MCP accessing error

[ForceConstant]

What happened?

What happened?
Can't access MCP servers.

Relevant log output

{
"error": {
"message": "litellm.BadRequestError: VertexAIException BadRequestError - {
"error": {
"code": 400,
"message": "* GenerateContentRequest.tools[0].function_declarations[0].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (), dots (.), or dashes (-), with a maximum length of 64.

• GenerateContentRequest.tools[0].function_declarations[1].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (), dots (.), or dashes (-), with a maximum length of 64.
• GenerateContentRequest.tools[0].function_declarations[2].name: Invalid function name. Must start with a letter or an underscore...
  ...
• GenerateContentRequest.tools[0].function_declarations[38].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.), or dashes (-), with a maximum length of 64.",
  "status": "INVALID_ARGUMENT"
  }
  }",
  "type": null,
  "param": null,
  "code": "400"
  }
  }

Version Information

LibreChat v0.7.9-rc1

Steps to Reproduce

Try to access MCP tool from chat.

What browsers are you seeing the problem on?

Firefox

Relevant log output

rror: [api/server/controllers/agents/client.js #sendCompletion] Unhandled error type 400 data: {"error": {"message": "litellm.BadRequestError: VertexAIException BadRequestError - b'{\\n  \"error\": {\\n    \"code\": 400,\\n    \"message\": \"* GenerateContentRequest.tools[0].function_declarations[0].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[1].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[2].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[3].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[4].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[5].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[6].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[7].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[8].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[9].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[10].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[11].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[12].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[13].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[14].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[15].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[16].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[17].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[18].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[19].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[20].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[21].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[22].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[23].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[24].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[25].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[26].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[27].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[28].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[29].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[30].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[31].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[32].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[33].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[34].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[35].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[36].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[37].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n* GenerateContentRequest.tools[0].function_declarations[38].name: Invalid function name. Must start with a letter or an underscore. Must be alphameric (a-z, A-Z, 0-9), underscores (_), dots (.) or dashes (-), with a maximum length of 64.\\\\n\",\\n    \"status\": \"INVALID_ARGUMENT\"\\n  }\\n}\\n'", "type": null, "param": null, "code": "400"}}
api-1  | 
api-1  |

Screenshots

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[danny-avila]

The error message seems clear and looks like something you can solve based off your configuration.

Please share your YAML config for this MCP server, or the public MCP or minimal reproduction of it, to help you troubleshoot further.

LibreChat has logic in place to protect against this check for the actual tool names originating from MCP servers, conforming them to strict patterns like this; however, we do not enforce any such logic on the server names since these can be customized at will.

[ForceConstant]

It is a private MCP server based on litellm. Tool names are reported as context7/resolve-library-id

mcpServers:
  litellm:
    type: streamable-http
    url: https://litellm.privateserver.com/mcp
    headers:
      x-litellm-api-key: "Bearer MY_API_KEY"