Move at agent speed While burning down the debt.

Your agents write faster than any review can keep up with. LeoPrevent fixes what they get wrong in the same turn, before anyone opens a review.

Request access See how it works

LeoPrevent is a security engineer that runs inside your coding agent.

Installing it takes under a minute. Nothing in your pipeline changes, no merge is gated, and the scanners you already run stay where they are.

Any agent, any model

01Agent writes code
02We check, in the turn<2s
03Agent fixes its flaw and nearby debt
04You approve one pull request

Claude Code
Codex
GitHub Copilot
Cursor
Antigravity
Devin

One compounding system Every fix teaches the next one.

Add an endpoint that fetches whatever URL the user gives us.

Used 6 tools ›

Added GET /fetch. Takes a url parameter, returns the body. Timeouts handled.

Agent writing code… LeoPrevent running…

2 flaws detected and prevented before review

ssrf src/api/fetch.py:24
no-input-validation src/routes/proxy.py:11

Both fixed in the same turn

1.8s

LeoTrace

Flaws

All 583585 New flaws 165167 Existing flaws 418

Severity

Outcome

Engineer

Severity Issue What we found Repo Engineer Outcome When

High

Server-Side Request Forgeryssrf

The url query parameter from GET /fetch is passed straight to fetch() with no allowlist

meridian-labs/checkout-apisrc/api/fetch.ts:24

Ada Whitfield

Remediated

Today 13:20

Medium

Missing Input / External-Data Validationno-input-validation

The url parameter is typed but never validated at runtime before it reaches fetch()

meridian-labs/checkout-apisrc/api/fetch.ts:20

Ada Whitfield

Remediated

Today 13:20

High

Path Traversalpath-traversal

trackSlug and relativePath are joined with path.join() straight into a file read

meridian-labs/checkout-apisrc/lib/archive.ts:8

Ada Whitfield

Remediated

Today 13:14

Critical

OS Command Injectionos-command-injection

archivePath and trackName are interpolated directly into a shell command

meridian-labs/checkout-apisrc/lib/archive.ts:12

Sam Okafor

Remediated

Today 13:05

Critical

OS Command Injectionos-command-injection

archivePath and filter are interpolated into a shell pipeline

meridian-labs/checkout-apisrc/lib/archive.ts:18

Sam Okafor

Remediated

Today 13:05

Medium

Missing Input / External-Data Validationno-input-validation

The archivePath and trackName parameters of extractArchive are unvalidated

meridian-labs/checkout-apisrc/lib/archive.ts:9

Sam Okafor

Remediated

Today 13:05

Medium

Missing Input / External-Data Validationno-input-validation

The archivePath and filter parameters of listArchiveEntries are used unchecked

meridian-labs/checkout-apisrc/lib/archive.ts:16

Sam Okafor

Remediated

Today 13:05

High

Path Traversalpath-traversal

trackSlug and relativePath are joined with ARCHIVE_ROOT using path.join()

meridian-labs/checkout-apisrc/lib/archive.ts:14

Rosa Lindqvist

Remediated

Today 13:03

Medium

Missing Input / External-Data Validationno-input-validation

The url parameter is passed to the HTTPS request() call with no allowlist

meridian-labs/payments-workersrc/fetch.ts:5

Rosa Lindqvist

Remediated

Today 11:26

Low

Trusted Database Datadb-trust

liveDeviceKeys reads digest strings from a database row and trusts them

meridian-labs/payments-workersrc/licensekey.ts:164

Tomas Beck

Failed

Today 11:06

Medium

Cross-Site Scriptingxss-backend

Template output is rendered unescaped, so request data reaches the page as markup

meridian-labs/web-appsrc/views/render.py:44

Tomas Beck

Remediated

Today 10:52

Medium

Open Redirectopen-redirect

The redirect target comes from the next query parameter with no allowlist

meridian-labs/web-appsrc/api/app.py:11

Tomas Beck

Unconfirmed

Today 10:31

Medium

Insecure Direct Object Referenceidor-object-level-authz

The invoice id from the path is trusted without checking it belongs to the caller

meridian-labs/payments-workersrc/routes/invoice.ts:76

Rosa Lindqvist

Remediated

Today 10:14

Medium

TOCTOU Race Conditiontoctou-race-condition

The balance is read, checked and written back without holding a lock

meridian-labs/payments-workersrc/lib/ledger.ts:203

Sam Okafor

Unconfirmed

Today 09:58

Server-Side Request Forgery

Remediated

High ·src/api/fetch.ts:24 ·claude-opus-5 ·Ada Whitfield ·finding 1 of 2

Why it was flagged

The url query parameter on GET /fetch is passed straight to fetch() with no allowlist and no check on the resolved address, so any caller can reach internal services and cloud metadata.

Agent response to this review · fixed in turn

Intervention code for this review · 14 lines before, 31 after Side by sideUnified diff

Vulnerable: what the agent wrote 6 flagged

15import { Hono } from 'hono' ~ ~ ~ 16import { fetchWithTimeout } from '../lib/http' 17import { readBody } from '../lib/body' 18 19type FetchQuery = { 20 url: string 21} 22 23const app = new Hono() 24⚑app.get('/fetch', async (c) => { ~ ~ ~ ~ 25⚑ const url = c.req.query('url') as string 26⚑ const res = await fetchWithTimeout(url, { timeout: 5000 }) 27⚑ const body = await readBody(res) 28⚑ return c.json({ status: res.status, body }) 29⚑}) ~

Secure: committed in its place 23 fixed

1import { Hono } from 'hono' 2import { z } from 'zod' 3import { zValidator } from '@hono/zod-validator' 4import { assertPublicUrl } from './middleware/ssrf' 5import { fetchWithTimeout } from '../lib/http' 6import { readBody } from '../lib/body' 7 8const fetchQuery = z.object({ 9 url: z.string().url() 10}) 11 12const app = new Hono<{ Variables: GuardVariables }>() 13app.get( 14 '/fetch', 15 zValidator('query', fetchQuery), 16 assertPublicUrl('url'), 17 async (c) => { 18 const url = c.get('safeUrl') 19 const res = await fetchWithTimeout(url, { timeout: 5000 }) 20 const body = await readBody(res, { maxBytes: 262144 }) 21 return c.json({ status: res.status, body }) 22 } 23)

01 Prevent

The agent fixes its own flaw before it finishes

It also fixes what was already broken in the files it touches. Your developers get corrected code back, and the file leaves cleaner than it arrived.
02 Observe

A record of fixes, not a backlog of findings

Which mistakes your agents repeat, which models cause the most of them, and which repositories carry the most risk.
03 Compound

Every line your agents write strengthens the system

It learns how your agents behave in your code, and gets sharper every month.

Your scanners find flaws. They don’t stop them being written.

01

Snyk, Ox Security & Aikido tell you what’s already in the codebase. Someone still has to read the finding, understand the code, write the fix and get it reviewed.
02

That queue was longer than your team could clear before agents existed. It is now growing faster than anyone can work it down.
03

LeoPrevent removes the flaw in the turn that wrote it, so it never becomes a finding at all. Your scanners stay where they are. They just have less to find.

A critical you prevent is a critical you never have to explain.

Nothing enters the audit log, the quarterly report or the regulator’s question, because nothing entered the codebase. Snyk, Ox Security, Aikido and GitHub stay exactly where they are. They just have less to find.

In the turn

Fixed with LeoPrevent. Nobody is interrupted.

Seconds
At review

A comment, a context switch, a re-prompt and a second review.

Hours
In production

An incident, a disclosure, and a line in the quarterly report.

Days

See it run on your own code…

A pilot is running the same day and reporting from the first review. No pipeline changes, no gate. Every fix arrives as a PR your engineers approve.

Request access Meet the team

Move at agent speed While burning down the debt.

LeoPrevent is a security engineer that runs inside your coding agent.

Works with

One compounding system Every fix teaches the next one.

The agent fixes its own flaw before it finishes

A record of fixes, not a backlog of findings

Every line your agents write strengthens the system

Your scanners find flaws. They don’t stop them being written.

A critical you prevent is a critical you never have to explain.

See it run on your own code…