diff --git a/CLAUDE.md b/CLAUDE.md
index f4953d6..5de7524 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -52,6 +52,7 @@ All new features, fixes, and significant changes should include tests whenever p
 ### Mocking Strategies
 
 #### Console Mocking
+
 When testing code that intentionally logs errors (like error handling paths), mock console methods to prevent stderr output that makes tests appear flaky:
 
 ```typescript
@@ -70,6 +71,7 @@ it("handles errors gracefully", async () => {
 ```
 
 #### E2E Integration Testing for Cross-Platform Code
+
 For code that calls platform-specific system APIs (like Windows PowerShell or Linux notify-send), use helper functions that build the command structure without execution. This allows CI to verify cross-platform compatibility on Linux-only containers:
 
 ```rust
@@ -99,6 +101,7 @@ fn test_e2e_notify_send_command_structure() {
 ```
 
 This approach:
+
 - Verifies command structure, argument order, and escaping logic
 - Tests cross-platform code paths without requiring the target platform
 - Allows CI to catch regressions in Windows-specific code whilst running on Linux
diff --git a/src-tauri/src/wsl_bridge.rs b/src-tauri/src/wsl_bridge.rs
index 9294fff..1c18302 100644
--- a/src-tauri/src/wsl_bridge.rs
+++ b/src-tauri/src/wsl_bridge.rs
@@ -678,6 +678,34 @@ fn handle_stderr(
                     }
                 }
 
+                // Check if this is a SubagentStop hook message
+                if line.contains("[SubagentStop Hook]") {
+                    if let Some(stop_data) = parse_subagent_stop_hook(&line) {
+                        tracing::debug!("Parsed SubagentStop hook: tool_use_id={:?}",
+                            stop_data.parent_tool_use_id);
+
+                        // Emit agent-end event if we have a tool_use_id
+                        if let Some(tool_use_id) = stop_data.parent_tool_use_id {
+                            let now = std::time::SystemTime::now()
+                                .duration_since(std::time::UNIX_EPOCH)
+                                .unwrap_or_default()
+                                .as_millis() as u64;
+
+                            let _ = app.emit(
+                                "claude:agent-end",
+                                AgentEndEvent {
+                                    tool_use_id,
+                                    ended_at: now,
+                                    is_error: false,
+                                    conversation_id: conversation_id.clone(),
+                                    duration_ms: None,
+                                    num_turns: None,
+                                },
+                            );
+                        }
+                    }
+                }
+
                 // Still emit the stderr line as output
                 let _ = app.emit(
                     "claude:output",
@@ -732,6 +760,30 @@ fn parse_subagent_start_hook(line: &str) -> Option<SubagentStartData> {
     })
 }
 
+#[derive(Debug)]
+struct SubagentStopData {
+    parent_tool_use_id: Option<String>,
+}
+
+fn parse_subagent_stop_hook(line: &str) -> Option<SubagentStopData> {
+    // Parse: [SubagentStop Hook] ... parent_tool_use_id=Some("toolu_xxx"), ...
+
+    // Extract parent_tool_use_id if present
+    let parent_tool_use_id = if line.contains("parent_tool_use_id=Some") {
+        line.split("parent_tool_use_id=Some(\"")
+            .nth(1)?
+            .split('"')
+            .next()
+            .map(|s| s.to_string())
+    } else {
+        None
+    };
+
+    Some(SubagentStopData {
+        parent_tool_use_id,
+    })
+}
+
 fn process_json_line(
     line: &str,
     app: &AppHandle,
@@ -1823,4 +1875,98 @@ mod tests {
         let manager = shared.lock();
         assert!(manager.get_active_conversations().is_empty());
     }
+
+    // SubagentStart hook parsing tests
+    #[test]
+    fn test_parse_subagent_start_hook_with_parent() {
+        let line = r#"[SubagentStart Hook] agent_id=agent-abc123, parent_tool_use_id=Some("toolu_01XYZ789"), session_id=123"#;
+        let result = parse_subagent_start_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.agent_id, "agent-abc123");
+        assert_eq!(data.parent_tool_use_id, Some("toolu_01XYZ789".to_string()));
+    }
+
+    #[test]
+    fn test_parse_subagent_start_hook_without_parent() {
+        let line = r#"[SubagentStart Hook] agent_id=agent-xyz789, parent_tool_use_id=None, session_id=456"#;
+        let result = parse_subagent_start_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.agent_id, "agent-xyz789");
+        assert_eq!(data.parent_tool_use_id, None);
+    }
+
+    #[test]
+    fn test_parse_subagent_start_hook_invalid() {
+        let line = "[SubagentStart Hook] invalid data";
+        let result = parse_subagent_start_hook(line);
+
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn test_parse_subagent_start_hook_with_extra_fields() {
+        let line = r#"[SubagentStart Hook] agent_id=agent-test, parent_tool_use_id=Some("toolu_test"), session_id=789, cwd=/home/user"#;
+        let result = parse_subagent_start_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.agent_id, "agent-test");
+        assert_eq!(data.parent_tool_use_id, Some("toolu_test".to_string()));
+    }
+
+    // SubagentStop hook parsing tests
+    #[test]
+    fn test_parse_subagent_stop_hook_with_parent() {
+        let line = r#"[SubagentStop Hook] stop_hook_active=true, parent_tool_use_id=Some("toolu_01ABC123"), session_id=123"#;
+        let result = parse_subagent_stop_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.parent_tool_use_id, Some("toolu_01ABC123".to_string()));
+    }
+
+    #[test]
+    fn test_parse_subagent_stop_hook_without_parent() {
+        let line = r#"[SubagentStop Hook] stop_hook_active=true, parent_tool_use_id=None, session_id=456"#;
+        let result = parse_subagent_stop_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.parent_tool_use_id, None);
+    }
+
+    #[test]
+    fn test_parse_subagent_stop_hook_minimal() {
+        let line = r#"[SubagentStop Hook] parent_tool_use_id=Some("toolu_minimal")"#;
+        let result = parse_subagent_stop_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.parent_tool_use_id, Some("toolu_minimal".to_string()));
+    }
+
+    #[test]
+    fn test_parse_subagent_stop_hook_with_extra_fields() {
+        let line = r#"[SubagentStop Hook] stop_hook_active=false, parent_tool_use_id=Some("toolu_extra"), session_id=789, transcript_path=/path/to/transcript"#;
+        let result = parse_subagent_stop_hook(line);
+
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.parent_tool_use_id, Some("toolu_extra".to_string()));
+    }
+
+    #[test]
+    fn test_parse_subagent_stop_hook_empty() {
+        let line = "[SubagentStop Hook]";
+        let result = parse_subagent_stop_hook(line);
+
+        // Should still return Some with None parent_tool_use_id
+        assert!(result.is_some());
+        let data = result.unwrap();
+        assert_eq!(data.parent_tool_use_id, None);
+    }
 }
diff --git a/src/lib/components/AgentMonitorPanel.svelte b/src/lib/components/AgentMonitorPanel.svelte
index 9c3dde7..9fcd85b 100644
--- a/src/lib/components/AgentMonitorPanel.svelte
+++ b/src/lib/components/AgentMonitorPanel.svelte
@@ -118,6 +118,8 @@
 
     try {
       await invoke("interrupt_claude", { conversationId: currentConversationId });
+      // Mark all running agents as errored after killing the process
+      agentStore.markAllErrored(currentConversationId);
     } catch (error) {
       console.error("Failed to kill Claude process:", error);
     }
diff --git a/src/lib/stores/agents.test.ts b/src/lib/stores/agents.test.ts
new file mode 100644
index 0000000..c82d649
--- /dev/null
+++ b/src/lib/stores/agents.test.ts
@@ -0,0 +1,325 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import { agentStore, getAgentsForConversation, runningAgentCount } from "./agents";
+import { get } from "svelte/store";
+import type { AgentInfo } from "$lib/types/agents";
+
+describe("agents store", () => {
+  const conversationId = "test-conversation-1";
+  const otherConversationId = "test-conversation-2";
+
+  const createMockAgent = (overrides?: Partial<AgentInfo>): AgentInfo => ({
+    toolUseId: "toolu_test123",
+    description: "Test agent",
+    subagentType: "Explore",
+    startedAt: Date.now(),
+    status: "running",
+    ...overrides,
+  });
+
+  beforeEach(() => {
+    // Clear all conversations by subscribing and getting state
+    let state: Record<string, AgentInfo[]> = {};
+    const unsub = agentStore.subscribe((s) => {
+      state = s;
+    });
+    unsub();
+
+    // Clear each conversation
+    for (const convId of Object.keys(state)) {
+      agentStore.clearConversation(convId);
+    }
+  });
+
+  describe("addAgent", () => {
+    it("adds an agent to a conversation", () => {
+      const agent = createMockAgent();
+      agentStore.addAgent(conversationId, agent);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents).toHaveLength(1);
+      expect(agents[0]).toEqual(agent);
+    });
+
+    it("adds multiple agents to the same conversation", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1" });
+      const agent2 = createMockAgent({ toolUseId: "tool2" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents).toHaveLength(2);
+      expect(agents[0]).toEqual(agent1);
+      expect(agents[1]).toEqual(agent2);
+    });
+
+    it("keeps agents in different conversations separate", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1" });
+      const agent2 = createMockAgent({ toolUseId: "tool2" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(otherConversationId, agent2);
+
+      const agents1 = get(getAgentsForConversation(conversationId));
+      const agents2 = get(getAgentsForConversation(otherConversationId));
+
+      expect(agents1).toHaveLength(1);
+      expect(agents2).toHaveLength(1);
+      expect(agents1[0]).toEqual(agent1);
+      expect(agents2[0]).toEqual(agent2);
+    });
+  });
+
+  describe("updateAgentId", () => {
+    it("updates the agent_id for a specific agent", () => {
+      const agent = createMockAgent({ agentId: undefined });
+      agentStore.addAgent(conversationId, agent);
+
+      agentStore.updateAgentId(conversationId, agent.toolUseId, "agent-abc123");
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].agentId).toBe("agent-abc123");
+    });
+
+    it("does nothing if conversation doesn't exist", () => {
+      agentStore.updateAgentId("nonexistent", "tool1", "agent1");
+      // Should not throw
+      expect(true).toBe(true);
+    });
+
+    it("does nothing if tool_use_id doesn't exist", () => {
+      const agent = createMockAgent();
+      agentStore.addAgent(conversationId, agent);
+
+      agentStore.updateAgentId(conversationId, "nonexistent-tool", "agent1");
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].agentId).toBeUndefined();
+    });
+  });
+
+  describe("endAgent", () => {
+    it("marks an agent as completed", () => {
+      const agent = createMockAgent({ status: "running" });
+      agentStore.addAgent(conversationId, agent);
+
+      const endTime = Date.now();
+      agentStore.endAgent(conversationId, agent.toolUseId, endTime, false);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].status).toBe("completed");
+      expect(agents[0].endedAt).toBe(endTime);
+      expect(agents[0].durationMs).toBeGreaterThanOrEqual(0); // Duration can be 0 if timestamps are the same
+    });
+
+    it("marks an agent as errored", () => {
+      const agent = createMockAgent({ status: "running" });
+      agentStore.addAgent(conversationId, agent);
+
+      const endTime = Date.now();
+      agentStore.endAgent(conversationId, agent.toolUseId, endTime, true);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].status).toBe("errored");
+      expect(agents[0].endedAt).toBe(endTime);
+    });
+
+    it("calculates duration correctly", () => {
+      const startTime = Date.now() - 5000; // 5 seconds ago
+      const agent = createMockAgent({ startedAt: startTime, status: "running" });
+      agentStore.addAgent(conversationId, agent);
+
+      const endTime = Date.now();
+      agentStore.endAgent(conversationId, agent.toolUseId, endTime, false);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].durationMs).toBeGreaterThanOrEqual(5000);
+      expect(agents[0].durationMs).toBeLessThanOrEqual(6000); // Allow some buffer
+    });
+
+    it("does nothing if conversation doesn't exist", () => {
+      agentStore.endAgent("nonexistent", "tool1", Date.now(), false);
+      // Should not throw
+      expect(true).toBe(true);
+    });
+
+    it("does nothing if agent doesn't exist", () => {
+      const agent = createMockAgent();
+      agentStore.addAgent(conversationId, agent);
+
+      agentStore.endAgent(conversationId, "nonexistent-tool", Date.now(), false);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].status).toBe("running"); // Status unchanged
+    });
+  });
+
+  describe("markAllErrored", () => {
+    it("marks all running agents as errored", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1", status: "running" });
+      const agent2 = createMockAgent({ toolUseId: "tool2", status: "running" });
+      const agent3 = createMockAgent({ toolUseId: "tool3", status: "completed" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+      agentStore.addAgent(conversationId, agent3);
+
+      agentStore.markAllErrored(conversationId);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].status).toBe("errored");
+      expect(agents[0].endedAt).toBeGreaterThan(0);
+      expect(agents[1].status).toBe("errored");
+      expect(agents[1].endedAt).toBeGreaterThan(0);
+      expect(agents[2].status).toBe("completed"); // Already completed, unchanged
+    });
+
+    it("does nothing if conversation doesn't exist", () => {
+      agentStore.markAllErrored("nonexistent");
+      // Should not throw
+      expect(true).toBe(true);
+    });
+
+    it("does nothing if conversation has no running agents", () => {
+      const agent = createMockAgent({ status: "completed" });
+      agentStore.addAgent(conversationId, agent);
+
+      agentStore.markAllErrored(conversationId);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents[0].status).toBe("completed"); // Unchanged
+    });
+  });
+
+  describe("clearCompleted", () => {
+    it("removes completed and errored agents", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1", status: "running" });
+      const agent2 = createMockAgent({ toolUseId: "tool2", status: "completed" });
+      const agent3 = createMockAgent({ toolUseId: "tool3", status: "errored" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+      agentStore.addAgent(conversationId, agent3);
+
+      agentStore.clearCompleted(conversationId);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents).toHaveLength(1);
+      expect(agents[0].toolUseId).toBe("tool1"); // Only running agent remains
+    });
+
+    it("does nothing if conversation doesn't exist", () => {
+      agentStore.clearCompleted("nonexistent");
+      // Should not throw
+      expect(true).toBe(true);
+    });
+
+    it("clears all agents if all are completed", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1", status: "completed" });
+      const agent2 = createMockAgent({ toolUseId: "tool2", status: "errored" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+
+      agentStore.clearCompleted(conversationId);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents).toHaveLength(0);
+    });
+  });
+
+  describe("clearConversation", () => {
+    it("removes all agents from a conversation", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1" });
+      const agent2 = createMockAgent({ toolUseId: "tool2" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+
+      agentStore.clearConversation(conversationId);
+
+      const agents = get(getAgentsForConversation(conversationId));
+      expect(agents).toHaveLength(0);
+    });
+
+    it("only removes agents from the specified conversation", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1" });
+      const agent2 = createMockAgent({ toolUseId: "tool2" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(otherConversationId, agent2);
+
+      agentStore.clearConversation(conversationId);
+
+      const agents1 = get(getAgentsForConversation(conversationId));
+      const agents2 = get(getAgentsForConversation(otherConversationId));
+
+      expect(agents1).toHaveLength(0);
+      expect(agents2).toHaveLength(1);
+      expect(agents2[0]).toEqual(agent2);
+    });
+
+    it("does nothing if conversation doesn't exist", () => {
+      agentStore.clearConversation("nonexistent");
+      // Should not throw
+      expect(true).toBe(true);
+    });
+  });
+
+  describe("runningAgentCount", () => {
+    it("counts running agents across all conversations", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1", status: "running" });
+      const agent2 = createMockAgent({ toolUseId: "tool2", status: "running" });
+      const agent3 = createMockAgent({ toolUseId: "tool3", status: "completed" });
+      const agent4 = createMockAgent({ toolUseId: "tool4", status: "running" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+      agentStore.addAgent(conversationId, agent3);
+      agentStore.addAgent(otherConversationId, agent4);
+
+      const count = get(runningAgentCount);
+      expect(count).toBe(3); // 2 from first conversation + 1 from second
+    });
+
+    it("returns 0 when no agents are running", () => {
+      const agent1 = createMockAgent({ status: "completed" });
+      const agent2 = createMockAgent({ status: "errored" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(otherConversationId, agent2);
+
+      const count = get(runningAgentCount);
+      expect(count).toBe(0);
+    });
+
+    it("updates when agents complete", () => {
+      const agent = createMockAgent({ status: "running" });
+      agentStore.addAgent(conversationId, agent);
+
+      let count = get(runningAgentCount);
+      expect(count).toBe(1);
+
+      agentStore.endAgent(conversationId, agent.toolUseId, Date.now(), false);
+
+      count = get(runningAgentCount);
+      expect(count).toBe(0);
+    });
+
+    it("updates when conversation is cleared", () => {
+      const agent1 = createMockAgent({ toolUseId: "tool1", status: "running" });
+      const agent2 = createMockAgent({ toolUseId: "tool2", status: "running" });
+
+      agentStore.addAgent(conversationId, agent1);
+      agentStore.addAgent(conversationId, agent2);
+
+      let count = get(runningAgentCount);
+      expect(count).toBe(2);
+
+      agentStore.clearConversation(conversationId);
+
+      count = get(runningAgentCount);
+      expect(count).toBe(0);
+    });
+  });
+});
diff --git a/src/lib/stores/conversations.ts b/src/lib/stores/conversations.ts
index 8c55e5d..3b9be8f 100644
--- a/src/lib/stores/conversations.ts
+++ b/src/lib/stores/conversations.ts
@@ -10,6 +10,7 @@ import type { CharacterState } from "$lib/types/states";
 import { cleanupConversationTracking } from "$lib/tauri";
 import { characterState } from "$lib/stores/character";
 import { sessionsStore } from "$lib/stores/sessions";
+import { agentStore } from "$lib/stores/agents";
 
 export interface ConversationSummary {
   generatedAt: Date;
@@ -333,6 +334,10 @@ function createConversationsStore() {
       // Clean up tracking for this conversation (including temp files)
       await cleanupConversationTracking(id);
 
+      // Clean up agent tracking for this conversation
+      // This prevents the badge from persisting after tab close
+      agentStore.clearConversation(id);
+
       conversations.update((c) => {
         c.delete(id);
         return c;
diff --git a/src/lib/tauri.ts b/src/lib/tauri.ts
index 7e42c1f..1d5d767 100644
--- a/src/lib/tauri.ts
+++ b/src/lib/tauri.ts
@@ -183,6 +183,9 @@ export async function initializeTauriListeners() {
       // (permission prompts trigger reconnects and agents may complete before reconnect)
       if (!skipNextGreeting && targetConversationId) {
         agentStore.markAllErrored(targetConversationId);
+        // Clear the conversation's agents from the store on real disconnect
+        // This prevents agents from persisting across sessions
+        agentStore.clearConversation(targetConversationId);
       }
 
       // Only remove from connected set if we're not about to reconnect