codex: fix CI failure on PR #13187

Update core test fixtures for plan-mode developer instructions and accept the resulting snapshot changes.

Co-authored-by: Codex <noreply@openai.com>

codex-rs/app-server/src/message_processor.rs

@@ -193,6 +193,7 @@ impl MessageProcessor {
                     .features
                     .enabled(codex_core::features::Feature::DefaultModeRequestUserInput),
             },
+            config.plan_mode_developer_instructions.clone(),
         ));
         thread_manager
             .plugins_manager()

codex-rs/core/config.schema.json

@@ -521,6 +521,9 @@
         "personality": {
           "$ref": "#/definitions/Personality"
         },
+        "plan_mode_developer_instructions": {
+          "type": "string"
+        },
         "plan_mode_reasoning_effort": {
           "$ref": "#/definitions/ReasoningEffort"
         },
@@ -2158,6 +2161,9 @@
       ],
       "description": "Optionally specify a personality for the model"
     },
+    "plan_mode_developer_instructions": {
+      "type": "string"
+    },
     "plan_mode_reasoning_effort": {
       "$ref": "#/definitions/ReasoningEffort"
     },

codex-rs/core/src/codex.rs

@@ -302,6 +302,7 @@ use codex_async_utils::OrCancelExt;
 use codex_otel::SessionTelemetry;
 use codex_otel::TelemetryAuthMode;
 use codex_protocol::config_types::CollaborationMode;
+use codex_protocol::config_types::CollaborationModeMask;
 use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::ReasoningSummary as ReasoningSummaryConfig;
 use codex_protocol::config_types::ServiceTier;
@@ -973,6 +974,26 @@ impl SessionConfiguration {
     }
 }
 
+fn merge_collaboration_mode_with_preset(
+    collaboration_mode: CollaborationMode,
+    preset: &CollaborationModeMask,
+) -> CollaborationMode {
+    CollaborationMode {
+        mode: collaboration_mode.mode,
+        settings: Settings {
+            model: collaboration_mode.settings.model,
+            reasoning_effort: collaboration_mode
+                .settings
+                .reasoning_effort
+                .or(preset.reasoning_effort.flatten()),
+            developer_instructions: collaboration_mode
+                .settings
+                .developer_instructions
+                .or_else(|| preset.developer_instructions.clone().flatten()),
+        },
+    }
+}
+
 #[derive(Default, Clone)]
 pub(crate) struct SessionSettingsUpdate {
     pub(crate) cwd: Option<PathBuf>,
@@ -988,6 +1009,23 @@ pub(crate) struct SessionSettingsUpdate {
 }
 
 impl Session {
+    fn resolve_session_settings_update(
+        &self,
+        mut updates: SessionSettingsUpdate,
+    ) -> SessionSettingsUpdate {
+        updates.collaboration_mode = updates.collaboration_mode.map(|collaboration_mode| {
+            self.services
+                .models_manager
+                .list_collaboration_modes()
+                .into_iter()
+                .find(|preset| preset.mode == Some(collaboration_mode.mode))
+                .map_or(collaboration_mode.clone(), |preset| {
+                    merge_collaboration_mode_with_preset(collaboration_mode, &preset)
+                })
+        });
+        updates
+    }
+
     /// Builds the `x-codex-beta-features` header value for this session.
     ///
     /// `ModelClient` is session-scoped and intentionally does not depend on the full `Config`, so
@@ -2081,6 +2119,7 @@ impl Session {
         &self,
         updates: SessionSettingsUpdate,
     ) -> ConstraintResult<()> {
+        let updates = self.resolve_session_settings_update(updates);
         let mut state = self.state.lock().await;
 
         match state.session_configuration.apply(&updates) {
@@ -2113,6 +2152,7 @@ impl Session {
         sub_id: String,
         updates: SessionSettingsUpdate,
     ) -> ConstraintResult<Arc<TurnContext>> {
+        let updates = self.resolve_session_settings_update(updates);
         let (
             session_configuration,
             sandbox_policy_changed,

codex-rs/core/src/codex_tests.rs

@@ -1899,6 +1899,7 @@ async fn session_new_fails_when_zsh_fork_enabled_without_zsh_path() {
         auth_manager.clone(),
         None,
         CollaborationModesConfig::default(),
+        None,
     ));
     let model = ModelsManager::get_model_offline_for_tests(config.model.as_deref());
     let model_info = ModelsManager::construct_model_info_offline_for_tests(model.as_str(), &config);
@@ -1987,6 +1988,7 @@ pub(crate) async fn make_session_and_context() -> (Session, TurnContext) {
         auth_manager.clone(),
         None,
         CollaborationModesConfig::default(),
+        None,
     ));
     let agent_control = AgentControl::default();
     let exec_policy = ExecPolicyManager::default();
@@ -2394,6 +2396,7 @@ pub(crate) async fn make_session_and_context_with_dynamic_tools_and_rx(
         auth_manager.clone(),
         None,
         CollaborationModesConfig::default(),
+        None,
     ));
     let agent_control = AgentControl::default();
     let exec_policy = ExecPolicyManager::default();

codex-rs/core/src/config/config_tests.rs

@@ -3066,6 +3066,7 @@ fn test_precedence_fixture_with_o3_profile() -> std::io::Result<()> {
             experimental_realtime_ws_startup_context: None,
             base_instructions: None,
             developer_instructions: None,
+            plan_mode_developer_instructions: None,
             compact_prompt: None,
             commit_attribution: None,
             forced_chatgpt_workspace_id: None,
@@ -3201,6 +3202,7 @@ fn test_precedence_fixture_with_gpt3_profile() -> std::io::Result<()> {
         experimental_realtime_ws_startup_context: None,
         base_instructions: None,
         developer_instructions: None,
+        plan_mode_developer_instructions: None,
         compact_prompt: None,
         commit_attribution: None,
         forced_chatgpt_workspace_id: None,
@@ -3334,6 +3336,7 @@ fn test_precedence_fixture_with_zdr_profile() -> std::io::Result<()> {
         experimental_realtime_ws_startup_context: None,
         base_instructions: None,
         developer_instructions: None,
+        plan_mode_developer_instructions: None,
         compact_prompt: None,
         commit_attribution: None,
         forced_chatgpt_workspace_id: None,
@@ -3453,6 +3456,7 @@ fn test_precedence_fixture_with_gpt5_profile() -> std::io::Result<()> {
         experimental_realtime_ws_startup_context: None,
         base_instructions: None,
         developer_instructions: None,
+        plan_mode_developer_instructions: None,
         compact_prompt: None,
         commit_attribution: None,
         forced_chatgpt_workspace_id: None,

codex-rs/core/src/config/mod.rs

@@ -433,6 +433,10 @@ pub struct Config {
     /// Plan preset. The `none` value means "no reasoning" (not "inherit the
     /// global default").
     pub plan_mode_reasoning_effort: Option<ReasoningEffort>,
+    /// Optional Plan-mode-specific developer instructions override.
+    ///
+    /// When unset, Plan mode uses the built-in Plan preset instructions.
+    pub plan_mode_developer_instructions: Option<String>,
 
     /// Optional value to use for `reasoning.summary` when making a request
     /// using the Responses API. When unset, the model catalog default is used.
@@ -1201,6 +1205,7 @@ pub struct ConfigToml {
 
     pub model_reasoning_effort: Option<ReasoningEffort>,
     pub plan_mode_reasoning_effort: Option<ReasoningEffort>,
+    pub plan_mode_developer_instructions: Option<String>,
     pub model_reasoning_summary: Option<ReasoningSummary>,
     /// Optional verbosity control for GPT-5 models (Responses API `text.verbosity`).
     pub model_verbosity: Option<Verbosity>,
@@ -2422,6 +2427,9 @@ impl Config {
             plan_mode_reasoning_effort: config_profile
                 .plan_mode_reasoning_effort
                 .or(cfg.plan_mode_reasoning_effort),
+            plan_mode_developer_instructions: config_profile
+                .plan_mode_developer_instructions
+                .or(cfg.plan_mode_developer_instructions),
             model_reasoning_summary: config_profile
                 .model_reasoning_summary
                 .or(cfg.model_reasoning_summary),

codex-rs/core/src/config/profile.rs

@@ -28,6 +28,7 @@ pub struct ConfigProfile {
     pub sandbox_mode: Option<SandboxMode>,
     pub model_reasoning_effort: Option<ReasoningEffort>,
     pub plan_mode_reasoning_effort: Option<ReasoningEffort>,
+    pub plan_mode_developer_instructions: Option<String>,
     pub model_reasoning_summary: Option<ReasoningSummary>,
     pub model_verbosity: Option<Verbosity>,
     /// Optional path to a JSON model catalog (applied on startup only).

codex-rs/core/src/models_manager/collaboration_mode_presets.rs

@@ -23,17 +23,25 @@ pub struct CollaborationModesConfig {
 
 pub(crate) fn builtin_collaboration_mode_presets(
     collaboration_modes_config: CollaborationModesConfig,
+    plan_mode_developer_instructions: Option<&str>,
 ) -> Vec<CollaborationModeMask> {
-    vec![plan_preset(), default_preset(collaboration_modes_config)]
+    vec![
+        plan_preset(plan_mode_developer_instructions),
+        default_preset(collaboration_modes_config),
+    ]
 }
 
-fn plan_preset() -> CollaborationModeMask {
+fn plan_preset(plan_mode_developer_instructions: Option<&str>) -> CollaborationModeMask {
     CollaborationModeMask {
         name: ModeKind::Plan.display_name().to_string(),
         mode: Some(ModeKind::Plan),
         model: None,
         reasoning_effort: Some(Some(ReasoningEffort::Medium)),
-        developer_instructions: Some(Some(COLLABORATION_MODE_PLAN.to_string())),
+        developer_instructions: Some(Some(
+            plan_mode_developer_instructions
+                .unwrap_or(COLLABORATION_MODE_PLAN)
+                .to_string(),
+        )),
     }
 }
 
@@ -109,17 +117,27 @@ mod tests {
 
     #[test]
     fn preset_names_use_mode_display_names() {
-        assert_eq!(plan_preset().name, ModeKind::Plan.display_name());
+        assert_eq!(plan_preset(None).name, ModeKind::Plan.display_name());
         assert_eq!(
             default_preset(CollaborationModesConfig::default()).name,
             ModeKind::Default.display_name()
         );
         assert_eq!(
-            plan_preset().reasoning_effort,
+            plan_preset(None).reasoning_effort,
             Some(Some(ReasoningEffort::Medium))
         );
     }
 
+    #[test]
+    fn plan_preset_uses_configured_developer_instructions_override() {
+        let override_instructions = "Use plan override.";
+        let plan = plan_preset(Some(override_instructions));
+        assert_eq!(
+            plan.developer_instructions,
+            Some(Some(override_instructions.to_string()))
+        );
+    }
+
     #[test]
     fn default_mode_instructions_replace_mode_names_placeholder() {
         let default_instructions = default_preset(CollaborationModesConfig {

codex-rs/core/src/models_manager/manager.rs

@@ -61,6 +61,7 @@ pub struct ModelsManager {
     etag: RwLock<Option<String>>,
     cache_manager: ModelsCacheManager,
     provider: ModelProviderInfo,
+    plan_mode_developer_instructions: Option<String>,
 }
 
 impl ModelsManager {
@@ -74,6 +75,7 @@ impl ModelsManager {
         auth_manager: Arc<AuthManager>,
         model_catalog: Option<ModelsResponse>,
         collaboration_modes_config: CollaborationModesConfig,
+        plan_mode_developer_instructions: Option<String>,
     ) -> Self {
         let cache_path = codex_home.join(MODEL_CACHE_FILE);
         let cache_manager = ModelsCacheManager::new(cache_path, DEFAULT_MODEL_CACHE_TTL);
@@ -96,6 +98,7 @@ impl ModelsManager {
             etag: RwLock::new(None),
             cache_manager,
             provider: ModelProviderInfo::create_openai_provider(),
+            plan_mode_developer_instructions,
         }
     }
 
@@ -121,7 +124,10 @@ impl ModelsManager {
         &self,
         collaboration_modes_config: CollaborationModesConfig,
     ) -> Vec<CollaborationModeMask> {
-        builtin_collaboration_mode_presets(collaboration_modes_config)
+        builtin_collaboration_mode_presets(
+            collaboration_modes_config,
+            self.plan_mode_developer_instructions.as_deref(),
+        )
     }
 
     /// Attempt to list models without blocking, using the current cached state.
@@ -380,6 +386,20 @@ impl ModelsManager {
         codex_home: PathBuf,
         auth_manager: Arc<AuthManager>,
         provider: ModelProviderInfo,
+    ) -> Self {
+        Self::with_provider_and_plan_instructions_for_tests(
+            codex_home,
+            auth_manager,
+            provider,
+            None,
+        )
+    }
+
+    pub(crate) fn with_provider_and_plan_instructions_for_tests(
+        codex_home: PathBuf,
+        auth_manager: Arc<AuthManager>,
+        provider: ModelProviderInfo,
+        plan_mode_developer_instructions: Option<String>,
     ) -> Self {
         let cache_path = codex_home.join(MODEL_CACHE_FILE);
         let cache_manager = ModelsCacheManager::new(cache_path, DEFAULT_MODEL_CACHE_TTL);
@@ -394,6 +414,7 @@ impl ModelsManager {
             etag: RwLock::new(None),
             cache_manager,
             provider,
+            plan_mode_developer_instructions,
         }
     }
 
@@ -522,6 +543,7 @@ mod tests {
             auth_manager,
             None,
             CollaborationModesConfig::default(),
+            None,
         );
         let known_slug = manager
             .get_remote_models()
@@ -562,6 +584,7 @@ mod tests {
                 models: vec![overlay],
             }),
             CollaborationModesConfig::default(),
+            None,
         );
 
         let model_info = manager
@@ -595,6 +618,7 @@ mod tests {
                 models: vec![remote],
             }),
             CollaborationModesConfig::default(),
+            None,
         );
         let namespaced_model = "custom/gpt-image".to_string();
 
@@ -620,6 +644,7 @@ mod tests {
             auth_manager,
             None,
             CollaborationModesConfig::default(),
+            None,
         );
         let known_slug = manager
             .get_remote_models()

codex-rs/core/src/test_support.rs

@@ -60,8 +60,14 @@ pub fn thread_manager_with_models_provider_and_home(
     auth: CodexAuth,
     provider: ModelProviderInfo,
     codex_home: PathBuf,
+    plan_mode_developer_instructions: Option<String>,
 ) -> ThreadManager {
-    ThreadManager::with_models_provider_and_home_for_tests(auth, provider, codex_home)
+    ThreadManager::with_models_provider_and_home_and_plan_instructions_for_tests(
+        auth,
+        provider,
+        codex_home,
+        plan_mode_developer_instructions,
+    )
 }
 
 pub fn models_manager_with_provider(
@@ -87,5 +93,6 @@ pub fn all_model_presets() -> &'static Vec<ModelPreset> {
 pub fn builtin_collaboration_mode_presets() -> Vec<CollaborationModeMask> {
     collaboration_mode_presets::builtin_collaboration_mode_presets(
         collaboration_mode_presets::CollaborationModesConfig::default(),
+        None,
     )
 }

codex-rs/core/src/thread_manager.rs

@@ -150,6 +150,7 @@ impl ThreadManager {
         session_source: SessionSource,
         model_catalog: Option<ModelsResponse>,
         collaboration_modes_config: CollaborationModesConfig,
+        plan_mode_developer_instructions: Option<String>,
     ) -> Self {
         let (thread_created_tx, _) = broadcast::channel(THREAD_CREATED_CHANNEL_CAPACITY);
         let plugins_manager = Arc::new(PluginsManager::new(codex_home.clone()));
@@ -168,6 +169,7 @@ impl ThreadManager {
                     auth_manager.clone(),
                     model_catalog,
                     collaboration_modes_config,
+                    plan_mode_developer_instructions,
                 )),
                 skills_manager,
                 plugins_manager,
@@ -207,6 +209,17 @@ impl ThreadManager {
         auth: CodexAuth,
         provider: ModelProviderInfo,
         codex_home: PathBuf,
+    ) -> Self {
+        Self::with_models_provider_and_home_and_plan_instructions_for_tests(
+            auth, provider, codex_home, None,
+        )
+    }
+
+    pub(crate) fn with_models_provider_and_home_and_plan_instructions_for_tests(
+        auth: CodexAuth,
+        provider: ModelProviderInfo,
+        codex_home: PathBuf,
+        plan_mode_developer_instructions: Option<String>,
     ) -> Self {
         set_thread_manager_test_mode_for_tests(true);
         let auth_manager = AuthManager::from_auth_for_testing(auth);
@@ -222,11 +235,14 @@ impl ThreadManager {
             state: Arc::new(ThreadManagerState {
                 threads: Arc::new(RwLock::new(HashMap::new())),
                 thread_created_tx,
-                models_manager: Arc::new(ModelsManager::with_provider_for_tests(
-                    codex_home,
-                    auth_manager.clone(),
-                    provider,
-                )),
+                models_manager: Arc::new(
+                    ModelsManager::with_provider_and_plan_instructions_for_tests(
+                        codex_home,
+                        auth_manager.clone(),
+                        provider,
+                        plan_mode_developer_instructions,
+                    ),
+                ),
                 skills_manager,
                 plugins_manager,
                 mcp_manager,

codex-rs/core/tests/common/test_codex.rs

@@ -186,12 +186,14 @@ impl TestCodexBuilder {
                 SessionSource::Exec,
                 Some(model_catalog),
                 CollaborationModesConfig::default(),
+                config.plan_mode_developer_instructions.clone(),
             )
         } else {
             codex_core::test_support::thread_manager_with_models_provider_and_home(
                 auth.clone(),
                 config.model_provider.clone(),
                 config.codex_home.clone(),
+                config.plan_mode_developer_instructions.clone(),
             )
         };
         let thread_manager = Arc::new(thread_manager);

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

@@ -824,6 +824,7 @@ async fn prefers_apikey_when_config_prefers_apikey_even_with_chatgpt_tokens() {
                 .features
                 .enabled(Feature::DefaultModeRequestUserInput),
         },
+        config.plan_mode_developer_instructions.clone(),
     );
     let NewThread { thread: codex, .. } = thread_manager
         .start_thread(config)

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

@@ -191,6 +191,70 @@ async fn collaboration_instructions_added_on_user_turn() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn plan_mode_uses_configured_developer_instructions_override() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let req = mount_sse_once(
+        &server,
+        sse(vec![ev_response_created("resp-1"), ev_completed("resp-1")]),
+    )
+    .await;
+
+    let override_text = "configured plan instructions";
+    let test = test_codex()
+        .with_config(move |config| {
+            config.plan_mode_developer_instructions = Some(override_text.to_string());
+        })
+        .build(&server)
+        .await?;
+    let collaboration_mode = CollaborationMode {
+        mode: ModeKind::Plan,
+        settings: Settings {
+            model: test.session_configured.model.clone(),
+            reasoning_effort: None,
+            developer_instructions: None,
+        },
+    };
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![UserInput::Text {
+                text: "hello".into(),
+                text_elements: Vec::new(),
+            }],
+            cwd: test.config.cwd.clone(),
+            approval_policy: test.config.permissions.approval_policy.value(),
+            sandbox_policy: test.config.permissions.sandbox_policy.get().clone(),
+            model: test.session_configured.model.clone(),
+            effort: None,
+            summary: Some(
+                test.config
+                    .model_reasoning_summary
+                    .unwrap_or(codex_protocol::config_types::ReasoningSummary::Auto),
+            ),
+            service_tier: None,
+            collaboration_mode: Some(collaboration_mode),
+            final_output_json_schema: None,
+            personality: None,
+        })
+        .await?;
+    wait_for_event(&test.codex, |ev| matches!(ev, EventMsg::TurnComplete(_))).await;
+
+    let input = req.single_request().input();
+    let dev_texts = developer_texts(&input);
+    let expected_text = collab_xml(override_text);
+    let collab_blocks = dev_texts
+        .iter()
+        .filter(|text| text.starts_with(COLLABORATION_MODE_OPEN_TAG))
+        .count();
+    assert_eq!(collab_blocks, 1);
+    assert_eq!(count_exact(&dev_texts, &expected_text), 1);
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn override_then_next_turn_uses_updated_collaboration_instructions() -> Result<()> {
     skip_if_no_network!(Ok(()));

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

@@ -18,6 +18,7 @@ async fn offline_model_info_without_tool_output_override() {
         auth_manager,
         None,
         CollaborationModesConfig::default(),
+        None,
     );
 
     let model_info = manager.get_model_info("gpt-5.1", &config).await;
@@ -41,6 +42,7 @@ async fn offline_model_info_with_tool_output_override() {
         auth_manager,
         None,
         CollaborationModesConfig::default(),
+        None,
     );
 
     let model_info = manager.get_model_info("gpt-5.1-codex", &config).await;

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

@@ -847,6 +847,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
 
     let expected_permissions_msg = body1["input"][0].clone();
     let expected_ui_msg = body1["input"][1].clone();
+    let expected_collaboration_mode_msg = body1["input"][2].clone();
 
     let shell = default_user_shell();
     let default_cwd_lossy = default_cwd.to_string_lossy();
@@ -868,6 +869,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
     let expected_input_1 = serde_json::Value::Array(vec![
         expected_permissions_msg.clone(),
         expected_contextual_user_msg_1.clone(),
+        expected_collaboration_mode_msg.clone(),
         expected_user_message_1.clone(),
     ]);
     assert_eq!(body1["input"], expected_input_1);
@@ -876,6 +878,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() -> a
     let expected_input_2 = serde_json::Value::Array(vec![
         expected_permissions_msg,
         expected_contextual_user_msg_1,
+        expected_collaboration_mode_msg,
         expected_user_message_1,
         expected_user_message_2,
     ]);
@@ -971,6 +974,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
 
     let expected_permissions_msg = body1["input"][0].clone();
     let expected_ui_msg = body1["input"][1].clone();
+    let expected_collaboration_mode_msg = body1["input"][2].clone();
 
     let shell = default_user_shell();
     let expected_env_text_1 = expected_ui_msg["content"][1]["text"]
@@ -989,6 +993,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
     let expected_input_1 = serde_json::Value::Array(vec![
         expected_permissions_msg.clone(),
         expected_contextual_user_msg_1.clone(),
+        expected_collaboration_mode_msg.clone(),
         expected_user_message_1.clone(),
     ]);
     assert_eq!(body1["input"], expected_input_1);
@@ -1013,6 +1018,7 @@ async fn send_user_turn_with_changes_sends_environment_context() -> anyhow::Resu
     let expected_input_2 = serde_json::Value::Array(vec![
         expected_permissions_msg,
         expected_contextual_user_msg_1,
+        expected_collaboration_mode_msg,
         expected_user_message_1,
         expected_settings_update_msg,
         expected_user_message_2,

codex-rs/core/tests/suite/snapshots/all__suite__compact__pre_sampling_model_switch_compaction_shapes.snap

@@ -1,6 +1,5 @@
 ---
 source: core/tests/suite/compact.rs
-assertion_line: 1791
 expression: "format_labeled_requests_snapshot(\"Pre-sampling compaction on model switch to a smaller context window: current behavior compacts using prior-turn history only (incoming user message excluded), and the follow-up request carries compacted history plus the new user message.\",\n&[(\"Initial Request (Previous Model)\", &requests[0]),\n(\"Pre-sampling Compaction Request\", &requests[1]),\n(\"Post-Compaction Follow-up Request (Next Model)\", &requests[2]),])"
 ---
 Scenario: Pre-sampling compaction on model switch to a smaller context window: current behavior compacts using prior-turn history only (incoming user message excluded), and the follow-up request carries compacted history plus the new user message.
@@ -10,7 +9,9 @@ Scenario: Pre-sampling compaction on model switch to a smaller context window: c
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 03:message/user:before switch
 
 ## Pre-sampling Compaction Request
@@ -18,7 +19,9 @@ Scenario: Pre-sampling compaction on model switch to a smaller context window: c
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 03:message/user:before switch
 04:message/assistant:before switch
 05:message/user:<SUMMARIZATION_PROMPT>
@@ -26,9 +29,10 @@ Scenario: Pre-sampling compaction on model switch to a smaller context window: c
 ## Post-Compaction Follow-up Request (Next Model)
 00:message/user:before switch
 01:message/user:<COMPACTION_SUMMARY>\nPRE_SAMPLING_SUMMARY
-02:message/developer[2]:
+02:message/developer[3]:
     [01] <model_switch>\nThe user was previously using a different model....
     [02] <PERMISSIONS_INSTRUCTIONS>
+    [03] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 03:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>

codex-rs/core/tests/suite/snapshots/all__suite__compact__pre_turn_compaction_including_incoming_shapes.snap

@@ -19,7 +19,9 @@ Scenario: Pre-turn auto-compaction with a context override emits the context dif
 00:message/user:USER_ONE
 01:message/user:USER_TWO
 02:message/user:<COMPACTION_SUMMARY>\nPRE_TURN_SUMMARY
-03:message/developer:<PERMISSIONS_INSTRUCTIONS>
+03:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 04:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=PRETURN_CONTEXT_DIFF_CWD>

codex-rs/core/tests/suite/snapshots/all__suite__compact__pre_turn_compaction_strips_incoming_model_switch_shapes.snap

@@ -1,6 +1,5 @@
 ---
 source: core/tests/suite/compact.rs
-assertion_line: 3188
 expression: "format_labeled_requests_snapshot(\"Pre-turn compaction during model switch (without pre-sampling model-switch compaction): current behavior strips incoming <model_switch> from the compact request and restores it in the post-compaction follow-up request.\",\n&[(\"Initial Request (Previous Model)\", &requests[0]),\n(\"Local Compaction Request\", &requests[1]),\n(\"Local Post-Compaction History Layout\", &requests[2]),])"
 ---
 Scenario: Pre-turn compaction during model switch (without pre-sampling model-switch compaction): current behavior strips incoming <model_switch> from the compact request and restores it in the post-compaction follow-up request.
@@ -10,7 +9,9 @@ Scenario: Pre-turn compaction during model switch (without pre-sampling model-sw
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 03:message/user:BEFORE_SWITCH_USER
 
 ## Local Compaction Request
@@ -18,7 +19,9 @@ Scenario: Pre-turn compaction during model switch (without pre-sampling model-sw
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 03:message/user:BEFORE_SWITCH_USER
 04:message/assistant:BEFORE_SWITCH_REPLY
 05:message/user:<SUMMARIZATION_PROMPT>
@@ -26,10 +29,11 @@ Scenario: Pre-turn compaction during model switch (without pre-sampling model-sw
 ## Local Post-Compaction History Layout
 00:message/user:BEFORE_SWITCH_USER
 01:message/user:<COMPACTION_SUMMARY>\nPRETURN_SWITCH_SUMMARY
-02:message/developer[3]:
+02:message/developer[4]:
     [01] <model_switch>\nThe user was previously using a different model....
     [02] <PERMISSIONS_INSTRUCTIONS>
-    [03] <personality_spec> The user has requested a new communication st...
+    [03] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
+    [04] <personality_spec> The user has requested a new communication st...
 03:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>

codex-rs/core/tests/suite/snapshots/all__suite__compact_remote__remote_pre_turn_compaction_including_incoming_shapes.snap

@@ -18,7 +18,9 @@ Scenario: Remote pre-turn auto-compaction with a context override emits the cont
 00:message/user:USER_ONE
 01:message/user:USER_TWO
 02:compaction:encrypted=true
-03:message/developer:<PERMISSIONS_INSTRUCTIONS>
+03:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
 04:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=PRETURN_CONTEXT_DIFF_CWD>

codex-rs/core/tests/suite/snapshots/all__suite__compact_remote__remote_pre_turn_compaction_strips_incoming_model_switch_shapes.snap

@@ -1,6 +1,5 @@
 ---
 source: core/tests/suite/compact_remote.rs
-assertion_line: 1514
 expression: "format_labeled_requests_snapshot(\"Remote pre-turn compaction during model switch currently excludes incoming user input, strips incoming <model_switch> from the compact request payload, and restores it in the post-compaction follow-up request.\",\n&[(\"Initial Request (Previous Model)\", &initial_turn_request),\n(\"Remote Compaction Request\", &compact_request),\n(\"Remote Post-Compaction History Layout\", &post_compact_turn_request),])"
 ---
 Scenario: Remote pre-turn compaction during model switch currently excludes incoming user input, strips incoming <model_switch> from the compact request payload, and restores it in the post-compaction follow-up request.
@@ -23,10 +22,11 @@ Scenario: Remote pre-turn compaction during model switch currently excludes inco
 ## Remote Post-Compaction History Layout
 00:message/user:BEFORE_SWITCH_USER
 01:compaction:encrypted=true
-02:message/developer[3]:
+02:message/developer[4]:
     [01] <model_switch>\nThe user was previously using a different model....
     [02] <PERMISSIONS_INSTRUCTIONS>
-    [03] <personality_spec> The user has requested a new communication st...
+    [03] <collaboration_mode># Collaboration Mode: Default\n\nYou are now...
+    [04] <personality_spec> The user has requested a new communication st...
 03:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>

codex-rs/core/tests/suite/snapshots/all__suite__model_visible_layout__model_visible_layout_cwd_change_does_not_refresh_agents.snap

@@ -9,7 +9,9 @@ Scenario: Second turn changes cwd to a directory with different AGENTS.md; curre
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now in Default mode. Any previous i...
 03:message/user:<ENVIRONMENT_CONTEXT:cwd=<CWD>>
 04:message/user:first turn in agents_one
 
@@ -18,7 +20,9 @@ Scenario: Second turn changes cwd to a directory with different AGENTS.md; curre
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now in Default mode. Any previous i...
 03:message/user:<ENVIRONMENT_CONTEXT:cwd=<CWD>>
 04:message/user:first turn in agents_one
 05:message/assistant:turn one complete

codex-rs/core/tests/suite/snapshots/all__suite__model_visible_layout__model_visible_layout_resume_override_matches_rollout_model.snap

@@ -18,5 +18,6 @@ Scenario: First post-resume turn where pre-turn override sets model to rollout m
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
 02:message/user:seed resume history
 03:message/assistant:recorded before resume
-04:message/user:<ENVIRONMENT_CONTEXT:cwd=PRETURN_CONTEXT_DIFF_CWD>
-05:message/user:first resumed turn after model override
+04:message/developer:<collaboration_mode># Collaboration Mode: Default\n\nYou are now in Default mode. Any previous i...
+05:message/user:<ENVIRONMENT_CONTEXT:cwd=PRETURN_CONTEXT_DIFF_CWD>
+06:message/user:first resumed turn after model override

codex-rs/core/tests/suite/snapshots/all__suite__model_visible_layout__model_visible_layout_resume_with_personality_change.snap

@@ -18,8 +18,9 @@ Scenario: First post-resume turn where resumed config model differs from rollout
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
 02:message/user:seed resume history
 03:message/assistant:recorded before resume
-04:message/developer[2]:
+04:message/developer[3]:
     [01] <model_switch>\nThe user was previously using a different model. Please continue the conversatio...
     [02] <PERMISSIONS_INSTRUCTIONS>
+    [03] <collaboration_mode># Collaboration Mode: Default\n\nYou are now in Default mode. Any previous i...
 05:message/user:<ENVIRONMENT_CONTEXT:cwd=PRETURN_CONTEXT_DIFF_CWD>
 06:message/user:resume and change personality

codex-rs/core/tests/suite/snapshots/all__suite__model_visible_layout__model_visible_layout_turn_overrides.snap

@@ -9,7 +9,9 @@ Scenario: Second turn changes cwd, approval policy, and personality while keepin
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now in Default mode. Any previous i...
 03:message/user:first turn
 
 ## Second Request (Turn Overrides)
@@ -17,7 +19,9 @@ Scenario: Second turn changes cwd, approval policy, and personality while keepin
 01:message/user[2]:
     [01] <AGENTS_MD>
     [02] <ENVIRONMENT_CONTEXT:cwd=<CWD>>
-02:message/developer:<PERMISSIONS_INSTRUCTIONS>
+02:message/developer[2]:
+    [01] <PERMISSIONS_INSTRUCTIONS>
+    [02] <collaboration_mode># Collaboration Mode: Default\n\nYou are now in Default mode. Any previous i...
 03:message/user:first turn
 04:message/assistant:turn one complete
 05:message/developer[2]:

codex-rs/exec/src/lib.rs

@@ -484,6 +484,7 @@ async fn run_exec_session(args: ExecRunArgs) -> anyhow::Result<()> {
                 .features
                 .enabled(codex_core::features::Feature::DefaultModeRequestUserInput),
         },
+        config.plan_mode_developer_instructions.clone(),
     ));
     let default_model = thread_manager
         .get_models_manager()

codex-rs/mcp-server/src/message_processor.rs

@@ -68,6 +68,7 @@ impl MessageProcessor {
                     .features
                     .enabled(codex_core::features::Feature::DefaultModeRequestUserInput),
             },
+            config.plan_mode_developer_instructions.clone(),
         ));
         Self {
             outgoing,

codex-rs/tui/src/app.rs

@@ -1585,6 +1585,7 @@ impl App {
                     .features
                     .enabled(codex_core::features::Feature::DefaultModeRequestUserInput),
             },
+            config.plan_mode_developer_instructions.clone(),
         ));
         let mut model = thread_manager
             .get_models_manager()

codex-rs/tui/src/chatwidget/tests.rs

@@ -1754,6 +1754,7 @@ async fn make_chatwidget_manual(
         auth_manager.clone(),
         None,
         CollaborationModesConfig::default(),
+        None,
     ));
     let reasoning_effort = None;
     let base_mode = CollaborationMode {
@@ -1884,6 +1885,7 @@ fn set_chatgpt_auth(chat: &mut ChatWidget) {
         chat.auth_manager.clone(),
         None,
         CollaborationModesConfig::default(),
+        None,
     ));
 }