diff --git a/codex-rs/core/src/agents_md_tests.rs b/codex-rs/core/src/agents_md_tests.rs
index 8bb628d9da..1ffeaf131b 100644
--- a/codex-rs/core/src/agents_md_tests.rs
+++ b/codex-rs/core/src/agents_md_tests.rs
@@ -3,6 +3,7 @@ use crate::config::ConfigBuilder;
 use crate::context::ContextualUserFragment;
 use crate::environment_selection::TurnEnvironmentSnapshot;
 use crate::environment_selection::TurnEnvironmentState;
+use crate::session::turn_context::EnvironmentConfig;
 use crate::session::turn_context::TurnEnvironment;
 use codex_config::ConfigLayerEntry;
 use codex_config::ConfigLayerStack;
@@ -337,6 +338,9 @@ fn resolved_local_environments<const N: usize>(
                     PathUri::from_abs_path(&cwd),
                     Vec::new(),
                     /*shell*/ None,
+                    EnvironmentConfig {
+                        allow_login_shell: true,
+                    },
                 ))
             })
             .collect(),
diff --git a/codex-rs/core/src/environment_selection.rs b/codex-rs/core/src/environment_selection.rs
index 433e50819a..1ebe44a749 100644
--- a/codex-rs/core/src/environment_selection.rs
+++ b/codex-rs/core/src/environment_selection.rs
@@ -22,6 +22,7 @@ use futures::future::BoxFuture;
 use futures::future::Shared;
 use tokio_util::task::AbortOnDropHandle;
 
+use crate::session::turn_context::EnvironmentConfig;
 use crate::session::turn_context::TurnEnvironment;
 use crate::shell::Shell;
 use crate::shell_snapshot::ShellSnapshot;
@@ -79,6 +80,8 @@ impl StartingTurnEnvironment {
 pub(crate) struct ThreadEnvironments {
     environment_manager: Arc<EnvironmentManager>,
     local_shell: Shell,
+    // Temporary thread-wide config source until environments supply their own config.
+    fallback_environment_config: EnvironmentConfig,
     shell_snapshot: ShellSnapshot,
     non_blocking_snapshots: bool,
     environments: ArcSwap<Vec<SelectedTurnEnvironment>>,
@@ -89,6 +92,7 @@ impl ThreadEnvironments {
     pub(crate) fn new(
         environment_manager: Arc<EnvironmentManager>,
         local_shell: Shell,
+        fallback_environment_config: EnvironmentConfig,
         shell_snapshot: ShellSnapshot,
         current: TurnEnvironmentSnapshot,
         non_blocking_snapshots: bool,
@@ -98,9 +102,11 @@ impl ThreadEnvironments {
             .environments
             .into_iter()
             .filter_map(|environment| {
-                let TurnEnvironmentState::Ready(environment) = environment else {
+                let TurnEnvironmentState::Ready(mut environment) = environment else {
                     return None;
                 };
+                // Child threads can have a different shell policy from their parent.
+                environment.config = fallback_environment_config.clone();
                 let selection = environment.selection();
                 let selected_environment = Arc::clone(&environment.environment);
                 let resolution: TurnEnvironmentResolution =
@@ -116,6 +122,7 @@ impl ThreadEnvironments {
         Self {
             environment_manager,
             local_shell,
+            fallback_environment_config,
             shell_snapshot,
             non_blocking_snapshots,
             environments: ArcSwap::from_pointee(environments),
@@ -166,6 +173,7 @@ impl ThreadEnvironments {
                 selected_environment.clone(),
                 Arc::clone(&environment),
                 self.local_shell.clone(),
+                self.fallback_environment_config.clone(),
                 self.shell_snapshot.clone(),
             )
             .remote_handle();
@@ -265,6 +273,7 @@ impl ThreadEnvironments {
         selection: TurnEnvironmentSelection,
         environment: Arc<Environment>,
         local_shell: Shell,
+        config: EnvironmentConfig,
         shell_snapshot: ShellSnapshot,
     ) -> BoxFuture<'static, TurnEnvironmentResult> {
         async move {
@@ -300,6 +309,7 @@ impl ThreadEnvironments {
                 selection.cwd,
                 selection.workspace_roots,
                 shell,
+                config,
             );
             let task = shell_snapshot
                 .build(turn_environment.clone())
@@ -506,6 +516,9 @@ mod tests {
         let turn_environments = Arc::new(ThreadEnvironments::new(
             environment_manager,
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot::default(),
             /*non_blocking_snapshots*/ false,
@@ -649,7 +662,7 @@ url = "ws://127.0.0.1:8765"
     }
 
     #[tokio::test]
-    async fn local_environment_uses_configured_shell() {
+    async fn local_environment_uses_configured_shell_and_login_policy() {
         let cwd = AbsolutePathBuf::current_dir().expect("cwd");
         let local_shell = Shell {
             shell_type: crate::shell::ShellType::Zsh,
@@ -658,6 +671,9 @@ url = "ws://127.0.0.1:8765"
         let turn_environments = ThreadEnvironments::new(
             Arc::new(EnvironmentManager::default_for_tests()),
             local_shell.clone(),
+            EnvironmentConfig {
+                allow_login_shell: false,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot::default(),
             /*non_blocking_snapshots*/ false,
@@ -669,13 +685,10 @@ url = "ws://127.0.0.1:8765"
         }]);
 
         let snapshot = turn_environments.snapshot().await;
+        let environment = snapshot.primary().expect("local environment");
 
-        assert_eq!(
-            snapshot
-                .primary()
-                .and_then(|environment| environment.shell.as_ref()),
-            Some(&local_shell)
-        );
+        assert_eq!(environment.shell.as_ref(), Some(&local_shell));
+        assert!(!environment.config.allow_login_shell);
     }
 
     #[tokio::test]
@@ -797,6 +810,9 @@ url = "ws://127.0.0.1:8765"
         let environments = Arc::new(ThreadEnvironments::new(
             manager,
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot::default(),
             /*non_blocking_snapshots*/ false,
@@ -850,6 +866,9 @@ url = "ws://127.0.0.1:8765"
         let turn_environments = ThreadEnvironments::new(
             manager,
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot::default(),
             /*non_blocking_snapshots*/ true,
@@ -924,6 +943,9 @@ url = "ws://127.0.0.1:8765"
         let environments = ThreadEnvironments::new(
             Arc::clone(&manager),
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot::default(),
             /*non_blocking_snapshots*/ true,
@@ -978,6 +1000,9 @@ url = "ws://127.0.0.1:8765"
         let environments = Arc::new(ThreadEnvironments::new(
             Arc::clone(&manager),
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot::default(),
             /*non_blocking_snapshots*/ true,
@@ -1050,7 +1075,7 @@ url = "ws://127.0.0.1:8765"
     }
 
     #[tokio::test]
-    async fn inherited_environment_reuses_parent_handle() {
+    async fn inherited_environment_reuses_parent_handle_and_uses_child_login_policy() {
         let cwd = AbsolutePathBuf::current_dir().expect("cwd");
         let selection = TurnEnvironmentSelection {
             environment_id: REMOTE_ENVIRONMENT_ID.to_string(),
@@ -1067,6 +1092,9 @@ url = "ws://127.0.0.1:8765"
             selection.cwd.clone(),
             Vec::new(),
             /*shell*/ None,
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
         );
         let manager = Arc::new(environment_manager_without_environments());
         manager
@@ -1079,6 +1107,9 @@ url = "ws://127.0.0.1:8765"
         let environments = ThreadEnvironments::new(
             manager,
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: false,
+            },
             ShellSnapshot::disabled(),
             TurnEnvironmentSnapshot {
                 environments: vec![TurnEnvironmentState::Ready(inherited)],
@@ -1089,13 +1120,9 @@ url = "ws://127.0.0.1:8765"
         environments.update_selections(std::slice::from_ref(&selection));
         let snapshot = environments.snapshot().await;
 
-        assert!(Arc::ptr_eq(
-            &snapshot
-                .primary()
-                .expect("inherited environment")
-                .environment,
-            &inherited_environment,
-        ));
+        let inherited = snapshot.primary().expect("inherited environment");
+        assert!(Arc::ptr_eq(&inherited.environment, &inherited_environment));
+        assert!(!inherited.config.allow_login_shell);
     }
 
     #[tokio::test]
@@ -1124,6 +1151,9 @@ url = "ws://127.0.0.1:8765"
                 cwd_uri.clone(),
                 Vec::new(),
                 /*shell*/ None,
+                EnvironmentConfig {
+                    allow_login_shell: true,
+                },
             ))],
         };
         let multiple = TurnEnvironmentSnapshot {
@@ -1135,6 +1165,9 @@ url = "ws://127.0.0.1:8765"
                     cwd_uri,
                     Vec::new(),
                     /*shell*/ None,
+                    EnvironmentConfig {
+                        allow_login_shell: true,
+                    },
                 )),
             ],
         };
diff --git a/codex-rs/core/src/mcp_openai_file.rs b/codex-rs/core/src/mcp_openai_file.rs
index 9075923115..1cc2e72a71 100644
--- a/codex-rs/core/src/mcp_openai_file.rs
+++ b/codex-rs/core/src/mcp_openai_file.rs
@@ -217,6 +217,7 @@ mod tests {
     use super::*;
     use crate::environment_selection::TurnEnvironmentState;
     use crate::session::tests::make_session_and_context;
+    use crate::session::turn_context::EnvironmentConfig;
     use crate::session::turn_context::TurnContext;
     use crate::session::turn_context::TurnEnvironment;
     use codex_utils_absolute_path::AbsolutePathBuf;
@@ -239,6 +240,7 @@ mod tests {
             PathUri::from_abs_path(&cwd),
             Vec::new(),
             primary.shell.clone(),
+            primary.config.clone(),
         );
     }
 
@@ -323,6 +325,9 @@ mod tests {
         let environments = crate::environment_selection::ThreadEnvironments::new(
             session.services.turn_environments.environment_manager(),
             crate::shell::default_user_shell(),
+            EnvironmentConfig {
+                allow_login_shell: turn_context.config.permissions.allow_login_shell,
+            },
             crate::shell_snapshot::ShellSnapshot::disabled(),
             Default::default(),
             /*non_blocking_snapshots*/ true,
diff --git a/codex-rs/core/src/mcp_tool_call_tests.rs b/codex-rs/core/src/mcp_tool_call_tests.rs
index 4db1cdbd5c..c0d93364fd 100644
--- a/codex-rs/core/src/mcp_tool_call_tests.rs
+++ b/codex-rs/core/src/mcp_tool_call_tests.rs
@@ -6,6 +6,7 @@ use crate::session::step_context::StepContext;
 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::EnvironmentConfig;
 use crate::session::turn_context::TurnEnvironment;
 use crate::state::ActiveTurn;
 use crate::test_support::models_manager_with_provider;
@@ -1102,6 +1103,9 @@ async fn mcp_sandbox_cwd_uses_matching_server_environment_uri() -> anyhow::Resul
             secondary_cwd.clone(),
             Vec::new(),
             /*shell*/ None,
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
         )));
 
     let step_context = StepContext::for_test(Arc::new(turn_context));
diff --git a/codex-rs/core/src/session/session.rs b/codex-rs/core/src/session/session.rs
index 4b40cbc2e7..e6f5627920 100644
--- a/codex-rs/core/src/session/session.rs
+++ b/codex-rs/core/src/session/session.rs
@@ -5,6 +5,7 @@ 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::EnvironmentConfig;
 use crate::shell_snapshot::ShellSnapshot;
 use crate::skills::SkillError;
 use crate::state::ActiveTurn;
@@ -939,6 +940,10 @@ impl Session {
             let turn_environments = Arc::new(ThreadEnvironments::new(
                 environment_manager,
                 default_shell.clone(),
+                // Temporary: preserve thread-level behavior until environments supply config.
+                EnvironmentConfig {
+                    allow_login_shell: config.permissions.allow_login_shell,
+                },
                 shell_snapshot,
                 inherited_environments.unwrap_or_default(),
                 config.features.enabled(Feature::DeferredExecutor),
diff --git a/codex-rs/core/src/session/tests.rs b/codex-rs/core/src/session/tests.rs
index c67aa14dd6..d2970beb45 100644
--- a/codex-rs/core/src/session/tests.rs
+++ b/codex-rs/core/src/session/tests.rs
@@ -1,4 +1,5 @@
 use super::mcp_refresh::McpRefresh;
+use super::turn_context::EnvironmentConfig;
 use super::turn_context::TurnEnvironment;
 use super::*;
 use crate::agents_md_manager::AgentsMdManager;
@@ -4869,6 +4870,12 @@ async fn resolved_environments_for_configuration(
     let turn_environments = ThreadEnvironments::new(
         Arc::clone(&environment_manager),
         default_user_shell(),
+        EnvironmentConfig {
+            allow_login_shell: session_configuration
+                .original_config_do_not_use
+                .permissions
+                .allow_login_shell,
+        },
         ShellSnapshot::disabled(),
         TurnEnvironmentSnapshot::default(),
         /*non_blocking_snapshots*/ false,
@@ -5667,6 +5674,9 @@ pub(crate) async fn make_session_and_context() -> (Session, TurnContext) {
     let turn_environments = Arc::new(ThreadEnvironments::new(
         environment_manager,
         default_user_shell(),
+        EnvironmentConfig {
+            allow_login_shell: config.permissions.allow_login_shell,
+        },
         ShellSnapshot::disabled(),
         resolved_environments,
         /*non_blocking_snapshots*/ false,
@@ -6470,6 +6480,7 @@ async fn request_permissions_tool_resolves_relative_paths_against_selected_envir
             PathUri::from_abs_path(&environment_cwd),
             Vec::new(),
             current_environment.shell,
+            current_environment.config,
         ));
 
     let call_id = "call-1".to_string();
@@ -7131,6 +7142,7 @@ async fn primary_environment_uses_first_turn_environment() {
             second_cwd_uri.clone(),
             Vec::new(),
             /*shell*/ None,
+            first_environment.config.clone(),
         )));
 
     assert_eq!(
@@ -7856,6 +7868,9 @@ where
     let turn_environments = Arc::new(ThreadEnvironments::new(
         environment_manager,
         default_user_shell(),
+        EnvironmentConfig {
+            allow_login_shell: config.permissions.allow_login_shell,
+        },
         ShellSnapshot::disabled(),
         resolved_turn_environments.clone(),
         /*non_blocking_snapshots*/ false,
@@ -8446,6 +8461,7 @@ async fn conflicting_ready_environment_root_ids_keep_first_location() {
             local_environment.cwd().clone(),
             local_environment.workspace_roots().to_vec(),
             local_environment.shell.clone(),
+            local_environment.config.clone(),
         ));
     }
     let environments = TurnEnvironmentSnapshot {
@@ -8656,6 +8672,7 @@ async fn record_context_updates_emits_environment_item_for_cwd_changes() {
             PathUri::from_abs_path(&cwd),
             Vec::new(),
             environment.shell,
+            environment.config,
         ));
 
     let update_items =
@@ -8721,6 +8738,7 @@ async fn record_context_updates_omits_environment_item_when_disabled() {
             PathUri::from_abs_path(&test_path_buf("/new-repo").abs()),
             Vec::new(),
             environment.shell,
+            environment.config,
         ));
 
     let update_items =
@@ -9172,6 +9190,7 @@ async fn turn_context_item_stores_local_cwd() {
         cwd,
         Vec::new(),
         environment.shell,
+        environment.config,
     ));
 
     #[allow(deprecated)]
diff --git a/codex-rs/core/src/session/turn_context.rs b/codex-rs/core/src/session/turn_context.rs
index 600f736d69..30ae7e2d81 100644
--- a/codex-rs/core/src/session/turn_context.rs
+++ b/codex-rs/core/src/session/turn_context.rs
@@ -27,6 +27,12 @@ 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 EnvironmentConfig {
+    pub(crate) allow_login_shell: bool,
+}
+
 #[derive(Clone)]
 pub(crate) struct TurnEnvironment {
     pub(crate) environment_id: String,
@@ -34,6 +40,7 @@ pub(crate) struct TurnEnvironment {
     cwd: PathUri,
     workspace_roots: Vec<PathUri>,
     pub(crate) shell: Option<shell::Shell>,
+    pub(crate) config: EnvironmentConfig,
     pub(crate) shell_snapshot: ShellSnapshotTask,
 }
 
@@ -44,6 +51,7 @@ impl TurnEnvironment {
         cwd: PathUri,
         workspace_roots: Vec<PathUri>,
         shell: Option<shell::Shell>,
+        config: EnvironmentConfig,
     ) -> Self {
         Self {
             environment_id,
@@ -51,6 +59,7 @@ impl TurnEnvironment {
             cwd,
             workspace_roots,
             shell,
+            config,
             shell_snapshot: futures::future::ready(None).boxed().shared(),
         }
     }
@@ -90,6 +99,7 @@ impl std::fmt::Debug for TurnEnvironment {
             .field("cwd", &self.cwd)
             .field("workspace_roots", &self.workspace_roots)
             .field("shell", &self.shell)
+            .field("config", &self.config)
             .finish_non_exhaustive()
     }
 }
diff --git a/codex-rs/core/src/tools/handlers/shell/shell_command.rs b/codex-rs/core/src/tools/handlers/shell/shell_command.rs
index 2b4cc7e2ed..7b975e2f71 100644
--- a/codex-rs/core/src/tools/handlers/shell/shell_command.rs
+++ b/codex-rs/core/src/tools/handlers/shell/shell_command.rs
@@ -91,14 +91,14 @@ impl ShellCommandHandler {
         turn_context: &TurnContext,
         turn_environment: &TurnEnvironment,
         cwd: AbsolutePathBuf,
-        allow_login_shell: bool,
     ) -> Result<ExecParams, FunctionCallError> {
         let session_shell = session.user_shell();
         let shell = turn_environment
             .shell
             .as_ref()
             .unwrap_or(session_shell.as_ref());
-        let use_login_shell = Self::resolve_use_login_shell(params.login, allow_login_shell)?;
+        let use_login_shell =
+            Self::resolve_use_login_shell(params.login, turn_environment.config.allow_login_shell)?;
         let command = Self::base_command(shell, &params.command, use_login_shell);
 
         let mut env = create_env(
@@ -214,7 +214,6 @@ impl ShellCommandHandler {
             turn.as_ref(),
             &turn_environment,
             cwd,
-            turn.config.permissions.allow_login_shell,
         )?;
         let shell_type = Some(
             turn_environment
diff --git a/codex-rs/core/src/tools/handlers/shell_tests.rs b/codex-rs/core/src/tools/handlers/shell_tests.rs
index f71f23ca1b..f7caa3a9e4 100644
--- a/codex-rs/core/src/tools/handlers/shell_tests.rs
+++ b/codex-rs/core/src/tools/handlers/shell_tests.rs
@@ -12,6 +12,7 @@ use crate::exec_env::inject_permission_profile_env;
 use crate::sandboxing::SandboxPermissions;
 use crate::session::step_context::StepContext;
 use crate::session::tests::make_session_and_context;
+use crate::session::turn_context::EnvironmentConfig;
 use crate::session::turn_context::TurnEnvironment;
 use crate::shell::Shell;
 use crate::shell::ShellType;
@@ -111,6 +112,9 @@ async fn shell_command_handler_to_exec_params_uses_selected_environment() {
         PathUri::from_abs_path(&selected_cwd),
         Vec::new(),
         Some(selected_shell),
+        EnvironmentConfig {
+            allow_login_shell: true,
+        },
     );
     let mut expected_env = create_env(
         &turn_context.config.permissions.shell_environment_policy,
@@ -136,7 +140,6 @@ async fn shell_command_handler_to_exec_params_uses_selected_environment() {
         &turn_context,
         &selected_environment,
         expected_cwd.clone(),
-        /*allow_login_shell*/ true,
     )
     .expect("login shells should be allowed");
 
@@ -192,10 +195,12 @@ fn shell_command_handler_respects_explicit_login_flag() {
 #[tokio::test]
 async fn shell_command_handler_defaults_to_non_login_when_disallowed() {
     let (session, turn_context) = make_session_and_context().await;
-    let turn_environment = turn_context
+    let mut turn_environment = turn_context
         .environments
         .primary()
-        .expect("primary environment");
+        .expect("primary environment")
+        .clone();
+    turn_environment.config.allow_login_shell = false;
     let cwd = turn_environment
         .cwd()
         .to_abs_path()
@@ -215,9 +220,8 @@ async fn shell_command_handler_defaults_to_non_login_when_disallowed() {
         &params,
         &session,
         &turn_context,
-        turn_environment,
+        &turn_environment,
         cwd,
-        /*allow_login_shell*/ false,
     )
     .expect("non-login shells should still be allowed");
 
@@ -257,7 +261,6 @@ async fn shell_command_handler_rejects_justification_without_sandbox_permissions
         &turn_context,
         turn_environment,
         cwd,
-        /*allow_login_shell*/ false,
     )
     .expect_err("justification without sandbox permissions should be rejected");
 
diff --git a/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs b/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs
index 16eed42a80..d6d5ab699b 100644
--- a/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs
+++ b/codex-rs/core/src/tools/handlers/unified_exec/exec_command.rs
@@ -235,7 +235,7 @@ impl ExecCommandHandler {
             &args,
             shell,
             &shell_mode,
-            turn.config.permissions.allow_login_shell,
+            turn_environment.config.allow_login_shell,
         )
         .map_err(FunctionCallError::RespondToModel)?;
         let command = resolved_command.command;
diff --git a/codex-rs/core/src/tools/handlers/unified_exec_tests.rs b/codex-rs/core/src/tools/handlers/unified_exec_tests.rs
index 9b107dd83d..626bb90414 100644
--- a/codex-rs/core/src/tools/handlers/unified_exec_tests.rs
+++ b/codex-rs/core/src/tools/handlers/unified_exec_tests.rs
@@ -9,6 +9,8 @@ use codex_utils_output_truncation::TruncationPolicy;
 use pretty_assertions::assert_eq;
 use std::sync::Arc;
 
+use crate::environment_selection::TurnEnvironmentState;
+use crate::function_tool::FunctionCallError;
 use crate::session::step_context::StepContext;
 use crate::session::tests::make_session_and_context;
 use crate::tools::context::ExecCommandToolOutput;
@@ -17,6 +19,7 @@ use crate::tools::context::ToolInvocation;
 use crate::tools::context::ToolPayload;
 use crate::tools::hook_names::HookToolName;
 use crate::tools::registry::CoreToolRuntime;
+use crate::tools::registry::ToolExecutor;
 use crate::turn_diff_tracker::TurnDiffTracker;
 use tokio::sync::Mutex;
 
@@ -168,6 +171,46 @@ fn test_get_command_rejects_explicit_login_when_disallowed() -> anyhow::Result<(
     Ok(())
 }
 
+#[tokio::test]
+async fn exec_command_rejects_login_when_selected_environment_disallows_it() {
+    let (session, mut turn) = make_session_and_context().await;
+    assert!(turn.config.permissions.allow_login_shell);
+    let TurnEnvironmentState::Ready(environment) = turn
+        .environments
+        .environments
+        .first_mut()
+        .expect("primary environment")
+    else {
+        panic!("primary environment should be ready");
+    };
+    environment.config.allow_login_shell = false;
+
+    let turn = Arc::new(turn);
+    let invocation = ToolInvocation {
+        session: session.into(),
+        step_context: StepContext::for_test(Arc::clone(&turn)),
+        turn,
+        cancellation_token: tokio_util::sync::CancellationToken::new(),
+        tracker: Arc::new(Mutex::new(TurnDiffTracker::new())),
+        call_id: "login-disallowed".to_string(),
+        tool_name: codex_tools::ToolName::plain("exec_command"),
+        source: ToolCallSource::Direct,
+        payload: ToolPayload::Function {
+            arguments: serde_json::json!({ "cmd": "echo hello", "login": true }).to_string(),
+        },
+    };
+
+    let Err(FunctionCallError::RespondToModel(message)) =
+        ExecCommandHandler::default().handle(invocation).await
+    else {
+        panic!("expected login-shell rejection");
+    };
+    assert_eq!(
+        message,
+        "login shell is disabled by config; omit `login` or set it to false."
+    );
+}
+
 #[test]
 fn test_get_command_rejects_explicit_shell_in_zsh_fork_mode() -> anyhow::Result<()> {
     let json = r#"{"cmd": "echo hello", "shell": "/bin/bash"}"#;
diff --git a/codex-rs/core/src/tools/handlers/view_image.rs b/codex-rs/core/src/tools/handlers/view_image.rs
index 20efe1b549..675f409b72 100644
--- a/codex-rs/core/src/tools/handlers/view_image.rs
+++ b/codex-rs/core/src/tools/handlers/view_image.rs
@@ -273,6 +273,7 @@ mod tests {
             PathUri::from_abs_path(&cwd),
             Vec::new(),
             current.shell,
+            current.config,
         ));
     }
 
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 3a879de8c9..146e571a3b 100644
--- a/codex-rs/core/src/tools/runtimes/apply_patch_tests.rs
+++ b/codex-rs/core/src/tools/runtimes/apply_patch_tests.rs
@@ -1,4 +1,5 @@
 use super::*;
+use crate::session::turn_context::EnvironmentConfig;
 use crate::tools::sandboxing::SandboxAttempt;
 use codex_protocol::config_types::WindowsSandboxLevel;
 use codex_protocol::models::AdditionalPermissionProfile;
@@ -21,6 +22,9 @@ fn test_turn_environment(environment_id: &str) -> crate::session::turn_context::
         PathUri::from_abs_path(&std::env::temp_dir().abs()),
         Vec::new(),
         /*shell*/ None,
+        EnvironmentConfig {
+            allow_login_shell: true,
+        },
     )
 }
 
diff --git a/codex-rs/core/src/tools/runtimes/shell_tests.rs b/codex-rs/core/src/tools/runtimes/shell_tests.rs
index 7ae93ab918..b4f43b6a38 100644
--- a/codex-rs/core/src/tools/runtimes/shell_tests.rs
+++ b/codex-rs/core/src/tools/runtimes/shell_tests.rs
@@ -1,4 +1,5 @@
 use super::*;
+use crate::session::turn_context::EnvironmentConfig;
 use codex_exec_server::Environment;
 use codex_utils_path_uri::PathUri;
 use pretty_assertions::assert_eq;
@@ -16,6 +17,9 @@ async fn approval_key_uses_path_uri_and_includes_environment_id() {
             PathUri::from_abs_path(&cwd),
             Vec::new(),
             /*shell*/ None,
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
         ),
         shell_type: None,
         hook_command: "echo hello".to_string(),
diff --git a/codex-rs/core/src/tools/runtimes/unified_exec.rs b/codex-rs/core/src/tools/runtimes/unified_exec.rs
index a2781fb890..40bc938c22 100644
--- a/codex-rs/core/src/tools/runtimes/unified_exec.rs
+++ b/codex-rs/core/src/tools/runtimes/unified_exec.rs
@@ -549,6 +549,7 @@ impl<'a> ToolRuntime<UnifiedExecRequest, UnifiedExecProcess> for UnifiedExecRunt
 mod tests {
     use super::*;
     use crate::exec::DEFAULT_EXEC_COMMAND_TIMEOUT_MS;
+    use crate::session::turn_context::EnvironmentConfig;
     use crate::tools::sandboxing::ToolRuntime;
     use codex_exec_server::Environment;
     use codex_exec_server::LOCAL_ENVIRONMENT_ID;
@@ -566,6 +567,9 @@ mod tests {
             cwd,
             Vec::new(),
             /*shell*/ None,
+            EnvironmentConfig {
+                allow_login_shell: true,
+            },
         )
     }
 
diff --git a/codex-rs/core/src/tools/spec_plan.rs b/codex-rs/core/src/tools/spec_plan.rs
index 36ab4758fa..0dbb5c0580 100644
--- a/codex-rs/core/src/tools/spec_plan.rs
+++ b/codex-rs/core/src/tools/spec_plan.rs
@@ -760,7 +760,7 @@ fn add_core_tool_sources(context: &CoreToolPlanContext<'_>, registry: &mut ToolR
         if environment_mode.has_environment() {
             let include_environment_id = matches!(environment_mode, ToolEnvironmentMode::Multiple);
             registry.add(ExecCommandHandler::new(ExecCommandHandlerOptions {
-                allow_login_shell: turn_context.config.permissions.allow_login_shell,
+                allow_login_shell: any_environment_allows_login_shell(context.environments),
                 exec_permission_approvals_enabled: false,
                 include_environment_id,
                 include_shell_parameter: unified_exec_should_include_shell_parameter(
@@ -800,6 +800,12 @@ fn tool_environment_mode(environments: &TurnEnvironmentSnapshot) -> ToolEnvironm
     ToolEnvironmentMode::from_count(environments.turn_environments().count())
 }
 
+fn any_environment_allows_login_shell(environments: &TurnEnvironmentSnapshot) -> bool {
+    environments
+        .turn_environments()
+        .any(|environment| environment.config.allow_login_shell)
+}
+
 #[instrument(level = "trace", skip_all)]
 fn add_shell_tools(context: &CoreToolPlanContext<'_>, registry: &mut ToolRegistry) {
     let turn_context = context.turn_context;
@@ -809,7 +815,7 @@ fn add_shell_tools(context: &CoreToolPlanContext<'_>, registry: &mut ToolRegistr
         return;
     }
 
-    let allow_login_shell = turn_context.config.permissions.allow_login_shell;
+    let allow_login_shell = any_environment_allows_login_shell(context.environments);
     let exec_permission_approvals_enabled = features.enabled(Feature::ExecPermissionApprovals);
     let include_environment_id = matches!(environment_mode, ToolEnvironmentMode::Multiple);
     let supports_shell_command = context.environments.single_local_environment().is_some();
diff --git a/codex-rs/core/src/tools/spec_plan_tests.rs b/codex-rs/core/src/tools/spec_plan_tests.rs
index 441eea6ed2..5d5adac913 100644
--- a/codex-rs/core/src/tools/spec_plan_tests.rs
+++ b/codex-rs/core/src/tools/spec_plan_tests.rs
@@ -661,6 +661,70 @@ async fn shell_family_registers_visible_unified_exec_and_hidden_legacy_shell() {
     assert!(has_parameter(plan.visible_spec("exec_command"), "shell"));
 }
 
+#[tokio::test]
+async fn login_shell_parameter_follows_selected_environment() {
+    for (tool_name, guardian) in [
+        ("shell_command", false),
+        ("exec_command", false),
+        ("exec_command", true),
+    ] {
+        for allow_login_shell in [false, true] {
+            let plan = probe(|turn| {
+                set_feature(turn, Feature::ShellTool, /*enabled*/ true);
+                set_feature(turn, Feature::UnifiedExec, tool_name == "exec_command");
+                set_feature(turn, Feature::ShellZshFork, /*enabled*/ false);
+                turn.model_info.shell_type = ConfigShellToolType::ShellCommand;
+                update_config(turn, |config| {
+                    config.permissions.allow_login_shell = !allow_login_shell;
+                });
+                let TurnEnvironmentState::Ready(environment) = turn
+                    .environments
+                    .environments
+                    .first_mut()
+                    .expect("primary environment")
+                else {
+                    panic!("primary environment should be ready");
+                };
+                environment.config.allow_login_shell = allow_login_shell;
+                if guardian {
+                    turn.session_source = codex_protocol::protocol::SessionSource::SubAgent(
+                        codex_protocol::protocol::SubAgentSource::Other(
+                            crate::guardian::GUARDIAN_REVIEWER_NAME.to_string(),
+                        ),
+                    );
+                }
+            })
+            .await;
+
+            assert_eq!(
+                has_parameter(plan.visible_spec(tool_name), "login"),
+                allow_login_shell
+            );
+        }
+    }
+}
+
+#[tokio::test]
+async fn login_shell_parameter_is_available_when_any_environment_allows_it() {
+    let plan = probe(|turn| {
+        set_features(turn, &[Feature::ShellTool, Feature::UnifiedExec]);
+        set_feature(turn, Feature::ShellZshFork, /*enabled*/ false);
+        update_config(turn, |config| {
+            config.permissions.allow_login_shell = false;
+        });
+        duplicate_primary_environment(turn);
+        for (index, environment) in turn.environments.environments.iter_mut().enumerate() {
+            let TurnEnvironmentState::Ready(environment) = environment else {
+                panic!("environment should be ready");
+            };
+            environment.config.allow_login_shell = index == 1;
+        }
+    })
+    .await;
+
+    assert!(has_parameter(plan.visible_spec("exec_command"), "login"));
+}
+
 #[tokio::test]
 async fn shell_command_is_not_registered_without_a_single_local_environment() {
     let remote_environment = probe(|turn| {
@@ -836,6 +900,9 @@ async fn zsh_fork_unified_exec_keeps_shell_parameter_when_remote_environment_ava
                     remote_cwd,
                     Vec::new(),
                     /*shell*/ None,
+                    crate::session::turn_context::EnvironmentConfig {
+                        allow_login_shell: true,
+                    },
                 ),
             ));
     })
diff --git a/codex-rs/core/tests/suite/unified_exec.rs b/codex-rs/core/tests/suite/unified_exec.rs
index 23f644da57..4848080c00 100644
--- a/codex-rs/core/tests/suite/unified_exec.rs
+++ b/codex-rs/core/tests/suite/unified_exec.rs
@@ -242,6 +242,58 @@ async fn create_workspace_directory(
     Ok(abs_path.into_path_buf())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn exec_command_hides_and_rejects_login_when_disabled() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let builder = test_codex().with_model("gpt-5.4").with_config(|config| {
+        config.permissions.allow_login_shell = false;
+        config.use_experimental_unified_exec_tool = true;
+        config
+            .features
+            .enable(Feature::UnifiedExec)
+            .expect("test config should allow feature update");
+    });
+    let harness = TestCodexHarness::with_builder(builder).await?;
+    let call_id = "exec-command-login-disabled";
+    let arguments = json!({
+        "cmd": "echo should not run",
+        "login": true,
+    });
+    let responses = mount_sse_sequence(
+        harness.server(),
+        vec![
+            sse(vec![
+                ev_response_created("resp-1"),
+                ev_function_call(call_id, "exec_command", &serde_json::to_string(&arguments)?),
+                ev_completed("resp-1"),
+            ]),
+            sse(vec![
+                ev_assistant_message("msg-1", "done"),
+                ev_completed("resp-2"),
+            ]),
+        ],
+    )
+    .await;
+
+    harness.submit("run the command with login").await?;
+
+    assert_eq!(
+        harness.function_call_stdout(call_id).await,
+        "login shell is disabled by config; omit `login` or set it to false."
+    );
+    let request = responses.requests()[0].body_json();
+    let exec_tool = request["tools"]
+        .as_array()
+        .expect("tools should be an array")
+        .iter()
+        .find(|tool| tool["name"] == "exec_command")
+        .expect("exec_command should be available");
+    assert!(exec_tool["parameters"]["properties"].get("login").is_none());
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn unified_exec_intercepts_apply_patch_exec_command() -> Result<()> {
     skip_if_no_network!(Ok(()));