Guides on claustro

Monorepo Setup

Mon, 01 Jan 0001 00:00:00 +0000

Monorepo Setup#

Run multiple sandboxes targeting different parts of a monorepo.

Named sandboxes#

sandboxes:
 api:
 workdir: ./services/api
 mounts:
 - ./libs:/workspace/libs:ro
 - ./proto:/workspace/proto:ro
 env:
 DATABASE_URL: postgresql://localhost:5432/dev

 web:
 workdir: ./packages/frontend
 env:
 API_URL: http://localhost:3000

Running#

claustro up --name api
claustro up --name web
claustro claude api
claustro claude web
claustro ls

Egress Firewall

Mon, 01 Jan 0001 00:00:00 +0000

Egress Firewall#

Restrict outbound network access from sandboxes.

Enable#

claustro up --firewall

Or in claustro.yaml:

firewall:
 enabled: true
 allow:
 - custom-registry.company.com
 - api.openai.com

Default whitelist#

When enabled, the following domains are always allowed:

api.anthropic.com — Anthropic API
registry.npmjs.org — npm
pypi.org — Python packages
github.com — Git operations
archive.ubuntu.com, security.ubuntu.com — System updates

Docker internal networks (172.16.0.0/12, 192.168.0.0/16, 10.0.0.0/8) are always allowed for compose-sibling services.

MCP Servers

Mon, 01 Jan 0001 00:00:00 +0000

MCP Servers#

claustro supports stdio-based and SSE-based MCP servers.

Pre-installed (stdio)#

The default image includes:

filesystem — file system access within /workspace
memory — persistent memory for Claude
fetch — HTTP fetching capability

Toggle in claustro.yaml:

image:
 mcp_servers:
 filesystem: true
 memory: true
 fetch: false

Project MCP config#

Place a .mcp.json in your project root. It will be merged with image defaults (project config wins).

SSE sibling containers#

mcp:
 sse:
 postgres:
 image: crystaldba/postgres-mcp-server:latest
 port: 8000
 env:
 DATABASE_URI: postgresql://postgres:postgres@db:5432/devdb

SSE servers run as sibling containers on the same Docker network.

Custom Image

Mon, 01 Jan 0001 00:00:00 +0000

Custom Image Configuration#

Language selection#

Choose which language runtimes to include. Node.js is always installed (required for Claude Code).

image:
 languages:
 node: true
 go: true
 rust: false
 python: true

Tool groups#

image:
 tools:
 dev: true
 build: true

Extra Dockerfile steps#

image:
 extra:
 - run: apt-get update && apt-get install -y ffmpeg
 - run: pip install black ruff

Using a completely custom image#

image: my-registry/my-image:latest

The custom image must have Claude Code pre-installed.