evidence-first-testing

evidence-first-testing is a skill for Codex from a1024053774/design-integrity-guardrails. It costs 56 tokens per session (945 once invoked), scanned A, original, MIT.

A testing method for keeping failure evidence and checking that tests actually reject broken behaviour before accepting a fix.

In plain words
What is it for?
It is for bug fixes, regression tests, test changes, flaky-test investigations, and changes with a clear acceptance requirement.
Why use it?
A passing test alone may not prove that it would have caught the original problem, especially for regressions or flaky tests.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit It is for bug fixes, regression tests, test changes, flaky-test investigations, and changes with a clear acceptance requirement.

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Install with agentmods
npx agentmods add skills/a1024053774/design-integrity-guardrails/evidence-first-testing
Install

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.

Any agent
npx skills add a1024053774/design-integrity-guardrails --skill evidence-first-testing
Clone the repo
git clone --depth 1 https://github.com/a1024053774/design-integrity-guardrails

Made for: Codex.

Wrote 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.

agentmods badge for evidence-first-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/a1024053774/design-integrity-guardrails/evidence-first-testing/github.svg)](https://agentmods.dev/skills/a1024053774/design-integrity-guardrails/evidence-first-testing)
Your own site
<a href="https://agentmods.dev/skills/a1024053774/design-integrity-guardrails/evidence-first-testing"><img src="https://agentmods.dev/badge/skills/a1024053774/design-integrity-guardrails/evidence-first-testing/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.

agentmods 80×15 button for evidence-first-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/a1024053774/design-integrity-guardrails/evidence-first-testing"><img src="https://agentmods.dev/badge/skills/a1024053774/design-integrity-guardrails/evidence-first-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 56 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 945 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00056 $0.00945
Opus 5 $0.00028 $0.00473
Sonnet 5 $0.00011 $0.00189
Haiku 4.5 $0.00006 $0.00094

Measured 5d ago against content hash 2e3fcd8850a0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

evidence-first-testing 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.

evidence-first-testing/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Evidence-First Testing

A green test proves only that the current code satisfies that test. To call a test regression evidence, show the counterfactual: the focused signal rejects the faulty behavior and accepts the repaired behavior.

Choose the claim and evidence

First classify what the red state means:

  • Defect reproduction: the current implementation violates an existing contract.
  • Contract test: requested new or changed behavior is not implemented yet; an expected red state is not proof of a pre-existing defect.
  • Flaky or environment-specific failure: logs, inputs, seeds, timing, versions, and environment details must travel with the result.

Before implementing or repairing the claimed behavior, obtain the smallest reliable signal:

  • an existing failing test;
  • a new focused test or minimal reproducer;
  • a build, type-check, request, trace, or command that exposes the defect;
  • for flaky or environment-specific failures, preserved logs, inputs, seeds, timing, and environment details.

Record the exact command or procedure, inputs, expected result, observed result, environment, and exit status. Confirm that the signal fails for the expected reason. An unrelated setup, fixture, import, or environment failure is not red-state evidence.

Enforce the gate

For bug fixes, regression tests, and behavior changes with a testable contract, use this order:

  1. Inspect and diagnose without changing the relevant behavior.
  2. Run the focused signal against the current code and record the red-state result.
  3. Make the smallest justified implementation change.
  4. Re-run the same signal and confirm it turns green.
  5. Run the smallest broader suite or check that is required by the repository, the user, or a still-credible failure category. Broaden only when the changed contract, boundary, or failure mode requires it; do not use a fixed test count or line-count comparison as a substitute for evidence.

Do not begin the implementation step until a focused signal exists. A bug fix requires defect-specific red-state evidence; a new behavior may use an expected-red contract test. If no safe red state or counterfactual can be established, report the evidence as INCOMPLETE instead of calling the test regression-proof. Reading code, adding diagnostic logging, or creating a test fixture is allowed when it does not repair or bypass the claim.

Read the full file on GitHub · 95 lines

Files

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.

Changes

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.

  1. 5d ago First seen · 95 lines · 56 tokens per session scan A 2e3fcd8850a0

Subscribe to this mod's changes

evidence-first-testing is a skill published in the GitHub repository a1024053774/design-integrity-guardrails (0 stars, last pushed today), licensed MIT. It adds 56 tokens to every session and 945 once invoked, about $0.0003 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 2026-09-07.

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