diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index f0f5815bcf..7f35bd38f4 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -1076,13 +1076,16 @@ impl Session {
             };
         session_configuration.thread_name = thread_name.clone();
         let mut state = SessionState::new(session_configuration.clone());
-        let network_proxy =
-            match config.network.as_ref() {
-                Some(spec) => Some(spec.start_proxy().await.map_err(|err| {
-                    anyhow::anyhow!("failed to start managed network proxy: {err}")
-                })?),
-                None => None,
-            };
+        let network_proxy = match config.network.as_ref() {
+            Some(spec) => Some(
+                spec.start_proxy(config.sandbox_policy.get())
+                    .await
+                    .map_err(|err| {
+                        anyhow::anyhow!("failed to start managed network proxy: {err}")
+                    })?,
+            ),
+            None => None,
+        };
         let session_network_proxy = network_proxy.as_ref().map(|started| {
             let proxy = started.proxy();
             SessionNetworkProxyRuntime {
diff --git a/codex-rs/core/src/config/network_proxy_spec.rs b/codex-rs/core/src/config/network_proxy_spec.rs
index ee3e8ebed1..e6709047b8 100644
--- a/codex-rs/core/src/config/network_proxy_spec.rs
+++ b/codex-rs/core/src/config/network_proxy_spec.rs
@@ -3,6 +3,7 @@ use crate::config_loader::NetworkConstraints;
 use async_trait::async_trait;
 use codex_network_proxy::ConfigReloader;
 use codex_network_proxy::ConfigState;
+use codex_network_proxy::NetworkDecision;
 use codex_network_proxy::NetworkProxy;
 use codex_network_proxy::NetworkProxyConfig;
 use codex_network_proxy::NetworkProxyConstraints;
@@ -11,6 +12,7 @@ use codex_network_proxy::NetworkProxyState;
 use codex_network_proxy::build_config_state;
 use codex_network_proxy::host_and_port_from_network_addr;
 use codex_network_proxy::validate_policy_against_constraints;
+use codex_protocol::protocol::SandboxPolicy;
 use std::sync::Arc;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -92,20 +94,27 @@ impl NetworkProxySpec {
         })
     }
 
-    pub async fn start_proxy(&self) -> std::io::Result<StartedNetworkProxy> {
+    pub async fn start_proxy(
+        &self,
+        sandbox_policy: &SandboxPolicy,
+    ) -> std::io::Result<StartedNetworkProxy> {
         let state =
             build_config_state(self.config.clone(), self.constraints.clone()).map_err(|err| {
                 std::io::Error::other(format!("failed to build network proxy state: {err}"))
             })?;
         let reloader = Arc::new(StaticNetworkProxyReloader::new(state.clone()));
         let state = NetworkProxyState::with_reloader(state, reloader);
-        let proxy = NetworkProxy::builder()
-            .state(Arc::new(state))
-            .build()
-            .await
-            .map_err(|err| {
-                std::io::Error::other(format!("failed to build network proxy: {err}"))
-            })?;
+        let mut builder = NetworkProxy::builder().state(Arc::new(state));
+        if should_ask_on_allowlist_miss(sandbox_policy) {
+            builder = builder.policy_decider(|_request| async {
+                // In restricted sandbox modes, allowlist misses should ask for
+                // explicit network approval instead of hard-denying.
+                NetworkDecision::ask("not_allowed")
+            });
+        }
+        let proxy = builder.build().await.map_err(|err| {
+            std::io::Error::other(format!("failed to build network proxy: {err}"))
+        })?;
         let handle = proxy
             .run()
             .await
@@ -169,3 +178,41 @@ impl NetworkProxySpec {
         (config, constraints)
     }
 }
+
+fn should_ask_on_allowlist_miss(sandbox_policy: &SandboxPolicy) -> bool {
+    matches!(
+        sandbox_policy,
+        SandboxPolicy::ReadOnly | SandboxPolicy::WorkspaceWrite { .. }
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use codex_protocol::protocol::NetworkAccess;
+
+    #[test]
+    fn restricted_sandbox_modes_ask_on_allowlist_miss() {
+        assert!(should_ask_on_allowlist_miss(&SandboxPolicy::ReadOnly));
+        assert!(should_ask_on_allowlist_miss(
+            &SandboxPolicy::WorkspaceWrite {
+                writable_roots: vec![],
+                network_access: false,
+                exclude_tmpdir_env_var: false,
+                exclude_slash_tmp: false,
+            }
+        ));
+    }
+
+    #[test]
+    fn yolo_and_external_modes_do_not_ask_on_allowlist_miss() {
+        assert!(!should_ask_on_allowlist_miss(
+            &SandboxPolicy::DangerFullAccess
+        ));
+        assert!(!should_ask_on_allowlist_miss(
+            &SandboxPolicy::ExternalSandbox {
+                network_access: NetworkAccess::Restricted,
+            }
+        ));
+    }
+}
diff --git a/codex-rs/network-proxy/src/network_policy.rs b/codex-rs/network-proxy/src/network_policy.rs
index b70c3e0b17..f2fede37d0 100644
--- a/codex-rs/network-proxy/src/network_policy.rs
+++ b/codex-rs/network-proxy/src/network_policy.rs
@@ -119,6 +119,10 @@ impl NetworkDecision {
         Self::deny_with_source(reason, NetworkDecisionSource::Decider)
     }
 
+    pub fn ask(reason: impl Into<String>) -> Self {
+        Self::ask_with_source(reason, NetworkDecisionSource::Decider)
+    }
+
     pub fn deny_with_source(reason: impl Into<String>, source: NetworkDecisionSource) -> Self {
         let reason = reason.into();
         let reason = if reason.is_empty() {
@@ -216,7 +220,7 @@ fn map_decider_decision(decision: NetworkDecision) -> NetworkDecision {
 #[cfg(test)]
 mod tests {
     use super::*;
-
+    use crate::reasons::REASON_NOT_ALLOWED;
     use crate::config::NetworkProxySettings;
     use crate::reasons::REASON_DENIED;
     use crate::reasons::REASON_NOT_ALLOWED_LOCAL;
@@ -336,4 +340,16 @@ mod tests {
         );
         assert_eq!(calls.load(Ordering::SeqCst), 0);
     }
+
+    #[test]
+    fn ask_uses_decider_source_and_ask_decision() {
+        assert_eq!(
+            NetworkDecision::ask(REASON_NOT_ALLOWED),
+            NetworkDecision::Deny {
+                reason: REASON_NOT_ALLOWED.to_string(),
+                source: NetworkDecisionSource::Decider,
+                decision: NetworkPolicyDecision::Ask,
+            }
+        );
+    }
 }