# X_AI_REQUEST_INVALID

## Means

the provider would reject this request

## Typical cause

a reasoning control the chosen model does not have — `effort` or adaptive `thinking` on a pre-4.6 model, or `thinking: 'disabled'` above a model's effort cap

## Fix

set `model:` on the `llm()` declaration to one whose `MODELS` row has the control, or drop `effort`/`thinking` from `definePrompt` — editing the template alone leaves the control in the request

[MCP and AI](/error-codes#mcp-and-ai)