Add Claude context usage hint via hooks in status bar

src/app.rs

@@ -62,6 +62,31 @@ fn should_process_key_event(key: &KeyEvent) -> bool {
     matches!(key.kind, KeyEventKind::Press | KeyEventKind::Repeat)
 }
 
+fn parse_context_percent_from_message(message: &str) -> Option<u8> {
+    let lowered = message.to_ascii_lowercase();
+    if !lowered.contains("context") {
+        return None;
+    }
+
+    let bytes = message.as_bytes();
+    let mut idx = 0usize;
+    while idx < bytes.len() {
+        if bytes[idx].is_ascii_digit() {
+            let start = idx;
+            while idx < bytes.len() && bytes[idx].is_ascii_digit() {
+                idx += 1;
+            }
+            if idx < bytes.len() && bytes[idx] == b'%' {
+                let value = message[start..idx].parse::<u16>().ok()?;
+                return Some(value.min(100) as u8);
+            }
+            continue;
+        }
+        idx += 1;
+    }
+    None
+}
+
 fn should_ignore_delete_shortcut(suppress_delete_until: &mut Option<Instant>) -> bool {
     let Some(until) = *suppress_delete_until else {
         return false;
@@ -363,11 +388,22 @@ impl App {
                 self.persist_session_stop(&worktree, session_id.as_deref());
             }
             HookEvent::SessionNotification {
-                worktree, message, ..
+                worktree,
+                message,
+                context_usage_percent,
+                ..
             } => {
+                let context_percent = context_usage_percent.or_else(|| {
+                    message
+                        .as_deref()
+                        .and_then(parse_context_percent_from_message)
+                });
                 // Update the worktree status to Waiting
                 if let Some(wt) = self.worktrees.iter_mut().find(|wt| wt.name == worktree) {
                     wt.status = WorktreeStatus::Waiting;
+                    if let Some(pct) = context_percent {
+                        wt.context_usage_percent = Some(pct);
+                    }
                 }
                 let msg = message.unwrap_or_default();
                 self.status_message = if msg.is_empty() {
@@ -566,6 +602,8 @@ impl App {
             &self.status_message,
             self.worktrees.len(),
             &self.remote_statuses,
+            self.selected_worktree()
+                .and_then(|wt| wt.context_usage_percent),
         );
 
         // Render active dialog on top
@@ -2822,7 +2860,14 @@ impl ForestApp {
             .and_then(|idx| self.repos.get(idx))
             .map(|r| r.worktrees.len())
             .unwrap_or(0);
-        ui::status_bar::render(frame, status_area, &self.status_message, repo_wt_count);
+        let selected_ctx = selected_wt.and_then(|wt| wt.context_usage_percent);
+        ui::status_bar::render(
+            frame,
+            status_area,
+            &self.status_message,
+            repo_wt_count,
+            selected_ctx,
+        );
 
         // Render active dialog on top
         match &self.dialog {

src/hooks/event.rs

@@ -38,6 +38,9 @@ pub enum HookEvent {
         timestamp: Option<DateTime<Utc>>,
         #[serde(default)]
         message: Option<String>,
+        /// Optional context usage percentage reported by hook payloads.
+        #[serde(default)]
+        context_usage_percent: Option<u8>,
     },
     /// A subagent stopped within a Claude Code session.
     SubagentStopped {
@@ -72,6 +75,47 @@ impl HookEvent {
     pub fn from_json(json: &str) -> Result<Self, serde_json::Error> {
         serde_json::from_str(json)
     }
+
+    /// Best-effort context usage percentage (0-100) for notification events.
+    pub fn context_usage_percent(&self) -> Option<u8> {
+        match self {
+            HookEvent::SessionNotification {
+                context_usage_percent,
+                message,
+                ..
+            } => (*context_usage_percent).or_else(|| {
+                message
+                    .as_deref()
+                    .and_then(parse_context_percent_from_message)
+            }),
+            _ => None,
+        }
+    }
+}
+
+fn parse_context_percent_from_message(message: &str) -> Option<u8> {
+    let lowered = message.to_ascii_lowercase();
+    if !lowered.contains("context") {
+        return None;
+    }
+
+    let bytes = message.as_bytes();
+    let mut idx = 0usize;
+    while idx < bytes.len() {
+        if bytes[idx].is_ascii_digit() {
+            let start = idx;
+            while idx < bytes.len() && bytes[idx].is_ascii_digit() {
+                idx += 1;
+            }
+            if idx < bytes.len() && bytes[idx] == b'%' {
+                let value = message[start..idx].parse::<u16>().ok()?;
+                return Some(value.min(100) as u8);
+            }
+            continue;
+        }
+        idx += 1;
+    }
+    None
 }
 
 #[cfg(test)]
@@ -129,4 +173,27 @@ mod tests {
             panic!("expected SessionNotification");
         }
     }
+
+    #[test]
+    fn notification_context_percent_parses_from_message() {
+        let json = r#"{
+            "event": "session_notification",
+            "worktree": "feature-auth",
+            "message": "Context window at 87% used"
+        }"#;
+        let event = HookEvent::from_json(json).unwrap();
+        assert_eq!(event.context_usage_percent(), Some(87));
+    }
+
+    #[test]
+    fn notification_context_percent_uses_explicit_field() {
+        let json = r#"{
+            "event": "session_notification",
+            "worktree": "feature-auth",
+            "message": "Waiting for input",
+            "context_usage_percent": 42
+        }"#;
+        let event = HookEvent::from_json(json).unwrap();
+        assert_eq!(event.context_usage_percent(), Some(42));
+    }
 }

src/hooks/install.rs

@@ -125,10 +125,29 @@ fi
 
 # Extract optional fields
 SESSION_ID=$(echo "$PAYLOAD" | grep -o '"session_id"[[:space:]]*:[[:space:]]*"[^"]*"' | head -1 | sed 's/.*"session_id"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/')
+MESSAGE=$(echo "$PAYLOAD" | grep -o '"message"[[:space:]]*:[[:space:]]*"[^"]*"' | head -1 | sed 's/.*"message"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/')
+MESSAGE_ESCAPED=$(printf '%s' "$MESSAGE" | sed 's/\\/\\\\/g; s/"/\\"/g')
+CONTEXT_PERCENT=$(echo "$PAYLOAD" | grep -o '"context_usage_percent"[[:space:]]*:[[:space:]]*[0-9]\{{1,3\}}' | head -1 | sed 's/.*:[[:space:]]*//')
+
+# Fallback: parse context percent from message text when present (e.g. "Context window at 82% used")
+if [ -z "$CONTEXT_PERCENT" ] && [ -n "$MESSAGE" ]; then
+    case "$(echo "$MESSAGE" | tr '[:upper:]' '[:lower:]')" in
+        *context*)
+            CONTEXT_PERCENT=$(echo "$MESSAGE" | grep -o '[0-9]\{{1,3\}}%' | head -1 | tr -d '%')
+            ;;
+    esac
+fi
 TIMESTAMP=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
 
 # Build the cwt event JSON
-EVENT='{{"event":"{cwt_event}","worktree":"'"$WORKTREE"'","session_id":"'"$SESSION_ID"'","timestamp":"'"$TIMESTAMP"'"}}'
+EVENT='{{"event":"{cwt_event}","worktree":"'"$WORKTREE"'","session_id":"'"$SESSION_ID"'","timestamp":"'"$TIMESTAMP"'"'
+if [ -n "$MESSAGE_ESCAPED" ]; then
+    EVENT="$EVENT,\"message\":\"$MESSAGE_ESCAPED\""
+fi
+if [ -n "$CONTEXT_PERCENT" ]; then
+    EVENT="$EVENT,\"context_usage_percent\":$CONTEXT_PERCENT"
+fi
+EVENT="$EVENT}}"
 
 # Write to socket (best-effort, non-blocking)
 printf '%s\n' "$EVENT" | nc -U -w1 "$SOCKET" 2>/dev/null || true

src/ui/status_bar.rs

@@ -8,8 +8,14 @@ const SHORTCUTS: &str =
     " {count} worktree(s) | n:new Ent:session h:handoff P:pr S:ship e:shell p:perm d:del g:gc r:restore t:tasks b:bcast m:mode o:provider ?:help q:quit";
 
 /// Render the status bar at the bottom.
-pub fn render(f: &mut Frame, area: Rect, message: &str, worktree_count: usize) {
-    render_with_remotes(f, area, message, worktree_count, &[]);
+pub fn render(
+    f: &mut Frame,
+    area: Rect,
+    message: &str,
+    worktree_count: usize,
+    context_usage_percent: Option<u8>,
+) {
+    render_with_remotes(f, area, message, worktree_count, &[], context_usage_percent);
 }
 
 /// Render the status bar with optional remote host status indicators.
@@ -19,6 +25,7 @@ pub fn render_with_remotes(
     message: &str,
     worktree_count: usize,
     remote_statuses: &[crate::remote::host::RemoteHostStatus],
+    context_usage_percent: Option<u8>,
 ) {
     let mut spans = vec![
         Span::styled(
@@ -57,6 +64,13 @@ pub fn render_with_remotes(
         spans.push(Span::raw(" | "));
         spans.push(Span::raw(message));
     }
+    if let Some(pct) = context_usage_percent {
+        spans.push(Span::raw(" | "));
+        spans.push(Span::styled(
+            format!("Claude ctx:{}% (/context via hooks)", pct),
+            Style::default().fg(Color::Yellow),
+        ));
+    }
 
     let line = Line::from(spans);
 
@@ -75,7 +89,7 @@ mod tests {
         let mut terminal = Terminal::new(backend).expect("test terminal");
 
         terminal
-            .draw(|frame| render(frame, frame.area(), message, 3))
+            .draw(|frame| render(frame, frame.area(), message, 3, None))
             .expect("render status bar");
 
         let buffer = terminal.backend().buffer();
@@ -94,4 +108,19 @@ mod tests {
         assert!(line.contains("P:pr"));
         assert!(line.contains("Sync in progress"));
     }
+
+    #[test]
+    fn shows_claude_context_usage_hint_when_available() {
+        let backend = TestBackend::new(240, 1);
+        let mut terminal = Terminal::new(backend).expect("test terminal");
+        terminal
+            .draw(|frame| render(frame, frame.area(), "", 3, Some(82)))
+            .expect("render status bar");
+        let buffer = terminal.backend().buffer();
+        let mut line = String::new();
+        for x in 0..buffer.area.width {
+            line.push_str(buffer[(x, 0)].symbol());
+        }
+        assert!(line.contains("Claude ctx:82%"));
+    }
 }

src/worktree/model.rs

@@ -43,6 +43,9 @@ pub struct Worktree {
     pub tmux_pane: Option<String>,
     #[serde(default)]
     pub status: WorktreeStatus,
+    /// Latest Claude context usage percentage (0-100), when available from hooks.
+    #[serde(default)]
+    pub context_usage_percent: Option<u8>,
     /// PR number on GitHub (if a PR has been created).
     #[serde(default)]
     pub pr_number: Option<u64>,
@@ -100,6 +103,7 @@ impl Worktree {
             last_session_id: None,
             tmux_pane: None,
             status: WorktreeStatus::Idle,
+            context_usage_percent: None,
             pr_number: None,
             pr_url: None,
             pr_status: PrStatus::None,