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 FerroxLabs/ijfw --skill ijfw-tddgit clone --depth 1 https://github.com/FerroxLabs/ijfwWrote 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/ferroxlabs/ijfw/ijfw-tdd)<a href="https://agentmods.dev/skills/ferroxlabs/ijfw/ijfw-tdd"><img src="https://agentmods.dev/badge/skills/ferroxlabs/ijfw/ijfw-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/ferroxlabs/ijfw/ijfw-tdd"><img src="https://agentmods.dev/badge/skills/ferroxlabs/ijfw/ijfw-tdd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Anti-Refusal · line 46 Skill instructs the agent to omit warnings, disclaimers, or ethical commentary. Stripping safety caveats hides risk from the user and is a common jailbreak preamble.Fix: Remove instructions that suppress warnings, disclaimers, or ethical commentary. Let the agent surface safety-relevant caveats to the user.
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 | $0.00045 | $0.01379 |
| Opus 5 | $0.00023 | $0.00690 |
| Sonnet 5 | $0.00009 | $0.00276 |
| Haiku 4.5 | $0.00005 | $0.00138 |
Grade A, and why
ijfw-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 4d 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 — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.
IJFW TDD -- RED-GREEN-REFACTOR
Write the test first. Watch it fail for the right reason. Write the minimum code to make it pass. Then improve structure without changing behavior.
Iron law: No production code without a failing test first. If you wrote code before the test, delete it. Implement fresh from the test.
This skill enforces three distinct moves. Each move has a green light that you must hit before advancing. Skipping a green light is not "pragmatic" -- it is the bug.
Move 1: RED -- write a test that fails for the RIGHT reason
Write ONE minimal test for ONE behavior. Use a descriptive name. Use real code (no mocks unless unavoidable).
Before running the test, write down the failure message you EXPECT to see. Example: "AssertionError: expected 'Email required', got undefined" or "AttributeError: module has no attribute 'retryOperation'".
Then run it:
npm test path/to/test.ts # or pytest, cargo test, go test, etc.
Paste the actual failure into your scratch. Compare against what you predicted.
Green light to advance: the test FAILS, and the failure message is the one you predicted (an assertion failure on the intended behavior, or a "missing symbol" error if the function does not exist yet).
Red flags that block advancing:
- Test passes immediately -- you are testing existing behavior. Rewrite.
- Test errors on a typo, import, or syntax issue -- fix and re-run until it fails meaningfully.
- Failure message surprises you -- you do not yet understand what you are building. Stop and think before writing implementation.
Move 2: GREEN -- write the minimum code to pass
Write the simplest implementation that turns the failing test green. No extra parameters. No "while I am here" cleanup. No anticipating tomorrow's tests. YAGNI.
Run the test. Paste the pass output. Run the full suite -- nothing else may regress.
Green light to advance: target test passes, full suite passes, output is pristine (no warnings, no stack-trace noise, no skipped tests you forgot about).
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.
- 4d ago First seen · 103 lines · 45 tokens per session scan A c38dd4cfb108
ijfw-tdd is a skill published in the GitHub repository FerroxLabs/ijfw (210 stars, last pushed yesterday), licensed MIT. It adds 45 tokens to every session and 1,379 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 2026-09-05.
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