feat: emit boot-scoped session id in lane events

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

rust/crates/runtime/src/lane_events.rs

@@ -244,6 +244,7 @@ pub struct LaneEventBuilder {
     event: LaneEventName,
     status: LaneEventStatus,
     emitted_at: String,
+    session_id: Option<String>,
     metadata: LaneEventMetadata,
     detail: Option<String>,
     failure_class: Option<LaneFailureClass>,
@@ -264,6 +265,7 @@ impl LaneEventBuilder {
             event,
             status,
             emitted_at: emitted_at.into(),
+            session_id: None,
             metadata: LaneEventMetadata::new(seq, provenance),
             detail: None,
             failure_class: None,
@@ -278,6 +280,13 @@ impl LaneEventBuilder {
         self
     }
 
+    /// Add boot-scoped session correlation id
+    #[must_use]
+    pub fn with_session_id(mut self, session_id: impl Into<String>) -> Self {
+        self.session_id = Some(session_id.into());
+        self
+    }
+
     /// Add ownership info
     #[must_use]
     pub fn with_ownership(mut self, ownership: LaneOwnership) -> Self {
@@ -328,6 +337,7 @@ impl LaneEventBuilder {
             event: self.event,
             status: self.status,
             emitted_at: self.emitted_at,
+            session_id: self.session_id,
             failure_class: self.failure_class,
             detail: self.detail,
             data: self.data,
@@ -405,7 +415,10 @@ pub enum BlockedSubphase {
     #[serde(rename = "blocked.branch_freshness")]
     BranchFreshness { behind_main: u32 },
     #[serde(rename = "blocked.test_hang")]
-    TestHang { elapsed_secs: u32, test_name: Option<String> },
+    TestHang {
+        elapsed_secs: u32,
+        test_name: Option<String>,
+    },
     #[serde(rename = "blocked.report_pending")]
     ReportPending { since_secs: u32 },
 }
@@ -462,6 +475,8 @@ pub struct LaneEvent {
     pub status: LaneEventStatus,
     #[serde(rename = "emittedAt")]
     pub emitted_at: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub session_id: Option<String>,
     #[serde(rename = "failureClass", skip_serializing_if = "Option::is_none")]
     pub failure_class: Option<LaneFailureClass>,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -485,6 +500,7 @@ impl LaneEvent {
             event,
             status,
             emitted_at: emitted_at.into(),
+            session_id: None,
             failure_class: None,
             detail: None,
             data: None,
@@ -543,7 +559,8 @@ impl LaneEvent {
             .with_failure_class(blocker.failure_class)
             .with_detail(blocker.detail.clone());
         if let Some(ref subphase) = blocker.subphase {
-            event = event.with_data(serde_json::to_value(subphase).expect("subphase should serialize"));
+            event =
+                event.with_data(serde_json::to_value(subphase).expect("subphase should serialize"));
         }
         event
     }
@@ -554,7 +571,8 @@ impl LaneEvent {
             .with_failure_class(blocker.failure_class)
             .with_detail(blocker.detail.clone());
         if let Some(ref subphase) = blocker.subphase {
-            event = event.with_data(serde_json::to_value(subphase).expect("subphase should serialize"));
+            event =
+                event.with_data(serde_json::to_value(subphase).expect("subphase should serialize"));
         }
         event
     }
@@ -562,8 +580,12 @@ impl LaneEvent {
     /// Ship prepared — §4.44.5
     #[must_use]
     pub fn ship_prepared(emitted_at: impl Into<String>, provenance: &ShipProvenance) -> Self {
-        Self::new(LaneEventName::ShipPrepared, LaneEventStatus::Ready, emitted_at)
-            .with_data(serde_json::to_value(provenance).expect("ship provenance should serialize"))
+        Self::new(
+            LaneEventName::ShipPrepared,
+            LaneEventStatus::Ready,
+            emitted_at,
+        )
+        .with_data(serde_json::to_value(provenance).expect("ship provenance should serialize"))
     }
 
     /// Ship commits selected — §4.44.5
@@ -573,22 +595,34 @@ impl LaneEvent {
         commit_count: u32,
         commit_range: impl Into<String>,
     ) -> Self {
-        Self::new(LaneEventName::ShipCommitsSelected, LaneEventStatus::Ready, emitted_at)
-            .with_detail(format!("{} commits: {}", commit_count, commit_range.into()))
+        Self::new(
+            LaneEventName::ShipCommitsSelected,
+            LaneEventStatus::Ready,
+            emitted_at,
+        )
+        .with_detail(format!("{} commits: {}", commit_count, commit_range.into()))
     }
 
     /// Ship merged — §4.44.5
     #[must_use]
     pub fn ship_merged(emitted_at: impl Into<String>, provenance: &ShipProvenance) -> Self {
-        Self::new(LaneEventName::ShipMerged, LaneEventStatus::Completed, emitted_at)
-            .with_data(serde_json::to_value(provenance).expect("ship provenance should serialize"))
+        Self::new(
+            LaneEventName::ShipMerged,
+            LaneEventStatus::Completed,
+            emitted_at,
+        )
+        .with_data(serde_json::to_value(provenance).expect("ship provenance should serialize"))
     }
 
     /// Ship pushed to main — §4.44.5
     #[must_use]
     pub fn ship_pushed_main(emitted_at: impl Into<String>, provenance: &ShipProvenance) -> Self {
-        Self::new(LaneEventName::ShipPushedMain, LaneEventStatus::Completed, emitted_at)
-            .with_data(serde_json::to_value(provenance).expect("ship provenance should serialize"))
+        Self::new(
+            LaneEventName::ShipPushedMain,
+            LaneEventStatus::Completed,
+            emitted_at,
+        )
+        .with_data(serde_json::to_value(provenance).expect("ship provenance should serialize"))
     }
 
     #[must_use]
@@ -614,6 +648,12 @@ impl LaneEvent {
         self.data = Some(data);
         self
     }
+
+    #[must_use]
+    pub fn with_session_id(mut self, session_id: impl Into<String>) -> Self {
+        self.session_id = Some(session_id.into());
+        self
+    }
 }
 
 #[must_use]
@@ -1044,6 +1084,7 @@ mod tests {
             42,
             EventProvenance::Test,
         )
+        .with_session_id("boot-abc123def4567890")
         .with_session_identity(SessionIdentity::new("test-lane", "/tmp", "test"))
         .with_ownership(LaneOwnership {
             owner: "bot-1".to_string(),
@@ -1055,6 +1096,7 @@ mod tests {
         .build();
 
         assert_eq!(event.event, LaneEventName::Started);
+        assert_eq!(event.session_id.as_deref(), Some("boot-abc123def4567890"));
         assert_eq!(event.metadata.seq, 42);
         assert_eq!(event.metadata.provenance, EventProvenance::Test);
         assert_eq!(
@@ -1084,4 +1126,34 @@ mod tests {
         assert_eq!(round_trip.provenance, EventProvenance::Healthcheck);
         assert_eq!(round_trip.nudge_id, Some("nudge-abc".to_string()));
     }
+
+    #[test]
+    fn lane_event_session_id_round_trips_through_serialization() {
+        let event = LaneEventBuilder::new(
+            LaneEventName::Started,
+            LaneEventStatus::Running,
+            "2026-04-04T00:00:00Z",
+            1,
+            EventProvenance::LiveLane,
+        )
+        .with_session_id("boot-0123456789abcdef")
+        .build();
+
+        let json = serde_json::to_value(&event).expect("should serialize");
+        assert_eq!(json["session_id"], "boot-0123456789abcdef");
+
+        let round_trip: LaneEvent = serde_json::from_value(json).expect("should deserialize");
+        assert_eq!(
+            round_trip.session_id.as_deref(),
+            Some("boot-0123456789abcdef")
+        );
+    }
+
+    #[test]
+    fn lane_event_session_id_omits_field_when_absent() {
+        let event = LaneEvent::started("2026-04-04T00:00:00Z");
+        let json = serde_json::to_value(&event).expect("should serialize");
+
+        assert!(json.get("session_id").is_none());
+    }
 }

rust/crates/runtime/src/lib.rs

@@ -36,6 +36,7 @@ mod remote;
 pub mod sandbox;
 mod session;
 pub mod session_control;
+mod session_identity;
 pub use session_control::SessionStore;
 mod sse;
 pub mod stale_base;
@@ -153,6 +154,9 @@ pub use session::{
     ContentBlock, ConversationMessage, MessageRole, Session, SessionCompaction, SessionError,
     SessionFork, SessionPromptEntry,
 };
+pub use session_identity::{
+    begin_session, current_boot_session_id, end_session, is_active_session,
+};
 pub use sse::{IncrementalSseParser, SseEvent};
 pub use stale_base::{
     check_base_commit, format_stale_base_warning, read_claw_base_file, resolve_expected_base,

rust/crates/runtime/src/session_identity.rs

@@ -0,0 +1,84 @@
+use std::collections::hash_map::DefaultHasher;
+use std::env;
+use std::hash::{Hash, Hasher};
+use std::process;
+use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
+use std::sync::OnceLock;
+use std::time::{SystemTime, UNIX_EPOCH};
+
+static BOOT_SESSION_ID: OnceLock<String> = OnceLock::new();
+static BOOT_SESSION_COUNTER: AtomicU64 = AtomicU64::new(0);
+static ACTIVE_SESSION: AtomicBool = AtomicBool::new(false);
+
+#[must_use]
+pub fn current_boot_session_id() -> &'static str {
+    BOOT_SESSION_ID.get_or_init(resolve_boot_session_id)
+}
+
+pub fn begin_session() {
+    ACTIVE_SESSION.store(true, Ordering::SeqCst);
+}
+
+pub fn end_session() {
+    ACTIVE_SESSION.store(false, Ordering::SeqCst);
+}
+
+#[must_use]
+pub fn is_active_session() -> bool {
+    ACTIVE_SESSION.load(Ordering::SeqCst)
+}
+
+fn resolve_boot_session_id() -> String {
+    match env::var("CLAW_SESSION_ID") {
+        Ok(value) if !value.trim().is_empty() => value,
+        _ => generate_boot_session_id(),
+    }
+}
+
+fn generate_boot_session_id() -> String {
+    let nanos = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_nanos();
+    let counter = BOOT_SESSION_COUNTER.fetch_add(1, Ordering::Relaxed);
+    let mut hasher = DefaultHasher::new();
+    process::id().hash(&mut hasher);
+    nanos.hash(&mut hasher);
+    counter.hash(&mut hasher);
+    format!("boot-{:016x}", hasher.finish())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{begin_session, current_boot_session_id, end_session, is_active_session};
+
+    #[test]
+    fn given_current_boot_session_id_when_called_twice_then_it_is_stable() {
+        let first = current_boot_session_id();
+        let second = current_boot_session_id();
+
+        assert_eq!(first, second);
+        assert!(first.starts_with("boot-"));
+    }
+
+    #[test]
+    fn given_current_boot_session_id_when_inspected_then_it_is_opaque_and_non_empty() {
+        let session_id = current_boot_session_id();
+
+        assert!(!session_id.trim().is_empty());
+        assert_eq!(session_id.len(), 21);
+        assert!(!session_id.contains(' '));
+    }
+
+    #[test]
+    fn given_begin_and_end_session_when_checked_then_active_state_toggles() {
+        end_session();
+        assert!(!is_active_session());
+
+        begin_session();
+        assert!(is_active_session());
+
+        end_session();
+        assert!(!is_active_session());
+    }
+}

rust/crates/runtime/src/worker_boot.rs

@@ -18,6 +18,8 @@ use std::time::{SystemTime, UNIX_EPOCH};
 
 use serde::{Deserialize, Serialize};
 
+use crate::current_boot_session_id;
+
 fn now_secs() -> u64 {
     SystemTime::now()
         .duration_since(UNIX_EPOCH)
@@ -768,6 +770,7 @@ fn push_event(
 #[derive(serde::Serialize)]
 struct StateSnapshot<'a> {
     worker_id: &'a str,
+    session_id: &'a str,
     status: WorkerStatus,
     is_ready: bool,
     trust_gate_cleared: bool,
@@ -790,6 +793,7 @@ fn emit_state_file(worker: &Worker) {
     let now = now_secs();
     let snapshot = StateSnapshot {
         worker_id: &worker.worker_id,
+        session_id: current_boot_session_id(),
         status: worker.status,
         is_ready: worker.status == WorkerStatus::ReadyForPrompt,
         trust_gate_cleared: worker.trust_gate_cleared,
@@ -1449,6 +1453,10 @@ mod tests {
             Some("spawning"),
             "initial status should be spawning"
         );
+        assert_eq!(
+            value["session_id"].as_str(),
+            Some(current_boot_session_id())
+        );
         assert_eq!(value["is_ready"].as_bool(), Some(false));
 
         // Transition to ReadyForPrompt by observing trust-cleared text