devvit-mcp
A companion MCP server for writing applications on Reddit's developer platform.
Installation
Add the following to your mcp.json for the editor or LLM of choice.
{
"mcpServers": {
"devvit-mcp": {
"command": "npx",
"args": ["-y", "@devvit/mcp"]
}
}
}
Opting Out Of Telemetry
{
"mcpServers": {
"devvit-mcp": {
"command": "npx",
"args": ["-y", "@devvit/mcp"],
"env": {
"DEVVIT_DISABLE_METRICS": "true"
}
}
}
}
Developing on the MCP Server
git clone git@github.com:reddit/devvit-mcp.git
cd devvit-mcp
nvm use
npm install
npm run dev
If you want to test your MCP server inside of other projects. Pass in the entire path to your node runtime and the location of /dist/index.js on your machine.
- Node path:
which node - Dist:
pwdfrom the root of yourdevvit-mcp+/dist/index.js
{
"mcpServers": {
"devvit-mcp": {
"command": "/Users/marcus.wood/.nvm/versions/node/v22.13.0/bin/node",
"args": ["/Users/marcus.wood/open-source/devvit-mcp/dist/index.js"]
}
}
}
MCP Gotchas
- Never put a
console.login the hot path of your app if you're trying to debug. You'll see weird error messages likeUnexpected token 'a', " at Anthrop"... is not valid JSON. We've shimmedloggerto automatically handle this conversion for you. - Only log console.error in your MCP when running through MCP.
Debugging
-
Using
npm run dev, going to tools, listing them out, and triggering is the best experience. -
To test this live with logs, use Claude desktop and connecting the MCP there. They have log files that report errors on your machine. You can view them by opening in VSCode or running
tailcommands. -
If you see something like this:
Error: Server does not support logging (required for notifications/message)
at Server.assertNotificationCapability
You need to add the capability to your new MCPServer. Use this permalink to know what key you should add.
Versioning
This package uses automated versioning managed by CI/CD. The version in package.json is a placeholder and will be automatically updated during the release process. Check git tags for the actual released versions.
Credits
Huge thanks to Arabold for open sourcing docs-mcp-server. Portions of this code is heavily inspired by this library. Please use it if you need other docs servers!