>/brainstorm.md) with Decision, Alternatives, and Assumptions sections, replacing prior content on re-runs. - Material alternatives only: Compares options that differ in observable behavior, contract, risk, or blast radius, and states when only one direction is viable. - Use Case: Given a request like "add a retry to the telemetry sink write path", the Skill inspects the sink code, picks a reasonable retry count, cites the file as evidence, and writes the capsule without pausing for user input. ## Quick Start Ask the agent to run the ptp brainstorming step in autonomous mode for your change request and write the decision capsule to the change's brainstorm.md path.