Analyzing Test Coverage

What it does

When your agent uses it

• Analyzing untested code
• With phrases like analyze coverage
• Check test coverage
• Find untested code

Example prompts

• “analyze coverage”
• “check test coverage”
• “find untested code”
• “/analyzing-test-coverage”

Requirements

• Python 3
• Node.js
• Compatibility (from SKILL.md): Designed for Claude Code
• Pre-approved tools (allowed-tools): Read, Write, Edit, Grep, Glob, Bash(test:coverage-*)

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

1. 1Run the test suite with coverage instrumentation enabled
2. 2Parse the coverage report and extract per-file metrics
3. 3Identify critical coverage gaps by prioritizing
4. 4Analyze uncovered branches specifically
5. 5Generate a prioritized action plan
6. 6Compare current coverage against the previous commit or baseline
7. 7Write coverage enforcement configuration (coverage thresholds in Jest config, .coveragerc, or CI checks).

What it can do on your machine

Read from SKILL.md and the folder at commit 80f86df. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Write
  • Edit
  • Grep
  • Glob
  • Bash(test:coverage-*)

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Ships 3 files in scripts/ (Python), which the agent can run.

  Shell commands in SKILL.md call:

  • go
  • node
  • python3
  • npx
  • pytest

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • istanbul.js.org
  • github.com
  • coverage.readthedocs.io
  • jacoco.org
  • go.dev
  • testing.googleblog.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Designed for Claude Code

  From compatibility in the SKILL.md frontmatter.

Context cost

Analyzing Test Coverage loads about 1.4k tokens when it runs, and up to ~1.5k if it reads all its reference files. Until then it costs about 58 tokens; SKILL.md has 513 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~58

When it runs · the whole SKILL.md, loaded when a task matches

~1.4k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~1.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.

SKILL.md

The full file from jeremylongshore/tons-of-skills-marketplace at commit 80f86df, republished under its MIT licence (© jeremylongshore). 513 words, ~1,449 tokens.

name

analyzing-test-coverage

description

Analyze code coverage metrics and identify untested code paths. Use when analyzing untested code or coverage gaps. Trigger with phrases like "analyze coverage", "check test coverage", or "find untested code".

allowed-tools

Read, Write, Edit, Grep, Glob, Bash(test:coverage-*)

compatibility

Designed for Claude Code

version

1.24.0

author

Jeremy Longshore <jeremy@intentsolutions.io>

license

MIT

tags

testing, analyzing-test

{
  "jest": {
    "coverageThreshold": {
      "global": {
        "branches": 70,
        "functions": 80,
        "lines": 80,
        "statements": 80
      },
      "src/utils/": {
        "branches": 90,
        "lines": 95
      }
    },
    "collectCoverageFrom": [
      "src/**/*.{ts,tsx}",
      "!src/**/*.d.ts",
      "!src/**/index.ts"
    ]
  }
}

Coverage Gaps (sorted by impact):
1. src/auth/oauth.ts        Lines: 45%  Branches: 30%  [Lines 42-67, 89-103 uncovered]
   Suggestion: Add tests for token refresh failure and expired session handling
2. src/api/middleware.ts     Lines: 62%  Branches: 41%  [Lines 28-35, 71-80 uncovered]
   Suggestion: Test rate limiting edge cases and malformed header handling
3. src/utils/parser.ts       Lines: 71%  Branches: 55%  [Lines 112-130 uncovered]
   Suggestion: Test malformed input, empty string, and encoding edge cases

© jeremylongshore, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 8 other files (scripts, references, assets) in skills/.curated/analyzing-test-coverage of jeremylongshore/tons-of-skills-marketplace.

• SKILL.md
• assets/README.md
• assets/configuration_template.yaml
• assets/example_coverage_report.html
• assets/report_template.html
• references/README.md
• scripts/README.md
• scripts/analyze_coverage.py
• scripts/generate_report.py

Open the folder on GitHubat commit 80f86df