opencode-plugin-mcp-registry

An OpenCode plugin that verifies MCP servers configured in OpenCode against a private MCP registry. Unregistered or deleted servers have their tool calls blocked; deprecated servers trigger a warning.

How it works

At startup the plugin fetches the complete server list from your registry and builds an in-memory lookup table keyed by the short name — the part after the / in the registry's reverse-DNS server names (e.g. io.github.jgraph/drawio-mcp → drawio-mcp).

OpenCode MCP config keys are matched against this short name, so your config key just needs to match the last segment of the registry name.

| Registry status | Behavior | | --------------- | ----------------------------------- | | active | Tools execute normally | | deprecated | Warning logged, tools still execute | | deleted | Tool call blocked with an error | | Not in registry | Tool call blocked with an error |

If the registry is unreachable at startup, the plugin fails open (logs a warning, allows all servers) so your workflow is not broken by a registry outage.

Install

Add the package to your OpenCode config:

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["opencode-plugin-mcp-registry"]
}

Configuration

| Environment variable | Default | Description | | -------------------- | ------------------------------------------------ | ----------------------------- | | MCP_REGISTRY_URL | https://your-registry.example.com | Base URL of your MCP registry |

Set it in your shell before starting OpenCode:

export MCP_REGISTRY_URL="https://your-registry.example.com"
opencode

Naming convention

Your OpenCode MCP config key must match the short name (part after /) of the registry server name:

{
  "mcp": {
    "drawio-mcp": {
      "type": "remote",
      "url": "https://mcp.draw.io/mcp"
    }
  }
}

This matches registry entry io.github.jgraph/drawio-mcp.

The match is case-insensitive and normalizes non-alphanumeric characters to _, so minor differences in punctuation are tolerated.

Development

npm install
npm run typecheck

To test locally, copy index.ts to .opencode/plugins/mcp-registry.ts in your project and set MCP_REGISTRY_URL in your environment.