GLM-5.3

Model ID

Model ID
`zai-org/GLM-5.3`

Its rates and rate limits are listed on the Models and Limits pages.

Limits

Limit	Tokens
Context length	1,048,576
Max output	131,072

The context length covers the input and max_tokens together. A request whose input plus max_tokens exceeds it returns 400. A max_tokens above 131,072 is accepted, but output stops at 131,072 tokens.

Thinking

GLM-5.3 always thinks, and thinking cannot be turned off. "reasoning_effort": "none" and "thinking": {"type": "disabled"} are not supported for this model, so don’t send them. reasoning_effort accepts minimal, low, medium, high, xhigh and max. Any other value returns 400. The reasoning arrives in message.reasoning_content, or in delta.reasoning_content when streaming, separate from content. usage.completion_tokens_details.reasoning_tokens counts it. Reasoning tokens are part of completion_tokens and are billed as output. max_tokens covers the reasoning and the answer together. If the reasoning uses the whole budget, the response ends with finish_reason: "length" and an empty content. Stop sequences are matched in the reasoning too, so a match there ends the response before the answer starts.

Parameters

Parameter	Notes
`max_tokens`, `max_completion_tokens`	Cover reasoning and answer together.
`temperature`	0 to 2.
`top_p`	Greater than 0, up to 1.
`top_k`, `presence_penalty`, `frequency_penalty`	Accepted.
`stop`	Also matched in the reasoning.
`seed`	Accepted, but does not make output reproducible.
`stream`, `stream_options`	Every stream ends with a usage chunk, with or without `include_usage`.
`tools`, `tool_choice`	`auto`, `required`, `none` or a named function.
`response_format`	`text`, `json_object` and `json_schema`.
`reasoning_effort`	See Thinking.
`user`	Accepted.

These return 400:

Parameter	`error.code`	`error.message`
`n` other than `1`	`unsupported_n`	`n must be 1`
`logprobs`, even `false`	`unsupported_parameter`	the parameter `logprobs` is not supported
`top_logprobs`	`unsupported_parameter`	the parameter `top_logprobs` is not supported
`logit_bias`	`unsupported_parameter`	the parameter `logit_bias` is not supported
Fields the API does not define, such as `chat_template_kwargs`	`unknown_parameter`	`unrecognized request argument supplied: chat_template_kwargs`

{
  "error": {
    "message": "the parameter `logprobs` is not supported",
    "type": "invalid_request_error",
    "param": null,
    "code": "unsupported_parameter"
  }
}

Out-of-range values, such as temperature: 3 or top_p: 0, also return 400.

Getting Started

Models

Inference APIs

Account

Model ID

Limits

Thinking

Parameters

​Model ID

​Limits

​Thinking

​Parameters

Model ID

Limits

Thinking

Parameters