One file defines your
AI context boundary

One file in git. After install, secrets become tokens —
the agent keeps working. Ignore, gates, CI.

curl -fsSL https://install.offsend.io/cli | bash

also runs offsend setup

Your project flows through .offsend.yml into AI Context, with sensitive files blocked

Supported tools

EditorRuntime gates
Cursorprompt, read, write, shell, MCP argsMCP response seal
Claude Codeprompt, read, write, shell, MCP argsMCP response seal
Windsurfprompt, read, write, shell, MCP argsno MCP response seal
Codexprompt onlyfile / MCP gates not supported yet

Hooksoffsend setup installs user-level Cursor and Claude hooks in any folder. Windsurf and Codex gates come from offsend sync in a repo. Claude path lock is permissions.deny in .claude/settings.json — not .claudeignore.

LimitsLocal-first CLI. Defense-in-depth — not a guarantee that an agent cannot read a file. Cloud agent sessions are outside local hooks.

Ignore-file supportGitHub Copilot, Continue, Gemini, LLM, Aider, Cline, Roo, Zed, Cody

AI context enters through more than prompts

Coding agents can read workspace files, follow file references, run shell commands, call tools, spawn subagents, and retain local transcripts.

Offsend sits between folders, files, shell, tools, history, and prompts that feed AI context

A repository needs boundaries across all of these paths — not only for committed files.

Check a repository

Three layers

The product starts on the machine. .offsend.yml is the second layer — the team boundary in git — not the only one.

  1. 01

    Machine

    Once per laptop · install / setup

    Seal key and user-level Cursor/Claude hooks. The agent keeps working; plaintext stays out of context. No YAML required.

  2. 02

    Repo

    When you own it · init

    Team policy in .offsend.yml — ignore, seal, policy checks, git pre-commit and post-merge.

  3. 03

    CI

    When there is GitHub

    check --policy fails on secrets and ignore drift — not on missing git or editor hooks on the runner.

Seal

MCP tools and file reads can put secrets into the model. Seal swaps those values for reversible tokens — the agent keeps working; plaintext stays out.

{{TYPE:v1.…}}

  • Restore

    Copy the agent reply, then run offsend unseal — clipboard, file, or pipe.

  • Without a key

    Secret-bearing MCP output is withheld. It is not passed through.

  • Machine default

    After setup, YAML is not required. init writes the same into .offsend.yml for the team.

  • Editor limits

    Cursor and Claude Code seal MCP responses. Windsurf has no MCP response seal. Codex is prompt-only — no file or MCP gates yet.

A context policy that belongs to the repository

The second layer: .offsend.yml keeps AI-context rules visible, reviewable, and versioned with the project.

Project tree with .offsend.yml at the repository root

Install already ran setup. Doctor the machine, then commit .offsend.yml when you own the repo.

curl -fsSL https://install.offsend.io/cli | bash

also runs offsend setup

after install — quick start

1.offsend doctor# cli, seal key, user hooks — no .offsend.yml
2.offsend init --template node# writes .offsend.yml (commit this file)
3.offsend protect# adds exposed paths to the policy
4.offsend sync# ignore files + git / editor hooks

then: git add .offsend.yml && git commit

# then in CI
- uses: Offsend/ai-hygiene@v1
  with:
    fail-on: block
    policy: true
Read the CLI docs

FAQ

What does Offsend protect?

Offsend is an open-source, local-first boundary layer for AI coding agents. After setup, Cursor and Claude hooks work in any folder without YAML. When you own the repo, a committed .offsend.yml is the team source of truth: offsend sync materializes AI ignore files and installs supported hooks. Ignore rules are the primary exclusion. Runtime gates then check prompts, file reads, shell, and MCP on editors that expose those hooks. On Cursor and Claude Code you can seal secrets in MCP responses (and optional sealed file copies) so the agent keeps working without plaintext. Local transcripts can be audited and scrubbed after the fact — that is recovery, not a live gate. Cloud sessions do not run local hooks.

Is Offsend a secret scanner?

Offsend includes content scanning (offsend check) for keys, tokens, and similar patterns in files, staged diffs, and stdin. Its primary job is still the AI context boundary — local seal, path policy, AI ignore sync, and runtime gates — not full git-history leak forensics or a cloud sandbox. Use it alongside Gitleaks, TruffleHog, or GitHub secret scanning when you need deep history coverage. Versus GitGuardian, the job is local seal and fail-closed without a key — not cloud block.

vs Secret scanners · vs GitGuardian

Does Offsend upload my code?

No. CLI checks run locally. Repository policies stay in the repo. Local history is audited locally. No cloud scanning is required.

Does one .offsend.yml guarantee that AI cannot read a file?

No. Offsend is defense-in-depth, not a guarantee. Ignore files are the primary exclusion. Gates cover only the hook surfaces each editor exposes — for example Codex has no file/MCP gates yet, Windsurf cannot seal MCP responses, and Claude subagents are not gated. Cloud agents never see local hooks. Keep secrets out of the repo; use CI check --policy for what left the machine.

Where should I start?

Install the CLI (that already runs offsend setup). Then offsend doctor — CLI, seal key, and user hooks, no YAML needed. In a repo you own: offsend init --template …, commit .offsend.yml, then protect and sync. After cloning a repo that already has YAML, run offsend sync. Found a public repo without installing? Use Check.

Check a public repo

What is Radar?

Radar researches AI-context risk signals across public repositories without reading file contents. Visit radar.offsend.io for the latest report.

Surfaces

CLI for repos. macOS, extension, and GitHub Action for the other paths.

Offsend CLI terminal icon

CLI

Setup on the machine. Commit .offsend.yml for the team. Sync ignore files and hooks. Doctor the local setup.

Install CLI
Offsend app icon in the macOS Dock

Desktop

Check files, folders, and clipboard text before sharing them with AI tools.

Download for macOS
Offsend browser extension toolbar icon

Browser Extension

Detect and mask sensitive values before browser prompts or attached files are sent.

Install extension
GitHub Actions icon for Offsend CI checks

GitHub Action

Run the same offsend check in CI before code lands.

Add to CI
Checklist graphic for Offsend online repository check

Check

Run a fast repository audit without installing the CLI.

Check repository
Radar graphic for Offsend AI-context research

Radar

Research showing AI-context risk signals across public repositories.

Read latest report