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What Is Lagune? AI-Driven Security for Any Codebase

Get started with Lagune, an open-source, defense-only security workflow that hardens any codebase: set the rules, detect risks, apply fixes, and verify.

Lagune helps your AI agent make a project more secure. You point it at your code, the agent figures out what your system actually does, then it guides you through the security work that matters for it.


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The idea in one line

Instead of running a generic checklist, Lagune detects the context of your system, then drives the fixes specific to that context.

Okay, two lines: the deep security knowledge is carried by the spec and its on-demand sub-skills, a baseline every user can build on: the more you know, the more you can drive it. A developer and a non-developer are served through the same flow, and every finding stays in plain language so you can act on it regardless of your technical depth.

Where to go next

  • New here? Start with Install
  • Want the command map? See Commands
  • Curious about the on-demand knowledge? Read about the sub-skills

Acknowledgements

Partners

Partners get an exclusive logo across the repositories and landing pages, plus a spot on a dedicated partners page.

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Supporters

Really thanks to everyone who has supported and keeps supporting this work.

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Frequently Asked Questions

Lagune is an open-source, defense-only security workflow that helps your AI agent harden any codebase. You point it at your code, it detects what your system actually does, then it guides the security fixes that matter for that context.

No. The /lagune command hardens work as it is written: it takes any prompt, builds what you asked, and hardens it with safe defaults, guided by the charter. The five-phase Blue Team flow audits what already exists.

Yes. The five-phase Blue Team flow audits what already exists: charter sets your security rules, detect maps what the system does and where the risks are, plan scores each finding and pairs it with a fix, harden applies the fixes, and verify proves they hold and closes them.

An agent reading on its own finds what looks like a vulnerability and skips what looks like a control. A list of blocked addresses reads as though someone already handled the risk, so nobody checks that it misses most of them, and the code ships. Lagune inverts that default: a guard already in the code is presumed unproven until it is checked, every sub-skill in the catalog gets an explicit verdict, and verify asks whether the risk is gone, not whether a control is there. Each finding also stays one tracked item across runs, so it can be proven closed and stood down, where a plain request gives you a different report every time with nothing to compare.

Asking for secure code leaves the definition of secure to the agent, and it assumes you know what to ask for. The requirement is usually already inside your request without either of you seeing it: asking for a page that shows the courses a user has access to states an authorization rule, and a check that is never written leaves nothing in the code to notice. The /lagune command loads your charter and the sub-skills that match what is about to be built before the first line is written, then re-reads the result against the defense it used. The safe shape rarely costs more than the unsafe one, so what decides the outcome is knowing which one to reach for, and that is what arrives up front.

Any. Lagune runs on Node.js under the hood, but it audits and hardens projects written in any programming language.

72, including Claude Code, Codex, Cursor, Gemini CLI, and GitHub Copilot.

SDH is the methodology Lagune implements: a context-aware, blue-team convention that detects a system's context, triages the risks that context carries, and guides the fixes. The security knowledge lives in the spec and its on-demand sub-skills, so a developer and a non-developer are served through the same flow.

No. Lagune reads code and never runs your system or sends it crafted requests. Verify confirms a control is present and correct in the source, which is a different question from whether it survives an attack on a live target, so "cannot tell from the code" is a legitimate verdict instead of a quiet pass. DAST answers the runtime question and Lagune answers the source question, so neither replaces the other. Even the optional prove command holds this line: its tests assert the safe behavior, never an attack payload.

No, definitely not! A pentest is an authorized engagement where a professional exercises judgment against your live system, chaining findings and probing the business logic that no per-surface rule describes. Findings from a pentest can enter the Lagune Blue Team flow, to detect the concerns, so what a professional reports gets planned, hardened, and verified.

No. It runs through your own AI agent, so no API keys are required.

Security Policy

Please check the SECURITY.md.

License

Lagune is under the MIT License.

Copyright © 2026-present Weslley Araújo and contributors.

Last updated on August 4, 2026.

Copyright © 2026-present Weslley Araújo and contributors. Lagune is under the MIT License. Please check the Security Policy.

All product names, trademarks, and registered trademarks mentioned are the property of their respective owners and are used for identification purposes only.