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/es6kr/skills/tddnpx skills add es6kr/skills --skill tddgit clone --depth 1 https://github.com/es6kr/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/es6kr/skills/tdd)<a href="https://agentmods.dev/skills/es6kr/skills/tdd"><img src="https://agentmods.dev/badge/skills/es6kr/skills/tdd.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 | $0.00153 | $0.00496 |
| Opus 5 | $0.00077 | $0.00248 |
| Sonnet 5 | $0.00031 | $0.00099 |
| Haiku 4.5 | $0.00015 | $0.00050 |
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 5d 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
TDD (Test-Driven Development)
Test-Driven Development: define expected behavior first, then make it pass with implementation.
Topics
| Topic | Description | Guide |
|---|---|---|
| cycle | Red→Green→Refactor cycle, bug-fix TDD, anti-patterns | cycle.md |
| run | Test execution workflow (environment detection→impact scope→execution→result reporting) | run.md |
| test-strategies | Boundary value·equivalence partitioning·decision table·error guessing·path coverage | test-strategies.md |
Quick Reference
Trigger entry (HARD STOP — first action)
When this skill is invoked, the FIRST tool call must be TaskCreate (Red/Green/Refactor/Verify) + Red test authoring. Diagnosis, planning, option asks, and medium decisions are forbidden before Red is authored + executed + failure confirmed. See cycle.md "Trigger entry".
TDD Cycle
Define expected behavior → natural failure → implement → pass → refactor. See cycle.md.
Test Execution
Environment detection → impact scope → execution (unit→integration→e2e) → result reporting. See run.md.
Test Design Techniques
Decide which test cases to write (boundary value, equivalence partitioning, etc.). See test-strategies.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.
- 5d ago First seen · 38 lines · 153 tokens per session scan A 2533fa0cbb1e
tdd is a skill published in the GitHub repository es6kr/skills (2 stars, last pushed yesterday), licensed MIT. It adds 153 tokens to every session and 496 once invoked, about $0.0008 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 2026-08-31.
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