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 rodolfochicone/rc-project --skill rc-tddgit clone --depth 1 https://github.com/rodolfochicone/rc-projectWrote 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/rodolfochicone/rc-project/rc-tdd)<a href="https://agentmods.dev/skills/rodolfochicone/rc-project/rc-tdd"><img src="https://agentmods.dev/badge/skills/rodolfochicone/rc-project/rc-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/rodolfochicone/rc-project/rc-tdd"><img src="https://agentmods.dev/badge/skills/rodolfochicone/rc-project/rc-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 | $0.00034 | $0.01044 |
| Opus 5 | $0.00017 | $0.00522 |
| Sonnet 5 | $0.00007 | $0.00209 |
| Haiku 4.5 | $0.00003 | $0.00104 |
Grade A, and why
rc-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 9d 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 — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Test-Driven Development
TDD is the red → green loop. This skill is what makes that loop produce tests worth keeping: what a good test is, where tests go, the anti-patterns, and the rules of the loop. Every section applies on every cycle — consult them during the loop, not after.
What a good test is
A test verifies behaviour through a public interface, never an implementation detail. The implementation can change entirely; the test should not. A good test reads like a specification — "user can check out with a valid cart" tells you exactly what capability exists — and survives a refactor because it never cared about internal structure.
Test what the code does, not what the mocks do. A mock is a means of isolation, never the subject.
Seams — where tests go
A seam is a place where you can alter behaviour without editing in that place — the interface
where behaviour is observable without reaching inside. rc-codebase-design owns that vocabulary
(module, interface, depth, seam, adapter) and the design decisions behind it; read it when the
question is where the seam should be rather than what to test at the one that exists.
Its third principle is this section's premise: the interface is the test surface. If a test has to reach past the interface — poking at internals, asserting through a side channel, needing a test-only accessor — that is information about the design, not about the test.
Test only at pre-agreed seams. Before writing any test, write down the seams under test and confirm them with the user. No test is written at an unconfirmed seam. You cannot test everything — agreeing the seams up front is how testing effort lands on the critical paths and the complex logic instead of on every edge case.
Ask: "What is the public interface here, and which seams should we test?"
The loop
- Red before green. Write the failing test first, watch it fail, then write only enough code to pass it. A test that has never been red proves nothing — it may be passing by construction.
- One vertical slice at a time. One seam, one test, one minimal implementation per cycle. Each test is a tracer bullet that responds to what the last cycle taught.
- Refactoring is not part of the loop. It belongs to review, not to the red → green cycle.
- Never weaken a test to make it pass. If the test is wrong, fix the test deliberately and say so; if the code is wrong, fix the code.
What ships with it
1 file 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.
- 9d ago First seen · 78 lines · 34 tokens per session scan A a1c6d8980693
rc-tdd is a skill published in the GitHub repository rodolfochicone/rc-project (19 stars, last pushed 1mo ago), licensed MIT. It adds 34 tokens to every session and 1,044 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 2026-08-30.
Other skills, from other repositories
taiyi-dev
A software-development stage that implements planned tasks using test-driven development, or TDD: write a failing test, make it pass, then improve the code. It checks the task plan, dependencies, file boundaries, and required completion evidence.
go
Go phase. Reads the approved SPEC file, maps Requirements to tasks (plan), executes via TDD (build), and integrates results verifying all Acceptance Criteria.
rpi-remediate
Validate and resolve every actionable pre-launch finding in ordered local waves with TDD, finding disposition and preservation of strategic exceptions.
tdd
Test-Driven Development enforcer. Red→Green→Refactor cycle with no production code without a failing test first. Use for new features and bug fixes.
lfe-tdd
Red-green-refactor quality pass on code the Builder just wrote. Use in the Builder sub-pipeline after lfe-builder completes implementation.
write-plan
Write a bite-sized TDD implementation plan from a spec before touching code. Saves under docs/plans/ / (gitignored WIP); promote to docs/features/ / when stable. Use when the user invokes write-plan, or when interview-plan hands off an assembled spec. Do not use to implement.