feat: add feature to monitor background agents (#125)

Also includes a fix to persist configuration across reconnects.

Reviewed-on: #125
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

src-tauri/src/types.rs

@@ -197,6 +197,8 @@ pub struct OutputEvent {
     pub conversation_id: Option<String>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub cost: Option<MessageCost>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub parent_tool_use_id: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -248,6 +250,33 @@ pub struct UserQuestionEvent {
     pub conversation_id: Option<String>,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct AgentStartEvent {
+    pub tool_use_id: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub agent_id: Option<String>,
+    pub description: String,
+    pub subagent_type: String,
+    pub started_at: u64,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub parent_tool_use_id: Option<String>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct AgentEndEvent {
+    pub tool_use_id: String,
+    pub ended_at: u64,
+    pub is_error: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub conversation_id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub duration_ms: Option<u64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub num_turns: Option<u32>,
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -369,6 +398,7 @@ mod tests {
             tool_name: None,
             conversation_id: None,
             cost: None,
+            parent_tool_use_id: None,
         };
 
         let serialized = serde_json::to_string(&event).unwrap();
@@ -388,6 +418,7 @@ mod tests {
                 output_tokens: 50,
                 cost_usd: 0.005,
             }),
+            parent_tool_use_id: None,
         };
 
         let serialized = serde_json::to_string(&event).unwrap();

src-tauri/src/wsl_bridge.rs

@@ -2,6 +2,7 @@ use std::io::{BufRead, BufReader, Write};
 use std::process::{Child, ChildStdin, Command, Stdio};
 use std::sync::Arc;
 use std::thread;
+use std::time::{SystemTime, UNIX_EPOCH};
 use tauri::{AppHandle, Emitter};
 use tempfile::NamedTempFile;
 
@@ -13,9 +14,9 @@ use crate::commands::record_cost;
 use crate::config::ClaudeStartOptions;
 use crate::stats::{calculate_cost, StatsUpdateEvent, UsageStats};
 use crate::types::{
-    CharacterState, ClaudeMessage, ConnectionEvent, ConnectionStatus, ContentBlock, MessageCost,
-    OutputEvent, PermissionPromptEvent, QuestionOption, SessionEvent, StateChangeEvent,
-    UserQuestionEvent, WorkingDirectoryEvent,
+    AgentEndEvent, AgentStartEvent, CharacterState, ClaudeMessage, ConnectionEvent,
+    ConnectionStatus, ContentBlock, MessageCost, OutputEvent, PermissionPromptEvent,
+    QuestionOption, SessionEvent, StateChangeEvent, UserQuestionEvent, WorkingDirectoryEvent,
 };
 use parking_lot::RwLock;
 
@@ -193,6 +194,8 @@ impl WslBridge {
                 "--input-format",
                 "stream-json",
                 "--verbose",
+                "--debug",
+                "hooks",
             ]);
 
             // Add model if specified
@@ -642,6 +645,25 @@ fn handle_stderr(
     for line in reader.lines() {
         match line {
             Ok(line) if !line.is_empty() => {
+                // Check if this is a SubagentStart hook message
+                if line.contains("[SubagentStart Hook]") {
+                    if let Some(agent_data) = parse_subagent_start_hook(&line) {
+                        eprintln!("[DEBUG] Parsed SubagentStart hook: agent_id={}, parent={:?}",
+                            agent_data.agent_id, agent_data.parent_tool_use_id);
+
+                        // Emit an agent-update event with the agent_id
+                        let _ = app.emit(
+                            "claude:agent-update",
+                            serde_json::json!({
+                                "conversationId": conversation_id.clone(),
+                                "toolUseId": agent_data.parent_tool_use_id,
+                                "agentId": agent_data.agent_id,
+                            }),
+                        );
+                    }
+                }
+
+                // Still emit the stderr line as output
                 let _ = app.emit(
                     "claude:output",
                     OutputEvent {
@@ -650,6 +672,7 @@ fn handle_stderr(
                         tool_name: None,
                         conversation_id: conversation_id.clone(),
                         cost: None,
+                        parent_tool_use_id: None,
                     },
                 );
             }
@@ -659,6 +682,41 @@ fn handle_stderr(
     }
 }
 
+#[derive(Debug)]
+struct SubagentStartData {
+    agent_id: String,
+    parent_tool_use_id: Option<String>,
+}
+
+fn parse_subagent_start_hook(line: &str) -> Option<SubagentStartData> {
+    // Parse: [SubagentStart Hook] agent_id=agent-xxx, parent_tool_use_id=Some("toolu_xxx"), ...
+
+    // Extract agent_id
+    let agent_id = line
+        .split("agent_id=")
+        .nth(1)?
+        .split(',')
+        .next()?
+        .trim()
+        .to_string();
+
+    // 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(SubagentStartData {
+        agent_id,
+        parent_tool_use_id,
+    })
+}
+
 fn process_json_line(
     line: &str,
     app: &AppHandle,
@@ -698,7 +756,7 @@ fn process_json_line(
             }
         }
 
-        ClaudeMessage::Assistant { message, .. } => {
+        ClaudeMessage::Assistant { message, parent_tool_use_id } => {
             let mut state = CharacterState::Typing;
             let mut tool_name = None;
 
@@ -790,7 +848,7 @@ fn process_json_line(
 
             for block in &message.content {
                 match block {
-                    ContentBlock::ToolUse { name, input, .. } => {
+                    ContentBlock::ToolUse { id, name, input } => {
                         tool_name = Some(name.clone());
                         state = get_tool_state(name);
 
@@ -807,6 +865,42 @@ fn process_json_line(
                             }
                         }
 
+                        // Emit agent-start event for Task tool invocations
+                        if name == "Task" {
+                            let description = input
+                                .get("description")
+                                .and_then(|v| v.as_str())
+                                .unwrap_or("Subagent")
+                                .to_string();
+                            let subagent_type = input
+                                .get("subagent_type")
+                                .and_then(|v| v.as_str())
+                                .unwrap_or("unknown")
+                                .to_string();
+                            let now = SystemTime::now()
+                                .duration_since(UNIX_EPOCH)
+                                .unwrap_or_default()
+                                .as_millis() as u64;
+
+                            eprintln!(
+                                "[DEBUG] Emitting agent-start: id={}, desc={}, type={}, parent={:?}",
+                                id, description, subagent_type, parent_tool_use_id
+                            );
+
+                            let _ = app.emit(
+                                "claude:agent-start",
+                                AgentStartEvent {
+                                    tool_use_id: id.clone(),
+                                    agent_id: None, // Will be updated when SubagentStart hook is received
+                                    description,
+                                    subagent_type,
+                                    started_at: now,
+                                    conversation_id: conversation_id.clone(),
+                                    parent_tool_use_id: parent_tool_use_id.clone(),
+                                },
+                            );
+                        }
+
                         let desc = format_tool_description(name, input);
                         let _ = app.emit(
                             "claude:output",
@@ -816,6 +910,7 @@ fn process_json_line(
                                 tool_name: Some(name.clone()),
                                 conversation_id: conversation_id.clone(),
                                 cost: None, // Tool use doesn't have separate cost
+                                parent_tool_use_id: parent_tool_use_id.clone(),
                             },
                         );
                     }
@@ -834,6 +929,7 @@ fn process_json_line(
                                 tool_name: None,
                                 conversation_id: conversation_id.clone(),
                                 cost: message_cost.clone(), // Include cost with assistant text
+                                parent_tool_use_id: parent_tool_use_id.clone(),
                             },
                         );
                     }
@@ -847,10 +943,34 @@ fn process_json_line(
                                 tool_name: None,
                                 conversation_id: conversation_id.clone(),
                                 cost: None,
+                                parent_tool_use_id: parent_tool_use_id.clone(),
+                            },
+                        );
+                    }
+                    ContentBlock::ToolResult {
+                        tool_use_id,
+                        is_error,
+                        ..
+                    } => {
+                        // Emit agent-end for all tool results
+                        // The frontend will ignore IDs that don't match known agents
+                        let now = SystemTime::now()
+                            .duration_since(UNIX_EPOCH)
+                            .unwrap_or_default()
+                            .as_millis() as u64;
+
+                        let _ = app.emit(
+                            "claude:agent-end",
+                            AgentEndEvent {
+                                tool_use_id: tool_use_id.clone(),
+                                ended_at: now,
+                                is_error: is_error.unwrap_or(false),
+                                conversation_id: conversation_id.clone(),
+                                duration_ms: None,
+                                num_turns: None,
                             },
                         );
                     }
-                    _ => {}
                 }
             }
 
@@ -905,7 +1025,8 @@ fn process_json_line(
             result,
             permission_denials,
             usage,
-            ..
+            duration_ms,
+            num_turns,
         } => {
             let state = if subtype == "success" {
                 CharacterState::Success
@@ -913,6 +1034,14 @@ fn process_json_line(
                 CharacterState::Error
             };
 
+            // Log turn metrics if available
+            if let Some(duration) = duration_ms {
+                println!("Turn completed in {}ms", duration);
+            }
+            if let Some(turns) = num_turns {
+                println!("Turn count: {}", turns);
+            }
+
             // Track token usage from Result messages if available
             // This captures tokens from tool outputs and other operations
             if let Some(usage_info) = usage {
@@ -1035,6 +1164,7 @@ fn process_json_line(
                             tool_name: None,
                             conversation_id: conversation_id.clone(),
                             cost: None,
+                            parent_tool_use_id: None,
                         },
                     );
                 }
@@ -1140,6 +1270,33 @@ fn process_json_line(
             // Increment message count for user messages
             stats.write().increment_messages();
 
+            // Process content blocks for tool results (e.g., background Task agent completions)
+            for block in &message.content {
+                if let ContentBlock::ToolResult {
+                    tool_use_id,
+                    is_error,
+                    ..
+                } = block
+                {
+                    let now = SystemTime::now()
+                        .duration_since(UNIX_EPOCH)
+                        .unwrap_or_default()
+                        .as_millis() as u64;
+
+                    let _ = app.emit(
+                        "claude:agent-end",
+                        AgentEndEvent {
+                            tool_use_id: tool_use_id.clone(),
+                            ended_at: now,
+                            is_error: is_error.unwrap_or(false),
+                            conversation_id: conversation_id.clone(),
+                            duration_ms: None,
+                            num_turns: None,
+                        },
+                    );
+                }
+            }
+
             // Extract text content from the message
             let message_text = message
                 .content