mcp_argument_missing

A required argument is missing. Answered with 400.

What it means

The tool call left out an argument the tool marks required, or sent it as null. Which arguments a tool requires is in the inputSchema tools/list hands out with it.

What to do

Add the argument the detail names and call the tool again. Do not retry the call unchanged.

The body

{
  "type": "https://tigby.eu/problems/mcp_argument_missing",
  "title": "A required argument is missing",
  "status": 400,
  "detail": "…what was refused, naming this request's own values",
  "code": "mcp_argument_missing",
  "doc_url": "https://docs.tigby.eu/errors/mcp_argument_missing",
  "agent_hint": "…the next step, for software"
}

Branch on code. The detail names this request's own Handle, id or limit and is not part of the contract.