spans changedapi/opentelemetry/spans
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Lines−4removed
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135
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14 Oct 2026
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Recorded edits5to this page, all time
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from line 135
135135| `anthropic.message.stop_reason` | `string` | The response's [`stop_reason`](https://platform.claude.com/docs/en/api/messages#stop_reason), for example `end_turn`. |
136136| `anthropic.response.service_tier` | `string` | The service tier that served the request: the response's [`usage.service_tier`](https://platform.claude.com/docs/en/api/messages#usage). See [how requests get assigned tiers](https://platform.claude.com/docs/en/api/service-tiers#how-requests-get-assigned-tiers). |
137137| `error.type` | `string` | A failed request's [error type](https://platform.claude.com/docs/en/api/errors#http-errors), for example `rate_limit_error`.<br />**SDK:** Also the other values in [SDK spans for requests](https://platform.claude.com/docs/en/api/opentelemetry/spans#anthropic-resources-method).<br />**API:** `api_error` when the API ends the request without an error response. |
138| `gen_ai.response.time_to_first_chunk` | `double` | Only on a streaming response's SDK span. The seconds from when the SDK first sent the request to the stream's first `content_block_delta` event, if it has one. |
138| `gen_ai.response.time_to_first_chunk` | `double` | Only on a streaming response's spans. The seconds to the stream's first `content_block_delta` event, if it has one. |
139139| `gen_ai.usage.reasoning.output_tokens` | `int` | The response's thinking tokens. They are part of the output tokens. Absent when the response's usage doesn't have details for the output tokens. |
140140| `anthropic.usage.compaction.input_tokens` | `int` | Input tokens of the request's [compactions](https://platform.claude.com/docs/en/build-with-claude/compaction), including cache reads and writes. Not part of `gen_ai.usage.input_tokens`. Absent when the response has no compaction. |
141141| `anthropic.usage.compaction.output_tokens` | `int` | Output tokens of the request's compactions. Not part of `gen_ai.usage.output_tokens`. Absent when the response has no compaction. |
from line 209
209209 * The [`anthropic.sessions.events.send`](https://platform.claude.com/docs/en/api/opentelemetry/spans#anthropic-sessions-events-send) span for the request in which the event was sent, for a turn that started because of an event, for example a [`user.message`](https://platform.claude.com/docs/en/api/beta/sessions/events#beta_managed_agents_user_message_event) event.
210210 * The [`anthropic.sessions.update`](https://platform.claude.com/docs/en/api/opentelemetry/spans#anthropic-sessions-update) span, for a turn that resumes because the session budget was raised or removed through the request.
211211 * The `anthropic.session.turn` span for the turn of [the agent that the session runs](https://platform.claude.com/docs/en/managed-agents/multiagent-orchestration) during which that agent started this turn, for a turn on another thread.
212 * None, for a turn that starts because an agent on another thread replied or finished its turn, such as an agent that the primary agent called.
212 * The `anthropic.session.turn` span for the turn that produced the reply, for a turn that starts because an agent on another thread replied, such as an agent that the primary agent called.
213 * None, for any other turn, such as a turn that starts because a [workflow run](https://platform.claude.com/docs/en/managed-agents/workflow-runs) ended.
213214
214215* **Children:**
215216
216217 * An [`anthropic.model_request`](https://platform.claude.com/docs/en/api/opentelemetry/spans#anthropic-model-request) span for each model request in the turn.
217218 * A tool span each time the API runs a tool in the turn, except in the [cases listed in the tool span section](https://platform.claude.com/docs/en/api/opentelemetry/spans#anthropic-tool-use-anthropic-mcp-tool-use-and-anthropic-custom-tool-use).
218 * An `anthropic.session.turn` span for each turn that the agent that the session runs started on another thread during this turn.
219 * An `anthropic.session.turn` span for each turn on another thread that was started during this turn by the agent that the session runs, or by this turn's reply.
219220 * An [`anthropic.session.outcome_evaluation`](https://platform.claude.com/docs/en/api/opentelemetry/spans#anthropic-session-outcome-evaluation) span for each iteration of an outcome evaluation that this turn starts.
220221
221222A turn starts when its thread enters the `running` state and ends when the thread leaves it.
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304305| `gen_ai.tool.description` | `string` | Only on SDK spans. The description in the tool definition. Absent when the description is empty. |
305306| `gen_ai.tool.type` | `string` | Only on SDK spans. `function` |
306307| `gen_ai.tool.call.arguments` | `string` | <Badge>Content</Badge> A JSON string that follows the OpenTelemetry [`ToolCallArguments`](https://github.com/open-telemetry/semantic-conventions-genai/blob/e57c543b4889619eb2a05702471937db5119165d/model/gen-ai/gen-ai-tool-call-arguments.json) schema. The tool use's [`input`](https://platform.claude.com/docs/en/api/messages#tool_use_block). |
307| `anthropic.tool_result.content` | `string` | <Badge>Content</Badge> A JSON string with an array of content blocks or with one object. The `content` of the tool result that goes back to the model. Also for an error result, except on Managed Agents when the connection to the MCP server failed.<br />**API:** On the Messages API, a string `content` becomes an array with one [`text`](https://platform.claude.com/docs/en/api/messages#text_block) block. |
308| `anthropic.tool_result.content` | `string` | <Badge>Content</Badge> A JSON string with an array of content blocks. The `content` of the tool result that goes back to the model. Also for an error result, except on Managed Agents when the connection to the MCP server failed. A string `content` becomes an array with one [`text`](https://platform.claude.com/docs/en/api/messages#text_block) block.<br />**API:** On the Messages API, when a server tool's result `content` is one object, such as a `code_execution_result`, it becomes an array with that object. |
308309
309310### `anthropic.compaction`
310311
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