feat(app-server): enforce managed remote control disable (#27961)

## Why

Managed deployments need a reliable deny gate for remote control.
Persisted enablement and explicit startup requests currently remain able
to start the transport, while the removed `features.remote_control` key
is intentionally only a compatibility no-op.

This adds a dedicated requirement that administrators can use to force
remote control off without deleting the user's persisted preference.
Removing the requirement and restarting restores the prior choice.

## What Changed

- Added top-level `allow_remote_control` requirements parsing, sourced
layer precedence, debug output, and `configRequirements/read` exposure
as `allowRemoteControl`.
- Added a typed transport policy captured from the startup requirements
snapshot. Managed disable forces the initial state to disabled and
prevents enrollment, refresh, connection, and persisted-preference
mutation.
- Rejected every `remoteControl/*` RPC before parameter deserialization
with JSON-RPC `-32600` and `remote control is disabled by managed
requirements`.
- Preserved the existing disabled status notification and the previous
behavior when the requirement is `true` or omitted.
- Regenerated app-server protocol schemas and documented the new
requirement.

## Verification

- Confirmed all remote-control RPCs, including a malformed request,
return the managed-policy error while the initial status notification
remains `disabled`.
- Confirmed explicit ephemeral startup and persisted enablement make no
backend connection and leave the SQLite preference unchanged.
- Confirmed `allow_remote_control = true` does not enable or block
remote control and `configRequirements/read` returns
`allowRemoteControl: false` for the deny policy.

Related issue: N/A (managed-policy hardening).

codex-rs/config/src/config_requirements.rs

@@ -149,6 +149,7 @@ pub struct ConfigRequirements {
     pub web_search_mode: ConstrainedWithSource<WebSearchMode>,
     pub allow_managed_hooks_only: Option<Sourced<bool>>,
     pub allow_appshots: Option<Sourced<bool>>,
+    pub allow_remote_control: Option<Sourced<bool>>,
     pub computer_use: Option<Sourced<ComputerUseRequirementsToml>>,
     pub feature_requirements: Option<Sourced<FeatureRequirementsToml>>,
     pub managed_hooks: Option<ConstrainedWithSource<ManagedHooksRequirementsToml>>,
@@ -189,6 +190,7 @@ impl Default for ConfigRequirements {
             ),
             allow_managed_hooks_only: None,
             allow_appshots: None,
+            allow_remote_control: None,
             computer_use: None,
             feature_requirements: None,
             managed_hooks: None,
@@ -828,6 +830,7 @@ pub struct ConfigRequirementsToml {
     pub allowed_web_search_modes: Option<Vec<WebSearchModeRequirement>>,
     pub allow_managed_hooks_only: Option<bool>,
     pub allow_appshots: Option<bool>,
+    pub allow_remote_control: Option<bool>,
     pub computer_use: Option<ComputerUseRequirementsToml>,
     pub windows: Option<WindowsRequirementsToml>,
     #[serde(rename = "features", alias = "feature_requirements")]
@@ -882,6 +885,7 @@ pub struct ConfigRequirementsWithSources {
     pub allowed_web_search_modes: Option<Sourced<Vec<WebSearchModeRequirement>>>,
     pub allow_managed_hooks_only: Option<Sourced<bool>>,
     pub allow_appshots: Option<Sourced<bool>>,
+    pub allow_remote_control: Option<Sourced<bool>>,
     pub computer_use: Option<Sourced<ComputerUseRequirementsToml>>,
     pub windows: Option<Sourced<WindowsRequirementsToml>>,
     pub feature_requirements: Option<Sourced<FeatureRequirementsToml>>,
@@ -924,6 +928,7 @@ impl ConfigRequirementsWithSources {
             allowed_web_search_modes: _,
             allow_managed_hooks_only: _,
             allow_appshots: _,
+            allow_remote_control: _,
             computer_use: _,
             windows: _,
             feature_requirements: _,
@@ -959,6 +964,7 @@ impl ConfigRequirementsWithSources {
                 allowed_web_search_modes,
                 allow_managed_hooks_only,
                 allow_appshots,
+                allow_remote_control,
                 computer_use,
                 windows,
                 feature_requirements,
@@ -992,6 +998,7 @@ impl ConfigRequirementsWithSources {
             allowed_web_search_modes,
             allow_managed_hooks_only,
             allow_appshots,
+            allow_remote_control,
             computer_use,
             windows,
             feature_requirements,
@@ -1015,6 +1022,7 @@ impl ConfigRequirementsWithSources {
             allowed_web_search_modes: allowed_web_search_modes.map(|sourced| sourced.value),
             allow_managed_hooks_only: allow_managed_hooks_only.map(|sourced| sourced.value),
             allow_appshots: allow_appshots.map(|sourced| sourced.value),
+            allow_remote_control: allow_remote_control.map(|sourced| sourced.value),
             computer_use: computer_use.map(|sourced| sourced.value),
             windows: windows.map(|sourced| sourced.value),
             feature_requirements: feature_requirements.map(|sourced| sourced.value),
@@ -1104,6 +1112,7 @@ impl ConfigRequirementsToml {
             && self.allowed_web_search_modes.is_none()
             && self.allow_managed_hooks_only.is_none()
             && self.allow_appshots.is_none()
+            && self.allow_remote_control.is_none()
             && self
                 .computer_use
                 .as_ref()
@@ -1156,6 +1165,7 @@ impl TryFrom<ConfigRequirementsWithSources> for ConfigRequirements {
             allowed_web_search_modes,
             allow_managed_hooks_only,
             allow_appshots,
+            allow_remote_control,
             computer_use,
             windows,
             feature_requirements,
@@ -1434,6 +1444,7 @@ impl TryFrom<ConfigRequirementsWithSources> for ConfigRequirements {
             web_search_mode,
             allow_managed_hooks_only,
             allow_appshots,
+            allow_remote_control,
             computer_use,
             feature_requirements,
             managed_hooks,
@@ -1525,6 +1536,7 @@ mod tests {
             allowed_web_search_modes,
             allow_managed_hooks_only,
             allow_appshots,
+            allow_remote_control,
             computer_use,
             windows,
             feature_requirements,
@@ -1555,6 +1567,8 @@ mod tests {
                 .map(|value| Sourced::new(value, RequirementSource::Unknown)),
             allow_appshots: allow_appshots
                 .map(|value| Sourced::new(value, RequirementSource::Unknown)),
+            allow_remote_control: allow_remote_control
+                .map(|value| Sourced::new(value, RequirementSource::Unknown)),
             computer_use: computer_use.map(|value| Sourced::new(value, RequirementSource::Unknown)),
             windows: windows.map(|value| Sourced::new(value, RequirementSource::Unknown)),
             feature_requirements: feature_requirements
@@ -1688,6 +1702,19 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn allow_remote_control_false_is_still_configured() -> Result<()> {
+        let requirements: ConfigRequirementsToml = from_str(
+            r#"
+                allow_remote_control = false
+            "#,
+        )?;
+
+        assert_eq!(requirements.allow_remote_control, Some(false));
+        assert!(!requirements.is_empty());
+        Ok(())
+    }
+
     #[test]
     fn deserialize_computer_use_requirements() -> Result<()> {
         let requirements: ConfigRequirementsToml = from_str(
@@ -1745,6 +1772,7 @@ mod tests {
             allowed_web_search_modes: Some(allowed_web_search_modes.clone()),
             allow_managed_hooks_only: Some(true),
             allow_appshots: Some(false),
+            allow_remote_control: Some(false),
             computer_use: Some(computer_use.clone()),
             windows: None,
             feature_requirements: Some(feature_requirements.clone()),
@@ -1787,6 +1815,10 @@ mod tests {
                     enforce_source.clone(),
                 )),
                 allow_appshots: Some(Sourced::new(/*value*/ false, enforce_source.clone(),)),
+                allow_remote_control: Some(Sourced::new(
+                    /*value*/ false,
+                    enforce_source.clone(),
+                )),
                 computer_use: Some(Sourced::new(computer_use, enforce_source.clone())),
                 windows: None,
                 feature_requirements: Some(Sourced::new(
@@ -1835,6 +1867,7 @@ mod tests {
                 allowed_web_search_modes: None,
                 allow_managed_hooks_only: None,
                 allow_appshots: None,
+                allow_remote_control: None,
                 computer_use: None,
                 windows: None,
                 feature_requirements: None,
@@ -1888,6 +1921,7 @@ mod tests {
                 allowed_web_search_modes: None,
                 allow_managed_hooks_only: None,
                 allow_appshots: None,
+                allow_remote_control: None,
                 computer_use: None,
                 windows: None,
                 feature_requirements: None,

codex-rs/config/src/requirements_layers/stack.rs

@@ -182,6 +182,7 @@ fn populate_merged_regular_fields_with_sources(
         allowed_web_search_modes,
         allow_managed_hooks_only,
         allow_appshots,
+        allow_remote_control,
         computer_use,
         windows,
         feature_requirements,
@@ -210,6 +211,7 @@ fn populate_merged_regular_fields_with_sources(
     set_sourced!(allowed_web_search_modes, &["allowed_web_search_modes"]);
     set_sourced!(allow_managed_hooks_only, &["allow_managed_hooks_only"]);
     set_sourced!(allow_appshots, &["allow_appshots"]);
+    set_sourced!(allow_remote_control, &["allow_remote_control"]);
     set_sourced!(computer_use, &["computer_use"]);
     set_sourced!(windows, &["windows"]);
     set_sourced!(feature_requirements, &["features", "feature_requirements"]);

codex-rs/config/src/requirements_layers/stack_tests.rs

@@ -63,6 +63,7 @@ fn top_level_values_use_toml_priority() {
 allowed_approval_policies = ["on-request"]
 allowed_sandbox_modes = ["workspace-write"]
 default_permissions = ":workspace"
+allow_remote_control = true
 
 [allowed_permission_profiles]
 ":read-only" = true
@@ -76,6 +77,7 @@ default_permissions = ":workspace"
 allowed_approval_policies = ["never"]
 allowed_sandbox_modes = ["read-only"]
 default_permissions = ":read-only"
+allow_remote_control = false
 
 [allowed_permission_profiles]
 ":danger-full-access" = false
@@ -93,6 +95,7 @@ default_permissions = ":read-only"
 allowed_approval_policies = ["never"]
 allowed_sandbox_modes = ["read-only"]
 default_permissions = ":read-only"
+allow_remote_control = false
 
 [allowed_permission_profiles]
 ":danger-full-access" = false
@@ -135,6 +138,7 @@ fn composition_strategy_applies_to_non_cloud_layers() {
                 format!(
                     r#"
 allowed_approval_policies = ["on-request"]
+allow_remote_control = true
 
 [features]
 shared = false
@@ -154,6 +158,7 @@ deny_read = [{low_path:?}]
                 format!(
                     r#"
 allowed_approval_policies = ["never"]
+allow_remote_control = false
 
 [features]
 shared = true
@@ -178,6 +183,7 @@ deny_read = [{high_path:?}]
         expected_requirements(format!(
             r#"
 allowed_approval_policies = ["never"]
+allow_remote_control = false
 
 [features]
 shared = true
@@ -198,7 +204,14 @@ deny_read = [{high_path:?}, {low_path:?}]
     );
     assert_eq!(
         composed.allowed_approval_policies,
-        Some(Sourced::new(vec![AskForApproval::Never], mdm_source))
+        Some(Sourced::new(
+            vec![AskForApproval::Never],
+            mdm_source.clone()
+        ))
+    );
+    assert_eq!(
+        composed.allow_remote_control,
+        Some(Sourced::new(/*value*/ false, mdm_source))
     );
 }
 

codex-rs/config/src/state.rs

@@ -73,14 +73,18 @@ impl LoaderOverrides {
         }
     }
 
-    /// Returns overrides with host MDM disabled and managed config loaded from `managed_config_path`.
+    /// Returns overrides with host MDM disabled and managed config loaded from
+    /// `managed_config_path`. System requirements are loaded from a sibling
+    /// `requirements.toml` fixture.
     ///
     /// This is intended for tests that supply an explicit managed config fixture.
     pub fn with_managed_config_path_for_tests(managed_config_path: PathBuf) -> Self {
+        let system_requirements_path = managed_config_path.with_file_name("requirements.toml");
         Self {
             user_config_path: None,
             user_config_profile: None,
             managed_config_path: Some(managed_config_path),
+            system_requirements_path: Some(system_requirements_path),
             ..Self::without_managed_config_for_tests()
         }
     }