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# bot-bottle

[![test](https://gitea.dideric.is/didericis/bot-bottle/actions/workflows/test.yml/badge.svg?branch=main)](https://gitea.dideric.is/didericis/bot-bottle/actions?workflow=test.yml)
[![coverage](https://img.shields.io/badge/coverage-83%25-brightgreen)](https://coverage.readthedocs.io/)
[![core coverage](https://img.shields.io/badge/core%20coverage-95%25-brightgreen)](https://gitea.dideric.is/didericis/bot-bottle/src/branch/main/docs/decisions/0004-coverage-policy.md)

**Problem:** Developer wants to run a coding agent without supervision, but they don't want a prompt injected or misbehaving agent wrecking their environment or exfiltrating sensitive data.

**Solution:** Ephemeral, per agent "bottles" the agent cannot modify that scan all traffic for data exfiltration and limit capabilities and egress to only what the agent needs.

## Features

- **Per-bottle egress allowlist** — TLS-bumped HTTP/HTTPS chokepoint with a per-manifest host allowlist; per-route path/method/header `matches` filtering; outbound DLP scanning for known tokens and secrets, inbound DLP scanning for prompt-injection attempts; DoH and arbitrary hosts blocked by default.
- **Per-route token-match policy** — each egress route picks what happens when the outbound DLP catches a token via `dlp.outbound_on_match`: `supervise` (default) holds the request and surfaces it in `./cli.py supervise` for approval (an approved value is remembered for the life of the proxy); `redact` scrubs the value and forwards; `block` is a hard `403`. Cuts false-positive friction without weakening default-deny.
- **Tokens the agent never sees** — host secrets live in a sidecar; the agent dials `http://sidecar:9099/<path>` and the proxy strips inbound `Authorization` and injects the real token before forwarding. `printenv` in the agent shows proxy URLs only.
- **Gitleaks-scanned push (git-gate)** — `bottle.git` remotes route through a per-bottle `git daemon` that gitleaks-scans incoming refs pre-receive and forwards clean refs upstream over SSH. The agent never holds the upstream credential.
- **Manifest-scoped skills + secrets** — each bottle declares its skills, env, git identity, remotes, and egress routes; unknown keys die at load.
- **Trust boundary at `$HOME`** — bottles (credentials, egress, remotes) live only under `~/.bot-bottle/bottles/`. Repos may ship agents but not bottles, so a cloned repo can't redirect an env var to an attacker host.
- **Composable bottles (`extends:`)** — keep provider/runtime policy in one base bottle (e.g. `claude.md`) and overlay task bottles on top.
- **Parallel, isolated bottles** — each bottle runs in its own backend-owned isolation boundary; bottles don't share state or talk to each other.
- **Provider templates (Claude, Codex)** — `Dockerfile.claude` / `Dockerfile.codex`, or a bottle-supplied Dockerfile. Claude auth via long-lived OAuth token; Codex via opt-in host device-auth forwarding.
- **gVisor auto-detect** — on Linux hosts where `runsc` is registered with Docker, every bottle launches under it for a userspace syscall barrier; no manifest config required.
- **Apple Container backend (macOS default when available)** — runs the agent and sidecar bundle with Apple's `container` CLI, using a host-only agent network plus a separate sidecar egress network.
- **Smolmachines backend** — runs the agent in a libkrun micro-VM while the sidecar bundle stays in Docker. TSI and smolmachines DNS filtering close the raw DNS exfiltration gap that exists in the legacy Docker backend. Runs on macOS (Hypervisor.framework) and Linux (KVM, `/dev/kvm`).
- **Legacy Docker backend** — still available for examples, CI, and hosts without Apple Container via `BOT_BOTTLE_BACKEND=docker` or `--backend=docker`.

## Architecture

On the default macOS Apple Container backend, a bottle is an agent container on a host-only internal network plus a sidecar bundle attached to both that internal network and a NAT egress network. The agent gets HTTP(S)_PROXY and CA bundle env vars pointing at the sidecar's internal-network IP, so HTTP/HTTPS traffic flows through the sidecar instead of direct egress. `bottle.git` / git-gate is intentionally deferred on this backend until a safe Apple Container key-delivery path exists.

On the smolmachines backend, a bottle is an agent micro-VM plus a Docker sidecar bundle for egress, git-gate, and supervise. The VM reaches the sidecars through a per-bottle loopback alias allowed by TSI; smolmachines handles DNS filtering below the guest OS.

On the legacy Docker backend, the same logical bottle is two containers per agent: an `agent` container and a `sidecars` container. They share a per-agent Docker `--internal` network; the agent has no default route off-box.

The Docker topology looks like this:

```
                            host  ( ./cli.py )
                                  │
                          starts  │  stops
                                  ▼
   ┌─────────────────────────── bottle ──────────────────────────────────┐
   │                                                                     │
   │   ┌──────────────────┐                   ┌──────────────────────┐   │
   │   │ agent image      │   HTTP(S) proxy   │ egress image         │   │
   │   │ (claude-code,    │ ─────────────────►│ (mitmproxy; TLS bump │   │  HTTPS to
   │   │  codex, etc)     │                   │  DLP scan, path      │───┼──►  allowlisted
   │   │                  │                   │  matching, auth      │   │     hosts
   │   │ environ: proxy   │                   │  injection)          │   │
   │   │ URLs only, no    │                   └──────────────────────┘   │
   │   │ real tokens      │                                              │
   │   │                  │    git proxy     ┌────────────────┐          │  SSH push/fetch
   │   │                  │ ────────────────►│ git-gate image │──────────┼──►  to bottle.git
   │   │                  │                  │ (gitleaks +    │          │      upstreams
   │   └──────────────────┘                  │  git daemon)   │          │     (direct — not
   │                                         └────────────────┘          │      via egress)
   │                                                                     │
   │   agent on internal network (no default route); egress and          │
   │   git-gate straddle internal + egress networks.                     │
   │   egress is the single HTTP/HTTPS chokepoint — all agent HTTP/HTTPS │
   │   traffic flows through it. git-gate's SSH egress is direct         │
   │   because egress is HTTP-only.                                      │
   └─────────────────────────────────────────────────────────────────────┘
```

When the agent exits, `cli.py` tears down every sidecar and both networks; nothing about a bottle persists between runs.

## Quickstart

On compatible macOS hosts, the default backend requires Apple's `container` CLI and does not require Docker. The smolmachines backend requires Docker on the host for the sidecar bundle plus `smolvm` (macOS or Linux). The legacy Docker backend requires Docker. Claude bottles also need a long-lived Claude Code OAuth token (`claude setup-token`) exported as `BOT_BOTTLE_CLAUDE_OAUTH_TOKEN`.

Use `BOT_BOTTLE_BACKEND=docker ./cli.py start <agent>` on hosts where Apple Container is not installed and Docker is the desired backend.

### smolmachines on Linux

The smolmachines backend runs on Linux as well as macOS. On Linux, `smolvm`/libkrun use KVM, so the host needs:

- **`/dev/kvm`** present and accessible. Load `kvm-intel` or `kvm-amd` (and enable virtualization in BIOS/firmware). The invoking user must be in the `kvm` group: `sudo usermod -aG kvm "$USER"` then re-login. bot-bottle preflights this and reports exactly what's missing.
- **`smolvm`** on `PATH`: `curl -sSL https://smolmachines.com/install.sh | sh`.
- **Docker** for the sidecar bundle and image build, same as macOS.

Per-bottle isolation works the same as macOS without any `ifconfig`/sudo step — all of `127.0.0.0/8` is already loopback on Linux, so each bottle's sidecar bundle is published on its own `127.0.0.<N>` and TSI's allowlist is scoped to that `/32`.

```sh
BOT_BOTTLE_BACKEND=smolmachines ./cli.py start <agent>
```

> **NixOS:** enable `virtualisation.docker`, ensure the KVM module is loaded (`boot.kernelModules = [ "kvm-intel" ];` or `kvm-amd`), and add your user to the `kvm` and `docker` groups. If you run bottles from a Gitea Actions runner, use a `host`-label runner so Docker, `smolvm`, and `/dev/kvm` are all reachable from the job. `smolvm` isn't in nixpkgs — install the release binary (pin the version) and put it on the runner's `PATH`.

```sh
./cli.py start <agent>   # builds the image on first run, drops you into claude
```

## Manifest

Bottles and agents are Markdown files with YAML frontmatter under `~/.bot-bottle/`. The Markdown body is the system prompt. Bottles live in `~/.bot-bottle/bottles/`; agents may also be shipped by a repo at `<repo>/.bot-bottle/agents/<name>.md`.

**Bottle** (`~/.bot-bottle/bottles/gitea-dev.md`):

````markdown
---
extends: claude          # inherit the Claude provider boundary

env:
  GIT_AUTHOR_NAME: didericis

git:
  user:
    name: "Eric Bauerfeld"
    email: "eric+claude@dideric.is"
  remotes:
    gitea.dideric.is:
      Name: bot-bottle
      Upstream: ssh://git@gitea.dideric.is:30009/didericis/bot-bottle.git
      IdentityFile: /Users/didericis/.ssh/id_ed25519_gitea
      KnownHostKey: ssh-ed25519 AAAA...

egress:
  routes:
    - host: gitea.dideric.is
      auth:
        scheme: token        # Bearer | token
        token_ref: BOT_BOTTLE_GITEA_TOKEN
      matches:               # optional — restrict to specific paths/methods/headers
        - paths:
            - {type: prefix, value: /api/v1/}
          methods: [GET, POST, PATCH, DELETE]
      dlp:                   # optional — per-route detector overrides (default: all on)
        outbound_detectors: [token_patterns, known_secrets]
        inbound_detectors: false   # disable response scanning for this host
---

The `gitea-dev` bottle. Provider auth via the inherited Claude route;
gitea over SSH for push, token over HTTPS for the API.
````

**Agent** (`~/.bot-bottle/agents/gitea-helper.md`):

````markdown
---
bottle: gitea-dev
skills:
  - init-prd
---

You help maintain Gitea-hosted projects.
````

**Egress route fields:**

| Field | Required | Description |
|---|---|---|
| `host` | yes | Hostname to allowlist. One entry per host. |
| `role` | no | Reserved for future use. The key is recognised but any value is currently rejected at load. Provider auth routes (e.g. Claude's `api.anthropic.com`) are injected automatically from `agent_provider.auth_token`, not via `role`. |
| `auth.scheme` | when `auth` present | `Bearer` or `token`. Injected by the proxy; the agent never sees the value. |
| `auth.token_ref` | when `auth` present | Env-var name holding the secret on the host. |
| `matches` | no | Array of `{paths, methods, headers}` filters. A request must match at least one entry (if any are given) to be forwarded. |
| `matches[].paths` | no | Array of `{type, value}`. `type` is `prefix` (default), `exact`, or `regex`. |
| `matches[].methods` | no | Array of HTTP method strings, e.g. `[GET, POST]`. |
| `matches[].headers` | no | Array of `{name, value, type}`. `type` is `exact` (default) or `regex`. |
| `dlp` | no | Per-route DLP overrides. Omit to use defaults (all detectors on). |
| `dlp.outbound_detectors` | no | `false` disables outbound scanning; list restricts to named detectors (`token_patterns`, `known_secrets`). |
| `dlp.inbound_detectors` | no | `false` disables inbound scanning; list restricts to named detectors (`naive_injection_detection`). |
| `dlp.outbound_on_match` | no | What to do when an outbound token is detected: `supervise` (default for manifest routes — hold for operator approval), `redact` (scrub the value and forward), or `block` (hard 403). Agent-provider routes (e.g. `api.anthropic.com`) default to `redact`. |
| `git.fetch` | no | `true` permits smart HTTP clone/fetch (`git-upload-pack`) for this host. Push (`git-receive-pack`) remains blocked. |

When an outbound DLP detector matches a token, the route's `dlp.outbound_on_match` policy decides what happens. Under the default `supervise`, the proxy queues an `egress-token-allow` proposal for the operator's `./cli.py supervise` TUI and holds the request open until it is answered (or `EGRESS_TOKEN_ALLOW_TIMEOUT_SECONDS`, default 300s, elapses — after which it fails closed). The operator never sees the raw token, only the host, method, path, and a redacted snippet; approving adds the value to an in-memory safelist for the life of the egress proxy. Under `redact`, the matched value is scrubbed from the body, headers, and path and the request is forwarded (failing closed if a match lands somewhere unredactable, like the hostname). Under `block` it stays a hard `403`. Structural blocks (CRLF injection) and not-in-allowlist host blocks are always hard `403`s regardless of policy.

More examples in `examples/`. Full design lives under `docs/prds/`; the trust-boundary rationale is in `docs/prds/0011-per-file-md-manifest.md`.

## Trademarks

bot-bottle is an independent project and is not affiliated with, endorsed by, or sponsored by Anthropic, PBC. "Claude" and "Claude Code" are trademarks of Anthropic, PBC; the project name uses "claude" descriptively to indicate that the tool runs Claude Code inside a sandbox.

## License

Copyright 2026 Eric Bauerfeld. Licensed under the Apache License, Version 2.0. See [LICENSE](LICENSE) for the full text.
