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HomeDocsClaude Code CLI 23 Oct 2026
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Observability with OpenTelemetry changedagent-sdk/observability

Nearest release: v2.1.309, published 6 hours before upstream edited the page. Shown because the two are within 24 hours of each other. Nothing here says the release caused the edit.

Upstream edited this page at 23 Oct 2026 02:37 UTC, give or take a minute or two: the time comes from Anthropic’s own sitemap rather than from a commit. This site recorded the change at 23 Oct 2026 03:07 UTC.

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223With end-user identity attached, the `tool_decision`, `tool_result`, `mcp_server_connection`, and `permission_mode_changed` events, which export as log records named with a `claude_code.` prefix, become a per-user audit trail you can forward to a Security Information and Event Management (SIEM) platform. See [Audit security events](/docs/en/monitoring-usage.md#audit-security-events) in the Monitoring reference for the full list of security-relevant events and the attributes each one carries.
223After you attach end-user identity, these events become a per-user audit trail you can forward to a Security Information and Event Management (SIEM) platform:
224224 
225* `tool_decision` and `tool_result`: each tool call, whether it was allowed or denied, and its result
226* `safety_event`: which check refused a tool call or required a permission prompt for it, such as a permission rule or the auto mode classifier. Some calls [have no safety event](/docs/en/monitoring-usage.md#calls-without-a-safety-event). Requires Claude Code v2.1.307 or later
227* `mcp_server_connection`: MCP server connections and connection failures
228* `permission_mode_changed`: permission mode changes
229 
230These events export as log records named with a `claude_code.` prefix, such as `claude_code.safety_event`. See [Audit security events](/docs/en/monitoring-usage.md#audit-security-events) in the Monitoring reference for the full list of security-relevant events and the attributes each one carries.
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225232## Control sensitive data in exports
226233 
227234Telemetry is structural by default. Durations, model names, and tool names are recorded on every span; token counts are recorded when the underlying API request returns usage data, so spans for failed or aborted requests may omit them. The content your agent reads and writes is not recorded by default. These opt-in variables add content to the exported data:
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229236| Variable | Adds |
230237| - | - |
231238| `OTEL_LOG_USER_PROMPTS=1` | Prompt text on `claude_code.user_prompt` events and on the `claude_code.interaction` span |
232| `OTEL_LOG_TOOL_DETAILS=1` | Tool input arguments such as file paths, shell commands, and search patterns on `claude_code.tool_result` events, and real agent, skill, plugin, and MCP server names on the [cost and token metrics](/docs/en/monitoring-usage.md#cost-counter) |
239| `OTEL_LOG_TOOL_DETAILS=1` | Tool input arguments such as file paths, shell commands, and search patterns on `claude_code.tool_result` events, and real agent, skill, plugin, and MCP server names on the [cost and token metrics](/docs/en/monitoring-usage.md#cost-counter). The built-in rule the auto mode classifier named when it blocked a call, as [`classifier_category`](/docs/en/monitoring-usage#tool-decision-event) on `claude_code.tool_decision` and `claude_code.safety_event` events |
233240| `OTEL_LOG_TOOL_CONTENT=1` | A [`tool.output` span event](/docs/en/monitoring-usage#tool-output-span-event) on `claude_code.tool` with file contents, Bash output, and what MCP tools, WebFetch, and WebSearch return, truncated at 60 KB by default, configurable via `CLAUDE_CODE_OTEL_CONTENT_MAX_LENGTH`, which requires Claude Code v2.1.214 or later. Results from MCP tools, WebFetch, and WebSearch require Claude Code v2.1.283 or later. Requires [tracing](#read-agent-traces) to be enabled. Span attributes carry tool content under [their own gates](/docs/en/monitoring-usage.md#new-context-gates) |
234241| `OTEL_LOG_RAW_API_BODIES` | Full Anthropic Messages API request and response JSON as `claude_code.api_request_body` and `claude_code.api_response_body` log events. Set to `1` for inline bodies truncated at 60 KB by default, or `file:<dir>` for untruncated bodies on disk with a `body_ref` path in the event. `CLAUDE_CODE_OTEL_CONTENT_MAX_LENGTH` configures the inline truncation limit, and requires Claude Code v2.1.214 or later. Bodies include the entire conversation history and have extended-thinking content redacted. Enabling this implies consent to everything the three variables above would reveal |
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