[GH-ISSUE #1831] [MCP] Invalid schema for `get-lists` tool when using providers conforming to OpenAI schema #1145

New issue

Open

opened 2026-03-02 11:55:20 +03:00 by kerem · 1 comment

kerem commented

2026-03-02 11:55:20 +03:00

Owner

Originally created by @TECHNOFAB11 on GitHub (Aug 10, 2025).
Original GitHub issue: https://github.com/karakeep-app/karakeep/issues/1831

Apparently the MCP spec doesn't specify "properties" as required, but OpenAI does (reference: https://github.com/openai/openai-agents-python/issues/449).
This results in errors when using OpenAI (also Github Copilot) endpoints:

POST "http://localhost:8080/v1/chat/completions": 400 Bad Request {"message":"Invalid schema for function 'mcp_karakeep_get-lists': None is not of type 'object'.","code":"invalid_function_parameters"}

From quickly looking at the code, it's probably because here the third parameter is omitted and not an object like with the other tools?:
github.com/karakeep-app/karakeep@9059ca2231/apps/mcp/src/lists.ts (L7-L10)

Technically it's OpenAI's fault, it works fine with Gemini's OpenAI compatible API, but if the solution is to just add {} I hope this would be fine :)

Originally created by @TECHNOFAB11 on GitHub (Aug 10, 2025). Original GitHub issue: https://github.com/karakeep-app/karakeep/issues/1831 Apparently the MCP spec doesn't specify "properties" as required, but OpenAI does (reference: https://github.com/openai/openai-agents-python/issues/449). This results in errors when using OpenAI (also Github Copilot) endpoints: ``` POST "http://localhost:8080/v1/chat/completions": 400 Bad Request {"message":"Invalid schema for function 'mcp_karakeep_get-lists': None is not of type 'object'.","code":"invalid_function_parameters"} ``` From quickly looking at the code, it's probably because here the third parameter is omitted and not an object like with the other tools?: https://github.com/karakeep-app/karakeep/blob/9059ca22312dec7878e398dd28a2fa18af560fc3/apps/mcp/src/lists.ts#L7-L10 Technically it's OpenAI's fault, it works fine with Gemini's OpenAI compatible API, but if the solution is to just add `{}` I hope this would be fine :)

kerem commented

2026-03-02 11:55:20 +03:00

Author

Owner

@PinkahPandah commented on GitHub (Nov 17, 2025):

I just stumbled on this when using karakeep MCP with metamcp in openwebui. Is this fixable on my end? Or do you have to do it?

@PinkahPandah commented on GitHub (Nov 17, 2025): I just stumbled on this when using karakeep MCP with metamcp in openwebui. Is this fixable on my end? Or do you have to do it?

No milestone

No project

No assignees

1 participant

Notifications

Due date

The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set.

Reference

starred/karakeep#1145

No description provided.

Rows
Columns

[GH-ISSUE #1831] [MCP] Invalid schema for get-lists tool when using providers conforming to OpenAI schema #1145

[GH-ISSUE #1831] [MCP] Invalid schema for `get-lists` tool when using providers conforming to OpenAI schema #1145