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 skills/ahmadulhoq/agentskel/test-driven-developmentnpx skills add ahmadulhoq/agentskel --skill test-driven-developmentgit clone --depth 1 https://github.com/ahmadulhoq/agentskelWrote 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/ahmadulhoq/agentskel/test-driven-development)<a href="https://agentmods.dev/skills/ahmadulhoq/agentskel/test-driven-development"><img src="https://agentmods.dev/badge/skills/ahmadulhoq/agentskel/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 | $0.00034 | $0.00409 |
| Opus 5 | $0.00017 | $0.00204 |
| Sonnet 5 | $0.00007 | $0.00082 |
| Haiku 4.5 | $0.00003 | $0.00041 |
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 yesterday.
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 Skill
Cycle: RED → GREEN → REFACTOR
Highly recommended during any logic implementation. Do not write production code before a failing test exists.
RED Phase — Write a Failing Test
- Identify the smallest unit of behavior to implement next.
- Write a test that asserts the expected output or behavior.
- Run the test. Confirm it fails.
- If it passes before any implementation, the test is wrong — fix it.
- Record:
[RED] <test name> — fails as expected
GREEN Phase — Minimum Code to Pass
- Write the minimum production code to make the test pass.
- No premature abstractions. No extra features. Bare minimum only.
- Run the test. Confirm it passes.
- Record:
[GREEN] <test name> — passes
- Record:
REFACTOR Phase — Clean Without Changing Behavior
- Refactor implementation if needed (remove duplication, improve names, simplify).
- Run the full test suite. All tests must still pass.
- Record:
[REFACTOR] <test name> — clean, all pass
- Record:
Rules
- Never skip RED. A test that was never failing proves nothing.
- Refactor only when GREEN — never while RED.
- One cycle = one behavior unit. Do not batch multiple behaviors into one RED-GREEN.
- Note failing test evidence in RESUME.md before moving to the next unit.
Exemptions
Skip this cycle only for: trivial config/boilerplate, pure UI layout with no logic, or when the user explicitly opts out. Document the exemption reason.
Gate: Do not write production code for a behavior unit without first having a failing test for that unit.
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.
- yesterday First seen · 44 lines · 34 tokens per session scan A cbb9e0b24d0b
test-driven-development is a skill published in the GitHub repository ahmadulhoq/agentskel (13 stars, last pushed 17d ago), licensed MIT. It adds 34 tokens to every session and 409 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 2026-09-02.
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