HTTP + SSE for Local Network Access

HTTP + SSE (Server-Sent Events) is a network-based transport for scenarios where STDIO isn’t suitable.

What is HTTP + SSE?

GameCatalyst’s MCP Bridge can expose an HTTP endpoint that accepts POST requests and streams responses via Server-Sent Events. This allows AI clients to connect over a network instead of through local process pipes.

When to use HTTP + SSE:

• You need to connect from a different machine on your local network
• You’re building a custom MCP client
• You want multiple AI clients to share a single MCP Bridge instance
• You’re testing or debugging connection issues

Benefits of HTTP + SSE:

• Network flexibility — Connect from any machine on your network
• Multi-client support — Multiple AI clients can share one MCP Bridge
• CORS support — Web-based clients can connect with proper headers
• Event history — The server maintains event history for reconnecting clients

How it works:

1. Enable HTTP transport in gamecatalyst-config.json
2. Configure host and port (default: 127.0.0.1:5003)
3. Start the MCP Bridge manually (it doesn’t auto-start for HTTP)
4. AI clients POST to /mcp endpoint with session headers
5. Responses stream back via Server-Sent Events

Security considerations:

• HTTP transport is disabled by default
• Bind to 127.0.0.1 for local-only access
• Use allowed_origins to restrict CORS access
• Consider enabling OAuth 2.1 for production use

HTTP + SSE is an advanced transport. Most users should stick with STDIO or Web Relay.

Setting up HTTP transport:

HTTP transport is disabled by default for security. To enable it, edit gamecatalyst-config.json and set transports.http.enabled to true. Configure the host (default 127.0.0.1 for local-only access) and port (default 5003). Then start the MCP Bridge — it does not auto-start for HTTP transport like it does for STDIO.

When HTTP makes sense:

Most users should stick with STDIO or Web Relay. HTTP + SSE is useful for advanced scenarios: building custom MCP clients, connecting from another machine on your local network, or running multiple AI clients through a shared MCP Bridge instance. If none of those apply to you, STDIO is simpler and faster.

Who should use HTTP + SSE:

Most users should stick with STDIO (for desktop clients) or Web Relay (for cloud clients). HTTP + SSE is an advanced transport designed for specific scenarios: building custom MCP clients, connecting from another machine on your local network, or running multiple AI clients through a shared MCP Bridge instance. If none of those apply to you, the simpler options will serve you better.