test-gap-analysis

test-gap-analysis is a skill for Claude Code, Codex from NickPolyder/NP.CoPilot.Config. It costs 40 tokens per session (1,053 once invoked), scanned A, original, MIT.

A read-only review of existing code that looks for untested paths, weak checks, and missing edge cases. It produces a prioritized report and separates the review from any later test writing.

In plain words
What is it for?
Use it to audit test coverage after development, identify risky gaps, and prepare concrete tests for gaps the user approves filling.
Why use it?
It reveals what the current test suite may fail to catch without changing production code or generating tests before approval.

Skill for Claude CodeCodex

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/nickpolyder/np.copilot.config/test-gap-analysis
Any agent
npx skills add NickPolyder/NP.CoPilot.Config --skill test-gap-analysis
Clone the repo
git clone --depth 1 https://github.com/NickPolyder/NP.CoPilot.Config

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 test-gap-analysis

README.md
[![agentmods](https://agentmods.dev/badge/skills/nickpolyder/np.copilot.config/test-gap-analysis.svg)](https://agentmods.dev/skills/nickpolyder/np.copilot.config/test-gap-analysis)
Your own site
<a href="https://agentmods.dev/skills/nickpolyder/np.copilot.config/test-gap-analysis"><img src="https://agentmods.dev/badge/skills/nickpolyder/np.copilot.config/test-gap-analysis.svg" alt="Measured on agentmods" height="20"></a>
Per session 40 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,053 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 $0.00040 $0.01053
Opus 5 $0.00020 $0.00526
Sonnet 5 $0.00008 $0.00211
Haiku 4.5 $0.00004 $0.00105

Measured 3d ago against content hash 632e674c3fe6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

test-gap-analysis 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 3d 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/test-gap-analysis/SKILL.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Purpose

Intent (anchor): Coordinate a two-phase test-gap workflow — audit first, then optionally fill — by sequencing the atomic test-gap-audit and test-gap-fill skills behind an approval gate. Always: run the read-only audit before generating anything; require explicit approval of which gaps to fill; keep audit and fill as separate atomic steps. Never: generate tests before the gap report is approved, or modify production code without asking.

Shared policy: Follow instructions/coordination.instructions.md for precedence, invocation, delegation, and handoffs. Apply instructions/workflow.instructions.md for proportional work and verification.

This skill is a thin coordinator. It owns the retroactive coverage flow and the gate between auditing and generating tests, but delegates the detailed procedures to two atomic skills:

  • test-gap-audit — read-only discovery of untested paths, weak assertions, and missing edge cases, with a risk-prioritized gap report.
  • test-gap-fill — generation of concrete, runnable tests for approved gaps, following project conventions.

For single-phase needs, invoke those skills directly. Use this coordinator when you want the full audit → approval → fill flow in one place.

Difference from test-strategy: test-strategy is forward-looking (plans tests for new work). This flow is retroactive — it audits existing code that may have shipped without adequate coverage.


When to use this skill

Use this skill whenever:

  • A bug shipped that "should have been caught by tests" — retroactively fill the gap.
  • Before a major refactoring — ensure the safety net exists before you lean on it.
  • During maintenance cycles — periodic test health check.
  • The user asks to "find untested code", "improve test coverage", or "audit tests for [module]".
  • After a production incident — identify what tests would have prevented it.

Do not use this skill for:

  • Planning tests for new features — use test-strategy instead.
  • Running or debugging existing tests — do that directly.
  • Code review — use git-commit-review or the code-reviewer agent.
  • A pure gap report (no intent to write tests) — invoke test-gap-audit directly.

Read the full file on GitHub · 98 lines

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. 3d ago First seen · 98 lines · 40 tokens per session scan A 632e674c3fe6

Subscribe to this mod's changes

test-gap-analysis is a skill published in the GitHub repository NickPolyder/NP.CoPilot.Config (2 stars, last pushed 9d ago), licensed MIT. It adds 40 tokens to every session and 1,053 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 2026-08-31.

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