[Frontend] OpenAI Responses API supports Tool/Function calling

[chaunceyjiang]

OpenAI Responses API supports Tool/Function calling

Follow up #20504

[github-actions]

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[gemini-code-assist]

Summary of Changes

Hello @chaunceyjiang, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly extends the functionality of the OpenAI Responses API by adding support for tool and function calling. The changes involve modifying the request processing pipeline to interpret tool definitions, dynamically generating guided decoding constraints for model output, and restructuring the API response to include detailed function call information. This enables the system to leverage external tools and APIs through the language model's capabilities.

Highlights

• Tool/Function Calling Support: Implemented comprehensive support for OpenAI-style tool/function calling within the Responses API, enabling the model to generate structured tool calls based on provided tool definitions and user prompts.
• Dynamic Guided Decoding for Tools: Enhanced the guided decoding mechanism to dynamically generate JSON schemas for tool calls. This allows the model to be constrained to output valid JSON for function arguments, based on the tool_choice and tools parameters in the request.
• Extended Response Format: Modified the ResponsesResponse output type to include ResponseFunctionToolCall objects. This ensures that the API can return structured information about the function calls generated by the model.
• Tool Parsing Integration: Integrated a ToolParser to extract and format function calls from the model's generated output. This supports various tool_choice modes, including 'auto', 'required', and specific named function calls.
• New Configuration Options: Introduced new configuration options (enable_auto_tools, expand_tools_even_if_tool_choice_none) to provide granular control over tool parsing behavior and how tool definitions are handled in the prompt.

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[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @chaunceyjiang.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[gemini-code-assist]

Code Review

This pull request introduces Tool/Function calling support to the OpenAI Responses API. The changes involve protocol modifications, serving engine updates, and response serving logic enhancements. The review identifies a critical bug related to empty responses, a high-severity issue concerning data mutation, and some medium-severity issues regarding debug statements and type checking.

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @chaunceyjiang.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @chaunceyjiang.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[chaunceyjiang]

@aarnphm PTAL.

[aarnphm]

@aarnphm PTAL.

Yes will get to it tn

[mergify]

This pull request has merge conflicts that must be resolved before it can be
merged. Please rebase the PR, @chaunceyjiang.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[madskildegaard]

Hey, what's the status of this? Getting this essential feature in the Responses API would be great!

[chaunceyjiang]

Hey, what's the status of this? Getting this essential feature in the Responses API would be great!

@madskildegaard It may still take some time

[madskildegaard]

Built tool/function call streaming on top of this branch, if anyone needs it

[mergify]

Documentation preview: https://vllm--20874.org.readthedocs.build/en/20874/

[chaunceyjiang]

Built chaunceyjiang#1 on top of this branch, if anyone needs it

Hi, @madskildegaard Could you resubmit your PR?

[chaunceyjiang]

Hi, @madskildegaard . I’ve submitted the contribution as a new PR #29947 and will include you as a co-author.

[madskildegaard]

Built chaunceyjiang#1 on top of this branch, if anyone needs it

Hi, @madskildegaard Could you resubmit your PR?

Hi @chaunceyjiang, it would probably need a few changes to be up-to-date with main branch, but I can look into it if you want.

Hi, @PedroMiolaSilva. I’ve submitted the contribution as a new PR #29947 and will include you as a co-author.

I suppose this comment was meant to be for me?

[chaunceyjiang]

@madskildegaard Yes. ❤️

[madskildegaard]

@chaunceyjiang, I see you already made some changes in the new draft to make it more up-to-date. Will you finish the draft yourself or do you want me to take a look if anything else needs be changed?