# What does Claude Code's OpenTelemetry output contain?

Three separate signals, each with its own enable switch. Metrics are counters for tokens, cost, sessions, and lines of code. Log events are structured records for each prompt, API request, API error, and tool result. Traces, still in beta, are spans for each interaction, model request, tool call, and hook, nested so a subagent's spans sit under the parent tool call that spawned it.

The trace spans are named `claude_code.interaction`, `claude_code.llm_request`, `claude_code.tool`, and `claude_code.hook`, Claude Code's own names, not the OpenTelemetry GenAI convention's `gen_ai.*` operation names. A backend built to read `gen_ai.operation.name` or `gen_ai.provider.name` won't recognize any of them without a mapping step first. Metrics and log events are the settled part of this output; traces can still change span names and attributes between releases. Content itself, prompt text and tool arguments, stays out of all three signals unless you opt in variable by variable, the same [content-leaves-the-agent decision](/answers/instrumentation/who-decides-what-content-leaves-an-agents-traces) every instrumentation layer has to make.

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Sources:
- Claude Docs: Observability with OpenTelemetry: https://code.claude.com/docs/en/agent-sdk/observability (fetched 2026-09-15)

Source: https://tessary.ai/answers/claude-agent-sdk-evals/what-does-claude-codes-opentelemetry-output-contain
More on Claude agent sdk evals: https://tessary.ai/answers/claude-agent-sdk-evals
From Tessary, agent reliability for AI agents in production: https://tessary.ai