MCP stdio

Local agent hosts run bobby mcp-stdio. It loads the bootstrap credential itself, connects to the shared local runtime (starting it if needed), and speaks MCP over stdin and stdout. Tools are listed in MCP tools.

Configure a host

bobby install writes the entry for you:

bobby install --host claude --yes

The entry carries no credential:

{
  "mcpServers": {
    "bobby-browser": {
      "command": "/usr/local/bin/bobby",
      "args": ["mcp-stdio"]
    }
  }
}

bobby init --emit <claude|zed|vscode|json> prints this fragment for hosts you configure by hand. --emit openshell prints the HTTP client form.

Shared runtime

All agents in a scope share one runtime owner on a loopback port. Each connection keeps its own MCP state and starting toolset. Browser profiles, storage, context and jobs belong to the owner.

• Disconnecting an agent closes the sessions that connection opened. Sessions of other connections stay.
• bobby runtime start, status, stop, restart and list manage the owner. stop and restart ask before disconnecting attached agents. Without a terminal, add --disconnect-agents.
• bobby runtime status reports a pending change, such as a new binary. bobby runtime restart applies it.
• Add --team <name> and --project <name> to any command to use an organized local scope. The scope is shared per OS user.

How many agents

Each attached agent uses one of interface.max_connections slots (default 64). When all are in use, a new agent is refused with resourceExhausted and a retry hint. Raise the setting to attach more.

Direct gateway

Hosts that cannot run bobby can launch the mcp-gateway binary. It needs four environment variables, which bobby init writes to bootstrap.env:

Missing or invalid values stop startup. bobby init --preset selects the capability floor: agent (default, no authority:admin), unrestricted, claude, codex or openshell. See Capabilities.

Limits

• Frames up to 1 MiB, tool input up to 256 KiB, event reads up to 256 records.
• Send initialize before any tool call.
• Stdout carries only JSON-RPC. Logs go to stderr.

bobby doctor performs a live initialize and tools/list and reports the catalog size against its 128 KiB budget.