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Kacper Zawojski
Kacper Zawojski

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Payload v4: the MCP plugin exposes your collections to LLMs — and it's opt-out

#payload #zavcode #tellmeicant #cms

@payloadcms/plugin-mcp turns your Payload CMS into an MCP server, exposing your collections as tools for LLMs.

Heads up for v4: after a refactor, every collection is now exposed with full CRUD by default. It's opt-out — you disable individual tools rather than enabling them:

mcpPlugin({
  collections: {
    // posts is exposed automatically — no entry needed
    users: { tools: { create: false, update: false, delete: false } }, // find only
  },
})
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Custom tools are defined with the defineTool builder, taking input via zod v4:

tools: {
  getPostScores: defineTool({
    description: 'Score recent posts',
    input: z.object({ since: z.string() }),
  }).handler(async ({ input, req }) => ({ content: [/* ... */] })),
}
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⚠️ The thing to actually do after upgrading: collections you never listed are suddenly reachable through MCP. Review them and disable anything sensitive — an exposed users collection with delete is not a great default to inherit by accident.

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