diff --git a/codex-rs/app-server-client/src/lib.rs b/codex-rs/app-server-client/src/lib.rs
index bfcf5522d8..10df3e01e0 100644
--- a/codex-rs/app-server-client/src/lib.rs
+++ b/codex-rs/app-server-client/src/lib.rs
@@ -53,6 +53,7 @@ use codex_config::ThreadConfigLoader;
 use codex_config::config_toml::ConfigToml;
 use codex_core::config::Config;
 pub use codex_core::otel_init::build_provider as build_otel_provider;
+pub use codex_core::otel_init::has_required_exporter as has_required_otel_exporter;
 use codex_core::personality_migration::PersonalityMigrationStatus;
 use codex_core::personality_migration::maybe_migrate_personality;
 pub use codex_exec_server::EnvironmentManager;
diff --git a/codex-rs/core/src/config/config_tests.rs b/codex-rs/core/src/config/config_tests.rs
index 3ad24fc2a2..d502c56c3d 100644
--- a/codex-rs/core/src/config/config_tests.rs
+++ b/codex-rs/core/src/config/config_tests.rs
@@ -11105,6 +11105,35 @@ async fn invalid_required_otel_trace_metadata_fails_closed() -> std::io::Result<
     Ok(())
 }
 
+#[tokio::test]
+async fn invalid_required_otel_exporter_headers_fail_closed() -> std::io::Result<()> {
+    for (exporter, header) in [
+        (
+            "otlp-http",
+            r#"headers = { "invalid header" = "secret" }, protocol = "binary""#,
+        ),
+        ("otlp-grpc", r#"headers = { valid = "\u007f" }"#),
+    ] {
+        let codex_home = TempDir::new()?;
+        let requirements = format!(
+            r#"
+[otel]
+exporter = {{ {exporter} = {{ endpoint = "https://otel.example", {header} }} }}
+"#,
+        );
+        let err = load_with_enterprise_requirement(&codex_home, requirements)
+            .await
+            .expect_err("invalid managed OTEL headers should fail startup");
+
+        assert_eq!(err.kind(), ErrorKind::InvalidInput);
+        assert!(
+            err.to_string()
+                .contains("invalid required `otel.exporter` header")
+        );
+    }
+    Ok(())
+}
+
 #[tokio::test]
 async fn required_otel_tracestate_survives_invalid_user_merge() -> std::io::Result<()> {
     let codex_home = TempDir::new()?;
diff --git a/codex-rs/core/src/config/otel.rs b/codex-rs/core/src/config/otel.rs
index 2e8ec3b3bf..745fcb52d8 100644
--- a/codex-rs/core/src/config/otel.rs
+++ b/codex-rs/core/src/config/otel.rs
@@ -7,6 +7,8 @@ use codex_config::types::DEFAULT_OTEL_ENVIRONMENT;
 use codex_config::types::OtelConfig;
 use codex_config::types::OtelConfigToml;
 use codex_config::types::OtelExporterKind;
+use http::HeaderName;
+use http::HeaderValue;
 
 pub(crate) fn resolve_config(
     config: OtelConfigToml,
@@ -119,6 +121,13 @@ pub(super) fn apply_requirement(
 }
 
 fn validate_requirement(requirement: &OtelConfigToml) -> std::io::Result<()> {
+    for (field, exporter) in [
+        ("exporter", requirement.exporter.as_ref()),
+        ("trace_exporter", requirement.trace_exporter.as_ref()),
+        ("metrics_exporter", requirement.metrics_exporter.as_ref()),
+    ] {
+        validate_exporter_headers(field, exporter)?;
+    }
     if let Some(span_attributes) = requirement.span_attributes.as_ref() {
         codex_otel::validate_span_attributes(span_attributes).map_err(|err| {
             std::io::Error::new(
@@ -138,6 +147,27 @@ fn validate_requirement(requirement: &OtelConfigToml) -> std::io::Result<()> {
     Ok(())
 }
 
+fn validate_exporter_headers(
+    field: &str,
+    exporter: Option<&OtelExporterKind>,
+) -> std::io::Result<()> {
+    let headers = match exporter {
+        Some(OtelExporterKind::OtlpHttp { headers, .. })
+        | Some(OtelExporterKind::OtlpGrpc { headers, .. }) => headers,
+        Some(OtelExporterKind::None | OtelExporterKind::Statsig) | None => return Ok(()),
+    };
+    for (name, value) in headers {
+        if HeaderName::from_bytes(name.as_bytes()).is_err() || HeaderValue::from_str(value).is_err()
+        {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::InvalidInput,
+                format!("invalid required `otel.{field}` header `{name}`"),
+            ));
+        }
+    }
+    Ok(())
+}
+
 /// Merges user-configured tracestate into a validated required base.
 ///
 /// Required member fields always win. Other configured fields are admitted one
diff --git a/codex-rs/core/src/otel_init.rs b/codex-rs/core/src/otel_init.rs
index 8b5aac5f78..5e19b60baf 100644
--- a/codex-rs/core/src/otel_init.rs
+++ b/codex-rs/core/src/otel_init.rs
@@ -10,6 +10,19 @@ use codex_otel::OtelSettings;
 use codex_otel::OtelTlsConfig as OtelTlsSettings;
 use std::error::Error;
 
+pub fn has_required_exporter(config: &Config) -> bool {
+    config
+        .config_layer_stack
+        .requirements()
+        .otel
+        .as_ref()
+        .is_some_and(|requirement| {
+            requirement.value.exporter.is_some()
+                || requirement.value.trace_exporter.is_some()
+                || requirement.value.metrics_exporter.is_some()
+        })
+}
+
 /// Build an OpenTelemetry provider from the app Config.
 ///
 /// Returns `None` when OTEL export is disabled.
diff --git a/codex-rs/exec/src/lib.rs b/codex-rs/exec/src/lib.rs
index eb84b6339e..1b52bb5100 100644
--- a/codex-rs/exec/src/lib.rs
+++ b/codex-rs/exec/src/lib.rs
@@ -484,6 +484,7 @@ pub async fn run_main(cli: Cli, arg0_paths: Arg0DispatchPaths) -> anyhow::Result
         std::process::exit(1);
     }
 
+    let required_otel_exporter = codex_core::otel_init::has_required_exporter(&config);
     let otel = match std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
         codex_core::otel_init::build_provider(
             &config,
@@ -493,10 +494,18 @@ pub async fn run_main(cli: Cli, arg0_paths: Arg0DispatchPaths) -> anyhow::Result
         )
     })) {
         Ok(Ok(otel)) => otel,
+        Ok(Err(e)) if required_otel_exporter => {
+            eprintln!("Could not create required otel exporter: {e}");
+            std::process::exit(1);
+        }
         Ok(Err(e)) => {
             eprintln!("Could not create otel exporter: {e}");
             None
         }
+        Err(_) if required_otel_exporter => {
+            eprintln!("Could not create required otel exporter: panicked during initialization");
+            std::process::exit(1);
+        }
         Err(_) => {
             eprintln!("Could not create otel exporter: panicked during initialization");
             None
diff --git a/codex-rs/tui/src/lib.rs b/codex-rs/tui/src/lib.rs
index e4f5b4d1a4..fdca7d7fae 100644
--- a/codex-rs/tui/src/lib.rs
+++ b/codex-rs/tui/src/lib.rs
@@ -1060,6 +1060,7 @@ pub async fn run_main(
     remove_legacy_tui_log_file(config.codex_home.as_path());
 
     let otel_originator = originator().value;
+    let required_otel_exporter = codex_app_server_client::has_required_otel_exporter(&config);
     let otel = match std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
         codex_app_server_client::build_otel_provider(
             &config,
@@ -1069,6 +1070,13 @@ pub async fn run_main(
         )
     })) {
         Ok(Ok(otel)) => otel,
+        Ok(Err(e)) if required_otel_exporter => {
+            #[allow(clippy::print_stderr)]
+            {
+                eprintln!("Could not create required otel exporter: {e}");
+            }
+            std::process::exit(1);
+        }
         Ok(Err(e)) => {
             #[allow(clippy::print_stderr)]
             {
@@ -1076,6 +1084,15 @@ pub async fn run_main(
             }
             None
         }
+        Err(_) if required_otel_exporter => {
+            #[allow(clippy::print_stderr)]
+            {
+                eprintln!(
+                    "Could not create required otel exporter: panicked during initialization"
+                );
+            }
+            std::process::exit(1);
+        }
         Err(_) => {
             #[allow(clippy::print_stderr)]
             {