Streaming chunks have different IDs when they should have the same ID

[stephentoub]

The OpenAI docs:
https://platform.openai.com/docs/api-reference/chat-streaming/streaming
state:

id
string
A unique identifier for the chat completion. Each chunk has the same ID.

Importantly, every chunk is supposed to have the same ID.

But the chunks coming back from foundry local have different IDs, e.g.

...
data: {"model":null,"choices":[{"delta":{"role":"assistant","content":",","name":null,"tool_call_id":null,"function_call":null,"tool_calls":[]},"message":{"role":"assistant","content":",","name":null,"tool_call_id":null,"function_call":null,"tool_calls":[]},"index":197,"finish_reason":null,"finish_details":null,"logprobs":null}],"usage":null,"system_fingerprint":null,"service_tier":null,"created":1749165718,"CreatedAt":"2025-06-05T23:21:58+00:00","id":"chat.id.4114","StreamEvent":null,"IsDelta":false,"Successful":true,"error":null,"HttpStatusCode":0,"HeaderValues":null,"object":"chat.completion.chunk"}

data: {"model":null,"choices":[{"delta":{"role":"assistant","content":" maybe","name":null,"tool_call_id":null,"function_call":null,"tool_calls":[]},"message":{"role":"assistant","content":" maybe","name":null,"tool_call_id":null,"function_call":null,"tool_calls":[]},"index":198,"finish_reason":null,"finish_details":null,"logprobs":null}],"usage":null,"system_fingerprint":null,"service_tier":null,"created":1749165718,"CreatedAt":"2025-06-05T23:21:58+00:00","id":"chat.id.4115","StreamEvent":null,"IsDelta":false,"Successful":true,"error":null,"HttpStatusCode":0,"HeaderValues":null,"object":"chat.completion.chunk"}

data: {"model":null,"choices":[{"delta":{"role":"assistant","content":" \u0022","name":null,"tool_call_id":null,"function_call":null,"tool_calls":[]},"message":{"role":"assistant","content":" \u0022","name":null,"tool_call_id":null,"function_call":null,"tool_calls":[]},"index":199,"finish_reason":"stop","finish_details":null,"logprobs":null}],"usage":null,"system_fingerprint":null,"service_tier":null,"created":1749165718,"CreatedAt":"2025-06-05T23:21:58+00:00","id":"chat.id.4116","StreamEvent":null,"IsDelta":false,"Successful":true,"error":null,"HttpStatusCode":0,"HeaderValues":null,"object":"chat.completion.chunk"}
...

Note the IDs:
"id":"chat.id.4114"
"id":"chat.id.4115"
"id":"chat.id.4116"

This breaks clients that try to group updates by completion id.

AB#66982

[samuel100]

@stephentoub thanks for raising an issue. This will be fixed in an upcoming release - I'll update here with an ETA in the next day or two.