feat(hooks): add compaction lifecycle hooks -- FROM EXTERNAL CONTRIBUTOR Vincent K

codex-rs/analytics/src/events.rs

@@ -671,6 +671,8 @@ fn analytics_hook_event_name(event_name: HookEventName) -> &'static str {
         HookEventName::PreToolUse => "PreToolUse",
         HookEventName::PermissionRequest => "PermissionRequest",
         HookEventName::PostToolUse => "PostToolUse",
+        HookEventName::PreCompact => "PreCompact",
+        HookEventName::PostCompact => "PostCompact",
         HookEventName::SessionStart => "SessionStart",
         HookEventName::UserPromptSubmit => "UserPromptSubmit",
         HookEventName::Stop => "Stop",

codex-rs/app-server-protocol/src/protocol/v2.rs

@@ -436,7 +436,7 @@ v2_enum_from_core!(
 
 v2_enum_from_core!(
     pub enum HookEventName from CoreHookEventName {
-        PreToolUse, PermissionRequest, PostToolUse, SessionStart, UserPromptSubmit, Stop
+        PreToolUse, PermissionRequest, PostToolUse, PreCompact, PostCompact, SessionStart, UserPromptSubmit, Stop
     }
 );
 

codex-rs/config/src/hook_config.rs

@@ -20,6 +20,10 @@ pub struct HookEventsToml {
     pub permission_request: Vec<MatcherGroup>,
     #[serde(rename = "PostToolUse", default)]
     pub post_tool_use: Vec<MatcherGroup>,
+    #[serde(rename = "PreCompact", default)]
+    pub pre_compact: Vec<MatcherGroup>,
+    #[serde(rename = "PostCompact", default)]
+    pub post_compact: Vec<MatcherGroup>,
     #[serde(rename = "SessionStart", default)]
     pub session_start: Vec<MatcherGroup>,
     #[serde(rename = "UserPromptSubmit", default)]
@@ -34,13 +38,17 @@ impl HookEventsToml {
             pre_tool_use,
             permission_request,
             post_tool_use,
+            pre_compact,
+            post_compact,
             session_start,
             user_prompt_submit,
             stop,
         } = self;
         pre_tool_use.is_empty()
             && permission_request.is_empty()
             && post_tool_use.is_empty()
+            && pre_compact.is_empty()
+            && post_compact.is_empty()
             && session_start.is_empty()
             && user_prompt_submit.is_empty()
             && stop.is_empty()
@@ -51,6 +59,8 @@ impl HookEventsToml {
             pre_tool_use,
             permission_request,
             post_tool_use,
+            pre_compact,
+            post_compact,
             session_start,
             user_prompt_submit,
             stop,
@@ -59,6 +69,8 @@ impl HookEventsToml {
             pre_tool_use,
             permission_request,
             post_tool_use,
+            pre_compact,
+            post_compact,
             session_start,
             user_prompt_submit,
             stop,
@@ -69,11 +81,13 @@ impl HookEventsToml {
         .sum()
     }
 
-    pub fn into_matcher_groups(self) -> [(HookEventName, Vec<MatcherGroup>); 6] {
+    pub fn into_matcher_groups(self) -> [(HookEventName, Vec<MatcherGroup>); 8] {
         [
             (HookEventName::PreToolUse, self.pre_tool_use),
             (HookEventName::PermissionRequest, self.permission_request),
             (HookEventName::PostToolUse, self.post_tool_use),
+            (HookEventName::PreCompact, self.pre_compact),
+            (HookEventName::PostCompact, self.post_compact),
             (HookEventName::SessionStart, self.session_start),
             (HookEventName::UserPromptSubmit, self.user_prompt_submit),
             (HookEventName::Stop, self.stop),

codex-rs/core/config.schema.json

@@ -865,13 +865,27 @@
           },
           "type": "array"
         },
+        "PostCompact": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
         "PostToolUse": {
           "default": [],
           "items": {
             "$ref": "#/definitions/MatcherGroup"
           },
           "type": "array"
         },
+        "PreCompact": {
+          "default": [],
+          "items": {
+            "$ref": "#/definitions/MatcherGroup"
+          },
+          "type": "array"
+        },
         "PreToolUse": {
           "default": [],
           "items": {

codex-rs/core/src/compact.rs

@@ -4,6 +4,9 @@ use std::time::Instant;
 use crate::Prompt;
 use crate::client::ModelClientSession;
 use crate::client_common::ResponseEvent;
+use crate::hook_runtime::PostCompactHookResult;
+use crate::hook_runtime::run_post_compact_hooks;
+use crate::hook_runtime::run_pre_compact_hooks;
 #[cfg(test)]
 use crate::session::PreviousTurnSettings;
 use crate::session::session::Session;
@@ -132,20 +135,38 @@ async fn run_compact_task_inner(
         phase,
     )
     .await;
+    run_pre_compact_hooks(
+        &sess,
+        &turn_context,
+        trigger,
+        reason,
+        phase,
+        CompactionImplementation::Responses,
+    )
+    .await;
     let result = run_compact_task_inner_impl(
         Arc::clone(&sess),
         Arc::clone(&turn_context),
         input,
         initial_context_injection,
     )
     .await;
-    attempt
-        .track(
-            sess.as_ref(),
-            compaction_status_from_result(&result),
-            result.as_ref().err().map(ToString::to_string),
-        )
-        .await;
+    let status = compaction_status_from_result(&result);
+    let error = result.as_ref().err().map(ToString::to_string);
+    run_post_compact_hooks(
+        &sess,
+        &turn_context,
+        trigger,
+        reason,
+        phase,
+        CompactionImplementation::Responses,
+        PostCompactHookResult {
+            status,
+            error: error.clone(),
+        },
+    )
+    .await;
+    attempt.track(sess.as_ref(), status, error).await;
     result
 }
 

codex-rs/core/src/compact_remote.rs

@@ -10,6 +10,9 @@ use crate::context_manager::ContextManager;
 use crate::context_manager::TotalTokenUsageBreakdown;
 use crate::context_manager::estimate_response_item_model_visible_bytes;
 use crate::context_manager::is_codex_generated_item;
+use crate::hook_runtime::PostCompactHookResult;
+use crate::hook_runtime::run_post_compact_hooks;
+use crate::hook_runtime::run_pre_compact_hooks;
 use crate::session::session::Session;
 use crate::session::turn::built_tools;
 use crate::session::turn_context::TurnContext;
@@ -91,15 +94,33 @@ async fn run_remote_compact_task_inner(
         phase,
     )
     .await;
+    run_pre_compact_hooks(
+        sess,
+        turn_context,
+        trigger,
+        reason,
+        phase,
+        CompactionImplementation::ResponsesCompact,
+    )
+    .await;
     let result =
         run_remote_compact_task_inner_impl(sess, turn_context, initial_context_injection).await;
-    attempt
-        .track(
-            sess.as_ref(),
-            compaction_status_from_result(&result),
-            result.as_ref().err().map(ToString::to_string),
-        )
-        .await;
+    let status = compaction_status_from_result(&result);
+    let error = result.as_ref().err().map(ToString::to_string);
+    run_post_compact_hooks(
+        sess,
+        turn_context,
+        trigger,
+        reason,
+        phase,
+        CompactionImplementation::ResponsesCompact,
+        PostCompactHookResult {
+            status,
+            error: error.clone(),
+        },
+    )
+    .await;
+    attempt.track(sess.as_ref(), status, error.clone()).await;
     if let Err(err) = result {
         let event = EventMsg::Error(
             err.to_error_event(Some("Error running remote compact task".to_string())),