> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fiddler.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# SpanAttributes

> Fiddler span attribute keys.

Fiddler span attribute keys.

Maps logical attribute names to their OpenTelemetry string keys
following the `gen_ai.*` semantic conventions.

## Values

| Constant                 | Value                          | Description                                                      |
| ------------------------ | ------------------------------ | ---------------------------------------------------------------- |
| `AGENT_ID`               | `"gen_ai.agent.id"`            | Unique agent identifier.                                         |
| `AGENT_NAME`             | `"gen_ai.agent.name"`          | Human-readable agent name.                                       |
| `CONVERSATION_ID`        | `"gen_ai.conversation.id"`     | Conversation or session identifier for multi-turn grouping.      |
| `GEN_AI_INPUT_MESSAGES`  | `"gen_ai.input.messages"`      | Full input message history as JSON.                              |
| `GEN_AI_OUTPUT_MESSAGES` | `"gen_ai.output.messages"`     | Full output messages as JSON.                                    |
| `LLM_CONTEXT`            | `"gen_ai.llm.context"`         | Retrieved context provided to the LLM (e.g. RAG context).        |
| `LLM_INPUT_SYSTEM`       | `"gen_ai.llm.input.system"`    | System prompt sent to the LLM.                                   |
| `LLM_INPUT_USER`         | `"gen_ai.llm.input.user"`      | User prompt or input sent to the LLM.                            |
| `LLM_OUTPUT`             | `"gen_ai.llm.output"`          | LLM completion/response text.                                    |
| `LLM_REQUEST_MODEL`      | `"gen_ai.request.model"`       | Requested model identifier (e.g. `"gpt-4o"`).                    |
| `LLM_SYSTEM`             | `"gen_ai.system"`              | LLM provider/system (e.g. `"openai"`, `"anthropic"`).            |
| `LLM_TOKEN_COUNT_INPUT`  | `"gen_ai.usage.input_tokens"`  | Number of input/prompt tokens.                                   |
| `LLM_TOKEN_COUNT_OUTPUT` | `"gen_ai.usage.output_tokens"` | Number of output/completion tokens.                              |
| `LLM_TOKEN_COUNT_TOTAL`  | `"gen_ai.usage.total_tokens"`  | Total token count.                                               |
| `SESSION_ID`             | `"session.id"`                 | Session identifier.                                              |
| `TOOL_DEFINITIONS`       | `"gen_ai.tool.definitions"`    | Tool/function definitions as JSON.                               |
| `TOOL_INPUT`             | `"gen_ai.tool.input"`          | Tool input payload.                                              |
| `TOOL_NAME`              | `"gen_ai.tool.name"`           | Tool/function name.                                              |
| `TOOL_OUTPUT`            | `"gen_ai.tool.output"`         | Tool output payload.                                             |
| `TYPE`                   | `"fiddler.span.type"`          | The Fiddler span type (`"llm"`, `"tool"`, `"chain"`, `"agent"`). |
| `USER_ID`                | `"user.id"`                    | User identifier.                                                 |