Accept "type": "" tool calls

Description

The OpenAI Compatible provider currently has two layers to verify that every tool call has a type of "function":

ai/packages/openai-compatible/src/openai-compatible-chat-language-model.ts

Lines 500 to 505 in 9e16bfd

    
           if (toolCallDelta.type !== 'function') { 
        
             throw new InvalidResponseDataError({ 
        
               data: toolCallDelta, 
        
               message: `Expected 'function' type.`, 
        
             }); 
        
           }

ai/packages/openai-compatible/src/openai-compatible-chat-language-model.ts

Line 700 in 9e16bfd

type: z.literal('function'),

But these checks are unnecessary and serve no purpose since the "function" is the only type of tool call OpenAI's ever declared. More importantly, they prevent me from using the OpenAI Compatible provider from connecting to Novita AI, a provider that sets the type of tool calls to "" after the first one, like it's a delta. Novita isn't changing how their API works - they're confident that this "complies with OpenAI guidelines", and it makes some intuitive sense (it is in the delta section of the stream after all). To solve this, these checks will have to be removed.

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feat (provider/openai-compatible): allow providers that do not specif…

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Identified as Feature
Confidence: High

Rationale

This requests broader compatibility and more permissive handling of tool-call deltas, rather than identifying a violation of documented SDK behavior.

Evidence

The provider currently requires every streamed tool-call type to equal "function".
Novita AI emits type: "" after the first tool-call delta, causing its responses to be rejected.
The request is to remove or relax validation to support this provider-specific response format.

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Accept `"type": ""` tool calls #7255

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	if (toolCallDelta.type !== 'function') {
	throw new InvalidResponseDataError({
	data: toolCallDelta,
	message: `Expected 'function' type.`,
	});
	}

Accept "type": "" tool calls #7255

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lgrammel commented on Jul 22, 2026

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Accept `"type": ""` tool calls #7255