MCP server can’t properly handle tool without args

[lingbingjiang]

Describe the bug
A clear and concise description of what the bug is.
MCP server currently set request handler of tool calling without args (no zod shape) called directly, without {}. However toolcallback type expects it. It is even worse when you use tool annotation.

To Reproduce
Steps to reproduce the behavior:

1. Create a tool without args by MCPServer.tool(name, desc, {}, function)
2. try to access extra as a parameter in the function. The type ToolCallback breaks.
3. it is worse when using tool annotation.

Expected behavior
A clear and concise description of what you expected to happen.
You can get inferred correct type of extra in the mcpserver.tool

Logs
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Additional context
Add any other context about the problem here.

[lingbingjiang]

server/mcp.ts
Line 141 167 176

[Cloudkkk]

same problem

[noctonic]

This also happens when the schema is undefined.