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 jggomez/expert-ai-developer-skills --skill test-driven-developmentgit clone --depth 1 https://github.com/jggomez/expert-ai-developer-skillsWrote 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/jggomez/expert-ai-developer-skills/test-driven-development)<a href="https://agentmods.dev/skills/jggomez/expert-ai-developer-skills/test-driven-development"><img src="https://agentmods.dev/badge/skills/jggomez/expert-ai-developer-skills/test-driven-development/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/jggomez/expert-ai-developer-skills/test-driven-development"><img src="https://agentmods.dev/badge/skills/jggomez/expert-ai-developer-skills/test-driven-development.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 | $0.00051 | $0.01609 |
| Opus 5.5 | $0.00020 | $0.00644 |
| Sonnet 5.5 | $0.00010 | $0.00322 |
| Haiku 4.5 | $0.00005 | $0.00161 |
Grade A, and why
test-driven-development 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 today.
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.
How it starts
The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test-Driven Development (TDD) Skill
Overview
This skill establishes a disciplined Test-Driven Development (TDD) workflow based on the Red-Green-Refactor cycle. It acts as a Software Quality and TDD Specialist, treating untested code as immediate technical debt. It enforces decoupled, highly testable architectures by defining verification contracts and behavioral specifications before writing any production implementation.
When to Use
Trigger Scenarios
- Implementing new features, user stories, domain models, or utility logic.
- Fixing software bugs by writing a reproducing regression test first.
- Refactoring complex systems while preserving exact behavior with a fast safety net.
- Measuring and enforcing test coverage boundaries across a codebase.
When NOT to Use
- Browser/UI End-to-End journeys: Route to
qa-tester. - BDD Gherkin specification authoring: Route to
testing-expert. - Pre-commit and linting pipelines: Route to
build-and-ci-gates. - Pure code smell identification without testing: Route to
code-smells-expert.
Process
Phase 1: Framework Discovery & Baseline Run
- Detect the project's testing framework (
pytest,jest,vitest,go test,flutter test). - Run existing tests to verify that the baseline suite is green before making any edits:
python3 ./skills/test-driven-development/scripts/verify_tests.py
Phase 2: Red-Green-Refactor Loop
For every atomic requirement or behavior:
- RED: Write a focused, failing unit test asserting the expected behavior. Follow the Arrange-Act-Assert (AAA) pattern.
- Run the test suite and confirm the test fails specifically due to the missing behavior (not due to a syntax error or broken import).
- GREEN: Write the minimal amount of production code required to satisfy the test assertions. Avoid premature abstractions. Confirm the test suite passes.
- REFACTOR: Clean up both production code and test code:
- Eliminate duplication, improve variable and function naming, extract cohesive helpers, and remove dead code.
- Run
verify_tests.pyafter each micro-refactoring step to confirm everything remains green.
What ships with it
2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- today First seen · 152 lines · 51 tokens per session scan A b405802a1f9f
test-driven-development is a skill published in the GitHub repository jggomez/expert-ai-developer-skills (30 stars, last pushed yesterday), licensed Apache-2.0. It adds 51 tokens to every session and 1,609 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 2026-11-06.
test-driven-development compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| test-driven-developmentjggomez/expert-ai-developer-skills | Skill | 30 | yesterday | Apache-2.0 | A | 51 | Claude Code, Codex |
| agui-dotnet-streaming-chatag-ui-protocol/ag-ui | Skill | 17k | yesterday | MIT | A | 223 | Claude Code |
| azure-mgmt-apicenter-dotnetmicrosoft/skills | Skill | 3.2k | yesterday | MIT | A | 97 | Claude Code |
| azure-communication-chat-javamicrosoft/skills | Skill | 3.2k | yesterday | MIT | A | 41 | Claude Code |
| minimal-apicodewithmukesh/dotnet-claude-kit | Skill | 805 | 2d ago | MIT | A | 101 | Claude Code |
| grpcmanagedcode/dotnet-skills | Skill | 508 | yesterday | MIT | A | 95 | Claude Code, Codex |
| azure-messaging-webpubsubservice-pybenjaminasterA/antigravity-awesome-skills | Skill | 461 | yesterday | MIT | A | 0 | Claude Code, Codex |