Seed files

Seed files are operator-managed configuration copied into each workspace after checkout and before the runner starts. Use them for agent configuration, instructions, output styles, and MCP server definitions that should not be committed to every repository.

Destinations

An absolute path must start with /. Paths cannot contain a .. segment, newline, or null byte. The limits are 256 KB per file and 32 files per workspace.

Claude configuration

A home seed file at .claude.json is merged with the workspace's existing file instead of replacing it. The seeded JSON must be an object; its keys win on conflict. Other destinations are written normally.

Use agent-specific configuration rather than controller-wide permission settings. For example, seed .claude/settings.json to configure Claude Code's permissions or output style.

MCP example

Keep OAuth credentials outside disposable workspaces and seed only a reachable MCP endpoint:

{
  "mcpServers": {
    "linear": { "type": "http", "url": "http://10.0.0.99:7777/mcp/linear" }
  }
}

For a long-lived bridge such as mcporter, bind it to a trusted LAN address, not 0.0.0.0, and restrict access with network policy. A seed file tells an agent about a server; it does not prevent other hosts that can route to that server from using it.