diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index 83ca0d11915e..9e369bd407d0 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -1821,6 +1821,7 @@ dependencies = [
  "codex-plugin",
  "codex-protocol",
  "codex-utils-absolute-path",
+ "codex-utils-log",
  "os_info",
  "pretty_assertions",
  "serde",
@@ -1852,6 +1853,7 @@ dependencies = [
  "chrono",
  "codex-client",
  "codex-protocol",
+ "codex-utils-log",
  "codex-utils-rustls-provider",
  "eventsource-stream",
  "futures",
@@ -1926,6 +1928,7 @@ dependencies = [
  "codex-utils-cargo-bin",
  "codex-utils-cli",
  "codex-utils-json-to-toml",
+ "codex-utils-log",
  "codex-utils-pty",
  "core_test_support",
  "flate2",
@@ -2532,6 +2535,7 @@ dependencies = [
  "codex-utils-cargo-bin",
  "codex-utils-home-dir",
  "codex-utils-image",
+ "codex-utils-log",
  "codex-utils-output-truncation",
  "codex-utils-path",
  "codex-utils-plugins",
@@ -3049,6 +3053,7 @@ dependencies = [
  "codex-otel",
  "codex-protocol",
  "codex-terminal-detection",
+ "codex-utils-log",
  "codex-utils-template",
  "core_test_support",
  "jsonwebtoken",
@@ -3493,6 +3498,7 @@ dependencies = [
  "codex-protocol",
  "codex-utils-cargo-bin",
  "codex-utils-home-dir",
+ "codex-utils-log",
  "codex-utils-pty",
  "futures",
  "keyring",
@@ -3800,6 +3806,7 @@ dependencies = [
  "codex-utils-elapsed",
  "codex-utils-fuzzy-match",
  "codex-utils-home-dir",
+ "codex-utils-log",
  "codex-utils-oss",
  "codex-utils-path",
  "codex-utils-plugins",
@@ -3964,6 +3971,14 @@ dependencies = [
  "toml 0.9.11+spec-1.1.0",
 ]
 
+[[package]]
+name = "codex-utils-log"
+version = "0.0.0"
+dependencies = [
+ "pretty_assertions",
+ "sha2",
+]
+
 [[package]]
 name = "codex-utils-oss"
 version = "0.0.0"
diff --git a/codex-rs/Cargo.toml b/codex-rs/Cargo.toml
index 7207fd3aba4d..a8be9085afce 100644
--- a/codex-rs/Cargo.toml
+++ b/codex-rs/Cargo.toml
@@ -84,6 +84,7 @@ members = [
     "utils/cache",
     "utils/image",
     "utils/json-to-toml",
+    "utils/log",
     "utils/home-dir",
     "utils/pty",
     "utils/readiness",
@@ -221,6 +222,7 @@ codex-utils-fuzzy-match = { path = "utils/fuzzy-match" }
 codex-utils-home-dir = { path = "utils/home-dir" }
 codex-utils-image = { path = "utils/image" }
 codex-utils-json-to-toml = { path = "utils/json-to-toml" }
+codex-utils-log = { path = "utils/log" }
 codex-utils-oss = { path = "utils/oss" }
 codex-utils-output-truncation = { path = "utils/output-truncation" }
 codex-utils-path = { path = "utils/path-utils" }
diff --git a/codex-rs/analytics/Cargo.toml b/codex-rs/analytics/Cargo.toml
index 918e7edc720e..15c9c8a1528c 100644
--- a/codex-rs/analytics/Cargo.toml
+++ b/codex-rs/analytics/Cargo.toml
@@ -19,6 +19,7 @@ codex-login = { workspace = true }
 codex-model-provider = { workspace = true }
 codex-plugin = { workspace = true }
 codex-protocol = { workspace = true }
+codex-utils-log = { workspace = true }
 os_info = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
diff --git a/codex-rs/analytics/src/client.rs b/codex-rs/analytics/src/client.rs
index fbcfa32dc5e1..f8f4dd5f599d 100644
--- a/codex-rs/analytics/src/client.rs
+++ b/codex-rs/analytics/src/client.rs
@@ -34,6 +34,7 @@ use codex_login::CodexAuth;
 use codex_login::default_client::create_client;
 use codex_plugin::PluginTelemetryMetadata;
 use codex_protocol::request_permissions::RequestPermissionsResponse;
+use codex_utils_log::bounded_str;
 use std::collections::HashSet;
 use std::sync::Arc;
 use std::sync::Mutex;
@@ -454,7 +455,7 @@ async fn send_track_events_request(auth: &CodexAuth, url: &str, events: Vec<Trac
         Ok(response) => {
             let status = response.status();
             let body = response.text().await.unwrap_or_default();
-            tracing::warn!("events failed with status {status}: {body}");
+            tracing::warn!("events failed with status {status}: {}", bounded_str(&body));
         }
         Err(err) => {
             tracing::warn!("failed to send events request: {err}");
diff --git a/codex-rs/app-server/Cargo.toml b/codex-rs/app-server/Cargo.toml
index 95baac4e9edf..5445ce808dd8 100644
--- a/codex-rs/app-server/Cargo.toml
+++ b/codex-rs/app-server/Cargo.toml
@@ -71,6 +71,7 @@ codex-thread-store = { workspace = true }
 codex-tools = { workspace = true }
 codex-utils-absolute-path = { workspace = true }
 codex-utils-json-to-toml = { workspace = true }
+codex-utils-log = { workspace = true }
 chrono = { workspace = true }
 clap = { workspace = true, features = ["derive"] }
 futures = { workspace = true }
diff --git a/codex-rs/app-server/src/message_processor.rs b/codex-rs/app-server/src/message_processor.rs
index fc835b82ecf0..45f32914879c 100644
--- a/codex-rs/app-server/src/message_processor.rs
+++ b/codex-rs/app-server/src/message_processor.rs
@@ -79,6 +79,7 @@ use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::W3cTraceContext;
 use codex_rollout::StateDbHandle;
 use codex_state::log_db::LogDbLayer;
+use codex_utils_log::bounded_debug;
 use tokio::sync::Mutex;
 use tokio::sync::Semaphore;
 use tokio::sync::broadcast;
@@ -615,14 +616,14 @@ impl MessageProcessor {
     pub(crate) async fn process_notification(&self, notification: JSONRPCNotification) {
         // Currently, we do not expect to receive any notifications from the
         // client, so we just log them.
-        tracing::info!("<- notification: {:?}", notification);
+        tracing::info!("<- notification: {}", bounded_debug(&notification));
     }
 
     /// Handles typed notifications from in-process clients.
     pub(crate) async fn process_client_notification(&self, notification: ClientNotification) {
         // Currently, we do not expect to receive any typed notifications from
         // in-process clients, so we just log them.
-        tracing::info!("<- typed notification: {:?}", notification);
+        tracing::info!("<- typed notification: {}", bounded_debug(&notification));
     }
 
     async fn run_request_with_context<F>(
@@ -722,14 +723,14 @@ impl MessageProcessor {
 
     /// Handle a standalone JSON-RPC response originating from the peer.
     pub(crate) async fn process_response(&self, response: JSONRPCResponse) {
-        tracing::info!("<- response: {:?}", response);
+        tracing::info!("<- response: {}", bounded_debug(&response));
         let JSONRPCResponse { id, result, .. } = response;
         self.outgoing.notify_client_response(id, result).await
     }
 
     /// Handle an error object received from the peer.
     pub(crate) async fn process_error(&self, err: JSONRPCError) {
-        tracing::error!("<- error: {:?}", err);
+        tracing::error!("<- error: {}", bounded_debug(&err));
         self.outgoing.notify_client_error(err.id, err.error).await;
     }
 
diff --git a/codex-rs/app-server/src/outgoing_message.rs b/codex-rs/app-server/src/outgoing_message.rs
index 97ef37f74234..75dd67df551a 100644
--- a/codex-rs/app-server/src/outgoing_message.rs
+++ b/codex-rs/app-server/src/outgoing_message.rs
@@ -18,11 +18,15 @@ use codex_otel::span_w3c_trace_context;
 use codex_protocol::ThreadId;
 use codex_protocol::protocol::W3cTraceContext;
 use codex_protocol::request_permissions::RequestPermissionsResponse;
+use codex_utils_log::bounded_debug;
+use codex_utils_log::bounded_display;
 use tokio::sync::Mutex;
 use tokio::sync::mpsc;
 use tokio::sync::oneshot;
 use tracing::Instrument;
+use tracing::Level;
 use tracing::Span;
+use tracing::enabled;
 use tracing::warn;
 
 use crate::error_code::internal_error;
@@ -342,7 +346,10 @@ impl OutgoingMessageSender {
         };
 
         if let Err(err) = send_result {
-            warn!("failed to send request {outgoing_message_id:?} to client: {err:?}");
+            warn!(
+                "failed to send request {outgoing_message_id:?} to client: {}",
+                bounded_debug(&err)
+            );
             let mut request_id_to_callback = self.request_id_to_callback.lock().await;
             request_id_to_callback.remove(&outgoing_message_id);
         }
@@ -365,7 +372,10 @@ impl OutgoingMessageSender {
                 })
                 .await
             {
-                warn!("failed to resend request to client: {err:?}");
+                warn!(
+                    "failed to resend request to client: {}",
+                    bounded_debug(&err)
+                );
             }
         }
     }
@@ -383,7 +393,10 @@ impl OutgoingMessageSender {
                         .track_server_response(completed_at_ms, response);
                 }
                 if let Err(err) = entry.callback.send(Ok(result)) {
-                    warn!("could not notify callback for {id:?} due to: {err:?}");
+                    warn!(
+                        "could not notify callback for {id:?} due to: {}",
+                        bounded_debug(&err)
+                    );
                 }
             }
             None => {
@@ -397,11 +410,17 @@ impl OutgoingMessageSender {
 
         match entry {
             Some((id, entry)) => {
-                warn!("client responded with error for {id:?}: {error:?}");
+                warn!(
+                    "client responded with error for {id:?}: {}",
+                    bounded_debug(&error)
+                );
                 self.analytics_events_client
                     .track_server_request_aborted(now_unix_timestamp_ms(), id.clone());
                 if let Err(err) = entry.callback.send(Err(error)) {
-                    warn!("could not notify callback for {id:?} due to: {err:?}");
+                    warn!(
+                        "could not notify callback for {id:?} due to: {}",
+                        bounded_debug(&err)
+                    );
                 }
             }
             None => {
@@ -437,7 +456,10 @@ impl OutgoingMessageSender {
                 && let Err(err) = entry.callback.send(Err(error.clone()))
             {
                 let request_id = entry.request.id();
-                warn!("could not notify callback for {request_id:?} due to: {err:?}");
+                warn!(
+                    "could not notify callback for {request_id:?} due to: {}",
+                    bounded_debug(&err)
+                );
             }
         }
     }
@@ -495,7 +517,10 @@ impl OutgoingMessageSender {
                 && let Err(err) = entry.callback.send(Err(error.clone()))
             {
                 let request_id = entry.request.id();
-                warn!("could not notify callback for {request_id:?} due to: {err:?}",);
+                warn!(
+                    "could not notify callback for {request_id:?} due to: {}",
+                    bounded_debug(&err)
+                );
             }
         }
     }
@@ -560,10 +585,13 @@ impl OutgoingMessageSender {
         connection_ids: &[ConnectionId],
         notification: ServerNotification,
     ) {
-        tracing::trace!(
-            targeted_connections = connection_ids.len(),
-            "app-server event: {notification}"
-        );
+        if enabled!(Level::TRACE) {
+            let notification_log = bounded_display(&notification);
+            tracing::trace!(
+                targeted_connections = connection_ids.len(),
+                "app-server event: {notification_log}"
+            );
+        }
         let outgoing_message = OutgoingMessage::AppServerNotification(notification.clone());
         if connection_ids.is_empty() {
             if let Err(err) = self
@@ -573,7 +601,10 @@ impl OutgoingMessageSender {
                 })
                 .await
             {
-                warn!("failed to send server notification to client: {err:?}");
+                warn!(
+                    "failed to send server notification to client: {}",
+                    bounded_debug(&err)
+                );
             }
             return;
         }
@@ -587,7 +618,10 @@ impl OutgoingMessageSender {
                 })
                 .await
             {
-                warn!("failed to send server notification to client: {err:?}");
+                warn!(
+                    "failed to send server notification to client: {}",
+                    bounded_debug(&err)
+                );
             }
         }
     }
@@ -597,7 +631,9 @@ impl OutgoingMessageSender {
         connection_id: ConnectionId,
         notification: ServerNotification,
     ) {
-        tracing::trace!("app-server event: {notification}");
+        if enabled!(Level::TRACE) {
+            tracing::trace!("app-server event: {}", bounded_display(&notification));
+        }
         let outgoing_message = OutgoingMessage::AppServerNotification(notification.clone());
         let (write_complete_tx, write_complete_rx) = oneshot::channel();
         if let Err(err) = self
@@ -609,7 +645,10 @@ impl OutgoingMessageSender {
             })
             .await
         {
-            warn!("failed to send server notification to client: {err:?}");
+            warn!(
+                "failed to send server notification to client: {}",
+                bounded_debug(&err)
+            );
         }
         let _ = write_complete_rx.await;
     }
@@ -678,7 +717,10 @@ impl OutgoingMessageSender {
         };
 
         if let Err(err) = send_result {
-            warn!("failed to send {message_kind} to client: {err:?}");
+            warn!(
+                "failed to send {message_kind} to client: {}",
+                bounded_debug(&err)
+            );
         }
     }
 }
diff --git a/codex-rs/codex-api/Cargo.toml b/codex-rs/codex-api/Cargo.toml
index 08f70cf33cf1..a12fea9fc5bf 100644
--- a/codex-rs/codex-api/Cargo.toml
+++ b/codex-rs/codex-api/Cargo.toml
@@ -12,6 +12,7 @@ bytes = { workspace = true }
 chrono = { workspace = true }
 codex-client = { workspace = true }
 codex-protocol = { workspace = true }
+codex-utils-log = { workspace = true }
 codex-utils-rustls-provider = { workspace = true }
 futures = { workspace = true }
 http = { workspace = true }
diff --git a/codex-rs/codex-api/src/endpoint/models.rs b/codex-rs/codex-api/src/endpoint/models.rs
index ec9ee7aac6d3..25bcd19fef23 100644
--- a/codex-rs/codex-api/src/endpoint/models.rs
+++ b/codex-rs/codex-api/src/endpoint/models.rs
@@ -6,6 +6,7 @@ use codex_client::HttpTransport;
 use codex_client::RequestTelemetry;
 use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelsResponse;
+use codex_utils_log::bounded_bytes_lossy;
 use http::HeaderMap;
 use http::Method;
 use http::header::ETAG;
@@ -65,7 +66,7 @@ impl<T: HttpTransport> ModelsClient<T> {
             .map_err(|e| {
                 ApiError::Stream(format!(
                     "failed to decode models response: {e}; body: {}",
-                    String::from_utf8_lossy(&resp.body)
+                    bounded_bytes_lossy(&resp.body)
                 ))
             })?;
 
diff --git a/codex-rs/codex-api/src/endpoint/realtime_call.rs b/codex-rs/codex-api/src/endpoint/realtime_call.rs
index b0342c53498d..3a4eec43b8ba 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_call.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_call.rs
@@ -8,6 +8,7 @@ use bytes::Bytes;
 use codex_client::HttpTransport;
 use codex_client::RequestBody;
 use codex_client::RequestTelemetry;
+use codex_utils_log::bounded_str;
 use http::HeaderMap;
 use http::HeaderValue;
 use http::Method;
@@ -119,7 +120,7 @@ impl<T: HttpTransport> RealtimeCallClient<T> {
         session_config: RealtimeSessionConfig,
         extra_headers: HeaderMap,
     ) -> Result<RealtimeCallResponse, ApiError> {
-        trace!(target: "codex_api::realtime_websocket::wire", "realtime call request SDP: {sdp}");
+        trace!(target: "codex_api::realtime_websocket::wire", "realtime call request SDP: {}", bounded_str(&sdp));
         // WebRTC can begin inference as soon as the peer connection comes up, so the initial
         // session payload is sent with call creation. The sideband WebSocket still sends its normal
         // session.update after it joins.
@@ -202,7 +203,7 @@ fn decode_call_id_from_location(headers: &HeaderMap) -> Result<String, ApiError>
         .ok_or_else(|| ApiError::Stream("realtime call response missing Location".to_string()))?
         .to_str()
         .map_err(|err| ApiError::Stream(format!("invalid realtime call Location: {err}")))?;
-    trace!("realtime call Location: {location}");
+    trace!("realtime call Location: {}", bounded_str(location));
 
     location
         .split('?')
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs
index 9fcca1c3e318..b776d713814d 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/methods.rs
@@ -18,6 +18,8 @@ use crate::provider::Provider;
 use codex_client::backoff;
 use codex_client::maybe_build_rustls_client_config_with_custom_ca;
 use codex_protocol::protocol::RealtimeTranscriptDelta;
+use codex_utils_log::bounded_debug;
+use codex_utils_log::bounded_str;
 use codex_utils_rustls_provider::ensure_rustls_crypto_provider;
 use futures::SinkExt;
 use futures::StreamExt;
@@ -345,7 +347,7 @@ impl RealtimeWebsocketWriter {
     async fn send_json(&self, message: &RealtimeOutboundMessage) -> Result<(), ApiError> {
         let payload = serde_json::to_string(message)
             .map_err(|err| ApiError::Stream(format!("failed to encode realtime request: {err}")))?;
-        debug!(?message, "realtime websocket request");
+        debug!(message = %bounded_debug(message), "realtime websocket request");
         self.send_payload(payload).await
     }
 
@@ -356,7 +358,7 @@ impl RealtimeWebsocketWriter {
             ));
         }
 
-        trace!(target: REALTIME_WIRE_LOG_TARGET, "realtime websocket request: {payload}");
+        trace!(target: REALTIME_WIRE_LOG_TARGET, "realtime websocket request: {}", bounded_str(&payload));
         self.stream
             .send(Message::Text(payload.into()))
             .await
@@ -390,10 +392,10 @@ impl RealtimeWebsocketEvents {
 
             match msg {
                 Message::Text(text) => {
-                    trace!(target: REALTIME_WIRE_LOG_TARGET, "realtime websocket event: {text}");
+                    trace!(target: REALTIME_WIRE_LOG_TARGET, "realtime websocket event: {}", bounded_str(&text));
                     if let Some(mut event) = parse_realtime_event(&text, self.event_parser) {
                         self.update_active_transcript(&mut event).await;
-                        debug!(?event, "realtime websocket parsed event");
+                        debug!(event = %bounded_debug(&event), "realtime websocket parsed event");
                         return Ok(Some(event));
                     }
                     debug!("realtime websocket ignored unsupported text frame");
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_common.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_common.rs
index 2c96280672f0..e5f9b0431189 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_common.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_common.rs
@@ -1,6 +1,7 @@
 use codex_protocol::protocol::RealtimeEvent;
 use codex_protocol::protocol::RealtimeTranscriptDelta;
 use codex_protocol::protocol::RealtimeTranscriptDone;
+use codex_utils_log::bounded_str;
 use serde_json::Value;
 use tracing::debug;
 
@@ -8,7 +9,10 @@ pub(super) fn parse_realtime_payload(payload: &str, parser_name: &str) -> Option
     let parsed: Value = match serde_json::from_str(payload) {
         Ok(message) => message,
         Err(err) => {
-            debug!("failed to parse {parser_name} event: {err}, data: {payload}");
+            debug!(
+                "failed to parse {parser_name} event: {err}, data: {}",
+                bounded_str(payload)
+            );
             return None;
         }
     };
@@ -16,7 +20,10 @@ pub(super) fn parse_realtime_payload(payload: &str, parser_name: &str) -> Option
     let message_type = match parsed.get("type").and_then(Value::as_str) {
         Some(message_type) => message_type.to_string(),
         None => {
-            debug!("received {parser_name} event without type field: {payload}");
+            debug!(
+                "received {parser_name} event without type field: {}",
+                bounded_str(payload)
+            );
             return None;
         }
     };
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs
index 3c1d25aed755..43cfbdd6a181 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v1.rs
@@ -6,6 +6,7 @@ use crate::endpoint::realtime_websocket::protocol_common::parse_transcript_done_
 use codex_protocol::protocol::RealtimeAudioFrame;
 use codex_protocol::protocol::RealtimeEvent;
 use codex_protocol::protocol::RealtimeHandoffRequested;
+use codex_utils_log::bounded_str;
 use serde_json::Value;
 use tracing::debug;
 
@@ -83,7 +84,10 @@ pub(super) fn parse_realtime_event_v1(payload: &str) -> Option<RealtimeEvent> {
         }
         "error" => parse_error_event(&parsed),
         _ => {
-            debug!("received unsupported realtime v1 event type: {message_type}, data: {payload}");
+            debug!(
+                "received unsupported realtime v1 event type: {message_type}, data: {}",
+                bounded_str(payload)
+            );
             None
         }
     }
diff --git a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v2.rs b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v2.rs
index ee0bba994614..a187be24f256 100644
--- a/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v2.rs
+++ b/codex-rs/codex-api/src/endpoint/realtime_websocket/protocol_v2.rs
@@ -11,6 +11,7 @@ use codex_protocol::protocol::RealtimeNoopRequested;
 use codex_protocol::protocol::RealtimeResponseCancelled;
 use codex_protocol::protocol::RealtimeResponseCreated;
 use codex_protocol::protocol::RealtimeResponseDone;
+use codex_utils_log::bounded_str;
 use serde_json::Map as JsonMap;
 use serde_json::Value;
 use tracing::debug;
@@ -72,7 +73,10 @@ pub(super) fn parse_realtime_event_v2(payload: &str) -> Option<RealtimeEvent> {
         })),
         "error" => parse_error_event(&parsed),
         _ => {
-            debug!("received unsupported realtime v2 event type: {message_type}, data: {payload}");
+            debug!(
+                "received unsupported realtime v2 event type: {message_type}, data: {}",
+                bounded_str(payload)
+            );
             None
         }
     }
diff --git a/codex-rs/codex-api/src/endpoint/responses_websocket.rs b/codex-rs/codex-api/src/endpoint/responses_websocket.rs
index f0a001981725..f8438214d214 100644
--- a/codex-rs/codex-api/src/endpoint/responses_websocket.rs
+++ b/codex-rs/codex-api/src/endpoint/responses_websocket.rs
@@ -11,6 +11,7 @@ use crate::sse::process_responses_event;
 use crate::telemetry::WebsocketTelemetry;
 use codex_client::TransportError;
 use codex_client::maybe_build_rustls_client_config_with_custom_ca;
+use codex_utils_log::bounded_str;
 use codex_utils_rustls_provider::ensure_rustls_crypto_provider;
 use futures::SinkExt;
 use futures::StreamExt;
@@ -702,7 +703,7 @@ async fn run_websocket_response_stream(
 
         match message {
             Message::Text(text) => {
-                trace!("websocket event: {text}");
+                trace!("websocket event: {}", bounded_str(&text));
                 if let Some(wrapped_error) = parse_wrapped_websocket_error_event(&text)
                     && let Some(error) =
                         map_wrapped_websocket_error_event(wrapped_error, text.to_string())
@@ -713,7 +714,10 @@ async fn run_websocket_response_stream(
                 let event = match serde_json::from_str::<ResponsesStreamEvent>(&text) {
                     Ok(event) => event,
                     Err(err) => {
-                        debug!("failed to parse websocket event: {err}, data: {text}");
+                        debug!(
+                            "failed to parse websocket event: {err}, data: {}",
+                            bounded_str(&text)
+                        );
                         continue;
                     }
                 };
@@ -787,7 +791,7 @@ async fn send_websocket_request(
             )));
         }
     };
-    trace!("websocket request: {request_text}");
+    trace!("websocket request: {}", bounded_str(&request_text));
 
     let request_start = Instant::now();
     let result = tokio::time::timeout(
diff --git a/codex-rs/codex-api/src/sse/responses.rs b/codex-rs/codex-api/src/sse/responses.rs
index c9f35e5a4ec8..cba1689e95df 100644
--- a/codex-rs/codex-api/src/sse/responses.rs
+++ b/codex-rs/codex-api/src/sse/responses.rs
@@ -8,6 +8,7 @@ use codex_client::StreamResponse;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::protocol::ModelVerification;
 use codex_protocol::protocol::TokenUsage;
+use codex_utils_log::bounded_str;
 use eventsource_stream::Eventsource;
 use futures::StreamExt;
 use serde::Deserialize;
@@ -415,7 +416,7 @@ pub async fn process_sse(
         let sse = match response {
             Ok(Some(Ok(sse))) => sse,
             Ok(Some(Err(e))) => {
-                debug!("SSE Error: {e:#}");
+                debug!("SSE Error: {}", bounded_str(&format!("{e:#}")));
                 let _ = tx_event.send(Err(ApiError::Stream(e.to_string()))).await;
                 return;
             }
@@ -434,12 +435,15 @@ pub async fn process_sse(
             }
         };
 
-        trace!("SSE event: {}", &sse.data);
+        trace!("SSE event: {}", bounded_str(&sse.data));
 
         let event: ResponsesStreamEvent = match serde_json::from_str(&sse.data) {
             Ok(event) => event,
             Err(e) => {
-                debug!("Failed to parse SSE event: {e}, data: {}", &sse.data);
+                debug!(
+                    "Failed to parse SSE event: {e}, data: {}",
+                    bounded_str(&sse.data)
+                );
                 continue;
             }
         };
diff --git a/codex-rs/core/Cargo.toml b/codex-rs/core/Cargo.toml
index 8472918dcae9..7756176a4556 100644
--- a/codex-rs/core/Cargo.toml
+++ b/codex-rs/core/Cargo.toml
@@ -65,6 +65,7 @@ codex-utils-absolute-path = { workspace = true }
 codex-utils-cache = { workspace = true }
 codex-utils-image = { workspace = true }
 codex-utils-home-dir = { workspace = true }
+codex-utils-log = { workspace = true }
 codex-utils-output-truncation = { workspace = true }
 codex-utils-path = { workspace = true }
 codex-utils-plugins = { workspace = true }
diff --git a/codex-rs/core/src/mcp_tool_call.rs b/codex-rs/core/src/mcp_tool_call.rs
index 8f6e3afaf5af..b65b9686cb6f 100644
--- a/codex-rs/core/src/mcp_tool_call.rs
+++ b/codex-rs/core/src/mcp_tool_call.rs
@@ -80,6 +80,7 @@ use codex_rmcp_client::ElicitationAction;
 use codex_rmcp_client::ElicitationResponse;
 use codex_rollout::state_db;
 use codex_utils_absolute_path::AbsolutePathBuf;
+use codex_utils_log::bounded_debug;
 use codex_utils_output_truncation::TruncationPolicy;
 use codex_utils_output_truncation::truncate_text;
 use codex_utils_pty::DEFAULT_OUTPUT_BYTES_CAP;
@@ -373,7 +374,7 @@ async fn handle_approved_mcp_tool_call(
     ))
     .await;
     if let Err(error) = &result {
-        tracing::warn!("MCP tool call error: {error:?}");
+        tracing::warn!("MCP tool call error: {}", bounded_debug(error));
     }
     let duration = start.elapsed();
     notify_mcp_tool_call_completed(
diff --git a/codex-rs/core/src/realtime_conversation.rs b/codex-rs/core/src/realtime_conversation.rs
index 249b3ae15f46..06332dc1ceb7 100644
--- a/codex-rs/core/src/realtime_conversation.rs
+++ b/codex-rs/core/src/realtime_conversation.rs
@@ -45,6 +45,7 @@ use codex_protocol::protocol::RealtimeHandoffRequested;
 use codex_protocol::protocol::RealtimeOutputModality;
 use codex_protocol::protocol::RealtimeVoice;
 use codex_protocol::protocol::RealtimeVoicesList;
+use codex_utils_log::bounded_debug;
 use http::HeaderMap;
 use http::HeaderValue;
 use http::header::AUTHORIZATION;
@@ -834,7 +835,7 @@ async fn handle_start_inner(
                 RealtimeEvent::AudioOut(_) => {}
                 _ => {
                     info!(
-                        event = ?event,
+                        event = %bounded_debug(&event),
                         "received realtime conversation event"
                     );
                 }
diff --git a/codex-rs/core/src/session/handlers.rs b/codex-rs/core/src/session/handlers.rs
index a26b9bb3f6fe..3a065477860f 100644
--- a/codex-rs/core/src/session/handlers.rs
+++ b/codex-rs/core/src/session/handlers.rs
@@ -5,6 +5,7 @@ use crate::realtime_conversation::handle_text as handle_realtime_conversation_te
 use async_channel::Receiver;
 use codex_otel::set_parent_from_w3c_trace_context;
 use codex_protocol::protocol::Submission;
+use codex_utils_log::bounded_debug;
 use tracing::Instrument;
 use tracing::debug_span;
 use tracing::info_span;
@@ -738,7 +739,7 @@ pub(super) async fn submission_loop(
     // To break out of this loop, send Op::Shutdown.
     let mut shutdown_received = false;
     while let Ok(sub) = rx_sub.recv().await {
-        debug!(?sub, "Submission");
+        debug!(submission = %bounded_debug(&sub), "Submission");
         let dispatch_span = submission_dispatch_span(&sub);
         let should_exit = async {
             match sub.op.clone() {
diff --git a/codex-rs/core/src/session/turn.rs b/codex-rs/core/src/session/turn.rs
index aee4bd360ff5..910b89069b12 100644
--- a/codex-rs/core/src/session/turn.rs
+++ b/codex-rs/core/src/session/turn.rs
@@ -3,6 +3,8 @@ use std::collections::HashSet;
 use std::sync::Arc;
 use std::sync::atomic::Ordering;
 
+use codex_utils_log::bounded_str;
+
 use crate::SkillInjections;
 use crate::SkillLoadOutcome;
 use crate::build_skill_injections;
@@ -662,7 +664,7 @@ pub(crate) async fn run_turn(
                 break;
             }
             Err(e) => {
-                info!("Turn error: {e:#}");
+                info!("Turn error: {}", bounded_str(&format!("{e:#}")));
                 let event = EventMsg::Error(e.to_error_event(/*message_prefix*/ None));
                 sess.send_event(&turn_context, event).await;
                 // let the user continue the conversation
diff --git a/codex-rs/core/src/stream_events_utils.rs b/codex-rs/core/src/stream_events_utils.rs
index bc44fe0c3b07..a17a1ec59e69 100644
--- a/codex-rs/core/src/stream_events_utils.rs
+++ b/codex-rs/core/src/stream_events_utils.rs
@@ -29,6 +29,7 @@ use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
 use codex_rollout::state_db;
 use codex_utils_absolute_path::AbsolutePathBuf;
+use codex_utils_log::bounded_debug;
 use codex_utils_stream_parser::strip_proposed_plan_blocks;
 use futures::Future;
 use tracing::debug;
@@ -454,7 +455,7 @@ pub(crate) async fn handle_non_tool_response_item(
     item: &ResponseItem,
     plan_mode: bool,
 ) -> Option<TurnItem> {
-    debug!(?item, "Output item");
+    debug!(item = %bounded_debug(item), "Output item");
 
     match item {
         ResponseItem::Message { .. }
diff --git a/codex-rs/login/Cargo.toml b/codex-rs/login/Cargo.toml
index e914fa0c7a98..e23c3d57ec07 100644
--- a/codex-rs/login/Cargo.toml
+++ b/codex-rs/login/Cargo.toml
@@ -20,6 +20,7 @@ codex-model-provider-info = { workspace = true }
 codex-otel = { workspace = true }
 codex-protocol = { workspace = true }
 codex-terminal-detection = { workspace = true }
+codex-utils-log = { workspace = true }
 codex-utils-template = { workspace = true }
 once_cell = { workspace = true }
 os_info = { workspace = true }
diff --git a/codex-rs/login/src/auth/manager.rs b/codex-rs/login/src/auth/manager.rs
index a2e4e8e0d866..aacbf8470394 100644
--- a/codex-rs/login/src/auth/manager.rs
+++ b/codex-rs/login/src/auth/manager.rs
@@ -42,6 +42,7 @@ use codex_protocol::account::PlanType as AccountPlanType;
 use codex_protocol::auth::PlanType as InternalPlanType;
 use codex_protocol::auth::RefreshTokenFailedError;
 use codex_protocol::auth::RefreshTokenFailedReason;
+use codex_utils_log::bounded_str;
 use serde_json::Value;
 use thiserror::Error;
 
@@ -842,7 +843,7 @@ async fn request_chatgpt_token_refresh(
         Ok(refresh_response)
     } else {
         let body = response.text().await.unwrap_or_default();
-        tracing::error!("Failed to refresh token: {status}: {body}");
+        tracing::error!("Failed to refresh token: {status}: {}", bounded_str(&body));
         if status == StatusCode::UNAUTHORIZED {
             let failed = classify_refresh_token_failure(&body);
             Err(RefreshTokenError::Permanent(failed))
@@ -869,7 +870,7 @@ fn classify_refresh_token_failure(body: &str) -> RefreshTokenFailedError {
     if reason == RefreshTokenFailedReason::Other {
         tracing::warn!(
             backend_code = normalized_code.as_deref(),
-            backend_body = body,
+            backend_body = %bounded_str(body),
             "Encountered unknown 401 response while refreshing token"
         );
     }
diff --git a/codex-rs/login/src/auth/util.rs b/codex-rs/login/src/auth/util.rs
index a993bbf4a378..efa9b94b61dc 100644
--- a/codex-rs/login/src/auth/util.rs
+++ b/codex-rs/login/src/auth/util.rs
@@ -1,7 +1,8 @@
+use codex_utils_log::bounded_str;
 use tracing::debug;
 
 pub(crate) fn try_parse_error_message(text: &str) -> String {
-    debug!("Parsing server error response: {}", text);
+    debug!("Parsing server error response: {}", bounded_str(text));
     let json = serde_json::from_str::<serde_json::Value>(text).unwrap_or_default();
     if let Some(error) = json.get("error")
         && let Some(message) = error.get("message")
diff --git a/codex-rs/rmcp-client/Cargo.toml b/codex-rs/rmcp-client/Cargo.toml
index 0efd8a4178aa..0b7f8b264ca8 100644
--- a/codex-rs/rmcp-client/Cargo.toml
+++ b/codex-rs/rmcp-client/Cargo.toml
@@ -20,6 +20,7 @@ codex-config = { workspace = true }
 codex-exec-server = { workspace = true }
 codex-keyring-store = { workspace = true }
 codex-protocol = { workspace = true }
+codex-utils-log = { workspace = true }
 codex-utils-pty = { workspace = true }
 codex-utils-home-dir = { workspace = true }
 bytes = { workspace = true }
diff --git a/codex-rs/rmcp-client/src/executor_process_transport.rs b/codex-rs/rmcp-client/src/executor_process_transport.rs
index 41f0b7660d95..fffe0cf190b1 100644
--- a/codex-rs/rmcp-client/src/executor_process_transport.rs
+++ b/codex-rs/rmcp-client/src/executor_process_transport.rs
@@ -20,7 +20,6 @@
 
 use std::future::Future;
 use std::io;
-use std::mem::take;
 use std::sync::Arc;
 use std::sync::atomic::AtomicUsize;
 use std::sync::atomic::Ordering;
@@ -41,9 +40,10 @@ use serde_json::to_vec;
 use tokio::runtime::Handle;
 use tokio::sync::broadcast;
 use tracing::debug;
-use tracing::info;
 use tracing::warn;
 
+use crate::stderr_log::StderrLogBuffer;
+
 static PROCESS_COUNTER: AtomicUsize = AtomicUsize::new(1);
 
 // Remote public implementation.
@@ -76,7 +76,7 @@ pub(super) struct ExecutorProcessTransport {
     stdout: Vec<u8>,
 
     /// Buffered stderr bytes for diagnostic logging.
-    stderr: Vec<u8>,
+    stderr: StderrLogBuffer,
 
     /// Whether the executor has reported process closure or a terminal
     /// subscription failure. Once closed, any remaining partial stdout line is
@@ -101,12 +101,13 @@ impl ExecutorProcessTransport {
         // process event log will replay anything that landed before this
         // subscriber was attached.
         let events = process.subscribe_events();
+        let stderr = StderrLogBuffer::new(program_name.clone());
         Self {
             process,
             events,
             program_name,
             stdout: Vec::new(),
-            stderr: Vec::new(),
+            stderr,
             closed: false,
             terminated: false,
             last_seq: 0,
@@ -312,33 +313,11 @@ impl ExecutorProcessTransport {
     }
 
     fn push_stderr(&mut self, bytes: &[u8]) {
-        // Keep stderr line-oriented in logs so a chatty MCP server does not
-        // produce one log record per byte chunk.
-        self.stderr.extend_from_slice(bytes);
-        while let Some(index) = self.stderr.iter().position(|byte| *byte == b'\n') {
-            let mut line = self.stderr.drain(..=index).collect::<Vec<_>>();
-            line.pop();
-            if line.last() == Some(&b'\r') {
-                line.pop();
-            }
-            info!(
-                "MCP server stderr ({}): {}",
-                self.program_name,
-                String::from_utf8_lossy(&line)
-            );
-        }
+        self.stderr.push(bytes);
     }
 
     fn flush_stderr(&mut self) {
-        if self.stderr.is_empty() {
-            return;
-        }
-        let line = take(&mut self.stderr);
-        info!(
-            "MCP server stderr ({}): {}",
-            self.program_name,
-            String::from_utf8_lossy(&line)
-        );
+        self.stderr.flush();
     }
 
     fn trim_trailing_carriage_return(mut line: Vec<u8>) -> Vec<u8> {
diff --git a/codex-rs/rmcp-client/src/lib.rs b/codex-rs/rmcp-client/src/lib.rs
index e1ee18c75324..79da406c0542 100644
--- a/codex-rs/rmcp-client/src/lib.rs
+++ b/codex-rs/rmcp-client/src/lib.rs
@@ -8,6 +8,7 @@ mod oauth;
 mod perform_oauth_login;
 mod program_resolver;
 mod rmcp_client;
+mod stderr_log;
 mod stdio_server_launcher;
 mod utils;
 
diff --git a/codex-rs/rmcp-client/src/logging_client_handler.rs b/codex-rs/rmcp-client/src/logging_client_handler.rs
index 0c3da0fe2cd1..df126d058c0d 100644
--- a/codex-rs/rmcp-client/src/logging_client_handler.rs
+++ b/codex-rs/rmcp-client/src/logging_client_handler.rs
@@ -1,5 +1,7 @@
 use std::sync::Arc;
 
+use codex_utils_log::bounded_debug;
+use codex_utils_log::bounded_display;
 use rmcp::ClientHandler;
 use rmcp::RoleClient;
 use rmcp::model::CancelledNotificationParam;
@@ -12,7 +14,9 @@ use rmcp::model::ProgressNotificationParam;
 use rmcp::model::ResourceUpdatedNotificationParam;
 use rmcp::service::NotificationContext;
 use rmcp::service::RequestContext;
+use tracing::Level;
 use tracing::debug;
+use tracing::enabled;
 use tracing::error;
 use tracing::info;
 use tracing::warn;
@@ -51,9 +55,11 @@ impl ClientHandler for LoggingClientHandler {
         params: CancelledNotificationParam,
         _context: NotificationContext<RoleClient>,
     ) {
+        let request_id = bounded_display(&params.request_id);
+        let reason = bounded_debug(&params.reason);
         info!(
-            "MCP server cancelled request (request_id: {}, reason: {:?})",
-            params.request_id, params.reason
+            "MCP server cancelled request (request_id: {}, reason: {})",
+            request_id, reason
         );
     }
 
@@ -62,9 +68,11 @@ impl ClientHandler for LoggingClientHandler {
         params: ProgressNotificationParam,
         _context: NotificationContext<RoleClient>,
     ) {
+        let progress_token = bounded_debug(&params.progress_token);
+        let message = bounded_debug(&params.message);
         info!(
-            "MCP server progress notification (token: {:?}, progress: {}, total: {:?}, message: {:?})",
-            params.progress_token, params.progress, params.total, params.message
+            "MCP server progress notification (token: {}, progress: {}, total: {:?}, message: {})",
+            progress_token, params.progress, params.total, message
         );
     }
 
@@ -73,7 +81,8 @@ impl ClientHandler for LoggingClientHandler {
         params: ResourceUpdatedNotificationParam,
         _context: NotificationContext<RoleClient>,
     ) {
-        info!("MCP server resource updated (uri: {})", params.uri);
+        let uri = bounded_display(&params.uri);
+        info!("MCP server resource updated (uri: {})", uri);
     }
 
     async fn on_resource_list_changed(&self, _context: NotificationContext<RoleClient>) {
@@ -108,28 +117,44 @@ impl ClientHandler for LoggingClientHandler {
             | LoggingLevel::Alert
             | LoggingLevel::Critical
             | LoggingLevel::Error => {
-                error!(
-                    "MCP server log message (level: {:?}, logger: {:?}, data: {})",
-                    level, logger, data
-                );
+                if enabled!(Level::ERROR) {
+                    let logger = bounded_debug(&logger);
+                    let data = bounded_display(&data);
+                    error!(
+                        "MCP server log message (level: {:?}, logger: {}, data: {})",
+                        level, logger, data
+                    );
+                }
             }
             LoggingLevel::Warning => {
-                warn!(
-                    "MCP server log message (level: {:?}, logger: {:?}, data: {})",
-                    level, logger, data
-                );
+                if enabled!(Level::WARN) {
+                    let logger = bounded_debug(&logger);
+                    let data = bounded_display(&data);
+                    warn!(
+                        "MCP server log message (level: {:?}, logger: {}, data: {})",
+                        level, logger, data
+                    );
+                }
             }
             LoggingLevel::Notice | LoggingLevel::Info => {
-                info!(
-                    "MCP server log message (level: {:?}, logger: {:?}, data: {})",
-                    level, logger, data
-                );
+                if enabled!(Level::INFO) {
+                    let logger = bounded_debug(&logger);
+                    let data = bounded_display(&data);
+                    info!(
+                        "MCP server log message (level: {:?}, logger: {}, data: {})",
+                        level, logger, data
+                    );
+                }
             }
             LoggingLevel::Debug => {
-                debug!(
-                    "MCP server log message (level: {:?}, logger: {:?}, data: {})",
-                    level, logger, data
-                );
+                if enabled!(Level::DEBUG) {
+                    let logger = bounded_debug(&logger);
+                    let data = bounded_display(&data);
+                    debug!(
+                        "MCP server log message (level: {:?}, logger: {}, data: {})",
+                        level, logger, data
+                    );
+                }
             }
         }
     }
diff --git a/codex-rs/rmcp-client/src/stderr_log.rs b/codex-rs/rmcp-client/src/stderr_log.rs
new file mode 100644
index 000000000000..2b318b7f7df6
--- /dev/null
+++ b/codex-rs/rmcp-client/src/stderr_log.rs
@@ -0,0 +1,110 @@
+use codex_utils_log::DEFAULT_BOUNDED_LOG_VALUE_BYTES;
+use codex_utils_log::bounded_bytes_lossy;
+use tracing::info;
+
+pub(crate) struct StderrLogBuffer {
+    program_name: String,
+    buffer: Vec<u8>,
+}
+
+impl StderrLogBuffer {
+    pub(crate) fn new(program_name: String) -> Self {
+        Self {
+            program_name,
+            buffer: Vec::new(),
+        }
+    }
+
+    pub(crate) fn push(&mut self, mut bytes: &[u8]) {
+        while !bytes.is_empty() {
+            if let Some(newline_index) = bytes.iter().position(|byte| *byte == b'\n') {
+                self.push_without_newline(&bytes[..newline_index]);
+                self.log_complete_line();
+                bytes = &bytes[newline_index + 1..];
+            } else {
+                self.push_without_newline(bytes);
+                return;
+            }
+        }
+    }
+
+    pub(crate) fn flush(&mut self) {
+        if self.buffer.is_empty() {
+            return;
+        }
+        self.log_line("MCP server stderr");
+        self.buffer.clear();
+    }
+
+    fn push_without_newline(&mut self, mut bytes: &[u8]) {
+        while !bytes.is_empty() {
+            let remaining_capacity =
+                DEFAULT_BOUNDED_LOG_VALUE_BYTES.saturating_sub(self.buffer.len());
+            if remaining_capacity == 0 {
+                self.log_line("MCP server stderr line exceeded limit");
+                self.buffer.clear();
+                continue;
+            }
+
+            let chunk_len = remaining_capacity.min(bytes.len());
+            self.buffer.extend_from_slice(&bytes[..chunk_len]);
+            bytes = &bytes[chunk_len..];
+
+            if self.buffer.len() >= DEFAULT_BOUNDED_LOG_VALUE_BYTES {
+                self.log_line("MCP server stderr line exceeded limit");
+                self.buffer.clear();
+            }
+        }
+    }
+
+    fn log_complete_line(&mut self) {
+        if self.buffer.last() == Some(&b'\r') {
+            self.buffer.pop();
+        }
+        if self.buffer.is_empty() {
+            return;
+        }
+        self.log_line("MCP server stderr");
+        self.buffer.clear();
+    }
+
+    fn log_line(&self, label: &str) {
+        info!(
+            "{} ({}): {}",
+            label,
+            self.program_name,
+            bounded_bytes_lossy(&self.buffer)
+        );
+    }
+
+    #[cfg(test)]
+    fn buffered_len(&self) -> usize {
+        self.buffer.len()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use pretty_assertions::assert_eq;
+
+    use super::*;
+
+    #[test]
+    fn push_without_newline_does_not_grow_past_log_limit() {
+        let mut buffer = StderrLogBuffer::new("server".to_string());
+        let bytes = vec![b'a'; DEFAULT_BOUNDED_LOG_VALUE_BYTES * 2 + 17];
+
+        buffer.push(&bytes);
+
+        assert_eq!(17, buffer.buffered_len());
+    }
+
+    #[test]
+    fn push_newline_clears_buffer() {
+        let mut buffer = StderrLogBuffer::new("server".to_string());
+
+        buffer.push(b"hello\n");
+
+        assert_eq!(0, buffer.buffered_len());
+    }
+}
diff --git a/codex-rs/rmcp-client/src/stdio_server_launcher.rs b/codex-rs/rmcp-client/src/stdio_server_launcher.rs
index 9928511bb6c7..6b3e5ee4433c 100644
--- a/codex-rs/rmcp-client/src/stdio_server_launcher.rs
+++ b/codex-rs/rmcp-client/src/stdio_server_launcher.rs
@@ -46,14 +46,13 @@ use rmcp::service::RxJsonRpcMessage;
 use rmcp::service::TxJsonRpcMessage;
 use rmcp::transport::Transport;
 use rmcp::transport::child_process::TokioChildProcess;
-use tokio::io::AsyncBufReadExt;
-use tokio::io::BufReader;
+use tokio::io::AsyncReadExt;
 use tokio::process::Command;
-use tracing::info;
 use tracing::warn;
 
 use crate::executor_process_transport::ExecutorProcessTransport;
 use crate::program_resolver;
+use crate::stderr_log::StderrLogBuffer;
 use crate::utils::create_env_for_mcp_server;
 use crate::utils::create_env_overlay_for_remote_mcp_server;
 use crate::utils::remote_mcp_env_var_names;
@@ -272,13 +271,16 @@ impl LocalStdioServerLauncher {
 
         if let Some(stderr) = stderr {
             tokio::spawn(async move {
-                let mut reader = BufReader::new(stderr).lines();
+                let mut stderr = stderr;
+                let mut stderr_log = StderrLogBuffer::new(program_name.clone());
+                let mut buffer = [0_u8; 8192];
                 loop {
-                    match reader.next_line().await {
-                        Ok(Some(line)) => {
-                            info!("MCP server stderr ({program_name}): {line}");
+                    match stderr.read(&mut buffer).await {
+                        Ok(0) => {
+                            stderr_log.flush();
+                            break;
                         }
-                        Ok(None) => break,
+                        Ok(bytes_read) => stderr_log.push(&buffer[..bytes_read]),
                         Err(error) => {
                             warn!("Failed to read MCP server stderr ({program_name}): {error}");
                             break;
diff --git a/codex-rs/tui/Cargo.toml b/codex-rs/tui/Cargo.toml
index c213e92bae41..4696f83d489a 100644
--- a/codex-rs/tui/Cargo.toml
+++ b/codex-rs/tui/Cargo.toml
@@ -62,6 +62,7 @@ codex-utils-cli = { workspace = true }
 codex-utils-elapsed = { workspace = true }
 codex-utils-fuzzy-match = { workspace = true }
 codex-utils-home-dir = { workspace = true }
+codex-utils-log = { workspace = true }
 codex-utils-oss = { workspace = true }
 codex-utils-path = { workspace = true }
 codex-utils-plugins = { workspace = true }
diff --git a/codex-rs/tui/src/app/app_server_events.rs b/codex-rs/tui/src/app/app_server_events.rs
index 413e8b8c8070..a301eed38fbc 100644
--- a/codex-rs/tui/src/app/app_server_events.rs
+++ b/codex-rs/tui/src/app/app_server_events.rs
@@ -121,7 +121,10 @@ impl App {
                 };
 
                 if let Err(err) = result {
-                    tracing::warn!("failed to enqueue app-server notification: {err}");
+                    tracing::warn!(
+                        "failed to enqueue app-server notification: {}",
+                        codex_utils_log::bounded_display(&err)
+                    );
                 }
                 return;
             }
@@ -180,7 +183,10 @@ impl App {
                 self.enqueue_thread_request(thread_id, request).await
             };
         if let Err(err) = result {
-            tracing::warn!("failed to enqueue app-server request: {err}");
+            tracing::warn!(
+                "failed to enqueue app-server request: {}",
+                codex_utils_log::bounded_display(&err)
+            );
         }
     }
 }
diff --git a/codex-rs/tui/src/app_event_sender.rs b/codex-rs/tui/src/app_event_sender.rs
index 5b8da9ec09d7..1d89a851008f 100644
--- a/codex-rs/tui/src/app_event_sender.rs
+++ b/codex-rs/tui/src/app_event_sender.rs
@@ -39,7 +39,10 @@ impl AppEventSender {
             session_log::log_inbound_app_event(&event);
         }
         if let Err(e) = self.app_event_tx.send(event) {
-            tracing::error!("failed to send event: {e}");
+            tracing::error!(
+                "failed to send event: {}",
+                codex_utils_log::bounded_display(&e)
+            );
         }
     }
 
diff --git a/codex-rs/tui/src/bottom_pane/chat_composer.rs b/codex-rs/tui/src/bottom_pane/chat_composer.rs
index e76b4c0b96a5..80fa6695b056 100644
--- a/codex-rs/tui/src/bottom_pane/chat_composer.rs
+++ b/codex-rs/tui/src/bottom_pane/chat_composer.rs
@@ -216,6 +216,7 @@ use codex_protocol::ThreadId;
 use codex_protocol::user_input::ByteRange;
 use codex_protocol::user_input::MAX_USER_INPUT_TEXT_CHARS;
 use codex_protocol::user_input::TextElement;
+use codex_utils_log::bounded_str;
 
 mod attachment_state;
 mod draft_state;
@@ -900,7 +901,7 @@ impl ChatComposer {
         // so we can directly try to read the image dimensions.
         match image::image_dimensions(&path_buf) {
             Ok((width, height)) => {
-                tracing::info!("OK: {pasted}");
+                tracing::info!("OK: {}", bounded_str(&pasted));
                 tracing::debug!("image dimensions={}x{}", width, height);
                 let format = pasted_image_format(&path_buf);
                 tracing::debug!("attached image format={}", format.label());
diff --git a/codex-rs/tui/src/chatwidget/protocol_requests.rs b/codex-rs/tui/src/chatwidget/protocol_requests.rs
index 5b53f44fdf8f..187e3aa1d14b 100644
--- a/codex-rs/tui/src/chatwidget/protocol_requests.rs
+++ b/codex-rs/tui/src/chatwidget/protocol_requests.rs
@@ -137,7 +137,10 @@ impl ChatWidget {
     }
 
     pub(super) fn on_turn_diff(&mut self, unified_diff: String) {
-        debug!("TurnDiffEvent: {unified_diff}");
+        debug!(
+            "TurnDiffEvent: {}",
+            codex_utils_log::bounded_str(&unified_diff)
+        );
         self.refresh_status_line();
     }
 
diff --git a/codex-rs/tui/src/lib.rs b/codex-rs/tui/src/lib.rs
index 871cdcc0dd90..6d57c25afa41 100644
--- a/codex-rs/tui/src/lib.rs
+++ b/codex-rs/tui/src/lib.rs
@@ -1216,7 +1216,7 @@ async fn run_ratatui_app(
     // (including backtraces) after we restore the terminal.
     let prev_hook = std::panic::take_hook();
     std::panic::set_hook(Box::new(move |info| {
-        tracing::error!("panic: {info}");
+        tracing::error!("panic: {}", codex_utils_log::bounded_display(info));
         prev_hook(info);
     }));
     let mut terminal = tui::init()?;
diff --git a/codex-rs/tui/src/markdown_stream.rs b/codex-rs/tui/src/markdown_stream.rs
index 66b5cab121f7..d9c993914544 100644
--- a/codex-rs/tui/src/markdown_stream.rs
+++ b/codex-rs/tui/src/markdown_stream.rs
@@ -8,6 +8,9 @@
 //! On finalization, `finalize_and_drain_source()` flushes whatever remains (the last line, which
 //! may lack a trailing newline).
 
+use codex_utils_log::bounded_debug;
+#[cfg(test)]
+use codex_utils_log::bounded_str;
 #[cfg(test)]
 use ratatui::text::Line;
 use std::path::Path;
@@ -75,7 +78,7 @@ impl MarkdownStreamCollector {
 
     /// Append a raw streaming delta to the internal source buffer.
     pub fn push_delta(&mut self, delta: &str) {
-        tracing::trace!("push_delta: {delta:?}");
+        tracing::trace!("push_delta: {}", bounded_debug(&delta));
         self.buffer.push_str(delta);
     }
 
@@ -174,7 +177,10 @@ impl MarkdownStreamCollector {
             self.buffer.len(),
             source.len()
         );
-        tracing::trace!("markdown finalize (raw source):\n---\n{source}\n---");
+        tracing::trace!(
+            "markdown finalize (raw source):\n---\n{}\n---",
+            bounded_str(&source)
+        );
 
         let mut rendered: Vec<Line<'static>> = Vec::new();
         markdown::append_markdown(&source, self.width, Some(self.cwd.as_path()), &mut rendered);
diff --git a/codex-rs/utils/log/BUILD.bazel b/codex-rs/utils/log/BUILD.bazel
new file mode 100644
index 000000000000..e27294af63cb
--- /dev/null
+++ b/codex-rs/utils/log/BUILD.bazel
@@ -0,0 +1,6 @@
+load("//:defs.bzl", "codex_rust_crate")
+
+codex_rust_crate(
+    name = "log",
+    crate_name = "codex_utils_log",
+)
diff --git a/codex-rs/utils/log/Cargo.toml b/codex-rs/utils/log/Cargo.toml
new file mode 100644
index 000000000000..82c42f3a6623
--- /dev/null
+++ b/codex-rs/utils/log/Cargo.toml
@@ -0,0 +1,17 @@
+[package]
+name = "codex-utils-log"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+sha2 = { workspace = true }
+
+[dev-dependencies]
+pretty_assertions = { workspace = true }
+
+[lib]
+doctest = false
diff --git a/codex-rs/utils/log/src/lib.rs b/codex-rs/utils/log/src/lib.rs
new file mode 100644
index 000000000000..cc47314a5006
--- /dev/null
+++ b/codex-rs/utils/log/src/lib.rs
@@ -0,0 +1,289 @@
+use std::fmt;
+
+use sha2::Digest;
+use sha2::Sha256;
+
+pub const DEFAULT_BOUNDED_LOG_VALUE_BYTES: usize = 16 * 1024;
+
+pub fn bounded_display<T>(value: &T) -> String
+where
+    T: fmt::Display + ?Sized,
+{
+    bounded_format_with_limit(format_args!("{value}"), DEFAULT_BOUNDED_LOG_VALUE_BYTES)
+}
+
+pub fn bounded_debug<T>(value: &T) -> String
+where
+    T: fmt::Debug + ?Sized,
+{
+    bounded_format_with_limit(format_args!("{value:?}"), DEFAULT_BOUNDED_LOG_VALUE_BYTES)
+}
+
+pub fn bounded_str(value: &str) -> String {
+    bounded_str_with_limit(value, DEFAULT_BOUNDED_LOG_VALUE_BYTES)
+}
+
+pub fn bounded_str_with_limit(value: &str, max_bytes: usize) -> String {
+    bounded_utf8_bytes(value.as_bytes(), max_bytes)
+}
+
+pub fn bounded_bytes_lossy(value: &[u8]) -> String {
+    bounded_bytes_lossy_with_limit(value, DEFAULT_BOUNDED_LOG_VALUE_BYTES)
+}
+
+pub fn bounded_bytes_lossy_with_limit(value: &[u8], max_bytes: usize) -> String {
+    if value.len() <= max_bytes {
+        return String::from_utf8_lossy(value).into_owned();
+    }
+
+    let (prefix, suffix) = split_bytes(value, max_bytes);
+    let shown_bytes = prefix.len().saturating_add(suffix.len());
+    assemble_bounded_log_value(
+        &String::from_utf8_lossy(prefix),
+        &String::from_utf8_lossy(suffix),
+        value.len(),
+        shown_bytes,
+        digest_hex(value),
+    )
+}
+
+fn bounded_utf8_bytes(value: &[u8], max_bytes: usize) -> String {
+    if value.len() <= max_bytes {
+        return String::from_utf8_lossy(value).into_owned();
+    }
+
+    let text = String::from_utf8_lossy(value);
+    let prefix_len = utf8_prefix_boundary(&text, max_bytes / 2);
+    let suffix_start = utf8_suffix_boundary(&text, max_bytes - max_bytes / 2);
+    let prefix = &text[..prefix_len];
+    let suffix = &text[suffix_start..];
+    let shown_bytes = prefix.len().saturating_add(suffix.len());
+    assemble_bounded_log_value(prefix, suffix, value.len(), shown_bytes, digest_hex(value))
+}
+
+fn bounded_format_with_limit(args: fmt::Arguments<'_>, max_bytes: usize) -> String {
+    let mut writer = BoundedFormatWriter::new(max_bytes);
+    if fmt::write(&mut writer, args).is_err() {
+        return String::from("<failed to format bounded log value>");
+    }
+    writer.finish()
+}
+
+struct BoundedFormatWriter {
+    max_bytes: usize,
+    head: String,
+    tail: String,
+    full: Option<String>,
+    original_bytes: usize,
+    digest: Sha256,
+}
+
+impl BoundedFormatWriter {
+    fn new(max_bytes: usize) -> Self {
+        Self {
+            max_bytes,
+            head: String::new(),
+            tail: String::new(),
+            full: Some(String::new()),
+            original_bytes: 0,
+            digest: Sha256::new(),
+        }
+    }
+
+    fn finish(self) -> String {
+        if let Some(full) = self.full {
+            return full;
+        }
+
+        let shown_bytes = self.head.len().saturating_add(self.tail.len());
+        let digest = self.digest.finalize();
+        assemble_bounded_log_value(
+            &self.head,
+            &self.tail,
+            self.original_bytes,
+            shown_bytes,
+            format!("{digest:x}"),
+        )
+    }
+
+    fn head_capacity(&self) -> usize {
+        self.max_bytes / 2
+    }
+
+    fn tail_capacity(&self) -> usize {
+        self.max_bytes - self.head_capacity()
+    }
+
+    fn push_head(&mut self, value: &str) {
+        let remaining = self.head_capacity().saturating_sub(self.head.len());
+        if remaining == 0 {
+            return;
+        }
+
+        let boundary = utf8_prefix_boundary(value, remaining);
+        self.head.push_str(&value[..boundary]);
+    }
+
+    fn push_tail(&mut self, value: &str) {
+        let capacity = self.tail_capacity();
+        if capacity == 0 {
+            return;
+        }
+
+        if value.len() >= capacity {
+            let start = utf8_suffix_boundary(value, capacity);
+            self.tail.clear();
+            self.tail.push_str(&value[start..]);
+            return;
+        }
+
+        self.tail.push_str(value);
+        if self.tail.len() > capacity {
+            let start = utf8_suffix_boundary(&self.tail, capacity);
+            self.tail.replace_range(..start, "");
+        }
+    }
+}
+
+impl fmt::Write for BoundedFormatWriter {
+    fn write_str(&mut self, value: &str) -> fmt::Result {
+        let original_bytes = self.original_bytes.saturating_add(value.len());
+        self.digest.update(value.as_bytes());
+        self.push_head(value);
+        self.push_tail(value);
+
+        if let Some(full) = &mut self.full {
+            if original_bytes <= self.max_bytes {
+                full.push_str(value);
+            } else {
+                self.full = None;
+            }
+        }
+
+        self.original_bytes = original_bytes;
+        Ok(())
+    }
+}
+
+fn split_bytes(value: &[u8], max_bytes: usize) -> (&[u8], &[u8]) {
+    let prefix_len = max_bytes / 2;
+    let suffix_len = max_bytes - prefix_len;
+    let suffix_start = value.len().saturating_sub(suffix_len);
+    (&value[..prefix_len], &value[suffix_start..])
+}
+
+fn utf8_prefix_boundary(value: &str, max_bytes: usize) -> usize {
+    if value.len() <= max_bytes {
+        return value.len();
+    }
+    let mut boundary = max_bytes;
+    while boundary > 0 && !value.is_char_boundary(boundary) {
+        boundary -= 1;
+    }
+    boundary
+}
+
+fn utf8_suffix_boundary(value: &str, max_bytes: usize) -> usize {
+    if value.len() <= max_bytes {
+        return 0;
+    }
+    let mut boundary = value.len().saturating_sub(max_bytes);
+    while boundary < value.len() && !value.is_char_boundary(boundary) {
+        boundary += 1;
+    }
+    boundary
+}
+
+fn assemble_bounded_log_value(
+    prefix: &str,
+    suffix: &str,
+    original_bytes: usize,
+    shown_bytes: usize,
+    sha256: String,
+) -> String {
+    let omitted_bytes = original_bytes.saturating_sub(shown_bytes);
+    format!(
+        "{prefix}...[truncated: original_bytes={original_bytes} shown_bytes={shown_bytes} omitted_bytes={omitted_bytes} sha256={sha256}]...{suffix}"
+    )
+}
+
+fn digest_hex(value: &[u8]) -> String {
+    let digest = Sha256::digest(value);
+    format!("{digest:x}")
+}
+
+#[cfg(test)]
+mod tests {
+    use pretty_assertions::assert_eq;
+
+    use super::*;
+
+    #[test]
+    fn bounded_str_returns_short_values_unchanged() {
+        assert_eq!("hello", bounded_str_with_limit("hello", /*max_bytes*/ 16));
+    }
+
+    #[test]
+    fn bounded_str_preserves_prefix_suffix_and_reports_metadata() {
+        let value = "abcdefghijklmnop";
+
+        let bounded = bounded_str_with_limit(value, /*max_bytes*/ 8);
+
+        assert!(bounded.starts_with("abcd...[truncated: original_bytes=16 shown_bytes=8"));
+        assert!(bounded.contains(" omitted_bytes=8 "));
+        assert!(bounded.contains(" sha256="));
+        assert!(bounded.ends_with("]...mnop"));
+    }
+
+    #[test]
+    fn bounded_str_respects_utf8_boundaries() {
+        let value = "αβγδεζηθ";
+
+        let bounded = bounded_str_with_limit(value, /*max_bytes*/ 9);
+
+        assert!(bounded.starts_with("αβ...[truncated:"));
+        assert!(bounded.ends_with("]...ηθ"));
+    }
+
+    #[test]
+    fn bounded_bytes_lossy_hashes_original_bytes() {
+        let value = b"abcdef\xffghijklmnop";
+
+        let bounded = bounded_bytes_lossy_with_limit(value, /*max_bytes*/ 8);
+
+        assert!(bounded.starts_with("abcd...[truncated: original_bytes=17 shown_bytes=8"));
+        assert!(bounded.ends_with("]...mnop"));
+        assert!(bounded.contains(&digest_hex(value)));
+    }
+
+    #[test]
+    fn bounded_debug_formats_then_bounds() {
+        let value = Some("a".repeat(DEFAULT_BOUNDED_LOG_VALUE_BYTES));
+
+        let bounded = bounded_debug(&value);
+
+        assert!(bounded.starts_with("Some(\""));
+        assert!(bounded.contains("[truncated:"));
+    }
+
+    #[test]
+    fn bounded_format_streams_prefix_suffix_and_hash() {
+        struct ChunkedDisplay;
+
+        impl fmt::Display for ChunkedDisplay {
+            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+                for chunk in ["abcd", "efgh", "ijkl", "mnop"] {
+                    f.write_str(chunk)?;
+                }
+                Ok(())
+            }
+        }
+
+        let bounded =
+            bounded_format_with_limit(format_args!("{ChunkedDisplay}"), /*max_bytes*/ 8);
+
+        assert!(bounded.starts_with("abcd...[truncated: original_bytes=16 shown_bytes=8"));
+        assert!(bounded.ends_with("]...mnop"));
+        assert!(bounded.contains(&digest_hex(b"abcdefghijklmnop")));
+    }
+}