add ALLOWED_OPENAI_PARAMS to openai pipeline

[ti3x]

This pull request updates the OpenAIPipeline backend to introduce support for specifying allowed OpenAI parameters, improving configurability and control over API requests. The main changes include defining a default set of allowed parameters, updating configuration logic, and ensuring these parameters are properly passed in API requests.

Configuration and parameter management improvements:

• Defined a new constant DEFAULT_ALLOWED_OPENAI_PARAMS (containing "tools" and "tool_choice") for use as the default allowed OpenAI parameters.
• Updated the pipeline configuration logic to set allowedOpenAIParams to the default value if not explicitly provided in the options.

API request handling enhancements:

• Modified request construction to resolve allowedOpenAIParams from multiple sources (request, options, or default) and ensure it is included in the completion parameters sent to the OpenAI API. [1] [2]add ALLOWED_OPENAI_PARAMS to openai pipeline

[ti3x]

@tarekziade not sure if these this.#options or config.allowedOpenAIParams check is necessary to allow future clients to set this value. Most of time we probably don't want to add this payload on every client call anyways.
I tested this and it shouldn’t break any non-TogetherAI inference servers — for example, it works fine with VertexAI and doesn’t affect the response payload. But if we want to be extra cautious, and don't want to do a conditional check against Model id in client-side code, we could do this in MLPA layer (check for model id prefix beign together_* and add this additional payload before passing off to Litellm)

Long term, LiteLLM should ideally support custom model configurations that allow passing through model-specific request parameters.

Would love to hear your thoughts on this.

[Mardak]

how do you expect this config to be set? if from createEngine, the allowed key options filters it out anyway https://searchfox.org/firefox-main/rev/77b6c9748bdd784eb5e0ee42603c408b34559d7d/toolkit/components/ml/content/EngineProcess.sys.mjs#769-770

at least for fork, we could conditional this on the modelId? quick test shows adding these params works for qwen, gpt4o, together but not mistral:

500 litellm.APIConnectionError: Vertex_aiException - b'
{"detail":[
{"type":"model_attributes_type","loc":["body","ChatCompletionRequest","tool_choice","ToolChoice"],"msg":"Input should be a valid dictionary or object to extract fields from","input":null},
{"type":"enum","loc":["body","ChatCompletionRequest","tool_choice","function-after[operator.attrgetter('value')(), str-enum[ToolChoiceEnum]]"],"msg":"Input should be 'auto', 'none', 'any' or 'required'","input":null,"ctx":{"expected":"'auto', 'none', 'any' or 'required'"}},
{"type":"missing","loc":["body","CompletionRequest","prompt"],"msg":"Field required","input":{"model":"mistral-small-2503","messages":[{"role":"system","content":"You are a …Today's date: Thursday, November 13, 2025"},{"role":"user","content":"hi"}]},
{"type":"extra_forbidden","loc":["body","OCRRequest","tools"],"msg":"Extra inputs are not permitted","input":[{"type":"function","function":{"name":"search_open_tabs","description":"Search …","parameters":{"type":"object","properties":{"type":{"type":"string","description":"The …"}},"required":["type"]}}},{"type":"function","function":{"name":"get_page_content","description":"Retrieve text from a specific browser tab. Choose whether to read the current viewport, Reader Mode, or full page content. The content is cleaned for analysis.","parameters":{"type":"object","properties":{"url":{"type":"string","description":"The …"},"mode":{"type":"string","enum":["viewport","reader","full"],"description":"Extraction …"}},"required":["url"]}}},{"type":"function","function":{"name":"search_history","description":"Search …","parameters":{"type":"object","properties":{"search_term":{"type":"string","description":"Keywords …"}},"required":["search_term"]}}}]},
{"type":"extra_forbidden","loc":["body","OCRRequest","tool_choice"],"msg":"Extra inputs are not permitted","input":null},
{"type":"extra_forbidden","loc":["body","OCRRequest","stream"],"msg":"Extra inputs are not permitted","input":true}
]}
'. Received Model Group=mistral-small-2503
Available Model Group Fallbacks=None