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 skills add viknesh20-20/claude-code-tool-kit --skill tddgit clone --depth 1 https://github.com/viknesh20-20/claude-code-tool-kitWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/viknesh20-20/claude-code-tool-kit/tdd)<a href="https://agentmods.dev/skills/viknesh20-20/claude-code-tool-kit/tdd"><img src="https://agentmods.dev/badge/skills/viknesh20-20/claude-code-tool-kit/tdd/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/viknesh20-20/claude-code-tool-kit/tdd"><img src="https://agentmods.dev/badge/skills/viknesh20-20/claude-code-tool-kit/tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What 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 5.1 | $0.00043 | $0.00556 |
| Opus 5.5 | $0.00017 | $0.00222 |
| Sonnet 5.5 | $0.00009 | $0.00111 |
| Haiku 4.5 | $0.00004 | $0.00056 |
Grade A, and why
tdd 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 1mo 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
Test-Driven Development
Detect Test Environment
!ls package.json pytest.ini pyproject.toml go.mod Cargo.toml *.csproj Gemfile mix.exs 2>/dev/null
!find . -type f \( -name "*.test.*" -o -name "*.spec.*" -o -name "test_*" -o -name "*_test.*" \) -not -path "*/node_modules/*" -not -path "*/.git/*" 2>/dev/null | head -5
The TDD Cycle
For the requested feature, repeat this cycle until complete:
RED — Write a Failing Test
- Write the smallest possible test that describes the next piece of behavior
- The test must import/reference the function or module (even if it doesn't exist yet)
- Run the test — it MUST fail
- Verify the failure message is meaningful (not just a compilation error)
GREEN — Make It Pass
- Write the absolute minimum code to make the test pass
- Hardcoding is acceptable at this stage — it will be cleaned up in refactor
- Don't add functionality the test doesn't require
- Run the test — it MUST pass
- Run all related tests — nothing else should break
REFACTOR — Clean Up
- Remove duplication in both production and test code
- Improve naming, extract methods, simplify logic
- Run tests after every refactoring step — they must stay green
- Stop when the code is clean
Test Progression
Start simple, add complexity gradually:
- Null/empty/zero case
- Single item / simplest valid input
- Multiple items / typical case
- Edge cases / boundary values
- Error cases / invalid input
- Async / concurrent behavior (if applicable)
Output
- Show each cycle clearly: RED (test code + failure), GREEN (impl + pass), REFACTOR
- Display test runner output at each step
- Final summary: all tests, coverage of the feature
Rules
- NEVER write implementation before a failing test
- NEVER skip the refactor step
- One behavior per cycle — don't batch multiple features
- If the test framework isn't set up, set it up first
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.
- 1mo ago First seen · 58 lines · 43 tokens per session scan A b8ce4de9326c
tdd is a skill published in the GitHub repository viknesh20-20/claude-code-tool-kit (7 stars, last pushed 5mo ago), licensed MIT. It adds 43 tokens to every session and 556 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-31.
Other skills, from other repositories
test-driven-development
Use when implementing any feature or bugfix, before writing implementation code.
behavior-contract
Bug condition/postcondition formalization as testable Behavior Contracts. Defines invariants that must be preserved across fixes.
ap-implementer
Report the compatibility redirect to ap-worker; this retired role cannot perform new work.
strict-tdd
Strict RED->GREEN->REFACTOR test-driven development with enforcement. Never write production code before a failing test. Atomic commits per TDD cycle.
test-driven-development
Strict RED-GREEN-REFACTOR cycle enforcement. Tests are never skipped or deferred. Run mode only, never watch mode. Exit code evidence mandatory.
tdd-enforcement
Red-Green-Refactor TDD methodology with mandatory failing tests, minimal implementation, quality refactoring, and 80% coverage gating.