[ez][codex-rs] Support approvals reviewer in app defaults (#27075)

[from codex]

## Summary

- add `approvals_reviewer` support to `[apps._default]`
- resolve connected-app reviewers in per-app, app-default, then global
order
- expose the setting through the v2 config API and regenerate schema
fixtures

## Context

PR #25167 added `apps.<connector_id>.approvals_reviewer`, but the shared
app defaults table could not specify the reviewer. This extends the same
behavior to `[apps._default]` while preserving per-app overrides.

Managed `allowed_approvals_reviewers` requirements still constrain both
default and per-app values. A disallowed app value falls back to the
global reviewer, and non-app MCP servers continue using the global
reviewer.

## Testing

- `just write-config-schema`
- `just write-app-server-schema`
- `just fmt`
- `just test -p codex-config`
- `just test -p codex-core app_approvals_reviewer`
- `just test -p codex-app-server-protocol`
- `just test -p codex-app-server config_read_includes_apps`

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.schemas.json

@@ -6584,6 +6584,16 @@
       },
       "AppsDefaultConfig": {
         "properties": {
+          "approvals_reviewer": {
+            "anyOf": [
+              {
+                "$ref": "#/definitions/v2/ApprovalsReviewer"
+              },
+              {
+                "type": "null"
+              }
+            ]
+          },
           "destructive_enabled": {
             "default": true,
             "type": "boolean"

codex-rs/app-server-protocol/schema/json/codex_app_server_protocol.v2.schemas.json

@@ -853,6 +853,16 @@
     },
     "AppsDefaultConfig": {
       "properties": {
+        "approvals_reviewer": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/ApprovalsReviewer"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
         "destructive_enabled": {
           "default": true,
           "type": "boolean"

codex-rs/app-server-protocol/schema/json/v2/ConfigReadResponse.json

@@ -133,6 +133,16 @@
     },
     "AppsDefaultConfig": {
       "properties": {
+        "approvals_reviewer": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/ApprovalsReviewer"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
         "destructive_enabled": {
           "default": true,
           "type": "boolean"

codex-rs/app-server-protocol/schema/typescript/v2/AppsDefaultConfig.ts

@@ -1,5 +1,6 @@
 // GENERATED CODE! DO NOT MODIFY BY HAND!
 
 // This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.
+import type { ApprovalsReviewer } from "./ApprovalsReviewer";
 
-export type AppsDefaultConfig = { enabled: boolean, destructive_enabled: boolean, open_world_enabled: boolean, };
+export type AppsDefaultConfig = { enabled: boolean, approvals_reviewer: ApprovalsReviewer | null, destructive_enabled: boolean, open_world_enabled: boolean, };

codex-rs/app-server-protocol/src/protocol/v2/config.rs

@@ -172,6 +172,7 @@ pub enum AppToolApproval {
 pub struct AppsDefaultConfig {
     #[serde(default = "default_enabled")]
     pub enabled: bool,
+    pub approvals_reviewer: Option<ApprovalsReviewer>,
     #[serde(default = "default_enabled")]
     pub destructive_enabled: bool,
     #[serde(default = "default_enabled")]

codex-rs/app-server/README.md

@@ -1775,13 +1775,18 @@ The server also emits `app/list/updated` notifications whenever either source (a
 ```
 
 Connected apps may override the thread's approval reviewer in `config.toml`.
-When omitted, the app inherits the top-level `approvals_reviewer` value:
+Use `apps._default.approvals_reviewer` to set the reviewer for all apps, and a
+per-app value to override that default. When both are omitted, the app inherits
+the top-level `approvals_reviewer` value:
 
 ```toml
 approvals_reviewer = "auto_review"
 
-[apps.demo-app]
+[apps._default]
 approvals_reviewer = "user"
+
+[apps.demo-app]
+approvals_reviewer = "auto_review"
 ```
 
 Setting the app value to `"user"` routes its approval prompts to the user

codex-rs/app-server/tests/suite/v2/config_rpc.rs

@@ -7,6 +7,7 @@ use codex_app_server_protocol::AppConfig;
 use codex_app_server_protocol::AppToolApproval;
 use codex_app_server_protocol::ApprovalsReviewer;
 use codex_app_server_protocol::AppsConfig;
+use codex_app_server_protocol::AppsDefaultConfig;
 use codex_app_server_protocol::AskForApproval;
 use codex_app_server_protocol::ConfigBatchWriteParams;
 use codex_app_server_protocol::ConfigEdit;
@@ -332,6 +333,9 @@ async fn config_read_includes_apps() -> Result<()> {
     write_config(
         &codex_home,
         r#"
+[apps._default]
+approvals_reviewer = "auto_review"
+
 [apps.app1]
 enabled = false
 approvals_reviewer = "user"
@@ -365,7 +369,12 @@ default_tools_approval_mode = "prompt"
     assert_eq!(
         config.apps,
         Some(AppsConfig {
-            default: None,
+            default: Some(AppsDefaultConfig {
+                enabled: true,
+                approvals_reviewer: Some(ApprovalsReviewer::AutoReview),
+                destructive_enabled: true,
+                open_world_enabled: true,
+            }),
             apps: std::collections::HashMap::from([(
                 "app1".to_string(),
                 AppConfig {
@@ -380,6 +389,16 @@ default_tools_approval_mode = "prompt"
             )]),
         })
     );
+    assert_eq!(
+        origins
+            .get("apps._default.approvals_reviewer")
+            .expect("origin")
+            .name,
+        ConfigLayerSource::User {
+            file: user_file.clone(),
+            profile: None,
+        }
+    );
     assert_eq!(
         origins.get("apps.app1.enabled").expect("origin").name,
         ConfigLayerSource::User {

codex-rs/config/src/types.rs

@@ -380,6 +380,10 @@ pub struct AppsDefaultConfig {
     #[serde(default = "default_enabled")]
     pub enabled: bool,
 
+    /// Reviewer for approval prompts unless overridden by per-app settings.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub approvals_reviewer: Option<ApprovalsReviewer>,
+
     /// Whether tools with `destructive_hint = true` are allowed by default.
     #[serde(
         default = "default_enabled",

codex-rs/core/config.schema.json

@@ -210,6 +210,14 @@
       "additionalProperties": false,
       "description": "Default settings that apply to all apps.",
       "properties": {
+        "approvals_reviewer": {
+          "allOf": [
+            {
+              "$ref": "#/definitions/ApprovalsReviewer"
+            }
+          ],
+          "description": "Reviewer for approval prompts unless overridden by per-app settings."
+        },
         "destructive_enabled": {
           "description": "Whether tools with `destructive_hint = true` are allowed by default.",
           "type": "boolean"

codex-rs/core/src/connectors.rs

@@ -601,6 +601,11 @@ pub(crate) fn mcp_approvals_reviewer(
             connector_id
                 .and_then(|connector_id| apps_config.apps.get(connector_id))
                 .and_then(|app| app.approvals_reviewer)
+                .or_else(|| {
+                    apps_config
+                        .default
+                        .and_then(|defaults| defaults.approvals_reviewer)
+                })
         })
     } else {
         None

codex-rs/core/src/connectors_tests.rs

@@ -269,6 +269,7 @@ fn app_tool_policy_uses_global_defaults_for_destructive_hints() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: true,
+            approvals_reviewer: None,
             destructive_enabled: false,
             open_world_enabled: true,
         }),
@@ -298,6 +299,7 @@ fn app_tool_policy_defaults_missing_destructive_hint_to_true() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: true,
+            approvals_reviewer: None,
             destructive_enabled: false,
             open_world_enabled: true,
         }),
@@ -327,6 +329,7 @@ fn app_tool_policy_defaults_missing_open_world_hint_to_true() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: true,
+            approvals_reviewer: None,
             destructive_enabled: true,
             open_world_enabled: false,
         }),
@@ -356,6 +359,7 @@ fn app_is_enabled_uses_default_for_unconfigured_apps() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: false,
+            approvals_reviewer: None,
             destructive_enabled: true,
             open_world_enabled: true,
         }),
@@ -371,6 +375,7 @@ fn app_is_enabled_prefers_per_app_override_over_default() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: false,
+            approvals_reviewer: None,
             destructive_enabled: true,
             open_world_enabled: true,
         }),
@@ -393,19 +398,23 @@ fn app_is_enabled_prefers_per_app_override_over_default() {
 }
 
 #[tokio::test]
-async fn app_approvals_reviewer_overrides_global_reviewer() {
+async fn app_approvals_reviewer_uses_app_then_default_then_global() {
-    for (global, app, expected_global, expected_app) in [
+    for (global, app_default, app, expected_global, expected_default, expected_app) in [
         (
             "user",
             "auto_review",
+            "user",
             ApprovalsReviewer::User,
             ApprovalsReviewer::AutoReview,
+            ApprovalsReviewer::User,
         ),
         (
             "auto_review",
             "user",
+            "auto_review",
             ApprovalsReviewer::AutoReview,
             ApprovalsReviewer::User,
+            ApprovalsReviewer::AutoReview,
         ),
     ] {
         let codex_home = tempdir().expect("tempdir should succeed");
@@ -415,6 +424,9 @@ async fn app_approvals_reviewer_overrides_global_reviewer() {
                 r#"
 approvals_reviewer = "{global}"
 
+[apps._default]
+approvals_reviewer = "{app_default}"
+
 [apps.calendar]
 approvals_reviewer = "{app}"
 "#
@@ -433,7 +445,15 @@ approvals_reviewer = "{app}"
         );
         assert_eq!(
             mcp_approvals_reviewer(&config, CODEX_APPS_MCP_SERVER_NAME, Some("drive")),
-            expected_global
+            expected_default
+        );
+        assert_eq!(
+            mcp_approvals_reviewer(
+                &config,
+                CODEX_APPS_MCP_SERVER_NAME,
+                /*connector_id*/ None
+            ),
+            expected_default
         );
         assert_eq!(
             mcp_approvals_reviewer(&config, "custom_server", Some("calendar")),
@@ -442,6 +462,36 @@ approvals_reviewer = "{app}"
     }
 }
 
+#[tokio::test]
+async fn default_app_approvals_reviewer_respects_global_reviewer_requirements() {
+    let codex_home = tempdir().expect("tempdir should succeed");
+    std::fs::write(
+        codex_home.path().join(CONFIG_TOML_FILE),
+        r#"
+approvals_reviewer = "auto_review"
+
+[apps._default]
+approvals_reviewer = "user"
+"#,
+    )
+    .expect("write config");
+    let config = ConfigBuilder::default()
+        .codex_home(codex_home.path().to_path_buf())
+        .cloud_config_bundle(
+            CloudConfigBundleFixture::loader_with_enterprise_requirement(
+                r#"allowed_approvals_reviewers = ["auto_review"]"#,
+            ),
+        )
+        .build()
+        .await
+        .expect("config should build");
+
+    assert_eq!(
+        mcp_approvals_reviewer(&config, CODEX_APPS_MCP_SERVER_NAME, Some("calendar")),
+        ApprovalsReviewer::AutoReview
+    );
+}
+
 #[tokio::test]
 async fn app_approvals_reviewer_respects_global_reviewer_requirements() {
     let codex_home = tempdir().expect("tempdir should succeed");
@@ -756,6 +806,7 @@ fn app_tool_policy_honors_default_app_enabled_false() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: false,
+            approvals_reviewer: None,
             destructive_enabled: true,
             open_world_enabled: true,
         }),
@@ -987,6 +1038,7 @@ fn app_tool_policy_allows_per_app_enable_when_default_is_disabled() {
     let apps_config = AppsConfigToml {
         default: Some(AppsDefaultConfig {
             enabled: false,
+            approvals_reviewer: None,
             destructive_enabled: true,
             open_world_enabled: true,
         }),

codex-rs/core/tests/suite/mcp_turn_metadata.rs

@@ -5,6 +5,7 @@ use anyhow::Result;
 use codex_config::types::AppToolApproval;
 use codex_core::config::Config;
 use codex_features::Feature;
+use codex_protocol::config_types::ApprovalsReviewer;
 use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Settings;
@@ -59,6 +60,32 @@ default_tools_approval_mode = "{approval_mode}"
         .with_user_config(&user_config_path, user_config);
 }
 
+fn set_calendar_approval_mode_and_default_reviewer(
+    config: &mut Config,
+    approval_mode: AppToolApproval,
+    default_approvals_reviewer: ApprovalsReviewer,
+) {
+    let approval_mode = match approval_mode {
+        AppToolApproval::Auto => "auto",
+        AppToolApproval::Prompt => "prompt",
+        AppToolApproval::Approve => "approve",
+    };
+    let user_config_path = config.codex_home.join("config.toml").abs();
+    let user_config = toml::from_str(&format!(
+        r#"
+[apps._default]
+approvals_reviewer = "{default_approvals_reviewer}"
+
+[apps.calendar]
+default_tools_approval_mode = "{approval_mode}"
+"#
+    ))
+    .expect("apps config should parse");
+    config.config_layer_stack = config
+        .config_layer_stack
+        .with_user_config(&user_config_path, user_config);
+}
+
 async fn submit_user_turn(
     test: &TestCodex,
     text: &str,
@@ -134,11 +161,17 @@ async fn approved_mcp_tool_call_metadata_records_prior_user_input_request() -> R
 
     let mut builder = search_capable_apps_builder(apps_server.chatgpt_base_url.clone())
         .with_config(|config| {
+            // Use the opposite global reviewer so this route must come from apps._default.
+            config.approvals_reviewer = ApprovalsReviewer::AutoReview;
             config
                 .features
                 .enable(Feature::ToolCallMcpElicitation)
                 .expect("test config should allow feature update");
-            set_calendar_approval_mode(config, AppToolApproval::Prompt);
+            set_calendar_approval_mode_and_default_reviewer(
+                config,
+                AppToolApproval::Prompt,
+                ApprovalsReviewer::User,
+            );
         });
     let test = builder.build(&server).await?;
 
@@ -160,11 +193,14 @@ async fn approved_mcp_tool_call_metadata_records_prior_user_input_request() -> R
     assert_eq!(begin.call_id, call_id);
 
     let EventMsg::ElicitationRequest(request) = wait_for_event(&test.codex, |event| {
-        matches!(event, EventMsg::ElicitationRequest(_))
+        matches!(
+            event,
+            EventMsg::ElicitationRequest(_) | EventMsg::TurnComplete(_)
+        )
     })
     .await
     else {
-        unreachable!("event guard guarantees ElicitationRequest");
+        panic!("expected apps._default user to route the app approval to the user");
     };
 
     test.codex
@@ -194,6 +230,110 @@ async fn approved_mcp_tool_call_metadata_records_prior_user_input_request() -> R
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn apps_default_auto_review_routes_actual_mcp_approval_to_guardian() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let apps_server = AppsTestServer::mount(&server).await?;
+    let call_id = "calendar-default-auto-review";
+    let calendar_args = serde_json::to_string(&json!({
+        "title": "Lunch",
+        "starts_at": "2026-03-10T12:00:00Z"
+    }))?;
+    let responses = mount_sse_sequence(
+        &server,
+        vec![
+            sse(vec![
+                ev_response_created("resp-parent-tool"),
+                ev_function_call_with_namespace(
+                    call_id,
+                    SEARCH_CALENDAR_NAMESPACE,
+                    SEARCH_CALENDAR_CREATE_TOOL,
+                    &calendar_args,
+                ),
+                ev_completed("resp-parent-tool"),
+            ]),
+            sse(vec![
+                ev_response_created("resp-guardian-review"),
+                ev_assistant_message(
+                    "msg-guardian-review",
+                    &json!({
+                        "risk_level": "low",
+                        "user_authorization": "high",
+                        "outcome": "allow",
+                        "rationale": "Creating this calendar event is low risk.",
+                    })
+                    .to_string(),
+                ),
+                ev_completed("resp-guardian-review"),
+            ]),
+            sse(vec![
+                ev_response_created("resp-parent-done"),
+                ev_assistant_message("msg-parent-done", "done"),
+                ev_completed("resp-parent-done"),
+            ]),
+        ],
+    )
+    .await;
+
+    let mut builder = search_capable_apps_builder(apps_server.chatgpt_base_url.clone())
+        .with_config(|config| {
+            // Use the opposite global reviewer so this route must come from apps._default.
+            config.approvals_reviewer = ApprovalsReviewer::User;
+            config
+                .features
+                .enable(Feature::ToolCallMcpElicitation)
+                .expect("test config should allow feature update");
+            set_calendar_approval_mode_and_default_reviewer(
+                config,
+                AppToolApproval::Prompt,
+                ApprovalsReviewer::AutoReview,
+            );
+        });
+    let test = builder.build(&server).await?;
+
+    submit_user_turn(
+        &test,
+        "Use [$calendar](app://calendar) to create a calendar event.",
+        AskForApproval::OnRequest,
+        /*collaboration_mode*/ None,
+    )
+    .await?;
+
+    let route_event = wait_for_event(&test.codex, |event| {
+        matches!(
+            event,
+            EventMsg::ElicitationRequest(_) | EventMsg::TurnComplete(_)
+        )
+    })
+    .await;
+    assert!(
+        matches!(route_event, EventMsg::TurnComplete(_)),
+        "expected apps._default auto_review to route the app approval to Guardian"
+    );
+
+    let guardian_request = responses
+        .requests()
+        .into_iter()
+        .find(|request| {
+            request
+                .instructions_text()
+                .starts_with("You are judging one planned coding-agent action.")
+        })
+        .expect("expected a Guardian request for the app MCP approval");
+    assert!(guardian_request.body_contains_text("calendar_create_event"));
+    assert!(guardian_request.body_contains_text("Lunch"));
+
+    let apps_tool_call = recorded_apps_tool_call_by_call_id(&server, call_id).await;
+    assert_eq!(
+        apps_tool_call.pointer("/params/arguments/title"),
+        Some(&json!("Lunch"))
+    );
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn mcp_tool_call_metadata_records_prior_request_user_input_tool() -> Result<()> {
     skip_if_no_network!(Ok(()));