douglance/sdlc-plugin/planning

<execution-contract> This skill defines the planning phase. Use the project-manager agent when a bounded planning task can proceed independently; otherwise work locally. Produce milestones, dependencies, risks, and out-of-scope boundaries. </execution-contract>

Use lifecycle-documentation only when the result needs a durable artifact or handoff.

<what-to-do>

Turn the goal into structure. Gather enough codebase context to understand the terrain, then break the work into a series of high-level milestones, each composed of commits. Ground the structure in cited prior art rather than generic architectural preference.

Stay high-level about future implementation details, but be exact about present evidence: cite the specific existing files and lines that justify each approach, dependency, risk, and estimate of scope. Ship the plan after the first draft; iterate during execution, not during planning.

When the proposed plan needs many compatibility rules, adapters, or exception paths, run find-simplifying-insight before accepting that complexity. Record the null hypothesis, the candidate simpler model, its novel prediction, and the cheapest decisive test.

</what-to-do>

<supporting-info>

What a plan contains

• Milestones — ordered checkpoints, each composed of a series of atomic commits (vertical slices). No count cap — the plan is as many milestones as the work needs.
• Dependencies — what each milestone needs from the others.
• Risks — what could go wrong, what's hard to reverse.
• Out-of-scope set — an explicit out_of_scope list. This is a hard constraint, not a suggestion. You own it: every downstream milestone inherits it verbatim.
• Evidence anchors — every milestone names the existing code, test, contract, or primary source that supports its shape. Use exact path:line citations.
• Prior-art comparison — identify the nearest analogous implementation, what can be reused, and where this work differs. If none exists, include the search commands that established that absence.
• Argument trace — separate observed facts from inferences and recommendations. Risks and sequencing decisions must point back to their evidence.

Evidence format

For external framework, standards, or research claims, cite a current primary source and include its version or publication date.

Principles

Prefer the smallest plan that delivers the goal. Keep the commit small — one logical change — and let a milestone be however many commits it takes to reach its checkpoint.

</supporting-info>