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The Errors view aggregates failures from all your agent traces into a structured error log. Instead of hunting through individual traces, you see errors grouped by type and agent so you can triage at scale.

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Error types

Zespan classifies errors into four categories:
TypeDescription
Model errorThe LLM returned an error response (e.g. content policy violation, invalid request)
Tool errorA tool call threw an exception or returned an error status
TimeoutA span exceeded its deadline — either an LLM call or a tool invocation
Rate limitA 429 response from a model provider

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Error list

The error list shows all errors in the selected time range, with:
  • Error message (truncated to 200 characters)
  • Error type
  • Agent that produced the error
  • Model (for model errors)
  • Tool name (for tool errors)
  • Timestamp and count (how many times this exact error occurred)
Errors with identical messages and sources are grouped automatically. A group showing 47 occurrences means the same error happened 47 times — not 47 unique bugs.

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Filtering

Filter by error type, agent, model, environment, or date range. The Only new toggle shows only errors that first appeared in the selected period — useful for spotting regressions after a deployment.

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Opening the source trace

Click any error row to open the trace that produced it. The flame graph highlights the failed span so you can see the full context — what the agent was doing when the error occurred, what inputs led to it, and what happened immediately before.

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Error rate metrics

The error rate chart at the top of the page shows errors per hour over the selected period. A flat baseline with sudden spikes indicates an external event (provider outage, a bad deployment). A gradually increasing baseline indicates a growing problem.

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Next steps

  • Incidents — AI-detected anomalies, including error surges
  • Alerts — set up notifications when error rates exceed a threshold
  • Traces — investigate individual failed runs