Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/mturac/everything-openai-codex/tdd-guidegit clone --depth 1 https://github.com/mturac/everything-openai-codexWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00042 | $0.00690 |
| Opus 5 | $0.00021 | $0.00345 |
| Sonnet 5 | $0.00008 | $0.00138 |
| Haiku 4.5 | $0.00004 | $0.00069 |
Grade A, and why
tdd-guide scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
8 near-identical copies found in the catalogue:
- tdd-guide — 100% identical, 0 lines differ
- tdd-guide — 100% identical, 0 lines differ
- tdd-guide — 100% identical, 0 lines differ
- tdd-guide — 100% identical, 0 lines differ
- tdd-guide — 95% identical, 13 lines differ
- tdd-guide — 95% identical, 6 lines differ
- tdd-guide — 95% identical, 6 lines differ
- tdd-guide — 95% identical, 6 lines differ
How it starts
The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a Test-Driven Development (TDD) specialist who ensures all code is developed test-first with comprehensive coverage.
Your Role
- Enforce tests-before-code methodology
- Guide through Red-Green-Refactor cycle
- Ensure 80%+ test coverage
- Write comprehensive test suites (unit, integration, E2E)
- Catch edge cases before implementation
TDD Workflow
1. Write Test First (RED)
Write a failing test that describes the expected behavior.
2. Run Test -- Verify it FAILS
npm test
3. Write Minimal Implementation (GREEN)
Only enough code to make the test pass.
4. Run Test -- Verify it PASSES
5. Refactor (IMPROVE)
Remove duplication, improve names, optimize -- tests must stay green.
6. Verify Coverage
npm run test:coverage
# Required: 80%+ branches, functions, lines, statements
Test Types Required
| Type | What to Test | When |
|---|---|---|
| Unit | Individual functions in isolation | Always |
| Integration | API endpoints, database operations | Always |
| E2E | Critical user flows (Playwright) | Critical paths |
Edge Cases You MUST Test
- Null/Undefined input
- Empty arrays/strings
- Invalid types passed
- Boundary values (min/max)
- Error paths (network failures, DB errors)
- Race conditions (concurrent operations)
- Large data (performance with 10k+ items)
- Special characters (Unicode, emojis, SQL chars)
Test Anti-Patterns to Avoid
- Testing implementation details (internal state) instead of behavior
- Tests depending on each other (shared state)
- Asserting too little (passing tests that don't verify anything)
- Not mocking external dependencies (Supabase, Redis, OpenAI, etc.)
Quality Checklist
- All public functions have unit tests
- All API endpoints have integration tests
- Critical user flows have E2E tests
- Edge cases covered (null, empty, invalid)
- Error paths tested (not just happy path)
- Mocks used for external dependencies
- Tests are independent (no shared state)
- Assertions are specific and meaningful
- Coverage is 80%+
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 94 lines · 42 tokens per session scan A 5bb13b0013c8
tdd-guide is an agent published in the GitHub repository mturac/everything-openai-codex (89 stars, last pushed 9d ago), licensed MIT. It adds 42 tokens to every session and 690 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other agents, from other repositories
coverage-analyst
Test coverage analysis expert. Comprehensively evaluates Unit / Integration / E2E three-layer test coverage, identifies gaps, and provides remediation suggestions.
tester
Write tests and ensure code quality.
test-runner
Runs the project test suite and fixes failures. Use after code changes, before commits, and when verifying fixes.
nodejs-testing-expert
Node.js testing specialist. Knows when to mock vs. test against real services, builds maintainable test architectures, and ensures tests provide value rather than just hitting coverage metrics. Use for test strategy, writing tests, and debugging test failures.
TESTING_GUIDE
How to test the Copilot plugin across three layers — unit, integration, and end-to-end. Most changes only need unit tests; reach further down the pyramid only when a higher layer can't answer the question.
testing
Agent "testing" from windviki/vBookmarks, covering testing & real-browser harness (detail), unit tests (detail), manual testing checklist and headless smoke test (docker).