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Claude Code has built-in OpenTelemetry. It emits log-events (not spans): api_request, tool_result, user_prompt, api_error, and tool_decision. RunAgain accepts these at its OTLP logs endpoint (/v1/logs) and turns each event into a span, grouping every session.id into a single trace.
This captures Claude Code running in your terminal — every session becomes one trace with its prompts, tool calls, API requests, token usage and cost.

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1. Generate an API key

In your project: Overview → onboarding → Claude Code (CLI) → Generate API key (or Settings → Create API key). Copy the sk_… value.

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2. Enable telemetry

Add these to your shell profile, or to ~/.claude/settings.json under "env":
The endpoint decodes OTLP/JSON only, so OTEL_EXPORTER_OTLP_PROTOCOL=http/json is required. Use the logs-specific endpoint (/v1/logs) and header variables so metrics export (if you enable it elsewhere) isn’t affected.

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3. Run Claude Code

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What you’ll see

Each session becomes one trace on your Traces page:
  • claude_code.api_request → a generation span with provider anthropic, the model, input/output/cache tokens, and cost.
  • claude_code.tool_result / tool_decision → tool spans (failures are marked as errors).
  • claude_code.user_prompt → the prompt (when OTEL_LOG_USER_PROMPTS=1).
Cost comes from Claude Code’s own cost_usd, so it’s accurate regardless of RunAgain’s pricing table.