---
requires: scratch/<branch>.md
produces: code, tests
default_agent: codex
action_style: procedural
---
Turn the design doc into working code.
## Orientation
Before starting, orient yourself in this branch:
- Read `scratch/` — design docs and notes for the current work live here
(`scratch/<branch>.md` is this PR's design; `scratch/questions.md` holds open
questions and assumptions).
- Read wave/PM context only when the seed names the exact wave, task, project,
or a concrete coordination question; never infer it or repair access as a
prerequisite.
- Read the repo's agent doc (`CLAUDE.md` / `AGENTS.md`) for conventions.
Write design artifacts, notes, and open questions under `scratch/`. Don't
re-derive what these already record.
## Goal
Working code with rough edges beats perfect code that took too long.
Produce a first draft quickly. Polish cleans it up. You can be re-invoked if needed. Don't block on ambiguity—make the simplest choice and keep moving.
## Workflow
The design doc and style guides are in your context.
1. **Understand the design**
The design doc has data structures, function signatures, constraints, and a "done when" check.
2. **Implement**
- Data structures first—get the core types right
- Functions one at a time, following the signatures
- Match existing patterns in the codebase
3. **Verify**
- Run tests to confirm nothing broke
- Run the "done when" check from the design doc
## Rules
**Match existing patterns.** Find similar code nearby and match its style. If the codebase uses `@dataclass`, use `@dataclass`. If it uses type hints, use type hints.
**Stay in scope.** Implement exactly what the design describes. Scope creep goes in `scratch/questions.md`, not the code.
**Tests prove it works.** Add tests for user-visible behavior. Don't test implementation details. Assert on results, not mock calls.
## Wave context
If `<lf:wave>` is present, check `wave/<wave>/GOAL.md` and `MEMORY.md` in docs:
- Follow the wave's intent and principles during implementation
- Respect decisions and constraints recorded in `MEMORY.md`
- Note drift from wave constraints in `scratch/questions.md`
## When the design is wrong
If the design doc is unclear, make the simplest choice and move on. Note your assumption in `scratch/questions.md`.
If implementation reveals a design flaw, note it but keep going. The design was scaffolding—diverge when reality demands it.
## Adaptation
If you had to discover a convention that wasn't documented — error handling pattern, test structure, naming style, import conventions — add it to the repo's style guide (CLAUDE.md, STYLE.md) so the next session doesn't have to rediscover it.