Invalid 'tools[0].function.name'

Questions
1

Invalid ‘tools[0].function.name’: string does not match pattern. Expected a string that matches the pattern ‘[1]+$’.

Always geting this error everytime I try to link the MCP Client tool, even after I rename it to something without any spaces or special characters

  1. a-zA-Z0-9_- ↩︎

2

Hi @Ricardo_Pereira1

Welcome to the community.

However I didn’t encounter this kind of issue.

Can you share what tool you are connecting in your MCP Server?

Screenshot_20250522_104956_w06cPMO5@2x
Screenshot_20250522_104956_w06cPMO5@2x1024×606 39.7 KB

3

Hi there, I’m having a similiar issue. Heres is my base workflow:

image
image991×385 56.2 KB

And heres is my MCP server

image
image1618×540 83.2 KB

Here is a sample of one of my tools connected to the MCP node:

image
image826×272 20.1 KB

This is the full error text:

Bad request - please check your parameters
Invalid 'tools[5].function.name': string does not match pattern. Expected a string that matches the pattern '^[a-zA-Z0-9_-]+$'.

And I got this also:

"error":{
   "message":"Invalid 'tools[5].function.name': string does not match pattern. Expected a string that matches the pattern '^[a-zA-Z0-9_-]+$'.",
   "type":"invalid_request_error",
   "param":"tools[5].function.name",
   "code":"invalid_value"
}

Any help would be of great value!

Thank you in advance!

Matias

4

Hey buddy! The issue is that your name in the MCP client has some characters that aren’t letters or numbers — maybe something from your local language or some punctuation. Try removing them and it should work.

2 Likes
5

Oh man, that did the trick. Thank you a lot.

I’m used to use any charecter I like to name my nodes that couldn’t see that coming.

Thank you, problem solved!

Matias

6

I spent 3 hours struggling, installing, and uninstalling things… it turned out the node name was “MCP - Tool” and the “-” was causing the error. You’re a genius!! Thanks a lot.