> ## Documentation Index > Fetch the complete documentation index at: https://praison.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # Trace Context • Rust AI Agent SDK > TraceContext: Context for a trace. # TraceContext > Defined in the [**trace**](../modules/trace) module. Rust AI Agent SDK Context for a trace. ## Fields | Name | Type | Description | | ------------ | ------------------- | ------------------ | | `id` | `String` | Trace ID | | `name` | `String` | Trace name | | `start_time` | `Instant` | Start time | | `spans` | `Vec<Span>` | All spans | | `span_stack` | `Vec<String>` | Current span stack | | `attributes` | `HashMap<String` | Attributes | | `serde_json` | `:Value>` | Attributes | ## Methods ### `new` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn new(name: impl Into) -> Self ``` Create a new trace context. **Parameters:** | Name | Type | | ------ | ------------------------- | | `name` | `impl Into<String>` | ### `elapsed` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn elapsed(&self) -> Duration ``` Get elapsed time since trace start. ### `start_span` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn start_span(&mut self, name: impl Into, kind: SpanKind) -> String ``` Start a new span. **Parameters:** | Name | Type | | ------ | ------------------------- | | `name` | `impl Into<String>` | | `kind` | `SpanKind` | ### `end_span` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn end_span(&mut self, span_id: &str) -> () ``` End a span. **Parameters:** | Name | Type | | --------- | ------ | | `span_id` | `&str` | ### `current_span_id` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn current_span_id(&self) -> Option<&str> ``` Get current span ID. ### `get_span` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn get_span(&self, span_id: &str) -> Option<&Span> ``` Get a span by ID. **Parameters:** | Name | Type | | --------- | ------ | | `span_id` | `&str` | ### `get_span_mut` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn get_span_mut(&mut self, span_id: &str) -> Option<&mut Span> ``` Get mutable span by ID. **Parameters:** | Name | Type | | --------- | ------ | | `span_id` | `&str` | ### `add_event` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn add_event(&mut self, name: impl Into) -> () ``` Add event to current span. **Parameters:** | Name | Type | | ------ | ------------------------- | | `name` | `impl Into<String>` | ### `set_attribute` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn set_attribute(&mut self, key: impl Into, value: impl Serialize) -> () ``` Set attribute on current span. **Parameters:** | Name | Type | | ------- | ------------------------- | | `key` | `impl Into<String>` | | `value` | `impl Serialize` | ### `spans` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn spans(&self) -> &[Span] ``` Get all spans. ### `span_count` ```rust theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} fn span_count(&self) -> usize ``` Get span count. ## Source `praisonai/src/trace/mod.rs` at line 207 *** ## Related Documentation