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Engineering 8 minute read

AI API observability: the fields that make incidents explainable

Instrument model requests for latency, tokens, cost, routing, fallbacks, and task outcomes.

In brief

  • Record model resolution and fallback state.
  • Separate provider latency from end-to-end task time.
  • Prefer safe metadata over raw prompt logging.
01

Start with the questions incidents ask

Which model served the request? Did routing or fallback change it? Was the slowdown in queueing, provider latency, streaming, or a downstream tool? Did the response complete, and did the task succeed?

02

Capture a compact request record

A useful event combines correlation IDs, requested and resolved model identity, timestamps, token usage, status, retry count, and a privacy-safe task category.

Core AI request dimensions
GroupFields
Identityrequest ID, trace ID, tenant-safe key
Routingrequested lane, selected model, resolved model
Performancequeue, first token, total latency
Usageinput, output, cached tokens, estimated cost
Outcomestatus, finish reason, retry, fallback, task result
03

Do not make raw prompts the default

Prompts can contain source code, customer data, secrets, or private conversations. Prefer hashes, sizes, categories, schema validation results, and sampled redacted payloads with explicit retention controls.

04

Build dashboards around decisions

Track reliability and latency by resolved model, task lane, and customer segment. Add quality or task-success signals where possible. A global average is useful for a status page but insufficient for model selection.

Frequently asked

Questions, answered plainly.

Should AI prompts be logged?+

Not by default. Use privacy-safe metadata and only retain redacted payloads under an explicit policy when debugging requires them.

What is time to first token?+

It measures the delay before streamed output begins. Track it separately from total completion time because users experience them differently.

How do I monitor model quality?+

Connect requests to task-specific outcomes such as schema validity, test results, reviewer acceptance, or user feedback—not only technical success.

Sources and next paths

Check the living surfaces.

Put it to work

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AI API observability: the fields that make incidents explainable | Xpersona Blog