Last updated 12 October 2026

Security

Breakspec runs your code to find the input that breaks it. Here is where that happens, what leaves your machine and when, and who decides what counts as a bug.

Your code stays where it is

Breakspec runs on your machine and in your own CI. We don’t run servers that receive your code, and checks, reruns and pull request checks work without an account.

Checks run in a sandbox

• No network access while your code runs.
• Your project is mounted read only, and the sandbox can’t write to it.
• No elevated privileges, a non-root user, and limits on memory, CPU and processes.
• If your code needs third-party packages, they are installed once when the sandbox is built, from your lockfile. Runs still have no network.
• Breakspec won’t run your code outside the sandbox unless someone on your team explicitly allows it.

What goes to an AI model, and when

AI is used for two things only: suggesting rules for a function, and writing the checks for the rules you approve. Running checks, rerunning them on every pull request and checking a fix never call a model.

• Before anything is sent, Breakspec shows you exactly what will go and where, and asks. Your coding agent can’t send code to a model until you have allowed it yourself.
• Requests go through your own model provider key, so your existing terms with that provider apply.
• By default, requests are routed only to providers that don’t store prompts or train on them. Zero data retention routing is one setting away.
• A stricter mode sends only the function’s name, signature, description and your intent, never its body.
• If you use the Claude Code hooks, what you ask your agent is kept on your machine and never committed. Requests that mention a function are added to that function’s rule suggestion, and you see them before anything is sent.

People decide what’s right

• Your coding agent can propose rules and check against them, but only a person can approve them.
• Rules nobody approved can warn you, but they never block a merge.
• When a pull request changes a rule, Breakspec flags it for review, and a rule file edited by hand is detected.
• A fix that only special-cases the failing input is caught and not marked as verified.

Anonymised pattern sharing is off

Breakspec can learn from bug patterns across teams, but only if you turn it on, for yourself, in a project that allows it. While it’s off, nothing is recorded. When it’s on, events never contain code, file paths or input values, you see an example before you agree, and a rule’s wording is only shared if you choose to share it.

Report a vulnerability

Email security@breakspec.com with what you found and how to reproduce it. We’ll confirm we’ve received it within two working days and keep you updated until it’s fixed. Please give us a reasonable time to fix an issue before you disclose it, and don’t access data that isn’t yours while testing.