Where does the bug appear (feature/product)? Cursor IDE Describe the Bug Product / feature Cursor MCP integration CallMcpTool tool used by agents Description There is a mismatch between the schema exposed to the agent for CallMcpTool and the actual runtime behavior. The schema shown to the age…

Hey, this is a known issue. A few users have already run into it. Quick clarification: the CallMcpTool schema actually does include an optional arguments field. The issue isn’t that the schema is missing the field. It’s that the model sometimes doesn’t populate it during MCP tool auto-calls. So the…

allMcpTool schema missing arguments field causes agents to call MCP tools without required params

Support Bug Reports

Topic		Replies	Views
CallMcpTool schema omits arguments, but runtime accepts it Bug Reports mcp	3	358	January 28, 2026
MCP tool called without required "key" arg during Agent auto-call, manual call works Bug Reports mcp	5	227	June 3, 2026
Cursro agent does not respect the input schema of MCP tools Bug Reports mcp , auto-mode	3	112	May 29, 2026
[3.12.x] MCP tool arguments not forwarded to server (all params undefined); works on 3.11.25 Bug Reports mcp	1	67	July 23, 2026
Can not see call args in mcp tool calls Bug Reports mcp	18	464	August 10, 2026

allMcpTool schema missing arguments field causes agents to call MCP tools without required params

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