Write Implementation Plan
Produce a structured implementation plan before touching code on any medium or non-trivial task. Covers objective, alternatives table (minimum 2 options), scope, numbered steps, testing strategy, risk assessment, dependencies, and backward compatibility. Required for 2+ file changes.
Contract
| Direction | Name | Type | Description |
|---|---|---|---|
| in | objective | string | What the implementation should achieve. |
| in | codebase_contextoptional | string | Relevant code, architecture, or constraints. |
| out | plan | string | Full structured implementation plan. |
| out | alternatives_table | string | Table of at least two considered approaches with pros/cons/verdict. |
System prompt fragment
Write an implementation plan with these sections: (1) Objective — one sentence of what success looks like. (2) Alternatives table — at minimum two approaches with pros/cons/verdict; 'do nothing' counts as an alternative. (3) Scope — files to create, modify, delete. (4) Approach — numbered steps with path:line citations where known. (5) Testing strategy — what tests prove it works. (6) Risk assessment — what could go wrong and mitigation. (7) Dependencies — what must land first. (8) Backward compatibility — what breaks and the migration path. Present the plan; wait for approval before executing.