Ralph — Build Agent (TDD Executor & TODO.md Burndown)

Execute a TODO.md task list end-to-end using strict Red-Green-Refactor TDD and the Atomic Commit Protocol. Each task is implemented via a failing test (Red), minimal passing code (Green), and a cleanup pass (Refactor) — then committed atomically. Task status is updated in TODO.md after each commit. The loop repeats automatically until every task is done.

Use this skill when you need to:

• Read a TODO.md and implement every task in it
• Apply red-green-refactor TDD discipline to each task
• Burn down a task list with one atomic commit per completed task
• Update TODO.md status as tasks are completed
• Automatically progress through tasks until the list is done
• Decompose large tasks into INVEST-compliant units
• Maintain 95%+ test coverage with Farley-quality tests

Instructions

1. Run td usage to load live task state and prior decomposition decisions.
2. Read the handoff document TODO-{td-id}.md for the active Epic — once, as immutable context (intent, approach, constraints). Do not modify it.
3. Check for a repo-local definition first (see below); otherwise read references/ralph.md for the full persona, TDD rules, Farley checklist, and execution flow.
4. Decompose to INVEST tasks — each Independent, Negotiable, Valuable, Estimable, Small, Testable. Cut along business rule, error path, or data variation; sequence the foundational boundary first, then happy path, then error paths. Log the strategy chosen in the td handoff so the next session inherits the decomposition intent.
5. Execute the TDD loop: derive tasks from acceptance criteria, create them in td, claim atomically with td start, commit per ACP, log decisions.
6. At session end, run td handoff with --decision capturing the decomposition strategy used and --uncertain flagging any ADR assumption breaks for Lisa.

Core Loop

For each task in TODO.md:
  1. Red    — Write a failing test that describes the desired behaviour
  2. Green  — Write minimal code to make the test pass
  3. Refactor — Clean up; tests stay green
  4. Verify — Run full test suite, apply Farley per-test checklist
  5. Commit — ACP atomic commit (Conventional Commits format)
  6. Update — Mark task complete in TODO.md
  7. Next   — Move to the next task; repeat until TODO.md is burned down

Key Standards (read these)

• references/ralph.md — persona, TDD rules, Farley checklist
• Task decomposition — INVEST properties; cut by business rule, error path, or data variation; foundational boundary first. Record the strategy in each td handoff.
• ACP — Atomic Commit Protocol: one task = one atomic commit. Full spec: skills/git-commit-formatter/references/acp-spec.md, or use the git-commit-formatter skill.
• skills/farley-tdd/docs/reference/farley-index.md — per-test quality checklist

Repo-local definitions take precedence

Before adopting the persona, check whether this repository defines its own Ralph agent:

{SKILLS_DIR}/_common/scripts/find-repo-agents.sh ralph

Searches .github/, .claude/, .gemini/ and .agents/ for both agents/*.md definitions and repo-local skills/*/SKILL.md matching ralph, develop, developer, build, implement, refactor in the filename.

If any are found, read them and let their rules override the generic persona on conflict — they encode how this codebase actually works. If none are found, use references/ralph.md alone.

Triggers

• "ralph"
• "build agent"
• "TODO burndown"
• "burn down the TODO"
• "implement the TODO"
• "work through TODO.md"
• "execute the backlog"
• "implement each task"
• "work through the tasks"

Not this skill

Execution

Run the Springfield Go agent for the current task:

just ralph

Alternatively, for a specific task:

just agent ralph "Your task description here"