Configuration File

MCPProxy uses a JSON configuration file located at ~/.mcpproxy/mcp_config.json.

Location

Complete Reference

{
  "listen": "127.0.0.1:8080",
  "data_dir": "~/.mcpproxy",
  "api_key": "your-secret-api-key",
  "enable_socket": true,
  "health_check_interval": "30s",
  "tool_discovery_interval": "5m",
  "tools_limit": 15,
  "tool_response_limit": 20000,
  "enable_code_execution": false,
  "code_execution_timeout_ms": 120000,
  "code_execution_max_tool_calls": 0,
  "code_execution_pool_size": 10,
  "features": {
    "enable_web_ui": true
  },
  "mcpServers": []
}

Options

Server Settings

Feature Flags

Tool Discovery Settings

Tool Discovery & Health Check Intervals

MCPProxy keeps upstream connections fresh with two independent background loops:

• a lightweight liveness probe that sends a standard MCP ping to confirm the connection is alive, and
• a periodic tool-discovery sweep that re-lists tools to rebuild the search index. (Tool changes are also picked up reactively via notifications/tools/list_changed; the sweep is a fallback for servers that don't advertise listChanged.)

Both cadences are configurable globally, and can be overridden per server (see Upstream Servers). Values are duration strings such as 30s, 5m, or 1h.

Resolution order: per-server value → global value → built-in default. Leaving a key unset preserves the previous behaviour, so existing configs are unaffected by an upgrade.

{
  "health_check_interval": "30s",
  "tool_discovery_interval": "5m",
  "mcpServers": [
    {
      "name": "chatty-server",
      "health_check_interval": "2m",
      "tool_discovery_interval": "0s"
    }
  ]
}

Notes:

• 0s = disabled. Disabling the discovery sweep for a server that does not support listChanged means tool changes are only picked up on (re)connect — fine for static servers, worth knowing for dynamic ones. With the liveness probe disabled, a dead transport is detected lazily (on the next real tool call or discovery sweep) rather than proactively.
• Docker-isolated servers: health_check_interval is a no-op — their liveness is monitored at the container level, not via MCP ping. tool_discovery_interval still applies. Remote (HTTP/SSE) servers benefit most from the ping-based probe.
• Hot reload: interval changes take effect on the next cycle without a full restart.
• These intervals are also editable in the Web UI and macOS app under Settings → Advanced → Tool discovery & health checks.

Code Execution Settings

MCP Servers

See Upstream Servers for detailed server configuration.

Hot Reload

MCPProxy watches the configuration file for changes and automatically reloads when modifications are detected. No restart is required for most configuration changes.

Environment Variable Overrides

Configuration options can be overridden using environment variables. See Environment Variables for details.