Custom MCP servers

Open Plugins → MCP servers to give bots tools from a trusted local MCP server — no config file editing required.

Add a server

1. Open Plugins → MCP servers → Add server.
2. Enter the executable command (for example npx).
3. Put each argument on its own line (for example -y and @modelcontextprotocol/server-github).
4. Add any environment variables as KEY=value, one per line.

Brainwrite saves a new server switched off. Use Test to start it briefly, complete the MCP handshake, and see the tools it advertises. Turn it on once you're satisfied — it becomes available to compatible bots on their next task, with no app restart needed.

This first version supports local stdio commands only. It deliberately does not accept remote MCP URLs or shell command strings.

Credentials are write-only

The API only ever returns environment variable names, never their values. When editing a server, leave an existing value's line blank to keep it saved, or remove the line entirely to delete it.

Testing is bounded

The connection test is stopped after the MCP handshake completes (or after eight seconds), its output is capped, and its stderr is never sent to the UI. It inherits none of Brainwrite's own workspace or provider credentials — only the environment variables you configured for that server are added.

Rules that keep this safe

• Permission cards by default. Custom servers are never pre-approved: their tools route through each engine's normal approval flow, the same way built-in tools do until you grant access.
• Reserved names are refused so a custom entry can never shadow a built-in tool surface. Names are lowercase letters, digits, _, or -, up to 32 characters, starting with a letter.
• One bad entry never takes the fleet down. Invalid entries are skipped with a logged reason; the rest still mount.
• Turning a server off parks it without deleting it.

Advanced: edit the file directly

The same registry lives in ~/.brainwrite/config.json, in the same shape Claude Code and similar tools use:

{
  "mcpServers": {
    "notes": {
      "command": "npx",
      "args": ["-y", "@example/notes-mcp"],
      "env": { "NOTES_TOKEN": "…" }
    }
  }
}

If you edit the file by hand, restart Brainwrite. Every bot whose engine can mount custom MCP servers gets the enabled tools on its next task.