Plan Brief

Turn the thread's design into a short, one-screen plan that gives implementation a sensible order and a way to check the result. You gather the thread's context, draft the plan body, create this invocation's plan folder, write its plan.md, and confirm the path. Writing the file is where you stop — do not stage, commit, or push.

A brief plan trades depth for speed: it orders the work and records overall verification. When the work genuinely needs more rigor than that, recommend plan-strict instead of inflating the brief plan (see ## When to recommend plan-strict).

Inputs

Gather all of these before drafting; everything below works from what you gather here.

• The project's AGENTS.md, when the file exists — the project's standing guidance for agents working in it.
• docs/glossary.md, when the file exists — the project's fixed terms, to be used in everything you write.
• docs/adr/ and docs/pdr/, read via /consult-decisions — the project decisions bearing on the design.
• The roadmap entry named by the seed frontmatter's roadmap mapping, when the seed carries one — the entry this thread answers: its sketch, its scope boundary and its planned behavior, found as the heading whose text is roadmap.entry in the index at roadmap.path.
• The design the plan implements — the primary input, in one of two accepted forms. The thread's spec.md is the form when the file exists, and it is the plan's authority; it comes in the shape <skill_path>/references/formats/spec.md defines. When the invocation names a referenced artifact instead — a repository path, a GitHub issue, or the user's own prompt when nothing else is named — that reference is the form; it is material, and it carries no authority over a spec.md the thread holds.
• The thread's seed.md — why the thread exists and what triggered it.
• The thread's delta/, when present — the thread's delta of the project layer, which inside the thread takes precedence over the project records. Where a step rests on one, the plan cites a delta document by its path and a decision record by its stem, rather than restating it; the form each kind is cited by is the one <skill_path>/references/instructions/read-and-cite-the-project-layer.md fixes.

Any other thread is history: it records how its own work was understood at the time, not what holds now, so do not read it unless the user or this thread's seed names it.