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/hoavdc/codexkit/codexkit-test-hardeningnpx skills add hoavdc/CodexKit --skill codexkit-test-hardeninggit clone --depth 1 https://github.com/hoavdc/CodexKitWrote 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/hoavdc/codexkit/codexkit-test-hardening)<a href="https://agentmods.dev/skills/hoavdc/codexkit/codexkit-test-hardening"><img src="https://agentmods.dev/badge/skills/hoavdc/codexkit/codexkit-test-hardening.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 | $0.00028 | $0.00451 |
| Opus 5 | $0.00014 | $0.00226 |
| Sonnet 5 | $0.00006 | $0.00090 |
| Haiku 4.5 | $0.00003 | $0.00045 |
Grade A, and why
codexkit-test-hardening 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 Hardening
Use this skill when code changes are underway or just landed and you need tests that actually protect behavior.
Focus areas
- changed execution paths
- high-risk conditionals
- error handling
- serialization or contract boundaries
- regressions that can silently return
Workflow
- Identify the behavior that must remain true.
- Choose the narrowest test level that can protect it.
- Cover happy path, failure path, and one realistic edge.
- Verify tests fail before the fix when possible.
- Keep fixtures readable and cheap to maintain.
Avoid
- snapshot-heavy tests with weak intent
- restating implementation details instead of behavior
- adding e2e coverage when a unit or integration test is enough
Quality Criteria
- Every finding is tied to a specific evidence source (log, test, metric)
- Pass/fail criteria are binary and measurable — no subjective judgments
- Severity levels are assigned with clear thresholds
- Remediation steps are provided for all critical and high findings
Verification (4C)
| Check | Question |
|---|---|
| Correctness | Are all pass/fail criteria applied against the correct standard or rule? |
| Completeness | Were all required dimensions or checklist items evaluated? |
| Context-fit | Does the verification scope match the actual risk level of the deliverable? |
| Consequence | If this passed verification but had a hidden flaw, what is the worst-case impact? |
Edge Cases
- Incomplete data for full assessment — Document which checks were limited and flag for re-verification when data becomes available.
- Ambiguous pass/fail criteria — Request clarification from the standard owner before scoring. Mark as 'Needs Review'.
- Multiple overlapping standards — Identify the governing standard and note where others diverge.
Changelog
- v1.0.0 — Initial release
What ships with it
2 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.
- yesterday First seen · 59 lines · 28 tokens per session scan A 60967a923b4b
codexkit-test-hardening is a skill published in the GitHub repository hoavdc/CodexKit (21 stars, last pushed 3mo ago), licensed MIT. It adds 28 tokens to every session and 451 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.
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