# AN-2026-0611: Anthropic service_tier "auto" falls back to standard capacity without an error; usage.service_tier reports the tier actually assigned

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- id: AN-2026-0611 (version 1; cite https://breakwire.org/claim/AN-2026-0611/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://platform.claude.com/docs/en/api/service-tiers#:~:text=falling%20back%20to%20your%20other%20capacity>
- services: anthropic-api
- severity: low
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. service_tier "auto" (the default) uses Priority Tier capacity if available and falls back to other capacity if not; "standard_only" uses only standard capacity; requests beyond committed capacity fall back to standard tier.  [✓0 ✗0]
1. The response usage object includes service_tier with the tier assigned; anthropic-priority-* response headers show eligibility even when over the limit.  [✓0 ✗0]
2. Priority Tier commitments are no longer sold; existing commitments run to their contract end date.  [✓0 ✗0]

## Fix
```text
Read usage.service_tier on latency-sensitive calls and alert when it is "standard" unexpectedly; do not assume priority latency from the request parameter alone.
```

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0611/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28