diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index bd194ece8..88601e938 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -2316,6 +2316,7 @@ name = "codex-cli"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "app_test_support",
  "assert_cmd",
  "assert_matches",
  "clap",
diff --git a/codex-rs/app-server/src/lib.rs b/codex-rs/app-server/src/lib.rs
index beed35848..0edb57d8a 100644
--- a/codex-rs/app-server/src/lib.rs
+++ b/codex-rs/app-server/src/lib.rs
@@ -912,7 +912,7 @@ pub async fn run_main_with_transport_options(
         async move {
             let mut listen_for_threads = true;
             let mut shutdown_state = ShutdownState::default();
-            loop {
+            let exit_reason = loop {
                 let running_turn_count = {
                     let running_turn_count = running_turn_count_rx.borrow();
                     *running_turn_count
@@ -925,7 +925,7 @@ pub async fn run_main_with_transport_options(
                     let _ = outbound_control_tx
                         .send(OutboundControlEvent::DisconnectAll)
                         .await;
-                    break;
+                    break "shutdown_requested";
                 }
 
                 tokio::select! {
@@ -947,7 +947,7 @@ pub async fn run_main_with_transport_options(
                     }
                     event = transport_event_rx.recv() => {
                         let Some(event) = event else {
-                            break;
+                            break "transport_channel_closed";
                         };
                         match event {
                             TransportEvent::ConnectionOpened {
@@ -977,7 +977,7 @@ pub async fn run_main_with_transport_options(
                                     .await
                                     .is_err()
                                 {
-                                    break;
+                                    break "outbound_router_closed";
                                 }
                                 connections.insert(
                                     connection_id,
@@ -1005,10 +1005,10 @@ pub async fn run_main_with_transport_options(
                                         .await;
                                 });
                                 if !outbound_closed {
-                                    break;
+                                    break "outbound_router_closed";
                                 }
                                 if shutdown_when_no_connections && connections.is_empty() {
-                                    break;
+                                    break "last_connection_closed";
                                 }
                             }
                             TransportEvent::IncomingMessage { connection_id, message } => {
@@ -1147,7 +1147,7 @@ pub async fn run_main_with_transport_options(
                         }
                     }
                 }
-            }
+            };
 
             if !shutdown_state.forced() {
                 futures::future::join_all(
@@ -1162,7 +1162,12 @@ pub async fn run_main_with_transport_options(
             } else {
                 connection_cleanup_tasks.abort();
             }
-            info!("processor task exited (channel closed)");
+            info!(
+                exit_reason,
+                remaining_connection_count = connections.len(),
+                shutdown_forced = shutdown_state.forced(),
+                "processor task exited"
+            );
         }
     });
 
diff --git a/codex-rs/app-server/tests/common/json_logging.rs b/codex-rs/app-server/tests/common/json_logging.rs
new file mode 100644
index 000000000..c6c78bd0a
--- /dev/null
+++ b/codex-rs/app-server/tests/common/json_logging.rs
@@ -0,0 +1,55 @@
+use std::path::Path;
+use std::process::Command;
+use std::process::Stdio;
+
+use anyhow::Context;
+use anyhow::Result;
+use serde_json::Value;
+use serde_json::json;
+
+pub fn app_server_json_shutdown_event(
+    binary: &str,
+    args: &[&str],
+    codex_home: &Path,
+) -> Result<Value> {
+    std::fs::write(
+        codex_home.join("config.toml"),
+        "[features]\nplugins = false\n",
+    )?;
+    let output = Command::new(codex_utils_cargo_bin::cargo_bin(binary)?)
+        .stdin(Stdio::null())
+        .env("CODEX_HOME", codex_home)
+        .env(
+            "CODEX_APP_SERVER_MANAGED_CONFIG_PATH",
+            codex_home.join("managed_config.toml"),
+        )
+        .env("LOG_FORMAT", "json")
+        .env("RUST_LOG", "codex_app_server=info")
+        .args(args)
+        .output()?;
+
+    let stderr = String::from_utf8(output.stderr)?;
+    anyhow::ensure!(output.status.success(), "app-server failed: {stderr}");
+
+    let events = stderr
+        .lines()
+        .filter(|line| !line.is_empty())
+        .map(serde_json::from_str::<Value>)
+        .collect::<serde_json::Result<Vec<_>>>()
+        .with_context(|| format!("app-server stderr was not JSONL: {stderr}"))?;
+    let event = events
+        .iter()
+        .find(|event| event["fields"]["message"] == "processor task exited")
+        .context("missing INFO shutdown event in app-server JSON logs")?;
+    let timestamp = event["timestamp"]
+        .as_str()
+        .context("shutdown event did not include a timestamp")?;
+    chrono::DateTime::parse_from_rfc3339(timestamp)
+        .with_context(|| format!("shutdown event timestamp was not RFC 3339: {timestamp}"))?;
+
+    Ok(json!({
+        "level": event["level"],
+        "fields": event["fields"],
+        "target": event["target"],
+    }))
+}
diff --git a/codex-rs/app-server/tests/common/lib.rs b/codex-rs/app-server/tests/common/lib.rs
index 76c4c85f2..fbc674806 100644
--- a/codex-rs/app-server/tests/common/lib.rs
+++ b/codex-rs/app-server/tests/common/lib.rs
@@ -3,6 +3,7 @@
 mod analytics_server;
 mod auth_fixtures;
 mod config;
+mod json_logging;
 mod mock_model_server;
 mod models_cache;
 mod responses;
@@ -26,6 +27,7 @@ pub use core_test_support::test_absolute_path;
 pub use core_test_support::test_path_buf_with_windows;
 pub use core_test_support::test_tmp_path;
 pub use core_test_support::test_tmp_path_buf;
+pub use json_logging::app_server_json_shutdown_event;
 pub use mock_model_server::create_mock_responses_server_repeating_assistant;
 pub use mock_model_server::create_mock_responses_server_sequence;
 pub use mock_model_server::create_mock_responses_server_sequence_unchecked;
diff --git a/codex-rs/app-server/tests/suite/logging.rs b/codex-rs/app-server/tests/suite/logging.rs
new file mode 100644
index 000000000..ea2c31a76
--- /dev/null
+++ b/codex-rs/app-server/tests/suite/logging.rs
@@ -0,0 +1,27 @@
+use anyhow::Result;
+use app_test_support::app_server_json_shutdown_event;
+use pretty_assertions::assert_eq;
+use serde_json::json;
+use tempfile::TempDir;
+
+#[test]
+fn standalone_app_server_emits_json_info_events() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    let event = app_server_json_shutdown_event("codex-app-server", &[], codex_home.path())?;
+
+    assert_eq!(
+        event,
+        json!({
+            "level": "INFO",
+            "fields": {
+                "message": "processor task exited",
+                "exit_reason": "last_connection_closed",
+                "remaining_connection_count": 0,
+                "shutdown_forced": false,
+            },
+            "target": "codex_app_server",
+        })
+    );
+
+    Ok(())
+}
diff --git a/codex-rs/app-server/tests/suite/mod.rs b/codex-rs/app-server/tests/suite/mod.rs
index bac309a93..09c40493f 100644
--- a/codex-rs/app-server/tests/suite/mod.rs
+++ b/codex-rs/app-server/tests/suite/mod.rs
@@ -1,5 +1,6 @@
 mod auth;
 mod conversation_summary;
 mod fuzzy_file_search;
+mod logging;
 mod strict_config;
 mod v2;
diff --git a/codex-rs/cli/Cargo.toml b/codex-rs/cli/Cargo.toml
index 7be1146df..9a8312ced 100644
--- a/codex-rs/cli/Cargo.toml
+++ b/codex-rs/cli/Cargo.toml
@@ -95,6 +95,7 @@ windows-sys = { version = "0.52", features = [
 ] }
 
 [dev-dependencies]
+app_test_support = { workspace = true }
 assert_cmd = { workspace = true }
 assert_matches = { workspace = true }
 codex-utils-cargo-bin = { workspace = true }
diff --git a/codex-rs/cli/tests/app_server.rs b/codex-rs/cli/tests/app_server.rs
index 4a2642379..6815c2be9 100644
--- a/codex-rs/cli/tests/app_server.rs
+++ b/codex-rs/cli/tests/app_server.rs
@@ -1,7 +1,10 @@
 use std::path::Path;
 
 use anyhow::Result;
+use app_test_support::app_server_json_shutdown_event;
 use predicates::str::contains;
+use pretty_assertions::assert_eq;
+use serde_json::json;
 use tempfile::TempDir;
 
 fn codex_command(codex_home: &Path) -> Result<assert_cmd::Command> {
@@ -28,3 +31,25 @@ foo = "bar"
 
     Ok(())
 }
+
+#[test]
+fn app_server_emits_json_info_events() -> Result<()> {
+    let codex_home = TempDir::new()?;
+    let event = app_server_json_shutdown_event("codex", &["app-server"], codex_home.path())?;
+
+    assert_eq!(
+        event,
+        json!({
+            "level": "INFO",
+            "fields": {
+                "message": "processor task exited",
+                "exit_reason": "last_connection_closed",
+                "remaining_connection_count": 0,
+                "shutdown_forced": false,
+            },
+            "target": "codex_app_server",
+        })
+    );
+
+    Ok(())
+}