A command that compares an existing test suite with constraints written in Z, a mathematical notation for describing software states and rules. It looks for tests covering those rules, including conditions, effects, and limits.

Use it with a Z specification and an optional test directory, with results shown as a table or JSON.

It shows which specified behaviors are not represented in the tests. This helps reveal gaps that ordinary test-coverage percentages may miss.

z-spec-dev — Plugin for Claude Code by punt-labs/z-spec

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.

Clone the repo

git clone --depth 1 https://github.com/punt-labs/z-spec

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/plugins/punt-labs/z-spec/plugin/github.svg)](https://agentmods.dev/plugins/punt-labs/z-spec/plugin)

Your own site

<a href="https://agentmods.dev/plugins/punt-labs/z-spec/plugin"><img src="https://agentmods.dev/badge/plugins/punt-labs/z-spec/plugin/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.

Your own site · 80×15

<a href="https://agentmods.dev/plugins/punt-labs/z-spec/plugin"><img src="https://agentmods.dev/badge/plugins/punt-labs/z-spec/plugin.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session not measured What this adds to a session before it is invoked.

When invoked not measured The manifest loads nothing itself; its 42 commands, 1 hook cost 400 tokens a session between them.

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.

Security

Grade A, and why

z-spec-dev 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 1mo 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.

plugin/.claude-plugin/plugin.json · 27 lines

What it actually says

{
  "name": "z-spec-dev",
  "description": "Create, validate, and test formal Z specifications for stateful systems using fuzz and probcli",
  "version": "0.20.5",
  "author": {
    "name": "Punt Labs",
    "email": "[email protected]"
  },
  "mcpServers": {
    "zspec": {
      "type": "stdio",
      "command": "uv",
      "args": [
        "run",
        "--directory",
        "${CLAUDE_PLUGIN_ROOT}",
        "z-spec",
        "mcp"
      ],
      "env": {
        "ZSPEC_PLUGIN_ROOT": "${CLAUDE_PLUGIN_ROOT}",
        "CLAUDE_PROJECT_DIR": "${CLAUDE_PROJECT_DIR}"
      }
    }
  }
}

Contents

What it installs

The manifest is a name and a version. 42 commands, 1 hook travel with it, and installing the plugin installs all of them — 400 tokens a session between them. Each is measured on its own page, and each can be installed alone.

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.

1mo ago Changed f517ad299edb
1mo ago First seen · 27 lines scan A c20b5f703b87

Subscribe to this mod's changes

z-spec-dev is a plugin published in the GitHub repository punt-labs/z-spec (5 stars, last pushed yesterday), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.

LaTeX Testing beta claude-code-plugin formal-methods z-notation z-notations

prfaq-dev

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A polygraph for your state machine. The agent does the hard part for you: it instruments your code, builds any test doubles needed to run it, and captures real execution traces — then has an LLM derive a transition-function spec from the source (default: a SAM v2 strict-profile module with named…

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dev-loop

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z-spec-dev

Getting it into your agent

Wrote this? Show the measurements

Grade A, and why

Nothing flagged

What it actually says

What it installs

What this file has done since we first saw it

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