I’m using AI Gateway with gemini-3.1-flash-lite and attempting to set thinkingLevel: “medium”, but the API returns an error stating only low|high are supported.
AI Gateway error: {
message: ‘Invalid option: expected one of “low”|“high”’,
type: ‘invalid_request_error’,
param: ‘thinking_config.thinking_level’,
code: ‘invalid_request_error’
}
According to the AI Gateway documentation, all four thinking levels (minimal, low, medium, high) should be supported for this model.
Expected behavior: medium reasoning effort should work as documented.
Actual behavior: Error indicating only low|high are valid values.
Additional note: minimal only seems to work when thinkingLevel is omitted entirely, rather than being explicitly set.
Is this a known issue or a documentation error?