graylog-mcp-fix

A local MCP proxy that sits between your AI client and a Graylog MCP server, fixing schema and response compatibility issues that prevent standard MCP clients from working with Graylog's API.

Why

Graylog's MCP implementation has several issues that cause MCP clients to reject its responses:

• Output schemas contain $ref/$defs references that clients cannot resolve
• datarows are returned as arrays-of-arrays instead of arrays-of-objects
• effective_timerange.from/.to are returned as primitives but schemas require objects
• Optional object fields (e.g. unit) are returned as null but schemas lack null support

This proxy transparently fixes all of these on the fly.

Setup

npm install

Create a .env file in the project root:

GRAYLOG_TOKEN=your_api_token_here
GRAYLOG_MCP_URL=https://your-graylog-instance/api/mcp

The token is used as HTTP Basic Auth: Authorization: Basic base64(token:token).

Running

node index.js

MCP client configuration

For opencode (~/.config/opencode/opencode.json):

{
  "mcp": {
    "graylog": {
      "type": "local",
      "command": "node /path/to/graylog-mcp-fix/index.js",
      "enabled": true,
      "environment": {
        "GRAYLOG_MCP_URL": "Graylog MCP endpoint URL",
        "GRAYLOG_TOKEN": "Graylog API token"
      }
    }
  }
}

Environment variables

| Variable | Default | Description | |---|---|---| | GRAYLOG_TOKEN | (empty) | Graylog API token | | GRAYLOG_MCP_URL | (built-in URL) | Graylog MCP endpoint URL |