LangChain incident
Agent tool calls failing on Anthropic Claude models
LangChain experienced a minor incident on August 5, 2026 affecting LangSmith Fleet, lasting —. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Aug 05, 2026, 03:27 PM UTC
Status: Investigating We're investigating an issue where agents and workflows using Anthropic Claude models with custom tools may fail to complete runs. Affected requests return a tool input validation error. We'll share more information as we have it. Affected components LangSmith Fleet (Degraded performance)
- identified Aug 05, 2026, 06:36 PM UTC
Status: Identified We're seeing elevated error rates when using Fleet with Claude models and certain MCP tools Affected components LangSmith Fleet (Degraded performance)
- monitoring Aug 05, 2026, 08:21 PM UTC
Status: Monitoring We're seeing elevated error rates when using Fleet with Claude models and certain MCP tools. Affected components LangSmith Fleet (Degraded performance)
- resolved Aug 05, 2026, 09:52 PM UTC
Status: Resolved Resolved. Fix is now deployed that skips an unsupported tool schema and logs a warning instead of failing the request. Affected components LangSmith Fleet (Operational)