Cursor + Gemini 3 Flash endless "incorrect tool argument" cycle

[hvesuk]

Often Cursor got stuck trying to access MCP tools with incorrect parameters

Cursor_gQ3F1ZN5xH.mp4

[Scriptwonder]

This happened a lot for me as well. I think we need to update the tool descriptions and add additional scaffolding for the tool to correctly call each tool.
Did you try letting it write a rule/skill indicating how each tool should work and see how that performs?

[hvesuk]

I just tried to get the LLM to use the command provided by the bridge instead of pasting comments as commands. I also fed it the MCP README, which should clarify things, but neither approach worked

[dsarno]

Same question here -- which tool calls are failing? What are you trying to do? In my experience, some smaller models can have trouble correctly formatting the tool requests when the parameters are more complicated. But it will help us to know if there are certain tools that are more problematic. I also think it may just be a limitation of smaller models right now, and will get better as time goes on

[Scriptwonder]

I want to add to this after switching to Gemini3 Pro (after Opus running out of quota on Antigravity) and using it with Unity-MCP for a while.
The experience is really bad with Gemini 3 for some unknown reason; it keeps thinking for a long time without triggering actual MCP tool calls, then hallucinates the tool call results as "false," and states invisible tool call errors in its thoughts process. For OPUS, it is just straight 40 MCP tool calls with actual implementation, and for Gemini 3 Pro, it is 20 thought processes with 1 tool call that checks the scene ID.

[dsarno]

I have not had the same issue -- I just asked Gemini 3 Flash to one-shot an inventory UI system with scriptable objects, and it did it very fast, with only a couple of "incorrect parameter" errors. I wonder if this is a "your mileage may vary" situation that depends on what you're asking it, or the "random shape" that Gemini is in that day?

It'd be nice to have some prompts to try to reproduce the error states you all are seeing.