MCP Server for Claude Code & Codex

Last updated 2026-11-06

When launched via stdio pipe, agen runs as an MCP server. Any MCP-compatible agent (Claude Code, Codex, OpenCode, etc.) can connect and use Agenvoy's tools — including building new ones on the fly.

What external agents gain

Sandboxed execution — all script tools run inside OS-native sandbox (macOS sandbox-exec / Linux bwrap), isolating ~/.ssh, ~/.aws, .env, *.pem and other sensitive paths
Auto tool creation — the server instructions tell the agent to search existing tools (script_*, ext_*) first; when none covers a request it calls tool_generate_guide, which starts from public_api_list: a fitting API is called directly, and only when none fits (or a user-supplied API needs a key) does the agent build a script tool with edit_tool(mode=write) → test_tool. The tool is persisted and reusable across sessions. API tools were Removed in v1.3.2; a script tool or a direct API call replaces them
Shared tool library — tools created by any agent (Agenvoy internal, Claude Code, Codex, etc.) are saved to ~/.config/agenvoy/tools/script/ and available to all connected agents. Build once, use everywhere
Live data access — public_api_list (built in since v1.3.2; formerly api_public_api_list) lists public API categories, or the keyless APIs in one category; the agent picks one, calls it, and answers with real data instead of training-knowledge guesses

Quick setup

There is no TUI installer (/mcp has no install action); add the entry to your agent's config by hand.
Config per agent:
Claude Code — ~/.claude.json

{ "mcpServers": { "agenvoy": { "command": "agen" } } }

Codex — ~/.codex/config.toml

[mcp_servers.agenvoy]
command = "agen"

OpenCode — ~/.config/opencode/opencode.jsonc

{ "mcp": { "agenvoy": { "type": "local", "command": ["agen"] } } }

Generic MCP client setup

For any MCP client not listed above, the only requirement is:

Transport: stdio (JSON-RPC over stdin/stdout)
Command: agen
Args: none
Prerequisite: agen binary in $PATH (curl -fsSL https://agenvoy.com/scripts/install.sh | bash)

The server speaks MCP protocol version 2024-11-05, supports tools/list (with listChanged notifications) and tools/call. No authentication required — the server runs locally as the current user.
Typical config pattern across MCP clients:

{
  "<servers_key>": {
    "agenvoy": {
      "command": "agen"
    }
  }
}

Where <servers_key> varies by client (mcpServers, mcp_servers, mcp, etc.). Some clients require an explicit "type": "stdio" or "type": "local" field. Check your client's documentation.