Model output quality
Investigating - Last week, we opened an incident to investigate degraded quality in some Claude model responses. We found two separate issues that we’ve now resolved. We are continuing to monitor for any ongoing quality issues, including reports of degradation for Claude Opus 4.1.

Resolved issue 1 - A small percentage of Claude Sonnet 4 requests experienced degraded output quality due to a bug from Aug 5-Sep 4, with the impact increasing from Aug 29-Sep 4. A fix has been rolled out and this incident has been resolved.

Resolved issue 2 - A separate bug affected output quality for some Claude Haiku 3.5 and Claude Sonnet 4 requests from Aug 26-Sep 5. A fix has been rolled out and this incident has been resolved.

Importantly, we never intentionally degrade model quality as a result of demand or other factors, and the issues mentioned above stem from unrelated bugs.

We're grateful to the detailed community reports that helped us identify and isolate these bugs. We're continuing to investigate and will share an update by the end of the week.
Sep 09, 2025 - 00:15 UTC
Uptime over the past 90 days. View historical uptime.
claude.ai Operational
90 days ago
99.14 % uptime
Today
console.anthropic.com Degraded Performance
90 days ago
99.5 % uptime
Today
api.anthropic.com Operational
90 days ago
99.44 % uptime
Today
Claude Code Operational
90 days ago
99.46 % uptime
Today
Operational
Degraded Performance
Partial Outage
Major Outage
Maintenance
Major outage
Partial outage
No downtime recorded on this day.
No data exists for this day.
had a major outage.
had a partial outage.

No incidents or maintenance related to this downtime.

Sep 9, 2025
Elevated latency for some Sonnet 4 requests
Resolved - This incident has been resolved.
Sep 9, 05:56 UTC
Investigating - We are currently investigating this issue.
Sep 9, 02:27 UTC
Sep 8, 2025

No incidents reported.

Sep 7, 2025

No incidents reported.

Sep 6, 2025

No incidents reported.

Sep 5, 2025
Unable to send messages to Opus 4.1
Resolved - This incident has been resolved.
Sep 5, 22:10 UTC
Update - We've re-enabled Opus 4.1 on Claude.ai
Sep 5, 21:40 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Sep 5, 21:33 UTC
Update - We've temporarily disabled Opus 4.1 on Claude.ai
Sep 5, 21:02 UTC
Identified - The issue has been identified and a fix is being implemented.
Sep 5, 21:01 UTC
Investigating - We are currently investigating this issue.
Sep 5, 20:31 UTC
Certain Claude.ai Orgs Unable to Submit Messages
Resolved - This incident has been resolved.
Sep 5, 19:24 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Sep 5, 19:22 UTC
Investigating - We are currently investigating this issue.
Sep 5, 19:09 UTC
Sep 4, 2025
Unable to connect to MCP (Connectors), API Tools
Resolved - This incident has been resolved.
Sep 4, 17:28 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Sep 4, 17:11 UTC
Investigating - We are currently investigating this issue.
Sep 4, 16:33 UTC
Elevated errors on Claude 4.1 Opus
Resolved - As of 8:15 PT / 15:15 UTC the errors have returned to the baseline.
Sep 4, 15:30 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Sep 4, 15:20 UTC
Investigating - We are investigating an issue with Claude Opus 4.1 that started at 7:30 PT / 14:30 UTC.
Sep 4, 14:51 UTC
Elevated errors on Claude Haiku 3.5
Resolved - As of 7:30 PT / 14:30 UTC we have resolved this incident.
Sep 4, 14:59 UTC
Investigating - We are investigating an issue with Claude Haiku 3.5 that started at 6:00 PT / 13:00 UTC.
Sep 4, 13:57 UTC
Elevated errors on Claude Sonnet 4.0
Resolved - As of 23:50 PT / 6:50 UTC, we have mitigated the incident.
Sep 4, 07:00 UTC
Investigating - We are investigating an issue with Claude Sonnet 4.0 that started at 23:25 PT / 6:25 UTC.
Sep 4, 06:44 UTC
Sep 3, 2025
Elevated errors on Claude Opus 4.1
Resolved - As of 00:15 PT / 7:15 UTC, we have mitigated the incident.
Sep 3, 07:59 UTC
Update - We are continuing to monitor for any further issues.
Sep 3, 07:21 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Sep 3, 07:19 UTC
Investigating - We are currently investigating this issue.
Sep 3, 06:39 UTC
Elevated error rates on API and claude.ai
Resolved - This incident has been resolved.
Sep 3, 01:45 UTC
Identified - The issue has been identified and a fix is being implemented.
Sep 3, 01:34 UTC
Sep 2, 2025

No incidents reported.

Sep 1, 2025
Elevated errors on Claude 3.5 Sonnet (Oct 2024)
Resolved - This incident has been resolved.
Sep 1, 08:55 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Sep 1, 08:19 UTC
Investigating - We are seeing an elevated amount of errors on Claude 3.5 Sonnet (Oct 2024) since 23:10 PT / 6:10 UTC.
Sep 1, 07:14 UTC
Aug 31, 2025
Claude.ai Research Failing to Start
Resolved - This incident has been resolved.
Aug 31, 18:21 UTC
Update - Fix has been implemented and is being deployed
Aug 31, 17:55 UTC
Investigating - We are continuing to investigate this issue.
Aug 31, 17:09 UTC
Elevated errors on Claude Sonnet 4.0
Resolved - As of 00:50 PT / 7:30 UTC, we have mitigated the incident.
Aug 31, 08:01 UTC
Investigating - We are investigating an issue with Claude Sonnet 4.0 that started at 22:30 PT / 5:30 UTC.
Aug 31, 07:32 UTC
Aug 30, 2025
Elevated errors on Claude Sonnet 4.0
Resolved - As of 1:15 PT / 8:15 UTC this incident has been mitigated.
Aug 30, 09:22 UTC
Update - This incident erroneously had Sonnet 4.1 in the title. The model affected was Sonnet 4.0.
Aug 30, 09:20 UTC
Investigating - We are investigating an issue with Claude Sonnet 4.0 that started at 22:30 PT / 5:30 UTC.
Aug 30, 07:05 UTC
Claude Opus 4.1 and Opus 4 degraded quality
Resolved - This incident has been resolved.
Aug 30, 02:12 UTC
Identified - From 17:30 UTC on Aug 25th to 02:00 UTC on Aug 28th, Claude Opus 4.1 experienced a degradation in quality for some requests. Users may have seen lower intelligence, malformed responses or issues with tool calling in Claude Code.

This was caused by a rollout of our inference stack, which we have since rolled back for Claude Opus 4.1. While we often make changes intended to improve the efficiency and throughput of our models, our intention is always to retain the same model response quality.

We’ve also discovered that Claude Opus 4.0 has been affected by the same issue and we are in the process of rolling it back.
Aug 29, 17:02 UTC
Aug 29, 2025
Elevated errors on Claude Sonnet 4.0
Resolved - As of 2:15 PT / 9:15 UTC this incident has been mitigated.
Aug 29, 09:27 UTC
Investigating - We are investigating an issue with Claude Sonnet 4.0 that started at 22:30 PT / 5:30 UTC.
Aug 29, 06:23 UTC
Upgrades to Connector Auth Storage
Completed - The scheduled maintenance has been completed.
Aug 29, 02:40 UTC
Verifying - Verification is currently underway for the maintenance items.
Aug 29, 02:14 UTC
In progress - Scheduled maintenance is currently in progress. We will provide updates as necessary.
Aug 29, 01:25 UTC
Scheduled - We are currently applying updates to systems used to store Connector Authentication.
Aug 29, 01:23 UTC
Aug 28, 2025
MCP tool calls failing on desktop
Resolved - This incident has been resolved.
Aug 28, 19:38 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Aug 28, 19:31 UTC
Identified - The issue has been identified and a fix is being implemented.
Aug 28, 19:03 UTC
Investigating - We are currently investigating this issue.
Aug 28, 18:47 UTC
Conversations stalling after Claude.ai messages
Resolved - This incident has been resolved.
Aug 28, 17:03 UTC
Monitoring - A fix has been implemented and we are monitoring the results.
Aug 28, 17:00 UTC
Identified - The issue has been identified and a fix is being implemented.
Aug 28, 16:47 UTC
Investigating - We are currently investigating this issue.
Aug 28, 16:20 UTC
Elevated errors on Claude Opus 4.1
Resolved - As of 7:20 PT / 14:20 UTC we have mitigated the incident.
Aug 28, 15:03 UTC
Investigating - We have seen errors return to the baseline level since 5:05 PT / 13:05 UTC.
Aug 28, 12:29 UTC
Elevated errors on Claude Opus 4.1
Resolved - As of 0:50 PT / 7:50 UTC we have mitigated the incident.
Aug 28, 11:20 UTC
Investigating - We are investigating an issue with Claude Opus 4.1 that started at 23:10 PT / 6:10 UTC.
Aug 28, 06:30 UTC
Aug 27, 2025
Elevated errors on Claude Opus 4.1
Resolved - As of 6:40 PT / 13:40 UTC we have mitigated the incident.
Aug 27, 13:46 UTC
Investigating - We are investigating an issue, with Claude Opus 4.1 similar to the one that happened earlier, this time starting with 4:14 PT / 11:14 UTC.
Aug 27, 11:29 UTC
Elevated errors on Claude Opus 4.1
Resolved - As of 00:46 PT / 7:46 UTC the errors are back to baseline.
Aug 27, 08:11 UTC
Investigating - We are investigating an issue with Claude Opus 4.1 that started at 23:08 PT / 6:08 UTC.
Aug 27, 06:23 UTC
Aug 26, 2025
Elevated errors on Claude Opus 4.0
Resolved - We have seen errors return to the baseline level since 7:45 PT / 14:45 UTC.
Aug 26, 15:03 UTC
Update - We are continuing to investigate this issue.
Aug 26, 13:53 UTC
Investigating - We are currently investigating this issue.
Aug 26, 13:52 UTC
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