tdd
Enforced RED-GREEN-REFACTOR with separate agents for tests and implementation.
This skill should be used when the user wants to implement features or fix bugs using test-driven development. Enforces the RED-GREEN-REFACTOR cycle with vertical slicing, context isolation between test writing and implementation, human checkpoints, and auto-test feedback loops. Uses multi-agent orchestration with the Task tool for architecturally enforced context isolation. Supports Jest, Vitest, pytest, Go test, cargo test, PHPUnit, and RSpec.
What it does
Enforces disciplined RED-GREEN-REFACTOR cycles using separate subagents for test writing and implementation. The core innovation: the Test Writer never sees implementation code, and the Implementer never sees the specification — preventing the LLM from leaking intent between roles.
Invocation modes
/tdd <feature>— interactive mode with approval checkpoints at each step/tdd --auto <feature>— autonomous mode, runs all slices without pausing/tdd --resume— resume an interrupted TDD session from saved state/tdd --dry-run <feature>— validate the entire pipeline without writing any code
Supported frameworks
Jest, Vitest, pytest, Go test, cargo test, PHPUnit, and RSpec.
How it works
- Phase 0 — detect test framework, verify baseline, extract API surface
- Phase 1 — decompose the feature into vertical slices (user approves)
- For each slice — RED (write failing test) → GREEN (implement to pass) → REFACTOR (clean up)
- Each phase runs in a separate subagent with architecturally enforced context isolation
When to use
When you want test-driven development with actual discipline — not just “write tests after.” Especially valuable for features where test quality matters, since the isolated agents prevent test-implementation contamination.