Error with MCP Server, when trying to call Slack

Questions
1

Node Error: MCP Server calling Slack

Error message

Error during node execution: filters.types.join is not a function

Debugging:

Used Claude desktop calling the MCP server to debug.
According to it:
“The error occurs because the Slack API expects the types parameter to be passed as a comma-separated string, but the node is trying to call .join() on a value that isn’t an array.”

Share the output returned by the last node

Environment details:

  • n8n version: 1.94.1 (Cloud)
  • n8n webapp (MacOS)
2

Hi there, welcome to the community

i think it would be great for each tool, on the tool description you explain what it can do explicitly, what can it calls, what filter can it do, which kind of data are you looking for, when, which field is an array and not, something like that

i think that would significantly reduce any error that you will get in the future.