diff --git a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json
index afeb27696a..7951770aa0 100644
--- a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json
+++ b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json
@@ -16737,6 +16737,12 @@
               "null"
             ]
           },
+          "log_sse_deltas": {
+            "type": [
+              "boolean",
+              "null"
+            ]
+          },
           "log_user_prompt": {
             "type": [
               "boolean",
diff --git a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json
index b6a76228a4..170870f46d 100644
--- a/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json
+++ b/codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json
@@ -12729,6 +12729,12 @@
             "null"
           ]
         },
+        "log_sse_deltas": {
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
         "log_user_prompt": {
           "type": [
             "boolean",
diff --git a/codex-rs/app-server-protocol/schema/json/v2/ConfigRequirementsReadResponse.json b/codex-rs/app-server-protocol/schema/json/v2/ConfigRequirementsReadResponse.json
index caa30bcab5..5f9311e3d7 100644
--- a/codex-rs/app-server-protocol/schema/json/v2/ConfigRequirementsReadResponse.json
+++ b/codex-rs/app-server-protocol/schema/json/v2/ConfigRequirementsReadResponse.json
@@ -1278,6 +1278,12 @@
             "null"
           ]
         },
+        "log_sse_deltas": {
+          "type": [
+            "boolean",
+            "null"
+          ]
+        },
         "log_user_prompt": {
           "type": [
             "boolean",
diff --git a/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-experimental.json.zst b/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-experimental.json.zst
index 5a2d0584e8..9f0c5f19b4 100644
Binary files a/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-experimental.json.zst and b/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-experimental.json.zst differ
diff --git a/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-stable.json.zst b/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-stable.json.zst
index 24ce1c7ad9..a4070a59a9 100644
Binary files a/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-stable.json.zst and b/codex-rs/app-server-protocol/schema/precomputed/app-server-exports-stable.json.zst differ
diff --git a/codex-rs/app-server-protocol/schema/typescript/v2/OtelRequirements.ts b/codex-rs/app-server-protocol/schema/typescript/v2/OtelRequirements.ts
index 7279fe8746..588d9993ee 100644
--- a/codex-rs/app-server-protocol/schema/typescript/v2/OtelRequirements.ts
+++ b/codex-rs/app-server-protocol/schema/typescript/v2/OtelRequirements.ts
@@ -4,4 +4,4 @@
 import type { OtelExporter } from "./OtelExporter";
 import type { OtelToolResultLogConfig } from "./OtelToolResultLogConfig";
 
-export type OtelRequirements = { tool_result: OtelToolResultLogConfig | null, log_user_prompt: boolean | null, log_agent_responses: boolean | null, log_guardian_assessments: boolean | null, environment: string | null, exporter: OtelExporter | null, trace_exporter: OtelExporter | null, metrics_exporter: OtelExporter | null, span_attributes: { [key in string]?: string } | null, tracestate: { [key in string]?: { [key in string]?: string } } | null, };
+export type OtelRequirements = { tool_result: OtelToolResultLogConfig | null, log_sse_deltas: boolean | null, log_user_prompt: boolean | null, log_agent_responses: boolean | null, log_guardian_assessments: boolean | null, environment: string | null, exporter: OtelExporter | null, trace_exporter: OtelExporter | null, metrics_exporter: OtelExporter | null, span_attributes: { [key in string]?: string } | null, tracestate: { [key in string]?: { [key in string]?: string } } | null, };
diff --git a/codex-rs/app-server-protocol/src/protocol/v2/config.rs b/codex-rs/app-server-protocol/src/protocol/v2/config.rs
index 177d000775..09006baf7e 100644
--- a/codex-rs/app-server-protocol/src/protocol/v2/config.rs
+++ b/codex-rs/app-server-protocol/src/protocol/v2/config.rs
@@ -506,6 +506,7 @@ pub struct FeedbackRequirements {
 #[ts(export_to = "v2/")]
 pub struct OtelRequirements {
     pub tool_result: Option<OtelToolResultLogConfig>,
+    pub log_sse_deltas: Option<bool>,
     pub log_user_prompt: Option<bool>,
     pub log_agent_responses: Option<bool>,
     pub log_guardian_assessments: Option<bool>,
diff --git a/codex-rs/app-server/src/config_manager_service_tests.rs b/codex-rs/app-server/src/config_manager_service_tests.rs
index a0738698fc..36bd51fc42 100644
--- a/codex-rs/app-server/src/config_manager_service_tests.rs
+++ b/codex-rs/app-server/src/config_manager_service_tests.rs
@@ -1870,6 +1870,7 @@ tracestate = { managed = { tenant = "enterprise" }, empty = {} }"#,
         otel,
         &serde_json::json!({
             "tool_result": { "max_bytes": 1234 },
+            "log_sse_deltas": null,
             "log_user_prompt": false,
             "log_agent_responses": null,
             "log_guardian_assessments": null,
diff --git a/codex-rs/app-server/src/otel_config.rs b/codex-rs/app-server/src/otel_config.rs
index c299989908..f9a1915003 100644
--- a/codex-rs/app-server/src/otel_config.rs
+++ b/codex-rs/app-server/src/otel_config.rs
@@ -18,6 +18,7 @@ pub(crate) fn map_otel_requirements_to_api(otel: OtelRequirementsToml) -> OtelRe
         tool_result: otel.tool_result.map(|value| OtelToolResultLogConfig {
             max_bytes: value.max_bytes,
         }),
+        log_sse_deltas: otel.log_sse_deltas,
         log_user_prompt: otel.log_user_prompt,
         log_agent_responses: otel.log_agent_responses,
         log_guardian_assessments: otel.log_guardian_assessments,
diff --git a/codex-rs/app-server/tests/suite/v2/config_rpc.rs b/codex-rs/app-server/tests/suite/v2/config_rpc.rs
index 8f21fc0edf..a80ce64350 100644
--- a/codex-rs/app-server/tests/suite/v2/config_rpc.rs
+++ b/codex-rs/app-server/tests/suite/v2/config_rpc.rs
@@ -717,6 +717,7 @@ async fn config_requirements_read_redacts_otel_exporter_headers(
         r#"[otel]
 tool_result = { max_bytes = 1024 }
 log_user_prompt = false
+log_sse_deltas = false
 log_agent_responses = true
 log_guardian_assessments = false
 environment = "managed"
@@ -736,6 +737,7 @@ tracestate = { managed = { tenant = "enterprise" } }"#
         json!({
             "tool_result": { "max_bytes": 1024 },
             "log_user_prompt": false,
+            "log_sse_deltas": false,
             "log_agent_responses": true,
             "log_guardian_assessments": false,
             "environment": "managed",
diff --git a/codex-rs/config/src/config_requirements.rs b/codex-rs/config/src/config_requirements.rs
index 0d1fcfdf98..e90c6ac020 100644
--- a/codex-rs/config/src/config_requirements.rs
+++ b/codex-rs/config/src/config_requirements.rs
@@ -1115,6 +1115,7 @@ pub struct ConfigRequirementsToml {
 #[serde(deny_unknown_fields)]
 pub struct OtelRequirementsToml {
     pub tool_result: Option<ToolResultLogConfig>,
+    pub log_sse_deltas: Option<bool>,
     pub log_user_prompt: Option<bool>,
     pub log_agent_responses: Option<bool>,
     pub log_guardian_assessments: Option<bool>,
@@ -1129,6 +1130,7 @@ pub struct OtelRequirementsToml {
 impl OtelRequirementsToml {
     pub(crate) fn is_empty(&self) -> bool {
         self.tool_result.is_none()
+            && self.log_sse_deltas.is_none()
             && self.log_user_prompt.is_none()
             && self.log_agent_responses.is_none()
             && self.log_guardian_assessments.is_none()
@@ -1772,7 +1774,7 @@ impl ConfigRequirementsToml {
             return Some("model_providers");
         }
         let otel = self.otel.as_ref();
-        let managed_fields: [(bool, &[&str], &'static str); 17] = [
+        let managed_fields: [(bool, &[&str], &'static str); 18] = [
             (
                 self.model_provider.is_some(),
                 &["model_provider"],
@@ -1823,6 +1825,11 @@ impl ConfigRequirementsToml {
                 &["otel", "log_user_prompt"],
                 "otel.log_user_prompt",
             ),
+            (
+                otel.is_some_and(|otel| otel.log_sse_deltas.is_some()),
+                &["otel", "log_sse_deltas"],
+                "otel.log_sse_deltas",
+            ),
             (
                 otel.is_some_and(|otel| otel.log_agent_responses.is_some()),
                 &["otel", "log_agent_responses"],
@@ -1914,6 +1921,7 @@ macro_rules! otel_merge_functions {
 
 otel_merge_functions!(
     tool_result,
+    log_sse_deltas,
     log_user_prompt,
     log_agent_responses,
     log_guardian_assessments,
@@ -2563,6 +2571,7 @@ mod tests {
     #[test_case::test_case(&["otel", "tool_result"], Some("otel.tool_result"); "tool_result")]
     #[test_case::test_case(&["otel", "tool_result", "max_bytes"], Some("otel.tool_result"); "tool_result_max_bytes")]
     #[test_case::test_case(&["otel", "log_user_prompt"], Some("otel.log_user_prompt"); "log_user_prompt")]
+    #[test_case::test_case(&["otel", "log_sse_deltas"], Some("otel.log_sse_deltas"); "log_sse_deltas")]
     #[test_case::test_case(&["otel", "environment"], Some("otel.environment"); "environment")]
     #[test_case::test_case(&["otel", "exporter", "otlp-http", "endpoint"], Some("otel.exporter"); "exporter_endpoint")]
     #[test_case::test_case(&["otel", "trace_exporter"], Some("otel.trace_exporter"); "trace_exporter")]
@@ -2586,6 +2595,7 @@ mod tests {
 tool_result = { max_bytes = 1024 }
 log_user_prompt = false
 environment = "managed"
+log_sse_deltas = false
 exporter = "none"
 trace_exporter = "none"
 metrics_exporter = "none"
@@ -2599,6 +2609,7 @@ tracestate = { managed = { tenant = "enterprise" }, empty = {} }
 tool_result = { max_bytes = 4096 }
 log_user_prompt = true
 environment = "user"
+log_sse_deltas = true
 exporter = "statsig"
 trace_exporter = { otlp-grpc = { endpoint = "https://user.example" } }
 metrics_exporter = "statsig"
@@ -2616,6 +2627,7 @@ tracestate = { managed = { tenant = "user", region = "us" }, other = { keep = "y
 tool_result = { max_bytes = 1024 }
 log_user_prompt = false
 environment = "managed"
+log_sse_deltas = false
 exporter = "none"
 trace_exporter = "none"
 metrics_exporter = "none"
diff --git a/codex-rs/config/src/types.rs b/codex-rs/config/src/types.rs
index 6ec41a99aa..8948588519 100644
--- a/codex-rs/config/src/types.rs
+++ b/codex-rs/config/src/types.rs
@@ -639,6 +639,9 @@ pub enum OtelExporterKind {
 pub struct OtelConfigToml {
     /// Byte limit for tool-result log output; independent of model-visible output.
     pub tool_result: Option<codex_protocol::config_types::ToolResultLogConfig>,
+    /// Log successful SSE events whose kind ends in `.delta`. Defaults to true.
+    /// Disabling this preserves errors, completion events, and metrics.
+    pub log_sse_deltas: Option<bool>,
     /// Log user prompt in traces
     pub log_user_prompt: Option<bool>,
     /// Opt in to logging final main-agent and spawned-subagent responses to an OTLP log exporter.
@@ -672,6 +675,7 @@ pub struct OtelConfigToml {
 #[derive(Debug, Clone, PartialEq)]
 pub struct OtelConfig {
     pub tool_result: codex_protocol::config_types::ToolResultLogConfig,
+    pub log_sse_deltas: bool,
     pub log_user_prompt: bool,
     pub log_agent_responses: bool,
     pub log_guardian_assessments: bool,
@@ -687,6 +691,7 @@ impl Default for OtelConfig {
     fn default() -> Self {
         OtelConfig {
             tool_result: Default::default(),
+            log_sse_deltas: true,
             log_user_prompt: false,
             log_agent_responses: false,
             log_guardian_assessments: false,
diff --git a/codex-rs/core/config.schema.json b/codex-rs/core/config.schema.json
index 6596cd18e9..16ec1c1f42 100644
--- a/codex-rs/core/config.schema.json
+++ b/codex-rs/core/config.schema.json
@@ -3780,6 +3780,10 @@
           "description": "Opt in to logging completed Guardian assessments to an OTLP log exporter. Defaults to false. Rationales can be sensitive and are capped at 64 KiB.",
           "type": "boolean"
         },
+        "log_sse_deltas": {
+          "description": "Log successful SSE events whose kind ends in `.delta`. Defaults to true. Disabling this preserves errors, completion events, and metrics.",
+          "type": "boolean"
+        },
         "log_user_prompt": {
           "description": "Log user prompt in traces",
           "type": "boolean"
diff --git a/codex-rs/core/src/config/config_tests.rs b/codex-rs/core/src/config/config_tests.rs
index 309e2d3d54..70cc395671 100644
--- a/codex-rs/core/src/config/config_tests.rs
+++ b/codex-rs/core/src/config/config_tests.rs
@@ -10327,6 +10327,7 @@ async fn metrics_exporter_defaults_to_statsig_when_missing() -> std::io::Result<
     .await?;
 
     assert_eq!(config.otel.metrics_exporter, OtelExporterKind::Statsig);
+    assert!(config.otel.log_sse_deltas);
     assert!(!config.otel.agent_response_logging_enabled());
     assert!(!config.otel.guardian_assessment_logging_enabled());
     Ok(())
@@ -10338,6 +10339,7 @@ async fn trace_exporter_defaults_to_none_when_log_exporter_is_set() -> std::io::
     let mut cfg = fixture.cfg.clone();
     cfg.otel = Some(OtelConfigToml {
         tool_result: Some(toml::from_str("max_bytes = 8192").expect("tool-result logging config")),
+        log_sse_deltas: Some(false),
         log_agent_responses: Some(true),
         log_guardian_assessments: Some(true),
         exporter: Some(OtelExporterKind::OtlpHttp {
@@ -10361,6 +10363,7 @@ async fn trace_exporter_defaults_to_none_when_log_exporter_is_set() -> std::io::
     .await?;
 
     assert_eq!(config.otel.tool_result.max_bytes, 8192);
+    assert!(!config.otel.log_sse_deltas);
     assert!(config.otel.agent_response_logging_enabled());
     assert!(config.otel.guardian_assessment_logging_enabled());
     assert!(matches!(
@@ -13975,6 +13978,10 @@ tracestate = { vendor = { tenant = "managed", region = "us" }, other = { keep =
     "[otel]\nlog_agent_responses = true\nlog_guardian_assessments = false",
     "[otel]\nlog_agent_responses = true\nlog_guardian_assessments = false", true; "managed_logging_flags"
 )]
+#[test_case::test_case(
+    "[otel]\nlog_sse_deltas = true", "[otel]\nlog_sse_deltas = false",
+    "[otel]\nlog_sse_deltas = false", true; "managed_sse_delta_logs"
+)]
 #[tokio::test]
 async fn otel_requirements_resolve_config(
     user_config: &str,
diff --git a/codex-rs/core/src/config/otel.rs b/codex-rs/core/src/config/otel.rs
index dd75994063..9195e8c066 100644
--- a/codex-rs/core/src/config/otel.rs
+++ b/codex-rs/core/src/config/otel.rs
@@ -28,6 +28,7 @@ pub(crate) fn resolve_config(
 
     OtelConfig {
         tool_result: config.tool_result.unwrap_or_default(),
+        log_sse_deltas: config.log_sse_deltas.unwrap_or(true),
         log_user_prompt,
         log_agent_responses: config.log_agent_responses.unwrap_or(false),
         log_guardian_assessments: config.log_guardian_assessments.unwrap_or(false),
diff --git a/codex-rs/core/src/session/session.rs b/codex-rs/core/src/session/session.rs
index a41f1471e4..37c22bc42d 100644
--- a/codex-rs/core/src/session/session.rs
+++ b/codex-rs/core/src/session/session.rs
@@ -1381,6 +1381,9 @@ impl Session {
             .with_auth_env(auth_env_telemetry.to_otel_metadata())
             .with_user_id(telemetry_auth.and_then(CodexAuth::get_chatgpt_user_id))
             .with_tool_result_log_config(config.otel.tool_result);
+            if !config.otel.log_sse_deltas {
+                session_telemetry = session_telemetry.without_sse_delta_logs();
+            }
             if let Some(metrics) = thread_extension_data.get::<codex_otel::MetricsClient>() {
                 session_telemetry = session_telemetry.with_metrics(metrics.as_ref().clone());
             }
diff --git a/codex-rs/core/tests/suite/otel.rs b/codex-rs/core/tests/suite/otel.rs
index 386312a2bf..82fec7895e 100644
--- a/codex-rs/core/tests/suite/otel.rs
+++ b/codex-rs/core/tests/suite/otel.rs
@@ -518,13 +518,14 @@ async fn process_sse_failed_event_logs_response_completed_parse_error() {
 
 #[tokio::test]
 #[traced_test]
-async fn process_sse_emits_completed_telemetry() {
+async fn process_sse_emits_completed_telemetry_with_delta_logs_disabled() {
     let server = start_mock_server().await;
 
-    mount_sse_once(
+    let mock = mount_sse_once(
         &server,
         sse(vec![
             ev_reasoning_item_added("reasoning-1", &[]),
+            ev_reasoning_summary_text_delta("Thinking"),
             serde_json::json!({
                 "type": "response.completed",
                 "response": {
@@ -545,7 +546,13 @@ async fn process_sse_emits_completed_telemetry() {
     )
     .await;
 
-    let TestCodex { codex, .. } = test_codex().build(&server).await.unwrap();
+    let TestCodex { codex, .. } = test_codex()
+        .with_config(|config| {
+            config.otel.log_sse_deltas = false;
+        })
+        .build_with_auto_env(&server)
+        .await
+        .unwrap();
 
     codex
         .start_or_steer_turn(TurnInputRequest::user_input(vec![UserInput::Text {
@@ -557,6 +564,19 @@ async fn process_sse_emits_completed_telemetry() {
 
     wait_for_event(&codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
 
+    let _request = mock.single_request();
+    logs_assert(|lines: &[&str]| {
+        let delta_logged = lines.iter().any(|line| {
+            line.contains("codex.sse_event")
+                && line.contains("event.kind=response.reasoning_summary_text.delta")
+        });
+        if delta_logged {
+            Err("unexpected successful SSE delta log".to_string())
+        } else {
+            Ok(())
+        }
+    });
+
     logs_assert(|lines: &[&str]| {
         lines
             .iter()
diff --git a/codex-rs/memories/write/src/runtime.rs b/codex-rs/memories/write/src/runtime.rs
index 03caf89fb6..042642df82 100644
--- a/codex-rs/memories/write/src/runtime.rs
+++ b/codex-rs/memories/write/src/runtime.rs
@@ -119,7 +119,7 @@ fn build_session_telemetry(
         &config.model_provider,
         auth_manager.codex_api_key_env_enabled(),
     );
-    SessionTelemetry::new(
+    let mut session_telemetry = SessionTelemetry::new(
         thread_id,
         model,
         model,
@@ -131,7 +131,11 @@ fn build_session_telemetry(
         user_agent(),
         source,
     )
-    .with_auth_env(auth_env_telemetry.to_otel_metadata())
+    .with_auth_env(auth_env_telemetry.to_otel_metadata());
+    if !config.otel.log_sse_deltas {
+        session_telemetry = session_telemetry.without_sse_delta_logs();
+    }
+    session_telemetry
 }
 
 impl MemoryStartupContext {
diff --git a/codex-rs/otel/src/events/session_telemetry.rs b/codex-rs/otel/src/events/session_telemetry.rs
index ced543ac75..43affe902d 100644
--- a/codex-rs/otel/src/events/session_telemetry.rs
+++ b/codex-rs/otel/src/events/session_telemetry.rs
@@ -120,6 +120,7 @@ pub struct SessionTelemetryMetadata {
 #[derive(Debug, Clone)]
 pub struct SessionTelemetry {
     tool_result_log_config: ToolResultLogConfig,
+    log_sse_deltas: bool,
     pub(crate) metadata: SessionTelemetryMetadata,
     pub(crate) metrics: Option<MetricsClient>,
     pub(crate) metrics_use_metadata_tags: bool,
@@ -142,6 +143,12 @@ pub fn bounded_product_sku(product_sku: Option<&str>) -> Option<&'static str> {
 }
 
 impl SessionTelemetry {
+    /// Suppress successful SSE delta logs while retaining errors and all metrics.
+    pub fn without_sse_delta_logs(mut self) -> Self {
+        self.log_sse_deltas = false;
+        self
+    }
+
     pub fn with_tool_result_log_config(mut self, config: ToolResultLogConfig) -> Self {
         self.tool_result_log_config = config;
         self
@@ -609,6 +616,7 @@ impl SessionTelemetry {
             });
         Self {
             tool_result_log_config: ToolResultLogConfig::default(),
+            log_sse_deltas: true,
             metadata: SessionTelemetryMetadata {
                 conversation_id,
                 agent_name,
@@ -1065,6 +1073,9 @@ impl SessionTelemetry {
             duration,
             &[("kind", kind), ("success", "true")],
         );
+        if !self.log_sse_deltas && kind.ends_with(".delta") {
+            return;
+        }
         log_event!(
             self,
             event.name = "codex.sse_event",
diff --git a/codex-rs/otel/tests/suite/otel_export_routing_policy.rs b/codex-rs/otel/tests/suite/otel_export_routing_policy.rs
index a943f71680..897e3f420c 100644
--- a/codex-rs/otel/tests/suite/otel_export_routing_policy.rs
+++ b/codex-rs/otel/tests/suite/otel_export_routing_policy.rs
@@ -1,6 +1,12 @@
+use crate::harness::attributes_to_map;
+use crate::harness::build_metrics_with_defaults;
+use crate::harness::find_metric;
+use crate::harness::latest_metrics;
 use codex_api::AgentIdentityTelemetry;
 use codex_otel::AuthEnvTelemetryMetadata;
 use codex_otel::OtelProvider;
+use codex_otel::SSE_EVENT_COUNT_METRIC;
+use codex_otel::SSE_EVENT_DURATION_METRIC;
 use codex_otel::SessionTelemetry;
 use codex_otel::TelemetryAuthMode;
 use opentelemetry::KeyValue;
@@ -9,12 +15,15 @@ use opentelemetry::trace::TracerProvider as _;
 use opentelemetry_sdk::logs::InMemoryLogExporter;
 use opentelemetry_sdk::logs::SdkLogRecord;
 use opentelemetry_sdk::logs::SdkLoggerProvider;
+use opentelemetry_sdk::metrics::data::AggregatedMetrics;
+use opentelemetry_sdk::metrics::data::MetricData;
 use opentelemetry_sdk::trace::InMemorySpanExporter;
 use opentelemetry_sdk::trace::SdkTracerProvider;
 use pretty_assertions::assert_eq;
 use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::path::PathBuf;
+use std::time::Duration;
 use tracing_subscriber::Layer;
 use tracing_subscriber::filter::filter_fn;
 use tracing_subscriber::layer::SubscriberExt;
@@ -32,7 +41,9 @@ use codex_protocol::protocol::GuardianAssessmentStatus;
 use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::SubAgentSource;
+use codex_protocol::protocol::TokenUsage;
 use codex_protocol::user_input::UserInput;
+use eventsource_stream::Event as StreamEvent;
 
 fn log_attributes(record: &SdkLogRecord) -> BTreeMap<String, String> {
     record
@@ -100,6 +111,154 @@ fn auth_env_metadata() -> AuthEnvTelemetryMetadata {
     }
 }
 
+#[test]
+fn suppressing_sse_delta_logs_preserves_errors_completions_and_metrics() -> codex_otel::Result<()> {
+    for log_sse_deltas in [true, false] {
+        let log_exporter = InMemoryLogExporter::default();
+        let logger_provider = SdkLoggerProvider::builder()
+            .with_simple_exporter(log_exporter.clone())
+            .build();
+        let subscriber = tracing_subscriber::registry().with(
+            opentelemetry_appender_tracing::layer::OpenTelemetryTracingBridge::new(
+                &logger_provider,
+            )
+            .with_filter(filter_fn(OtelProvider::log_export_filter)),
+        );
+        let (metrics, metric_exporter) = build_metrics_with_defaults(&[])?;
+        let mut manager = SessionTelemetry::new(
+            ThreadId::new(),
+            "gpt-5.1",
+            "gpt-5.1",
+            /*account_id*/ None,
+            /*account_email*/ None,
+            /*auth_mode*/ None,
+            "test_originator".to_string(),
+            /*log_user_prompts*/ false,
+            "tty".to_string(),
+            SessionSource::Cli,
+        )
+        .with_metrics_without_metadata_tags(metrics);
+        if !log_sse_deltas {
+            manager = manager.without_sse_delta_logs();
+        }
+        let events = [
+            ("response.output_text.delta", "{}", true),
+            ("response.reasoning_summary_text.delta", "{}", true),
+            ("response.custom_tool_call_input.delta", "{}", true),
+            ("response.output_text.done", "{}", true),
+            ("response.completed", "{}", true),
+            ("response.output_text.delta", "{", false),
+            ("response.failed", r#"{"error":"failed"}"#, false),
+        ];
+        tracing::subscriber::with_default(subscriber, || {
+            tracing::callsite::rebuild_interest_cache();
+            for (kind, data, _) in events {
+                manager.log_sse_event::<&str>(
+                    &Ok(Some(Ok(StreamEvent {
+                        event: kind.to_string(),
+                        data: data.to_string(),
+                        id: String::new(),
+                        retry: None,
+                    }))),
+                    Duration::from_millis(10),
+                );
+            }
+            manager.sse_event_completed(
+                &TokenUsage {
+                    input_tokens: 7,
+                    ..Default::default()
+                },
+                /*ttft_ms*/ Some(10),
+            );
+        });
+        logger_provider.force_flush().expect("flush logs");
+        let logs = log_exporter.get_emitted_logs().expect("exported logs");
+        let exported_events = logs
+            .iter()
+            .map(|log| {
+                let attributes = log_attributes(&log.record);
+                (
+                    attributes["event.kind"].clone(),
+                    attributes.contains_key("error.message"),
+                    attributes.get("input_token_count").cloned(),
+                )
+            })
+            .collect::<Vec<_>>();
+        let mut expected_events = Vec::new();
+        if log_sse_deltas {
+            expected_events.extend([
+                ("response.output_text.delta".to_string(), false, None),
+                (
+                    "response.reasoning_summary_text.delta".to_string(),
+                    false,
+                    None,
+                ),
+                (
+                    "response.custom_tool_call_input.delta".to_string(),
+                    false,
+                    None,
+                ),
+            ]);
+        }
+        expected_events.extend([
+            ("response.output_text.done".to_string(), false, None),
+            ("response.completed".to_string(), false, None),
+            ("response.output_text.delta".to_string(), true, None),
+            ("response.failed".to_string(), true, None),
+            (
+                "response.completed".to_string(),
+                false,
+                Some("7".to_string()),
+            ),
+        ]);
+        assert_eq!(exported_events, expected_events);
+
+        manager.shutdown_metrics()?;
+        let resource_metrics = latest_metrics(&metric_exporter);
+        let expected_counts = events
+            .iter()
+            .map(|(kind, _, success)| {
+                (
+                    BTreeMap::from([
+                        ("kind".to_string(), kind.to_string()),
+                        ("success".to_string(), success.to_string()),
+                    ]),
+                    1,
+                )
+            })
+            .collect::<BTreeMap<_, _>>();
+        let counter = find_metric(&resource_metrics, SSE_EVENT_COUNT_METRIC).expect("SSE counter");
+        let AggregatedMetrics::U64(MetricData::Sum(sum)) = counter.data() else {
+            panic!("expected SSE counter");
+        };
+        assert_eq!(
+            sum.data_points()
+                .map(|point| (attributes_to_map(point.attributes()), point.value()))
+                .collect::<BTreeMap<_, _>>(),
+            expected_counts,
+        );
+        let duration =
+            find_metric(&resource_metrics, SSE_EVENT_DURATION_METRIC).expect("SSE duration");
+        let AggregatedMetrics::F64(MetricData::Histogram(histogram)) = duration.data() else {
+            panic!("expected SSE duration histogram");
+        };
+        assert_eq!(
+            histogram
+                .data_points()
+                .map(|point| (
+                    attributes_to_map(point.attributes()),
+                    (point.count(), point.sum())
+                ))
+                .collect::<BTreeMap<_, _>>(),
+            expected_counts
+                .into_keys()
+                .map(|tags| (tags, (1, 10.0)))
+                .collect(),
+        );
+    }
+    Ok(())
+}
+
 #[test]
 fn otel_export_routing_policy_routes_prompt_and_guardian_payloads() {
     let log_exporter = InMemoryLogExporter::default();
diff --git a/sdk/python/src/openai_codex/generated/v2_all.py b/sdk/python/src/openai_codex/generated/v2_all.py
index c3a2c63d9c..82a5c8c088 100644
--- a/sdk/python/src/openai_codex/generated/v2_all.py
+++ b/sdk/python/src/openai_codex/generated/v2_all.py
@@ -9257,6 +9257,7 @@ class OtelRequirements(BaseModel):
     exporter: OtelExporter | None = None
     log_agent_responses: bool | None = None
     log_guardian_assessments: bool | None = None
+    log_sse_deltas: bool | None = None
     log_user_prompt: bool | None = None
     metrics_exporter: OtelExporter | None = None
     span_attributes: dict[str, Any] | None = None