lagune.prove

lagune.prove is a skill for Claude Code from wellwelwel/lagune. It costs 55 tokens per session (3,993 once invoked), scanned A, original, Apache-2.0.

A proof-building command that creates defensive JavaScript tests and advisories for security findings that can be demonstrated.

In plain words
What is it for?
Use it to produce regression tests that fail while a security issue remains and pass after the issue is fixed, plus disclosure-ready explanations.
Why use it?
It gives maintainers runnable evidence of secure behaviour without writing exploits or changing the project's source.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter.

Good fit Use it to produce regression tests that fail while a security issue remains and pass after the issue is fixed, plus disclosure-ready explanations.

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Install with agentmods
npx agentmods add skills/wellwelwel/lagune/lagune.prove
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 wellwelwel/lagune --skill lagune.prove
Clone the repo
git clone --depth 1 https://github.com/wellwelwel/lagune

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.

agentmods badge for lagune.prove

README.md
[![agentmods](https://agentmods.dev/badge/skills/wellwelwel/lagune/lagune.prove/github.svg)](https://agentmods.dev/skills/wellwelwel/lagune/lagune.prove)
Your own site
<a href="https://agentmods.dev/skills/wellwelwel/lagune/lagune.prove"><img src="https://agentmods.dev/badge/skills/wellwelwel/lagune/lagune.prove/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.

agentmods 80×15 button for lagune.prove

Your own site · 80×15
<a href="https://agentmods.dev/skills/wellwelwel/lagune/lagune.prove"><img src="https://agentmods.dev/badge/skills/wellwelwel/lagune/lagune.prove.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,993 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.
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 $0.00055 $0.03993
Opus 5.5 $0.00022 $0.01597
Sonnet 5.5 $0.00011 $0.00799
Haiku 4.5 $0.00006 $0.00399

Measured 3d ago against content hash 5dadab3b43ac, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

lagune.prove 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/lagune.prove/SKILL.md · 207 lines

How it starts

The opening of the file, as written. The whole thing — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.

User Input

$ARGUMENTS

The User Input above decides how this command runs. Read it before proceeding.

Outline

You are producing proofs under .lagune/proofs/: for each detected finding you can demonstrate, a runnable test and a self-contained advisory that a maintainer can take into responsible disclosure. The detect map at .lagune/memory/detect.md is the primary input, and every proof points back at a finding that map really carries.

This command is optional and autonomous. It is not one of the five phases and not part of the tracking chain. It writes only into .lagune/proofs/, and it is read-only on the reconciled phase artifacts (detect.md, plan.md, harden.md, charter.md) and on the user's source under test. Only verify writes across the chain, so this command never removes or rewrites a finding.

Each proof is two things, kept as a unit in its own directory:

  • A test that asserts the safe path: it expects success on the secure behavior, so it fails while the issue persists and passes once the code is fixed. This is defensive regression evidence, never an exploit or an attack payload. The test comes first, it is the evidence that actually runs.
  • A self-contained advisory the user can paste straight into a private GitHub Gist per vulnerability, so it never relies on a parent README or sibling files. Its Proof of Concept is a runnable reproduction through the project's public API, derived from the test and written only after it: a reviewer copies the block, runs it, and sees the symptom from the code's own output, the way a disclosure report shows the path a user reaches the issue through.

Step 1: Decide the scope from the input

The User Input above selects one of three modes:

  • No input (the User Input is empty): prove every finding in the detect map.
  • Findings, files, or directories given (the input names one or more finding names from the map, or paths in the project): prove only the matching findings. Match a name to the map's findings, and match a path to the findings through the tracking map (.lagune/tracking.json), which records the paths each finding points at. Leave the rest untouched.
  • A concern described (the input describes what to focus on, for example "the SQL handling"): prove only the findings that touch that concern.

Read the full file on GitHub · 207 lines

Files

What ships with it

1 file 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. 3d ago First seen · 207 lines · 55 tokens per session scan A 5dadab3b43ac

Subscribe to this mod's changes

lagune.prove is a skill published in the GitHub repository wellwelwel/lagune (173 stars, last pushed 2d ago), licensed Apache-2.0. It adds 55 tokens to every session and 3,993 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-10-26.

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