Support JSON mode with schema forcing for providers that support it (e.g. Fireworks)

[dzhulgakov]

Checked

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Feature request

with_structured_output (https://python.langchain.com/docs/guides/structured_output) currently passes the desired schema in the prompt only and sets "response_format": {"type": "json_object"} in the request. That's what OpenAI supports.

Other providers support passing JSON schema directly to the server to guide the generation. E.g. for Fireworks.ai: https://readme.fireworks.ai/docs/structured-response-formatting#structured-response-modes

Motivation

It'd improve quality of JSON generation even further for model providers that support it.

Proposal (If applicable)

No response

[aviadr1]

isnt this already solved? I think with_structured_output doesnt modify the prompt anymore, instead it adds the schema to the request metadata