Anthropic: Elevated errors: Invalid `signature` in `thinking` block
Timeline of updates
- resolved
This issue is resolved for new requests. However, for responses from one platform received between 2026-01-23 00:00 UTC - 2026-01-23 08:00 UTC that are subsequently included in requests sent to a different platform, there may still be errors.
From Anthropic’s published incident history: for incidents before Rewindex began polling this status page, only the final update text is available.
Archive proof
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This incident predates live tracking (October 17, 2026). It came from the vendor’s own published history, which is not covered by checkpoints.
Impact, status and times are the vendor’s own, as last archived. View on status.anthropic.com (opens in new tab).
Cite this
Status incident (vendor impact label: minor) posted by Anthropic, started 2026-01-23 05:09 UTC, resolved after 2.6 h, 1 update(s).
- Title
- Elevated errors: Invalid `signature` in `thinking` block
- Vendor
- Anthropic
- Date
- URL
- https://rewindex.com/company/anthropic/incidents/5dvcj03m4d57
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