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 notque/vexjoy-agent --skill test-driven-developmentgit clone --depth 1 https://github.com/notque/vexjoy-agentWrote 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/notque/vexjoy-agent/test-driven-development)<a href="https://agentmods.dev/skills/notque/vexjoy-agent/test-driven-development"><img src="https://agentmods.dev/badge/skills/notque/vexjoy-agent/test-driven-development.svg" alt="Measured on agentmods" 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 | $0.00020 | $0.01182 |
| Opus 5 | $0.00010 | $0.00591 |
| Sonnet 5 | $0.00004 | $0.00236 |
| Haiku 4.5 | $0.00002 | $0.00118 |
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 3d 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.
How it starts
The opening of the file, as written. The whole thing — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test-Driven Development (TDD) Skill
Enforce the RED-GREEN-REFACTOR cycle for all code changes. Tests are written before implementation code, verified to fail for the right reasons, and maintained through disciplined development cycles.
Reference Loading Table
| Signal | Load These Files | Why |
|---|---|---|
| errors, error handling | error-handling.md |
Loads detailed guidance from error-handling.md. |
| full RED-GREEN-REFACTOR walkthroughs in Go, Python, JavaScript | examples.md |
Loads detailed guidance from examples.md. |
| detailed phase steps, rationale, or language-specific test commands | phase-guidance.md |
Loads detailed guidance from phase-guidance.md. |
Instructions
Before starting any TDD cycle, read and follow repository CLAUDE.md files. Project instructions override default TDD behaviors because local conventions (test frameworks, directory layout, naming) vary across codebases.
Full phase guidance (steps, rationale, code examples, language commands) lives in references/phase-guidance.md. Load it when you need detailed instructions or examples. The sections below are the lean phase skeleton plus the mandatory gates.
Phase 1: Write a Failing Test (RED)
Write a test that describes the desired behavior before any implementation exists. Use specific assertions, descriptive names, Arrange-Act-Assert pattern, and one concept per test. Run the test and show full output. Details: references/phase-guidance.md.
RED Phase Gate
Proceed to the GREEN phase only after all of these are true:
- Test file is created and saved
- Test has been executed
- Test output shows FAILURE (not syntax/import error)
- Failure message indicates missing implementation
Phase 2: Verify Failure Reason (RED Verification)
The test must fail because the feature is not implemented, NOT because of syntax errors, import errors, wrong test setup, or unrelated failures. Expected patterns per language and recovery steps: references/phase-guidance.md.
What ships with it
4 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.
- 3d ago First seen · 110 lines · 20 tokens per session scan A 1cab8adf959c
test-driven-development is a skill published in the GitHub repository notque/vexjoy-agent (419 stars, last pushed yesterday), licensed MIT. It adds 20 tokens to every session and 1,182 once invoked, about $0.0001 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 2026-09-03.
Other skills, from other repositories
tdd
TDD with red-green-refactor loop and vertical slices. Triggers: TDD, test-first, red-green-refactor, test driving development.
triage-issue
Bug triage: explores codebase for root cause, files GitHub issue with TDD fix plan. Triggers: triage, investigate bug, fix plan, root cause, file issue, bug report.
ai-observability-promptfoo
Testing and evaluation framework for LLM prompts and applications -- promptfooconfig.yaml, assertions, model-graded evals, red teaming, CI/CD integration, custom providers, and comparative evaluation.
tdd-workflow
Enforce practical Test-Driven Development for code changes in Go services. Use for new features, bug fixes, refactors, API changes, and new modules. Requires Red-Green-Refactor evidence, defect-hypothesis-driven tests, killer cases, and coverage gates (line + risk-path).
writing-skills
Use when creating new skills, editing existing skills, or verifying skills work before deployment.
test-driven-development
Write software using the RED-GREEN-REFACTOR cycle for reliable, well-tested code.