# SessionMetadata
**Description**: Session metadata containing static information for monitoring sessions.
**Implementation**:
```rust
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SessionMetadata {
pub session_id: String,
pub signal_names: Vec<String>,
pub active_indices: Vec<usize>,
pub primary_signal_index: usize,
pub session_start: f64,
}
```
**Notes**:
- Static information written once per monitoring session
- Used by [[DiskWriter]] for data persistence context
- Contains signal mapping and session identification