blueprint-derive-tests

blueprint-derive-tests is a skill for Claude Code from laurigates/claude-plugins. It costs 37 tokens per session (2,447 once invoked), scanned A, original, MIT.

A test-planning tool that examines Git history to find bug fixes and features that changed code without adding corresponding tests. It produces a prioritized regression-test backlog.

In plain words
What is it for?
Use it to identify untested fixes and features, assess test health during onboarding, and create a backlog of tests to add.
Why use it?
It reveals likely test coverage gaps in projects where changes were shipped without tests. A regression test is a test that helps ensure a previously fixed problem does not return.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: model in frontmatter; names the AskUserQuestion tool.

Part of the blueprint-plugin plugin — 35 skills shipped together

Good fit Use it to identify untested fixes and features, assess test health during onboarding, and create a backlog of tests to add.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/laurigates/claude-plugins/blueprint-derive-tests
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 laurigates/claude-plugins --skill blueprint-derive-tests
Clone the repo
git clone --depth 1 https://github.com/laurigates/claude-plugins

Made for: Claude Code.

Or install blueprint-plugin, the plugin that ships this one along with the rest of its 35 skills.

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 blueprint-derive-tests

README.md
[![agentmods](https://agentmods.dev/badge/skills/laurigates/claude-plugins/blueprint-derive-tests.svg)](https://agentmods.dev/skills/laurigates/claude-plugins/blueprint-derive-tests)
Your own site
<a href="https://agentmods.dev/skills/laurigates/claude-plugins/blueprint-derive-tests"><img src="https://agentmods.dev/badge/skills/laurigates/claude-plugins/blueprint-derive-tests.svg" alt="Measured on agentmods" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,447 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. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Excessive Agency · line 9
    Skill selects an external model or provider that may use a different account or billing plan than the operator expects. Undisclosed model switches can cause unexpected cost or quota consumption.
    Fix: Remove the model/provider override or disclose it prominently and require explicit operator approval before invoking an external coding CLI or billed model.
How audits are shown
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 $0.00037 $0.02447
Opus 5 $0.00018 $0.01223
Sonnet 5 $0.00007 $0.00489
Haiku 4.5 $0.00004 $0.00245

Measured 4d ago against content hash 7fee5764446d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

blueprint-derive-tests 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 4d ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/blueprint-derive-tests.sh, scripts/tests/test-blueprint-derive-tests.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

blueprint-plugin/skills/blueprint-derive-tests/SKILL.md · 211 lines

How it starts

The opening of the file, as written. The whole thing — 211 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/blueprint:derive-tests

Analyze git history to identify fix and feature commits lacking corresponding test changes, then generate a structured Test Regression Plan (TRP) document as a prioritized test backlog.

Use case: Systematically close test coverage gaps by mining commit history for bug fixes and features that shipped without regression tests.

When to Use This Skill

Use this skill when... Use alternative when...
Bug fixes ship without regression tests You need to run existing tests (/test:run)
Want a prioritized test backlog from history Writing tests for a specific feature (manual TDD)
Onboarding a project and assessing test health Checking current test coverage metrics
Need to find which fixes lack test coverage Designing a test strategy from scratch (/test:architecture)

Context

  • Git repository: !git rev-parse --git-dir
  • Blueprint initialized: !find . -path '*/docs/blueprint/*' -maxdepth 3 -name 'manifest.json' -type f
  • Total commits: !git rev-list --count HEAD
  • Test framework: !find . -maxdepth 3 \( -name 'vitest.config.*' -o -name 'jest.config.*' -o -name 'pytest.ini' -o -name 'pyproject.toml' -o -name 'Cargo.toml' -o -name 'go.mod' \) -type f -print -quit
  • Test files: !find . -maxdepth 4 -type f \( -name '*.test.*' -o -name '*.spec.*' -o -name 'test_*' -o -name '*_test.*' \) -print
  • Conventional commits sample: !git log --format="%s" --max-count=10

Parameters

Parse these from $ARGUMENTS:

  • --quick: Fast scan (last 50 commits only)
  • --since DATE: Analyze commits from specific date (e.g., --since 2024-06-01)
  • --scope AREA: Filter to commits touching a specific area/scope (e.g., --scope auth)

Default behavior without flags: Analyze last 200 commits.

For detailed templates, severity matrix, and test mapping rules, see REFERENCE.md.

Execution

Execute this test regression plan derivation workflow:

Read the full file on GitHub · 211 lines

Files

What ships with it

3 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.

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. 4d ago First seen · 211 lines · 37 tokens per session scan A 7fee5764446d

Subscribe to this mod's changes

blueprint-derive-tests is a skill published in the GitHub repository laurigates/claude-plugins (58 stars, last pushed today), licensed MIT. It adds 37 tokens to every session and 2,447 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 2026-09-03.