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bug: MCP search_docs tool broken - Mintlify renamed SearchTriggerDev to search_trigger_dev #3236

@poloniki

Description

@poloniki

Bug Description

The search_docs MCP tool returns an error because the Mintlify docs endpoint (https://trigger.dev/docs/mcp) renamed its tool from SearchTriggerDev to search_trigger_dev.

Error

MCP error -32602: Invalid tools/call result: [
  {
    "expected": "object",
    "code": "invalid_type",
    "path": [],
    "message": "Invalid input: expected object, received undefined"
  }
]

Root Cause

In dist/esm/mcp/mintlifyClient.js, the performSearch function calls:

const body = callToolBody("SearchTriggerDev", { query });

But the Mintlify endpoint now only has a tool named search_trigger_dev:

curl -s -X POST "https://trigger.dev/docs/mcp" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "MCP-Protocol-Version: 2025-06-18" \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}'

Returns:

{"result":{"tools":[{"name":"search_trigger_dev",...}]}}

And calling SearchTriggerDev returns:

{"error":{"code":-32602,"message":"MCP error -32602: Tool SearchTriggerDev not found"}}

Fix

In mintlifyClient.ts, change:

const body = callToolBody("SearchTriggerDev", { query });

to:

const body = callToolBody("search_trigger_dev", { query });

Additionally, the handler in tools/docs.ts does return results.result but should handle the case where results wraps the response in an SSE data event that already contains the result key — currently when the API returns an error (tool not found), results.result is undefined, causing the Zod validation error.

Reproduction

  1. Run npx trigger.dev@latest mcp
  2. Call the search_docs tool with any query
  3. Observe the -32602 error

Environment

  • trigger.dev CLI: 4.4.3
  • Affects all versions since Mintlify renamed the tool

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