feat(hooks): add user-configurable hook system

crates/forge_app/src/agent_executor.rs

@@ -111,6 +111,8 @@ impl<S: Services + EnvironmentInfra<Config = forge_config::ForgeConfig>> AgentEx
                 ChatResponse::ToolCallStart { .. } => ctx.send(message).await?,
                 ChatResponse::ToolCallEnd(_) => ctx.send(message).await?,
                 ChatResponse::RetryAttempt { .. } => ctx.send(message).await?,
+                ChatResponse::HookError { .. } => ctx.send(message).await?,
+                ChatResponse::HookWarning { .. } => ctx.send(message).await?,
                 ChatResponse::Interrupt { reason } => {
                     return Err(Error::AgentToolInterrupted(reason))
                         .context(format!(

crates/forge_app/src/app.rs

@@ -11,11 +11,13 @@ use crate::changed_files::ChangedFiles;
 use crate::dto::ToolsOverview;
 use crate::hooks::{
     CompactionHandler, DoomLoopDetector, PendingTodosHandler, TitleGenerationHandler,
-    TracingHandler,
+    TracingHandler, UserHookHandler,
 };
 use crate::init_conversation_metrics::InitConversationMetrics;
 use crate::orch::Orchestrator;
-use crate::services::{AgentRegistry, CustomInstructionsService, ProviderAuthService};
+use crate::services::{
+    AgentRegistry, CustomInstructionsService, ProviderAuthService, UserHookConfigService,
+};
 use crate::set_conversation_id::SetConversationId;
 use crate::system_prompt::SystemPrompt;
 use crate::tool_registry::ToolRegistry;
@@ -157,7 +159,7 @@ impl<S: Services + EnvironmentInfra<Config = forge_config::ForgeConfig>> ForgeAp
             tracing_handler.clone().and(title_handler.clone())
         };
 
-        let hook = Hook::default()
+        let internal_hook = Hook::default()
             .on_start(tracing_handler.clone().and(title_handler))
             .on_request(tracing_handler.clone().and(DoomLoopDetector::default()))
             .on_response(
@@ -169,6 +171,29 @@ impl<S: Services + EnvironmentInfra<Config = forge_config::ForgeConfig>> ForgeAp
             .on_toolcall_end(tracing_handler)
             .on_end(on_end_hook);
 
+        // Load user-configurable hooks from settings files
+        let user_hook_config = services.get_user_hook_config().await?;
+
+        let hook = if !user_hook_config.is_empty() {
+            let user_handler = UserHookHandler::new(
+                services.hook_command_service().clone(),
+                services.get_env_vars(),
+                user_hook_config,
+                environment.cwd.clone(),
+                conversation.id.to_string(),
+            );
+            let user_hook = Hook::default()
+                .on_start(user_handler.clone())
+                .on_request(user_handler.clone())
+                .on_response(user_handler.clone())
+                .on_toolcall_start(user_handler.clone())
+                .on_toolcall_end(user_handler.clone())
+                .on_end(user_handler);
+            internal_hook.zip(user_hook)
+        } else {
+            internal_hook
+        };
+
         let orch = Orchestrator::new(
             services.clone(),
             conversation,

crates/forge_app/src/hooks/compaction.rs

@@ -31,7 +31,7 @@ impl CompactionHandler {
 impl EventHandle<EventData<ResponsePayload>> for CompactionHandler {
     async fn handle(
         &self,
-        _event: &EventData<ResponsePayload>,
+        _event: &mut EventData<ResponsePayload>,
         conversation: &mut Conversation,
     ) -> anyhow::Result<()> {
         if let Some(context) = &conversation.context {

crates/forge_app/src/hooks/doom_loop.rs

@@ -222,7 +222,7 @@ impl DoomLoopDetector {
 impl EventHandle<EventData<RequestPayload>> for DoomLoopDetector {
     async fn handle(
         &self,
-        event: &EventData<RequestPayload>,
+        event: &mut EventData<RequestPayload>,
         conversation: &mut Conversation,
     ) -> anyhow::Result<()> {
         if let Some(consecutive_calls) = self.detect_from_conversation(conversation) {

crates/forge_app/src/hooks/mod.rs

@@ -3,9 +3,12 @@ mod doom_loop;
 mod pending_todos;
 mod title_generation;
 mod tracing;
+mod user_hook_executor;
+mod user_hook_handler;
 
 pub use compaction::CompactionHandler;
 pub use doom_loop::DoomLoopDetector;
 pub use pending_todos::PendingTodosHandler;
 pub use title_generation::TitleGenerationHandler;
 pub use tracing::TracingHandler;
+pub use user_hook_handler::UserHookHandler;

crates/forge_app/src/hooks/pending_todos.rs

@@ -42,7 +42,7 @@ impl PendingTodosHandler {
 impl EventHandle<EventData<EndPayload>> for PendingTodosHandler {
     async fn handle(
         &self,
-        _event: &EventData<EndPayload>,
+        _event: &mut EventData<EndPayload>,
         conversation: &mut Conversation,
     ) -> anyhow::Result<()> {
         let pending_todos = conversation.metrics.get_active_todos();
@@ -157,17 +157,21 @@ mod tests {
     }
 
     fn fixture_event() -> EventData<EndPayload> {
-        EventData::new(fixture_agent(), ModelId::new("test-model"), EndPayload)
+        EventData::new(
+            fixture_agent(),
+            ModelId::new("test-model"),
+            EndPayload::default(),
+        )
     }
 
     #[tokio::test]
     async fn test_no_pending_todos_does_nothing() {
         let handler = PendingTodosHandler::new();
-        let event = fixture_event();
+        let mut event = fixture_event();
         let mut conversation = fixture_conversation(vec![]);
 
         let initial_msg_count = conversation.context.as_ref().unwrap().messages.len();
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
 
         let actual = conversation.context.as_ref().unwrap().messages.len();
         let expected = initial_msg_count;
@@ -177,13 +181,13 @@ mod tests {
     #[tokio::test]
     async fn test_pending_todos_injects_reminder() {
         let handler = PendingTodosHandler::new();
-        let event = fixture_event();
+        let mut event = fixture_event();
         let mut conversation = fixture_conversation(vec![
             Todo::new("Fix the build").status(TodoStatus::Pending),
             Todo::new("Write tests").status(TodoStatus::InProgress),
         ]);
 
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
 
         let actual = conversation.context.as_ref().unwrap().messages.len();
         let expected = 1;
@@ -193,13 +197,13 @@ mod tests {
     #[tokio::test]
     async fn test_reminder_contains_formatted_list() {
         let handler = PendingTodosHandler::new();
-        let event = fixture_event();
+        let mut event = fixture_event();
         let mut conversation = fixture_conversation(vec![
             Todo::new("Fix the build").status(TodoStatus::Pending),
             Todo::new("Write tests").status(TodoStatus::InProgress),
         ]);
 
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
 
         let entry = &conversation.context.as_ref().unwrap().messages[0];
         let actual = entry.message.content().unwrap();
@@ -210,14 +214,14 @@ mod tests {
     #[tokio::test]
     async fn test_completed_todos_not_included() {
         let handler = PendingTodosHandler::new();
-        let event = fixture_event();
+        let mut event = fixture_event();
         let mut conversation = fixture_conversation(vec![
             Todo::new("Completed task").status(TodoStatus::Completed),
             Todo::new("Cancelled task").status(TodoStatus::Cancelled),
         ]);
 
         let initial_msg_count = conversation.context.as_ref().unwrap().messages.len();
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
 
         let actual = conversation.context.as_ref().unwrap().messages.len();
         let expected = initial_msg_count;
@@ -227,32 +231,32 @@ mod tests {
     #[tokio::test]
     async fn test_reminder_not_duplicated_for_same_todos() {
         let handler = PendingTodosHandler::new();
-        let event = fixture_event();
+        let mut event = fixture_event();
         let mut conversation =
             fixture_conversation(vec![Todo::new("Fix the build").status(TodoStatus::Pending)]);
 
         // First call should inject a reminder
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
         let after_first = conversation.context.as_ref().unwrap().messages.len();
         assert_eq!(after_first, 1);
 
         // Second call with the same pending todos should NOT add another reminder
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
         let after_second = conversation.context.as_ref().unwrap().messages.len();
         assert_eq!(after_second, 1); // Still 1, no duplicate
     }
 
     #[tokio::test]
     async fn test_reminder_added_when_todos_change() {
         let handler = PendingTodosHandler::new();
-        let event = fixture_event();
+        let mut event = fixture_event();
         let mut conversation = fixture_conversation(vec![
             Todo::new("Fix the build").status(TodoStatus::Pending),
             Todo::new("Write tests").status(TodoStatus::InProgress),
         ]);
 
         // First call should inject a reminder
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
         let after_first = conversation.context.as_ref().unwrap().messages.len();
         assert_eq!(after_first, 1);
 
@@ -265,7 +269,7 @@ mod tests {
         ]);
 
         // Second call with different pending todos should add a new reminder
-        handler.handle(&event, &mut conversation).await.unwrap();
+        handler.handle(&mut event, &mut conversation).await.unwrap();
         let after_second = conversation.context.as_ref().unwrap().messages.len();
         assert_eq!(after_second, 2); // New reminder added because todos changed
     }

crates/forge_app/src/hooks/title_generation.rs

@@ -35,7 +35,7 @@ impl<S> TitleGenerationHandler<S> {
 impl<S: AgentService> EventHandle<EventData<StartPayload>> for TitleGenerationHandler<S> {
     async fn handle(
         &self,
-        event: &EventData<StartPayload>,
+        event: &mut EventData<StartPayload>,
         conversation: &mut Conversation,
     ) -> anyhow::Result<()> {
         if conversation.title.is_some() {
@@ -85,7 +85,7 @@ impl<S: AgentService> EventHandle<EventData<StartPayload>> for TitleGenerationHa
 impl<S: AgentService> EventHandle<EventData<EndPayload>> for TitleGenerationHandler<S> {
     async fn handle(
         &self,
-        _event: &EventData<EndPayload>,
+        _event: &mut EventData<EndPayload>,
         conversation: &mut Conversation,
     ) -> anyhow::Result<()> {
         if let Some((_, entry)) = self.title_tasks.remove(&conversation.id) {
@@ -176,7 +176,7 @@ mod tests {
         conversation.title = Some("existing".into());
 
         handler
-            .handle(&event(StartPayload), &mut conversation)
+            .handle(&mut event(StartPayload), &mut conversation)
             .await
             .unwrap();
 
@@ -195,7 +195,7 @@ mod tests {
             .insert(conversation.id, TitleGenerationState { rx, handle });
 
         handler
-            .handle(&event(StartPayload), &mut conversation)
+            .handle(&mut event(StartPayload), &mut conversation)
             .await
             .unwrap();
 
@@ -215,7 +215,7 @@ mod tests {
             .insert(conversation.id, TitleGenerationState { rx, handle });
 
         handler
-            .handle(&event(EndPayload), &mut conversation)
+            .handle(&mut event(EndPayload::default()), &mut conversation)
             .await
             .unwrap();
 
@@ -237,7 +237,7 @@ mod tests {
             .insert(conversation.id, TitleGenerationState { rx, handle });
 
         handler
-            .handle(&event(EndPayload), &mut conversation)
+            .handle(&mut event(EndPayload::default()), &mut conversation)
             .await
             .unwrap();
 
@@ -262,7 +262,7 @@ mod tests {
             .insert(conversation.id, TitleGenerationState { rx, handle });
 
         handler
-            .handle(&event(EndPayload), &mut conversation)
+            .handle(&mut event(EndPayload::default()), &mut conversation)
             .await
             .unwrap();
 
@@ -290,7 +290,7 @@ mod tests {
             joins.push(tokio::spawn(async move {
                 barrier.wait().await;
                 handler
-                    .handle(&event(StartPayload), &mut conv)
+                    .handle(&mut event(StartPayload), &mut conv)
                     .await
                     .unwrap();
             }));