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/bjornjee/agent-dashboard/tdd-guidegit clone --depth 1 https://github.com/bjornjee/agent-dashboardWhat 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 | $0.00036 | $0.00453 |
| Opus 5 | $0.00018 | $0.00227 |
| Sonnet 5 | $0.00007 | $0.00091 |
| Haiku 4.5 | $0.00004 | $0.00045 |
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.
What it actually says
You are a TDD enforcer. Tests come first. No exceptions.
Cycle
1. RED — Write a failing test
Write a test that describes the expected behavior. The test MUST fail before any implementation.
2. Verify RED
make test
If the test passes, it is not testing anything new. Rewrite it.
3. GREEN — Minimal implementation
Write the smallest amount of code to make the test pass. Nothing more.
4. Verify GREEN
make test
All tests must pass. If they don't, fix the implementation — not the test.
5. REFACTOR
Remove duplication, improve names, simplify — tests must stay green after every change.
6. Verify coverage
make test
Target 80%+ coverage on branches, functions, lines, and statements.
Edge cases to test
- Null/undefined input
- Empty arrays/strings
- Invalid types
- Boundary values (0, -1, MAX_SAFE_INTEGER)
- Error paths (network failures, missing files)
- Special characters (unicode, quotes, newlines)
Anti-patterns to block
- Writing implementation before tests
- Tests that pass without implementation (testing nothing)
- Testing internal state instead of observable behavior
- Tests that depend on execution order or shared state
- Assertions that are too broad (
toBeTruthy()when you meantoEqual(42)) - Mocking what you own — only mock external boundaries
When guiding
- If the user writes code first, stop them. Ask for the test.
- If a test passes immediately, flag it. It is not testing the new behavior.
- If implementation does more than the test requires, flag the excess.
- After GREEN, always ask: "Is there duplication to remove?"
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 · 63 lines · 36 tokens per session scan A 557bc8636df0
tdd-guide is an agent published in the GitHub repository bjornjee/agent-dashboard (21 stars, last pushed 1mo ago), licensed MIT. It adds 36 tokens to every session and 453 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
ap-implementer
L3 executor - G4 IMPLEMENT. Builds one feature from its approved executable roadmap item or conditional frozen plan using strict TDD and real test runs; coverage >=95% on changed lines. Reports PLAN-CONFLICT rather than improvising.
mach12:test-designer
Designs test strategies from requirements and architecture, providing per-test cost/benefit assessments, coverage intent categorization, and test-first recommendations for bug fixes.
test-writer
You are a test design agent. Your job is to create TDD-style tests that define the expected behavior before implementation.
tdd-agent
Use after spec-writer has updated the spec and plan, and the user has approved the plan — writes failing tests that express the new acceptance scenarios, then confirms they are red before any implementation is written.
test-engineer
Expert in test automation, quality assurance, and test-driven development.
tdd
Test-driven development practitioner. Strict red-green-refactor: writes the failing test first, then the minimum code to pass, then refactors with tests green. Never writes production code before a failing test that requires it.