Claude 4 Sonnet Completion Metrics Explained

Claude 4 Sonnet Completion Metrics Explained | Generated by AI

Home 2025.09

Short version: it ended normally. finish_reason: "stop" means the model reached a natural end of its reply (hit a stop sequence like the assistant-end token) and did not run into a length cap, error, or cancel.

Here’s what the rest of that record is telling you, in plain English:

Model & route You called anthropic/claude-4-sonnet-20250522 via Google Vertex (provider_name: "Google"). That’s why you see a provider_responses entry with status 200.
Timing / speed
- latency: 2850 → ~2.85 s until the first token showed up.
- generation_time: 76365 → about 76.4 s total to finish the reply.
- With tokens_completion: 2376, that’s roughly 31 tokens/sec throughput across the whole generation (2376 ÷ 76.4 ≈ 31.1).
Token counts (two sets)
- tokens_prompt: 8446, tokens_completion: 2376 → your aggregator’s counts.
- native_tokens_prompt: 9007, native_tokens_completion: 2511 → the provider’s own tokenizer/accounting. These often differ due to different tokenizers, system wrappers, or hidden control tokens.
- native_tokens_reasoning: 0 → this run didn’t use a “reasoning tokens” meter (some providers expose this when a special reasoning mode is on).
- native_tokens_cached: 0 → no prompt caching hit.
Streaming & cancelation
- streamed: true → tokens were streamed to you.
- cancelled: false → you didn’t interrupt it.
Why not “length”? If it had hit the max token limit, you’d see finish_reason: "length". You didn’t, so the model completed before any cap.
When did this happen? created_at: "2025-09-02T17:26:45.92824+00:00" (UTC). In your timezone (Asia/Taipei, UTC+8) that’s 2025-09-03 01:26:45.
Costs/usage fields
- usage: 0.064686 → your system’s cost/usage metric (units depend on your billing layer).
- Several null fields just mean your router didn’t record extra details (moderation latency, search results, etc.).
Misc.
- finish_reason: "stop" (again) is the key: normal stop via stop token.
- origin: "", app_id: null → no specific app tag.
- is_byok: false → not a bring-your-own-key call.

If you want, paste a second example where you saw length or cancelled, and I’ll contrast them line-by-line (no tables).

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