secure-fix-validation

secure-fix-validation is a skill for Claude Code, Codex from Robotti-io/copilot-security-instructions. It costs 20 tokens per session (386 once invoked), scanned A, original, Apache-2.0.

A checklist for checking that a security fix works and does not break existing behavior.

In plain words
What is it for?
Use it after implementing a security fix or while reviewing a pull request to record reproduction steps, tests, verification evidence, and deployment notes.
Why use it?
It makes the verification cover the original failure, malicious and edge inputs, information leaks, regression tests, and rollout risks.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

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.

agentmods
npx agentmods add skills/robotti-io/copilot-security-instructions/secure-fix-validation
Any agent
npx skills add Robotti-io/copilot-security-instructions --skill secure-fix-validation
Clone the repo
git clone --depth 1 https://github.com/Robotti-io/copilot-security-instructions

Made for: Claude Code, 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 secure-fix-validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/robotti-io/copilot-security-instructions/secure-fix-validation.svg)](https://agentmods.dev/skills/robotti-io/copilot-security-instructions/secure-fix-validation)
Your own site
<a href="https://agentmods.dev/skills/robotti-io/copilot-security-instructions/secure-fix-validation"><img src="https://agentmods.dev/badge/skills/robotti-io/copilot-security-instructions/secure-fix-validation.svg" alt="Measured on agentmods" height="20"></a>
Per session 20 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 386 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00020 $0.00386
Opus 5 $0.00010 $0.00193
Sonnet 5 $0.00004 $0.00077
Haiku 4.5 $0.00002 $0.00039

Measured 6d ago against content hash 9bb91467375b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

secure-fix-validation 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 6d 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.

skills/secure-fix-validation/SKILL.md · 57 lines

What it actually says

Secure Fix Validation

When to use

Use this skill after implementing a security fix, or when reviewing a PR.

Inputs to collect (if available)

  • Vulnerability description and expected secure behavior
  • Repro steps (request, payload, or test)
  • Affected components and entry points
  • Deployment/rollout constraints (feature flags, backwards compatibility)

Step-by-step process

  1. Reproduce the issue pre-fix
    • Minimal failing test or request example
  2. Verify the fix
    • Confirm the repro now fails safely
  3. Regression coverage
    • Add unit/integration tests for:
      • expected valid inputs
      • malicious/edge inputs
      • authorization bypass attempts (if relevant)
  4. Non-functional checks
    • Error handling (no stack traces/secret leakage)
    • Logging redaction (no PII/secrets)
    • Performance impact in hot paths
  5. Rollout safety
    • Feature flags where appropriate
    • Backwards compatibility notes
    • Monitoring/alerts to detect new failure modes

Output

  • Commands run
  • Tests added/updated
  • Verification evidence (logs/screenshots/snippets)
  • Rollout notes

Output format

  • Repro (pre-fix): how it failed
  • Verification (post-fix): what now happens
  • Tests: added/updated + what they cover
  • Evidence: logs/screenshots/snippets (redacted)
  • Rollout notes: monitoring, flags, compatibility

Examples

  • “Fix: block IDOR on /users/:id” → add negative test for cross-user access; verify 403 and tenant scoping on DB query.
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. 6d ago First seen · 57 lines · 20 tokens per session scan A 9bb91467375b

Subscribe to this mod's changes

secure-fix-validation is a skill published in the GitHub repository Robotti-io/copilot-security-instructions (42 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 20 tokens to every session and 386 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 2026-08-30.

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