Upgrade

Polyglot 2.0 is centered around explicit request fields.

The main migration points are:

• remove old output mode usage
• set responseFormat for native JSON or JSON schema
• set tools and toolChoice for tool calling
• use stream()->deltas() for streaming

Response Model

Polyglot is now explicitly the raw inference layer.

• InferenceResponse is the final raw provider response
• streaming yields PartialInferenceDelta
• structured value ownership belongs to higher-level packages such as Instructor

If older code assumed that Polyglot streaming yielded accumulated partial response snapshots, update that code to work from deltas instead.

Before

<?php

$data = $inference
    ->with(
        messages: 'Return JSON.',
        mode: $oldMode,
    )
    ->asJsonData();

After

<?php

use Cognesy\Messages\Messages;
use Cognesy\Polyglot\Inference\Data\ResponseFormat;
use Cognesy\Polyglot\Inference\Inference;

$data = Inference::using('openai')
    ->withMessages(Messages::fromString('Return JSON.'))
    ->withResponseFormat(new ResponseFormat(type: 'json_object'))
    ->asJsonData();

Markdown-JSON fallback is no longer a Polyglot concern. Use Instructor when you need higher-level structured output strategies.

Streaming Migration

Update old streaming code like this:

• replace partial-response iteration with stream()->deltas()
• assemble final raw output with final()
• move partial structured parsing to Instructor or your own delta accumulator