# Claude: Issues with responses using structured outputs on the API

> Claude status incident “Issues with responses using structured outputs on the API” on 2026-04-23: impact none (vendor’s label), 0 min, 1 update(s). Archived by Rewindex.

Canonical: https://rewindex.com/company/claude/incidents/t6v0k97s0802
Last updated: 2026-04-23T02:00:00Z

- Impact (vendor’s label): none
- Status: resolved
- Started: 2026-04-23 02:00 UTC · Resolved: 2026-04-23 02:00 UTC · Duration: 0 min
- Updates: 1
- [Vendor status page: https://status.claude.com/incidents/t6v0k97s0802](https://status.claude.com/incidents/t6v0k97s0802)
- [Company: Claude](https://rewindex.com/company/claude.md)

## Timeline of updates

- **resolved** 2026-04-23 02:00 UTC: We have identified and resolved an issue which resulted in issues with model responses when making use of structured outputs via the Anthropic API between 16:10 UTC on April 22 and 01:59 UTC on April 23. During this period, structured outputs containing some forms of grammar requirements returned with reduced quality. This did not impact any requests not using structured outputs, as detailed here: https://platform.claude.com/docs/en/build-with-claude/structured-outputs.

_From the vendor’s published history: only the final update text is available for incidents before Rewindex began polling this page._

## Cite this

Status incident (vendor impact label: none) posted by Claude, started 2026-04-23 02:00 UTC, resolved after 0 min, 1 update(s).

- Canonical URL: https://rewindex.com/company/claude/incidents/t6v0k97s0802
- Citation: Claude, “Issues with responses using structured outputs on the API” (2026-04-23 02:00 UTC). Archived by Rewindex: https://rewindex.com/company/claude/incidents/t6v0k97s0802 (CC BY 4.0).
- Markdown link: `[Claude: Issues with responses using structured outputs on the API (2026-04-23)](https://rewindex.com/company/claude/incidents/t6v0k97s0802)`


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Canonical: https://rewindex.com/company/claude/incidents/t6v0k97s0802 · Markdown: https://rewindex.com/company/claude/incidents/t6v0k97s0802.md · JSON: https://rewindex.com/api/v1/companies/claude/incidents/t6v0k97s0802 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-11-04T15:28:36.170Z