Metric: gen_ai.server.time_to_first_token

[spurs30]

What problem do you want to solve?

In Semantic Conventions 1.38.0, there is a standard definition for the TTFT (Time to First Transaction) metric in the metrics section. However, the current agent does not yet implement this metric. Is there any plan to implement this metric in the future? If not, what would be the approach to customizing the implementation of this metric?

Describe the solution you'd like

1. Follow-up plan for achieving the TTFT metric.
2. Developer's approach to customizing the TTFT metric.

Describe alternatives you've considered

No response

Additional Context

No response

Would you like to implement a fix?

None

Tip

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[xrmx]

First thing is that implemented stuff is per-instrumentation and not globally, second thing is that this is a server metric and AFAICS we only have client instrumentations.

[spurs30]

Yes, currently, the agent only has client-side metrics. How can we define this metric for a specific instrumentation? For example, vLLM, SGLang.