diff --git a/codex-rs/core/src/agents_md_tests.rs b/codex-rs/core/src/agents_md_tests.rs
index 1703978f0e..f5dd78977f 100644
--- a/codex-rs/core/src/agents_md_tests.rs
+++ b/codex-rs/core/src/agents_md_tests.rs
@@ -5,7 +5,6 @@ use crate::context::ContextualUserFragment;
 use crate::environment_selection::TurnEnvironmentSnapshot;
 use crate::environment_selection::TurnEnvironmentState;
 use crate::session::turn_context::TurnEnvironment;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use codex_config::ConfigLayerEntry;
 use codex_config::ConfigLayerStack;
 use codex_config::ConfigRequirements;
@@ -23,6 +22,7 @@ use codex_exec_server::RemoveOptions;
 use codex_extension_api::UserInstructions;
 use codex_features::Feature;
 use codex_protocol::models::PermissionProfile;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::TurnEnvironmentSelection;
 use codex_utils_absolute_path::AbsolutePathBuf;
@@ -345,12 +345,12 @@ fn resolved_local_environments<const N: usize>(
                             .expect("local environment"),
                     ),
                     /*shell*/ None,
-                    TurnEnvironmentConfig {
+                    EnvironmentConfig {
                         allow_login_shell: true,
                         permission_profile: PermissionProfileSnapshot::legacy(
                             PermissionProfile::read_only(),
                         ),
-                        selected_capability_roots: None,
+                        selected_capability_roots: Vec::new(),
                     },
                 ))
             })
diff --git a/codex-rs/core/src/environment_selection.rs b/codex-rs/core/src/environment_selection.rs
index bbf2e428a4..d256bd03f4 100644
--- a/codex-rs/core/src/environment_selection.rs
+++ b/codex-rs/core/src/environment_selection.rs
@@ -31,7 +31,6 @@ use tokio_util::task::AbortOnDropHandle;
 
 use crate::session::turn_context::ShellSnapshotTask;
 use crate::session::turn_context::TurnEnvironment;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use crate::shell::Shell;
 use crate::shell_snapshot::ShellSnapshot;
 
@@ -67,7 +66,7 @@ struct ResolvedEnvironment {
 #[derive(Clone)]
 struct SelectedTurnEnvironment {
     selection: TurnEnvironmentSelection,
-    config: TurnEnvironmentConfig,
+    config: EnvironmentConfig,
     environment: Arc<Environment>,
     // Selection clones share one listener; the final handle drop aborts it.
     connection_events_task: Option<Arc<AbortOnDropHandle<()>>>,
@@ -77,7 +76,7 @@ struct SelectedTurnEnvironment {
 #[derive(Clone)]
 pub(crate) struct StartingTurnEnvironment {
     pub(crate) selection: TurnEnvironmentSelection,
-    config: TurnEnvironmentConfig,
+    config: EnvironmentConfig,
     resolution: TurnEnvironmentResolution,
 }
 
@@ -85,17 +84,11 @@ impl SelectedTurnEnvironment {
     fn apply_configuration(
         &mut self,
         selection_config: EnvironmentConfigState,
-        thread_config: &TurnEnvironmentConfig,
+        thread_config: &EnvironmentConfig,
     ) {
         self.config = match &selection_config {
             EnvironmentConfigState::FromThread => thread_config.clone(),
-            EnvironmentConfigState::Ready(config) => TurnEnvironmentConfig {
-                allow_login_shell: config.allow_login_shell,
-                // temp read from thread_config; will go away once perms on EnvironmentConfig,
-                // then we can just assign passed config directly
-                permission_profile: thread_config.permission_profile.clone(),
-                selected_capability_roots: Some(config.selected_capability_roots.clone()),
-            },
+            EnvironmentConfigState::Ready(config) => config.clone(),
             EnvironmentConfigState::Pending => {
                 unreachable!("pending environment configuration is not supported yet")
             }
@@ -133,7 +126,7 @@ impl ThreadEnvironments {
     pub(crate) fn new(
         environment_manager: Arc<EnvironmentManager>,
         local_shell: Shell,
-        thread_environment_config: TurnEnvironmentConfig,
+        thread_environment_config: EnvironmentConfig,
         shell_snapshot: ShellSnapshot,
         current: TurnEnvironmentSnapshot,
         non_blocking_snapshots: bool,
@@ -186,7 +179,7 @@ impl ThreadEnvironments {
     pub(crate) fn update_selections(
         &self,
         environments: &[TurnEnvironmentSelection],
-        thread_environment_config: &TurnEnvironmentConfig,
+        thread_environment_config: &EnvironmentConfig,
     ) {
         let previous = self.environments.load();
         let mut seen_environment_ids = HashSet::with_capacity(environments.len());
@@ -306,7 +299,7 @@ impl ThreadEnvironments {
             .unwrap_or_default()
     }
 
-    pub(crate) fn update_environment_configs(&self, config: &TurnEnvironmentConfig) {
+    pub(crate) fn update_environment_configs(&self, config: &EnvironmentConfig) {
         let environments = self
             .environments
             .load()
@@ -353,9 +346,8 @@ impl ThreadEnvironments {
         let environments = self.environments.load();
         let mut selected_capability_roots = thread_selected_capability_roots.to_vec();
         for environment in environments.iter() {
-            if let Some(roots) = &environment.config.selected_capability_roots {
-                selected_capability_roots.extend(roots.iter().cloned());
-            }
+            selected_capability_roots
+                .extend(environment.config.selected_capability_roots.iter().cloned());
         }
         let mut seen_root_ids = HashSet::with_capacity(selected_capability_roots.len());
         selected_capability_roots.retain(|root| seen_root_ids.insert(root.id.clone()));
@@ -706,11 +698,11 @@ mod tests {
 
     use super::*;
 
-    fn test_environment_config() -> TurnEnvironmentConfig {
-        TurnEnvironmentConfig {
+    fn test_environment_config() -> EnvironmentConfig {
+        EnvironmentConfig {
             allow_login_shell: true,
             permission_profile: PermissionProfileSnapshot::legacy(PermissionProfile::read_only()),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         }
     }
 
@@ -874,14 +866,14 @@ url = "ws://127.0.0.1:8765"
             shell_type: crate::shell::ShellType::Zsh,
             shell_path: std::path::PathBuf::from("/configured/zsh"),
         };
-        let expected_config = TurnEnvironmentConfig {
+        let expected_config = EnvironmentConfig {
             allow_login_shell: false,
             permission_profile: PermissionProfileSnapshot::active_with_profile_workspace_roots(
                 PermissionProfile::read_only(),
                 ActivePermissionProfile::read_only(),
                 vec![cwd.join("profile-root")],
             ),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         };
         let turn_environments = ThreadEnvironments::new(
             Arc::new(EnvironmentManager::default_for_tests()),
@@ -1075,14 +1067,14 @@ url = "ws://127.0.0.1:8765"
             .await,
         );
         let cwd = AbsolutePathBuf::current_dir().expect("cwd");
-        let expected_config = TurnEnvironmentConfig {
+        let expected_config = EnvironmentConfig {
             allow_login_shell: false,
             permission_profile: PermissionProfileSnapshot::active_with_profile_workspace_roots(
                 PermissionProfile::read_only(),
                 ActivePermissionProfile::read_only(),
                 vec![cwd.join("profile-root")],
             ),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         };
         let cwd = PathUri::from_abs_path(&cwd);
         let remote = TurnEnvironmentSelection {
@@ -1244,7 +1236,7 @@ url = "ws://127.0.0.1:8765"
                 /*connect_timeout*/ None,
             )
             .expect("replacement environment");
-        let next_config = TurnEnvironmentConfig {
+        let next_config = EnvironmentConfig {
             allow_login_shell: false,
             ..test_environment_config()
         };
@@ -1394,14 +1386,14 @@ url = "ws://127.0.0.1:8765"
                 /*connect_timeout*/ None,
             )
             .expect("replacement environment");
-        let child_config = TurnEnvironmentConfig {
+        let child_config = EnvironmentConfig {
             allow_login_shell: false,
             permission_profile: PermissionProfileSnapshot::active_with_profile_workspace_roots(
                 PermissionProfile::read_only(),
                 ActivePermissionProfile::read_only(),
                 vec![cwd.join("child-profile-root")],
             ),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         };
         let environments = ThreadEnvironments::new(
             manager,
@@ -1423,7 +1415,7 @@ url = "ws://127.0.0.1:8765"
     }
 
     #[tokio::test]
-    async fn installed_environment_config_is_inherited_and_reset_for_new_cwd() {
+    async fn owner_environment_config_is_inherited_and_reset_for_new_cwd() {
         let cwd = AbsolutePathBuf::current_dir().expect("cwd");
         let selection = TurnEnvironmentSelection {
             environment_id: LOCAL_ENVIRONMENT_ID.to_string(),
@@ -1441,17 +1433,16 @@ url = "ws://127.0.0.1:8765"
         let manager = Arc::new(EnvironmentManager::default_for_tests());
         let parent =
             resolve_turn_environments(Arc::clone(&manager), std::slice::from_ref(&selection)).await;
+        let parent_owner_config = EnvironmentConfig {
+            allow_login_shell: false,
+            permission_profile: PermissionProfileSnapshot::legacy(PermissionProfile::read_only()),
+            selected_capability_roots: vec![root("parent-root")],
+        };
         parent
-            .environment_ready(
-                &selection,
-                EnvironmentConfig {
-                    allow_login_shell: false,
-                    selected_capability_roots: vec![root("parent-root")],
-                },
-            )
+            .environment_ready(&selection, parent_owner_config.clone())
             .expect("install environment config");
 
-        let child_thread_config = TurnEnvironmentConfig {
+        let child_thread_config = EnvironmentConfig {
             permission_profile: PermissionProfileSnapshot::legacy(
                 PermissionProfile::workspace_write(),
             ),
@@ -1468,14 +1459,12 @@ url = "ws://127.0.0.1:8765"
         let child_snapshot = child.snapshot().await;
         let child_environment = child_snapshot.primary().expect("child environment");
 
+        let cleared_parent_owner_config = EnvironmentConfig {
+            selected_capability_roots: Vec::new(),
+            ..parent_owner_config.clone()
+        };
         parent
-            .environment_ready(
-                &selection,
-                EnvironmentConfig {
-                    allow_login_shell: false,
-                    selected_capability_roots: Vec::new(),
-                },
-            )
+            .environment_ready(&selection, cleared_parent_owner_config.clone())
             .expect("clear parent roots");
         let cleared_snapshot = parent.snapshot().await;
         assert_eq!(
@@ -1483,20 +1472,9 @@ url = "ws://127.0.0.1:8765"
                 .primary()
                 .expect("environment with cleared roots")
                 .config,
-            TurnEnvironmentConfig {
-                allow_login_shell: false,
-                selected_capability_roots: Some(Vec::new()),
-                ..test_environment_config()
-            }
-        );
-        assert_eq!(
-            child_environment.config,
-            TurnEnvironmentConfig {
-                allow_login_shell: false,
-                selected_capability_roots: Some(vec![root("parent-root")]),
-                ..child_thread_config
-            }
+            cleared_parent_owner_config
         );
+        assert_eq!(child_environment.config, parent_owner_config);
 
         let changed_selection = TurnEnvironmentSelection {
             cwd: PathUri::from_abs_path(&cwd.join("changed")),
diff --git a/codex-rs/core/src/guardian/review_session.rs b/codex-rs/core/src/guardian/review_session.rs
index 381ba8f81a..9d548e5867 100644
--- a/codex-rs/core/src/guardian/review_session.rs
+++ b/codex-rs/core/src/guardian/review_session.rs
@@ -21,6 +21,7 @@ use codex_protocol::models::BaseInstructionsProvenance;
 use codex_protocol::models::ContentItem;
 use codex_protocol::models::ImageDetail;
 use codex_protocol::models::PermissionProfile;
+use codex_protocol::models::PermissionProfileSnapshot;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::openai_models::InputModality;
@@ -28,6 +29,7 @@ use codex_protocol::openai_models::ModelMessages;
 use codex_protocol::openai_models::ReasoningEffort as ReasoningEffortConfig;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::CodexErrorInfo;
+use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::ErrorEvent;
 use codex_protocol::protocol::Event;
 use codex_protocol::protocol::EventMsg;
@@ -1050,8 +1052,23 @@ async fn run_review_on_session(
         .total_token_usage()
         .await
         .unwrap_or_default();
-    let guardian_permission_profile = params.spawn_config.permissions.permission_profile().clone();
-    let parent_turn_environments = params.parent_context.environments().to_selections();
+    let guardian_permission_snapshot = params
+        .spawn_config
+        .permissions
+        .permission_profile_state()
+        .snapshot();
+    let mut parent_turn_environments = params.parent_context.environments().to_selections();
+    // FromThread inherits the Guardian profile below. Once Core normalizes FromThread
+    // to Ready(config), every selection will carry explicit config and this conditional can be
+    // removed.
+    for selection in &mut parent_turn_environments {
+        if let EnvironmentConfigState::Ready(config) = &mut selection.config {
+            config.permission_profile =
+                PermissionProfileSnapshot::legacy(read_only_guardian_permission_profile(
+                    config.permission_profile.permission_profile(),
+                ));
+        }
+    }
     // TODO(anp): Migrate guardian review thread settings to a PathUri fallback cwd so foreign
     // parent environments do not fall back to the host-native config cwd.
     let parent_turn_legacy_fallback_cwd = params
@@ -1071,7 +1088,7 @@ async fn run_review_on_session(
                 )),
                 approval_policy: Some(AskForApproval::Never),
                 sandbox_policy: None,
-                permission_profile: Some(guardian_permission_profile),
+                permission_profile: Some(guardian_permission_snapshot.permission_profile().clone()),
                 summary: Some(params.reasoning_summary),
                 personality: params.personality,
                 collaboration_mode: Some(codex_protocol::config_types::CollaborationMode {
@@ -1275,6 +1292,16 @@ fn event_matches_turn(event: &Event, expected_turn_id: &str) -> bool {
     }
 }
 
+fn read_only_guardian_permission_profile(
+    permission_profile: &PermissionProfile,
+) -> PermissionProfile {
+    permission_profile
+        .intersect_with_read_only()
+        .unwrap_or(PermissionProfile::External {
+            network: codex_protocol::permissions::NetworkSandboxPolicy::Restricted,
+        })
+}
+
 pub(crate) fn build_guardian_review_session_config(
     parent_config: &Config,
     live_network_config: Option<codex_network_proxy::NetworkProxyConfig>,
@@ -1303,13 +1330,8 @@ pub(crate) fn build_guardian_review_session_config(
     guardian_config.notify = None;
     guardian_config.developer_instructions = None;
     guardian_config.permissions.approval_policy = Constrained::allow_only(AskForApproval::Never);
-    let guardian_permission_profile = parent_config
-        .permissions
-        .permission_profile()
-        .intersect_with_read_only()
-        .unwrap_or(PermissionProfile::External {
-            network: codex_protocol::permissions::NetworkSandboxPolicy::Restricted,
-        });
+    let guardian_permission_profile =
+        read_only_guardian_permission_profile(parent_config.permissions.permission_profile());
     guardian_config
         .permissions
         .set_permission_profile(guardian_permission_profile)
diff --git a/codex-rs/core/src/mcp_tool_call_tests.rs b/codex-rs/core/src/mcp_tool_call_tests.rs
index 55bcf165a7..7195ebb7b2 100644
--- a/codex-rs/core/src/mcp_tool_call_tests.rs
+++ b/codex-rs/core/src/mcp_tool_call_tests.rs
@@ -7,7 +7,6 @@ use crate::session::tests::make_session_and_context;
 use crate::session::tests::make_session_and_context_with_rx;
 use crate::session::tests::mcp_config_for_test;
 use crate::session::turn_context::TurnEnvironment;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use crate::state::ActiveTurn;
 use crate::test_support::models_manager_with_provider;
 use crate::tools::hook_names::HookToolName;
@@ -26,6 +25,7 @@ use codex_hooks::HooksConfig;
 use codex_model_provider::create_model_provider;
 use codex_protocol::models::PermissionProfile;
 use codex_protocol::protocol::AskForApproval;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::GranularApprovalConfig;
@@ -1116,14 +1116,14 @@ async fn mcp_sandbox_cwd_uses_matching_server_environment_uri() -> anyhow::Resul
             },
             environment,
             /*shell*/ None,
-            TurnEnvironmentConfig {
+            EnvironmentConfig {
                 allow_login_shell: true,
                 permission_profile: turn_context
                     .config
                     .permissions
                     .permission_profile_state()
                     .snapshot(),
-                selected_capability_roots: None,
+                selected_capability_roots: Vec::new(),
             },
         )));
 
diff --git a/codex-rs/core/src/session/mcp.rs b/codex-rs/core/src/session/mcp.rs
index 1690591239..cfddb30f17 100644
--- a/codex-rs/core/src/session/mcp.rs
+++ b/codex-rs/core/src/session/mcp.rs
@@ -445,13 +445,11 @@ impl Session {
             .selected_capability_roots
             .iter()
             .cloned()
-            .chain(environments.turn_environments().flat_map(|environment| {
-                environment
-                    .config
-                    .selected_capability_roots
-                    .clone()
-                    .unwrap_or_else(|| environment.environment.selected_capability_roots())
-            }))
+            .chain(
+                environments
+                    .turn_environments()
+                    .flat_map(|environment| environment.config.selected_capability_roots.clone()),
+            )
             .enumerate()
         {
             if let Some(kept_location) = root_locations_by_id.get(&root.id) {
diff --git a/codex-rs/core/src/session/session.rs b/codex-rs/core/src/session/session.rs
index 84829d90f1..dfd6ca1bb9 100644
--- a/codex-rs/core/src/session/session.rs
+++ b/codex-rs/core/src/session/session.rs
@@ -5,7 +5,6 @@ use crate::agents_md_manager::AgentsMdManager;
 use crate::config::ConstraintError;
 use crate::environment_selection::ThreadEnvironments;
 use crate::environment_selection::TurnEnvironmentSnapshot;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use crate::shell_snapshot::ShellSnapshot;
 use crate::state::ActiveTurn;
 use codex_extension_api::ExtensionDataInit;
@@ -20,6 +19,7 @@ use codex_protocol::config_types::ServiceTier;
 use codex_protocol::mcp::ClientMcpExtensions;
 use codex_protocol::permissions::FileSystemPath;
 use codex_protocol::permissions::FileSystemSpecialPath;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::HookCompletedEvent;
 use codex_protocol::protocol::MultiAgentVersion;
 use codex_protocol::protocol::ThreadHistoryMode;
@@ -136,14 +136,14 @@ impl SessionConfiguration {
         &self.permission_profile_state
     }
 
-    pub(super) fn turn_environment_config(&self) -> TurnEnvironmentConfig {
-        TurnEnvironmentConfig {
+    pub(super) fn turn_environment_config(&self) -> EnvironmentConfig {
+        EnvironmentConfig {
             allow_login_shell: self
                 .original_config_do_not_use
                 .permissions
                 .allow_login_shell,
             permission_profile: self.permission_profile_state.snapshot(),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         }
     }
 
@@ -1070,7 +1070,6 @@ impl Session {
             let turn_environments = Arc::new(ThreadEnvironments::new(
                 environment_manager,
                 default_shell.clone(),
-                // Temporary: preserve thread-level behavior until environments supply config.
                 session_configuration.turn_environment_config(),
                 shell_snapshot,
                 inherited_environments.unwrap_or_default(),
diff --git a/codex-rs/core/src/session/tests.rs b/codex-rs/core/src/session/tests.rs
index d6f1a0bc9b..46f351e0bb 100644
--- a/codex-rs/core/src/session/tests.rs
+++ b/codex-rs/core/src/session/tests.rs
@@ -8598,25 +8598,10 @@ async fn mcp_refresh_updates_plugin_auth_mode_before_checking_pending_state() {
     );
 }
 
-struct PendingNoiseConnectProvider;
-
-impl codex_exec_server::NoiseRendezvousConnectProvider for PendingNoiseConnectProvider {
-    fn connect_bundle(
-        &self,
-        _: codex_exec_server::NoiseChannelPublicKey,
-    ) -> futures::future::BoxFuture<
-        '_,
-        Result<codex_exec_server::NoiseRendezvousConnectBundle, codex_exec_server::ExecServerError>,
-    > {
-        Box::pin(futures::future::pending())
-    }
-}
-
 #[tokio::test]
 #[tracing_test::traced_test]
 async fn conflicting_ready_environment_root_ids_keep_first_location() {
     let (session, turn_context) = make_session_and_context().await;
-    let environment_manager = session.services.turn_environments.environment_manager();
     let selected_root =
         |environment_id: &str, path: &str| codex_protocol::capabilities::SelectedCapabilityRoot {
             id: "shared-root".to_string(),
@@ -8639,29 +8624,21 @@ async fn conflicting_ready_environment_root_ids_keep_first_location() {
             environment_id,
             ..
         } = &selected_root.location;
-        let provider = Arc::new(PendingNoiseConnectProvider);
-        let environment = environment_manager
-            .materialize_pending_noise_environment(environment_id.clone(), provider.clone())
-            .expect("materialize deferred environment");
-        environment_manager
-            .report_environment_provisioning_status(
-                environment_id.clone(),
-                Ok(codex_exec_server::EnvironmentReadyInfo {
-                    selected_capability_roots: vec![selected_root.clone()],
-                }),
-                provider,
-            )
-            .expect("report environment ready");
+        let mut environment_config = local_environment.config.clone();
+        environment_config.selected_capability_roots = vec![selected_root.clone()];
         turn_environments.push(TurnEnvironment::new(
             TurnEnvironmentSelection {
                 environment_id: environment_id.clone(),
                 cwd: local_environment.cwd().clone(),
                 workspace_roots: local_environment.workspace_roots().to_vec(),
-                config: EnvironmentConfigState::FromThread,
+                config: EnvironmentConfigState::Ready(environment_config.clone()),
             },
-            environment,
+            Arc::new(
+                codex_exec_server::Environment::create_for_tests(/*exec_server_url*/ None)
+                    .expect("create test environment"),
+            ),
             local_environment.shell.clone(),
-            local_environment.config.clone(),
+            environment_config,
         ));
     }
     let environments = TurnEnvironmentSnapshot {
diff --git a/codex-rs/core/src/session/turn_context.rs b/codex-rs/core/src/session/turn_context.rs
index 2a968e65af..a11bef12f4 100644
--- a/codex-rs/core/src/session/turn_context.rs
+++ b/codex-rs/core/src/session/turn_context.rs
@@ -11,10 +11,10 @@ use codex_file_system::FileSystemSandboxContext;
 use codex_model_provider::SharedModelProvider;
 use codex_protocol::SessionId;
 use codex_protocol::ThreadId;
-use codex_protocol::capabilities::SelectedCapabilityRoot;
 use codex_protocol::models::AdditionalPermissionProfile;
 use codex_protocol::openai_models::MODEL_SPECIALTY_CYBER;
 use codex_protocol::openai_models::ModelInfo;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::ErrorEvent;
 use codex_protocol::protocol::MultiAgentVersion;
 use codex_protocol::protocol::ThreadHistoryMode;
@@ -31,21 +31,12 @@ use tracing::instrument;
 
 pub(crate) type ShellSnapshotTask = Shared<BoxFuture<'static, Option<Arc<ShellSnapshotFile>>>>;
 
-/// Effective per-environment config; fields move here as executor config is migrated.
-#[derive(Clone, Debug, PartialEq, Eq)]
-pub(crate) struct TurnEnvironmentConfig {
-    pub(crate) allow_login_shell: bool,
-    pub(crate) permission_profile: PermissionProfileSnapshot,
-    /// None preserves legacy executor roots; Some, including empty, is owner-installed.
-    pub(crate) selected_capability_roots: Option<Vec<SelectedCapabilityRoot>>,
-}
-
 #[derive(Clone)]
 pub(crate) struct TurnEnvironment {
     pub(crate) selection: TurnEnvironmentSelection,
     pub(crate) environment: Arc<Environment>,
     pub(crate) shell: Option<shell::Shell>,
-    pub(crate) config: TurnEnvironmentConfig,
+    pub(crate) config: EnvironmentConfig,
     pub(crate) shell_snapshot: ShellSnapshotTask,
 }
 
@@ -54,7 +45,7 @@ impl TurnEnvironment {
         selection: TurnEnvironmentSelection,
         environment: Arc<Environment>,
         shell: Option<shell::Shell>,
-        config: TurnEnvironmentConfig,
+        config: EnvironmentConfig,
     ) -> Self {
         Self {
             selection,
diff --git a/codex-rs/core/src/tools/handlers/shell_tests.rs b/codex-rs/core/src/tools/handlers/shell_tests.rs
index 742083e247..1a7fed0194 100644
--- a/codex-rs/core/src/tools/handlers/shell_tests.rs
+++ b/codex-rs/core/src/tools/handlers/shell_tests.rs
@@ -14,7 +14,6 @@ use crate::sandboxing::SandboxPermissions;
 use crate::session::step_context::StepContext;
 use crate::session::tests::make_session_and_context;
 use crate::session::turn_context::TurnEnvironment;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use crate::shell::Shell;
 use crate::shell::ShellType;
 use crate::tools::context::FunctionToolOutput;
@@ -25,6 +24,7 @@ use crate::tools::handlers::ShellCommandHandler;
 use crate::tools::hook_names::HookToolName;
 use crate::tools::registry::CoreToolRuntime;
 use crate::turn_diff_tracker::TurnDiffTracker;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::TurnEnvironmentSelection;
 use codex_shell_command::is_safe_command::is_known_safe_command;
@@ -119,13 +119,13 @@ async fn shell_command_handler_to_exec_params_uses_selected_environment() {
                 .environment,
         ),
         Some(selected_shell),
-        TurnEnvironmentConfig {
+        EnvironmentConfig {
             allow_login_shell: true,
             permission_profile: PermissionProfileSnapshot::active(
                 permission_profile,
                 active_permission_profile.clone(),
             ),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         },
     );
     let mut expected_env = create_env(
diff --git a/codex-rs/core/src/tools/runtimes/apply_patch_tests.rs b/codex-rs/core/src/tools/runtimes/apply_patch_tests.rs
index 08ddeaa815..b62882c471 100644
--- a/codex-rs/core/src/tools/runtimes/apply_patch_tests.rs
+++ b/codex-rs/core/src/tools/runtimes/apply_patch_tests.rs
@@ -1,12 +1,12 @@
 use super::*;
 use crate::config::PermissionProfileSnapshot;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use crate::tools::sandboxing::SandboxAttempt;
 use codex_protocol::config_types::WindowsSandboxLevel;
 use codex_protocol::models::AdditionalPermissionProfile;
 use codex_protocol::models::FileSystemPermissions;
 use codex_protocol::models::PermissionProfile;
 use codex_protocol::permissions::NetworkSandboxPolicy;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::GranularApprovalConfig;
 use codex_protocol::protocol::TurnEnvironmentSelection;
@@ -28,10 +28,10 @@ fn test_turn_environment(environment_id: &str) -> crate::session::turn_context::
         },
         std::sync::Arc::new(codex_exec_server::Environment::default_for_tests()),
         /*shell*/ None,
-        TurnEnvironmentConfig {
+        EnvironmentConfig {
             allow_login_shell: true,
             permission_profile: PermissionProfileSnapshot::legacy(PermissionProfile::read_only()),
-            selected_capability_roots: None,
+            selected_capability_roots: Vec::new(),
         },
     )
 }
diff --git a/codex-rs/core/src/tools/runtimes/shell_tests.rs b/codex-rs/core/src/tools/runtimes/shell_tests.rs
index 1fe33bb8b2..a336983a53 100644
--- a/codex-rs/core/src/tools/runtimes/shell_tests.rs
+++ b/codex-rs/core/src/tools/runtimes/shell_tests.rs
@@ -1,9 +1,9 @@
 use super::*;
 use crate::config::PermissionProfileSnapshot;
-use crate::session::turn_context::TurnEnvironmentConfig;
 use crate::tools::approvals::ApprovalCacheKey;
 use codex_exec_server::Environment;
 use codex_protocol::models::PermissionProfile;
+use codex_protocol::protocol::EnvironmentConfig;
 use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::TurnEnvironmentSelection;
 use codex_utils_path_uri::PathUri;
@@ -25,12 +25,12 @@ async fn approval_key_uses_path_uri_and_includes_environment_id() {
             },
             Arc::new(Environment::default_for_tests()),
             /*shell*/ None,
-            TurnEnvironmentConfig {
+            EnvironmentConfig {
                 allow_login_shell: true,
                 permission_profile: PermissionProfileSnapshot::legacy(
                     PermissionProfile::read_only(),
                 ),
-                selected_capability_roots: None,
+                selected_capability_roots: Vec::new(),
             },
         ),
         shell_type: None,
diff --git a/codex-rs/core/src/tools/runtimes/unified_exec.rs b/codex-rs/core/src/tools/runtimes/unified_exec.rs
index 21ca88c384..b49843feba 100644
--- a/codex-rs/core/src/tools/runtimes/unified_exec.rs
+++ b/codex-rs/core/src/tools/runtimes/unified_exec.rs
@@ -515,11 +515,11 @@ mod tests {
     use super::*;
     use crate::config::PermissionProfileSnapshot;
     use crate::exec::DEFAULT_EXEC_COMMAND_TIMEOUT_MS;
-    use crate::session::turn_context::TurnEnvironmentConfig;
     use crate::tools::sandboxing::ToolRuntime;
     use codex_exec_server::Environment;
     use codex_exec_server::LOCAL_ENVIRONMENT_ID;
     use codex_protocol::models::PermissionProfile;
+    use codex_protocol::protocol::EnvironmentConfig;
     use codex_protocol::protocol::EnvironmentConfigState;
     use codex_protocol::protocol::TurnEnvironmentSelection;
     use codex_tools::ZshForkConfig;
@@ -540,12 +540,12 @@ mod tests {
             },
             Arc::new(Environment::default_for_tests()),
             /*shell*/ None,
-            TurnEnvironmentConfig {
+            EnvironmentConfig {
                 allow_login_shell: true,
                 permission_profile: PermissionProfileSnapshot::legacy(
                     PermissionProfile::read_only(),
                 ),
-                selected_capability_roots: None,
+                selected_capability_roots: Vec::new(),
             },
         )
     }
diff --git a/codex-rs/core/src/tools/spec_plan_tests.rs b/codex-rs/core/src/tools/spec_plan_tests.rs
index ddc34326e3..8eca4327aa 100644
--- a/codex-rs/core/src/tools/spec_plan_tests.rs
+++ b/codex-rs/core/src/tools/spec_plan_tests.rs
@@ -917,14 +917,14 @@ async fn zsh_fork_unified_exec_keeps_shell_parameter_when_remote_environment_ava
                         .expect("remote test environment"),
                     ),
                     /*shell*/ None,
-                    crate::session::turn_context::TurnEnvironmentConfig {
+                    codex_protocol::protocol::EnvironmentConfig {
                         allow_login_shell: true,
                         permission_profile: turn
                             .config
                             .permissions
                             .permission_profile_state()
                             .snapshot(),
-                        selected_capability_roots: None,
+                        selected_capability_roots: Vec::new(),
                     },
                 ),
             ));
diff --git a/codex-rs/core/tests/suite/guardian_review.rs b/codex-rs/core/tests/suite/guardian_review.rs
index 6c940cc56e..757990ba2e 100644
--- a/codex-rs/core/tests/suite/guardian_review.rs
+++ b/codex-rs/core/tests/suite/guardian_review.rs
@@ -25,6 +25,7 @@ use codex_login::CodexAuth;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::ApprovalsReviewer;
 use codex_protocol::models::PermissionProfile;
+use codex_protocol::models::PermissionProfileSnapshot;
 use codex_protocol::openai_models::MODEL_SPECIALTY_CYBER;
 use codex_protocol::openai_models::ModelsResponse;
 use codex_protocol::permissions::FileSystemAccessMode;
@@ -33,6 +34,8 @@ use codex_protocol::permissions::FileSystemSandboxEntry;
 use codex_protocol::permissions::FileSystemSandboxPolicy;
 use codex_protocol::permissions::NetworkSandboxPolicy;
 use codex_protocol::protocol::AskForApproval;
+use codex_protocol::protocol::EnvironmentConfig;
+use codex_protocol::protocol::EnvironmentConfigState;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::Op;
 use codex_protocol::protocol::SandboxPolicy;
@@ -511,6 +514,19 @@ async fn guardian_session_is_reused_for_consecutive_tool_reviews_without_prewarm
         ],
     )
     .await;
+    let mut parent_environments = local_selections(test.config.cwd.clone());
+    let parent_environment_config = EnvironmentConfig {
+        allow_login_shell: test.config.permissions.allow_login_shell,
+        permission_profile: PermissionProfileSnapshot::legacy(
+            test.config.permissions.permission_profile().clone(),
+        ),
+        selected_capability_roots: Vec::new(),
+    };
+    parent_environments
+        .environments
+        .first_mut()
+        .expect("local environment selection")
+        .config = EnvironmentConfigState::Ready(parent_environment_config);
 
     test.codex
         .start_or_steer_turn(
@@ -519,7 +535,7 @@ async fn guardian_session_is_reused_for_consecutive_tool_reviews_without_prewarm
                 text_elements: Vec::new(),
             }])
             .with_thread_settings(ThreadSettingsOverrides {
-                environments: Some(local_selections(test.config.cwd.clone())),
+                environments: Some(parent_environments),
                 approval_policy: Some(approval_policy),
                 approvals_reviewer: Some(ApprovalsReviewer::AutoReview),
                 ..Default::default()
diff --git a/codex-rs/core/tests/suite/mcp_tool_exposure.rs b/codex-rs/core/tests/suite/mcp_tool_exposure.rs
index c08c83335a..5a666df086 100644
--- a/codex-rs/core/tests/suite/mcp_tool_exposure.rs
+++ b/codex-rs/core/tests/suite/mcp_tool_exposure.rs
@@ -18,6 +18,7 @@ use codex_mcp::McpResourceClient;
 use codex_protocol::capabilities::CapabilityRootLocation;
 use codex_protocol::capabilities::SelectedCapabilityRoot;
 use codex_protocol::models::PermissionProfile;
+use codex_protocol::models::PermissionProfileSnapshot;
 use codex_protocol::protocol::AskForApproval;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::Op;
@@ -478,6 +479,9 @@ async fn root_reconciliation_reuses_pending_apps_startup() -> Result<()> {
             &selection,
             EnvironmentConfig {
                 allow_login_shell: false,
+                permission_profile: PermissionProfileSnapshot::legacy(
+                    test.config.permissions.permission_profile().clone(),
+                ),
                 selected_capability_roots: vec![SelectedCapabilityRoot {
                     id: "calendar-root".to_string(),
                     location: CapabilityRootLocation::Environment {
diff --git a/codex-rs/core/tests/suite/remote_env.rs b/codex-rs/core/tests/suite/remote_env.rs
index 89c250aa9b..69604aab33 100644
--- a/codex-rs/core/tests/suite/remote_env.rs
+++ b/codex-rs/core/tests/suite/remote_env.rs
@@ -46,6 +46,7 @@ use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Settings;
 use codex_protocol::models::FileSystemPermissions;
 use codex_protocol::models::PermissionProfile;
+use codex_protocol::models::PermissionProfileSnapshot;
 use codex_protocol::models::SandboxPermissions;
 use codex_protocol::permissions::FileSystemAccessMode;
 use codex_protocol::permissions::FileSystemPath;
@@ -435,6 +436,105 @@ async fn explicit_remote_shell_runs_in_remote_cwd() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn ready_environment_permissions_override_thread_permissions() -> Result<()> {
+    const CALL_ID: &str = "attachment-specific-permissions";
+    const FILE_NAME: &str = "attachment-read-only-marker.txt";
+
+    skip_if_target_windows!(
+        Ok(()),
+        "Windows sandbox enforcement is covered by the platform-specific suite"
+    );
+
+    let server = start_mock_server().await;
+    let mut builder = test_codex().with_config(|config| {
+        config.use_experimental_unified_exec_tool = true;
+        config
+            .features
+            .enable(Feature::UnifiedExec)
+            .expect("test config should allow feature update");
+        config
+            .permissions
+            .set_permission_profile(PermissionProfile::workspace_write())
+            .expect("thread should allow workspace writes");
+    });
+    let test = builder.build_with_auto_env(&server).await?;
+    let mut selection = test.executor_environment().selection().clone();
+    let marker = selection.cwd.join(FILE_NAME)?;
+    selection.config = EnvironmentConfigState::Ready(EnvironmentConfig {
+        allow_login_shell: test.config.permissions.allow_login_shell,
+        permission_profile: PermissionProfileSnapshot::legacy(PermissionProfile::read_only()),
+        selected_capability_roots: Vec::new(),
+    });
+
+    let (shell, command) = match test_target_os() {
+        TestTargetOs::Linux => (
+            "bash",
+            format!(
+                "if printf blocked > {FILE_NAME}; then echo WRITE_SUCCEEDED; else echo WRITE_DENIED; fi"
+            ),
+        ),
+        TestTargetOs::MacOs => (
+            "zsh",
+            format!(
+                "if printf blocked > {FILE_NAME}; then echo WRITE_SUCCEEDED; else echo WRITE_DENIED; fi"
+            ),
+        ),
+        TestTargetOs::Windows => (
+            "powershell",
+            format!(
+                "try {{ Set-Content -Path '{FILE_NAME}' -Value blocked -ErrorAction Stop; Write-Output WRITE_SUCCEEDED }} catch {{ Write-Output WRITE_DENIED }}"
+            ),
+        ),
+    };
+    let arguments = serde_json::to_string(&json!({
+        "cmd": command,
+        "shell": shell,
+        "login": false,
+        "yield_time_ms": 10_000,
+        "sandbox_permissions": SandboxPermissions::UseDefault,
+    }))?;
+    let response_mock = mount_sse_sequence(
+        &server,
+        vec![
+            sse(vec![
+                ev_response_created("resp-1"),
+                ev_function_call(CALL_ID, "exec_command", &arguments),
+                ev_completed("resp-1"),
+            ]),
+            sse(vec![
+                ev_response_created("resp-2"),
+                ev_assistant_message("msg-1", "done"),
+                ev_completed("resp-2"),
+            ]),
+        ],
+    )
+    .await;
+
+    test.submit_turn_with_environments("try to write a file", Some(vec![selection]))
+        .await?;
+
+    let output = response_mock
+        .last_request()
+        .context("model should receive the command output")?
+        .function_call_output_text(CALL_ID)
+        .context("shell tool result should be present")?;
+    assert!(
+        output.contains("WRITE_DENIED"),
+        "unexpected output: {output}"
+    );
+    assert!(!output.contains("WRITE_SUCCEEDED"));
+    assert!(
+        test.fs()
+            .read_file_text(&marker, /*sandbox*/ None)
+            .await
+            .is_err(),
+        "read-only attachment unexpectedly wrote {FILE_NAME}"
+    );
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn step_world_state_gates_deferred_prompt_independently_of_host_config() -> Result<()> {
     for deferred_executor_enabled in [false, true] {
@@ -1007,11 +1107,14 @@ async fn shared_executor_keeps_ready_capability_roots_scoped_to_each_attachment(
             path: selection.cwd.clone(),
         },
     };
+    let permission_profile =
+        PermissionProfileSnapshot::legacy(test.config.permissions.permission_profile().clone());
 
     for config in [
         EnvironmentConfigState::Pending,
         EnvironmentConfigState::Ready(EnvironmentConfig {
             allow_login_shell: false,
+            permission_profile: permission_profile.clone(),
             selected_capability_roots: vec![root("duplicate"), root("duplicate")],
         }),
     ] {
@@ -1045,6 +1148,7 @@ async fn shared_executor_keeps_ready_capability_roots_scoped_to_each_attachment(
             environments: Some(vec![TurnEnvironmentSelection {
                 config: EnvironmentConfigState::Ready(EnvironmentConfig {
                     allow_login_shell: true,
+                    permission_profile: permission_profile.clone(),
                     selected_capability_roots: vec![root("startup-root"), root("second-root")],
                 }),
                 ..selection.clone()
@@ -1062,6 +1166,7 @@ async fn shared_executor_keeps_ready_capability_roots_scoped_to_each_attachment(
                 vec![TurnEnvironmentSelection {
                     config: EnvironmentConfigState::Ready(EnvironmentConfig {
                         allow_login_shell: false,
+                        permission_profile: permission_profile.clone(),
                         selected_capability_roots: vec![root("first-root")],
                     }),
                     ..selection.clone()
@@ -1118,6 +1223,7 @@ async fn shared_executor_keeps_ready_capability_roots_scoped_to_each_attachment(
                     vec![TurnEnvironmentSelection {
                         config: EnvironmentConfigState::Ready(EnvironmentConfig {
                             allow_login_shell: false,
+                            permission_profile: permission_profile.clone(),
                             selected_capability_roots: vec![root("first-updated-root")],
                         }),
                         ..selection.clone()
@@ -1283,7 +1389,7 @@ async fn ready_before_selection_exposes_remote_tools_and_capability_context_afte
         .report_environment_provisioning_status(
             REMOTE_ENVIRONMENT_ID.to_string(),
             Ok(EnvironmentReadyInfo {
-                selected_capability_roots: vec![ready_root],
+                selected_capability_roots: Vec::new(),
             }),
             Arc::new(ReadyNoiseConnectProvider {
                 websocket_url: format!("{rendezvous_url}/relay?role=harness"),
@@ -1327,7 +1433,13 @@ async fn ready_before_selection_exposes_remote_tools_and_capability_context_afte
             environment_id: REMOTE_ENVIRONMENT_ID.to_string(),
             cwd: PathUri::from_abs_path(&test.config.cwd),
             workspace_roots: vec![PathUri::from_abs_path(&test.config.cwd)],
-            config: EnvironmentConfigState::FromThread,
+            config: EnvironmentConfigState::Ready(EnvironmentConfig {
+                allow_login_shell: true,
+                permission_profile: PermissionProfileSnapshot::legacy(
+                    test.config.permissions.permission_profile().clone(),
+                ),
+                selected_capability_roots: vec![ready_root],
+            }),
         }]),
     )
     .await?;
diff --git a/codex-rs/protocol/src/environment.rs b/codex-rs/protocol/src/environment.rs
index 54a55f3af4..3ed127c310 100644
--- a/codex-rs/protocol/src/environment.rs
+++ b/codex-rs/protocol/src/environment.rs
@@ -1,4 +1,5 @@
 use crate::capabilities::SelectedCapabilityRoot;
+use crate::models::PermissionProfileSnapshot;
 
 /// Configuration supplied for a thread's selected environment.
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -11,11 +12,13 @@ pub enum EnvironmentConfigState {
     Ready(EnvironmentConfig),
 }
 
-/// Resolved configuration supplied by the owner of a thread/environment attachment.
+/// Resolved configuration for a thread/environment attachment.
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct EnvironmentConfig {
     /// Whether shell tools may start login shells in this environment.
     pub allow_login_shell: bool,
+    /// Resolved permissions for this thread's environment attachment.
+    pub permission_profile: PermissionProfileSnapshot,
     /// Capability roots selected for this thread's environment attachment.
     pub selected_capability_roots: Vec<SelectedCapabilityRoot>,
 }