Output Formats

TokenHub can shape provider responses into specific output formats. This is useful for applications that need structured data from LLM responses.

Configuration

Set the output_format field in your chat request:

{
  "output_format": {
    "type": "json",
    "schema": "{\"type\":\"object\",\"properties\":{\"answer\":{\"type\":\"string\"}}}",
    "max_tokens": 500,
    "strip_think": true
  }
}

Format Types

JSON

Validates the response against a JSON Schema. If the provider's output doesn't match the schema, TokenHub returns a validation error.

{
  "output_format": {
    "type": "json",
    "schema": "{\"type\":\"array\",\"items\":{\"type\":\"object\",\"properties\":{\"name\":{\"type\":\"string\"},\"value\":{\"type\":\"number\"}}}}"
  }
}

The schema is passed as a string (not a nested object) to allow maximum flexibility.

Markdown

Requests the provider to format its response as Markdown:

{
  "output_format": {
    "type": "markdown"
  }
}

Text

Plain text output with optional truncation:

{
  "output_format": {
    "type": "text",
    "max_tokens": 200
  }
}

XML

Requests XML-formatted output:

{
  "output_format": {
    "type": "xml"
  }
}

Output Format Fields

Field	Type	Description
`type`	string	Output format: `json`, `markdown`, `text`, `xml`
`schema`	string	JSON Schema for validation (only with `type: "json"`)
`max_tokens`	int	Maximum output tokens to request from the provider
`strip_think`	bool	Remove `<think>...</think>` reasoning blocks from the response

Think Block Stripping

Some models (particularly those with chain-of-thought reasoning) wrap their internal reasoning in <think>...</think> tags. Setting strip_think: true removes these blocks from the final response:

Before stripping:

<think>
The user wants to know the capital of France. This is a straightforward factual question.
</think>
The capital of France is Paris.

After stripping:

The capital of France is Paris.

JSON Schema Validation

When type: "json" is specified with a schema, TokenHub:

Sends the request to the provider (with a system message hint to produce JSON)
Parses the provider's response as JSON
Validates against the provided JSON Schema
Returns the validated JSON in the response

If validation fails, the error is returned in the response body with a 502 status.

TokenHub Documentation