Reduce finish_reason reliance

[Nick-Source]

Non-auto tool choices will result in a finish_reason of "stop" rather than "tool_calls". The current code assumes "stop" means there are no tool calls to be made when this isn't true. Instead, it should simply check for any available tool calls.

This is talked about by OpenAI staff in this thread: https://community.openai.com/t/new-api-feature-forcing-function-calling-via-tool-choice-required/731488/13

Interestingly, these recent tests show different results: https://community.openai.com/t/function-call-with-finish-reason-of-stop/437226/45

I couldn't find any conclusive reference of this on the Docs/API page, but regardless it should be safer this way to rely on the presence/absence of tool_calls.

Alongside, the last message in a chat completion stream isn't guaranteed to have the finish_reason. Instead we should check for any reasons to stop as we collect chunks and then use that at the end. The openAI python library follows a similar manner when processing chunks:
https://github.com/openai/openai-python/blob/e6c6757553bbdb777c31d0daf5916fb9e2b47ff8/src/openai/lib/streaming/chat/_completions.py#L361

Fixes #88

[Copilot]

Pull Request Overview

This PR addresses issues with how tool calls are detected in OpenAI chat completions by reducing reliance on the finish_reason field. The main issue is that non-auto tool choices return a finish_reason of "stop" even when tool calls are present, causing the current logic to incorrectly assume no tool calls exist.

• Replace finish_reason-based tool call detection with direct checking of tool_calls presence
• Track tool call state during streaming to handle finish_reason inconsistencies
• Simplify logic to only stop processing for "length" finish_reason or absence of tool calls

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
streamChatCompletion.py	Replaces finish_reason logic with tool_call tracking and direct tool_calls checking
chatCompletion.py	Updates condition to check for tool_calls presence instead of relying on finish_reason

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[Copilot]

Use not tool_call instead of tool_call == False for boolean comparison. This is more pythonic and consistent with PEP 8 style guidelines.

Suggested change

	continue
	if fully_done or not tool_call:
	logger.debug("no tool calls found")
	fully_done = True
	continue