Describe the bug
I have some OpenAI-Agents-SDK Agent using OpenRouter & LiteLLM to send (i) streaming and (ii) non-streaming messages to LLM providers (e.g. OpenAI, Anthropic, etc). The token counts for each span are always the same between the LLM providers vs OpenRouter.

But for (i) streaming messages, the token counts on Phoenix are lower for every span vs. LLM providers & OpenRouter.

Is this a bug on Phoenix or is there something wrong with the implementation on my end?

For example, here's an Agent trace with token counts for each span:

This is what the actual token counts were for each span, in the same order:

The Agent code is like this:

I auto-instrument the tracing with:

• openinference-instrumentation-litellm==0.1.25
• openinference-instrumentation-openai-agents==1.1.0
  as I'm practically sending all LLM messages via LiteLLM (but not all via OpenRouter)

I also saw this OpenRouter tracing page, but I think this would create triple-nested spans and triple count the token usage.

Additional context

arize-phoenix-client                        1.15.3
arize-phoenix-otel                          0.12.1
litellm                                     1.72.2
openai-agents                               0.2.11
openinference-instrumentation               0.1.35
opentelemetry-sdk                           1.36.0