diff --git a/codex-rs/app-server-protocol/src/protocol/v2.rs b/codex-rs/app-server-protocol/src/protocol/v2.rs
index 022532a050..14a3fe532f 100644
--- a/codex-rs/app-server-protocol/src/protocol/v2.rs
+++ b/codex-rs/app-server-protocol/src/protocol/v2.rs
@@ -6,6 +6,7 @@ use codex_protocol::account::PlanType;
 use codex_protocol::approvals::ExecPolicyAmendment as CoreExecPolicyAmendment;
 use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::ForcedLoginMethod;
+use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::SandboxMode as CoreSandboxMode;
 use codex_protocol::config_types::Verbosity;
@@ -1079,6 +1080,7 @@ pub struct ThreadStartParams {
     pub config: Option<HashMap<String, JsonValue>>,
     pub base_instructions: Option<String>,
     pub developer_instructions: Option<String>,
+    pub personality: Option<Personality>,
     /// If true, opt into emitting raw response items on the event stream.
     ///
     /// This is for internal use only (e.g. Codex Cloud).
@@ -1133,6 +1135,7 @@ pub struct ThreadResumeParams {
     pub config: Option<HashMap<String, serde_json::Value>>,
     pub base_instructions: Option<String>,
     pub developer_instructions: Option<String>,
+    pub personality: Option<Personality>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
@@ -1608,6 +1611,8 @@ pub struct TurnStartParams {
     pub effort: Option<ReasoningEffort>,
     /// Override the reasoning summary for this turn and subsequent turns.
     pub summary: Option<ReasoningSummary>,
+    /// Override the personality for this turn and subsequent turns.
+    pub personality: Option<Personality>,
     /// Optional JSON Schema used to constrain the final assistant message for this turn.
     pub output_schema: Option<JsonValue>,
 
diff --git a/codex-rs/app-server/README.md b/codex-rs/app-server/README.md
index c990b1ac3d..659e2bf72c 100644
--- a/codex-rs/app-server/README.md
+++ b/codex-rs/app-server/README.md
@@ -114,6 +114,7 @@ Start a fresh thread when you need a new Codex conversation.
     "cwd": "/Users/me/project",
     "approvalPolicy": "never",
     "sandbox": "workspaceWrite",
+    "personality": "friendly"
 } }
 { "id": 10, "result": {
     "thread": {
@@ -126,10 +127,13 @@ Start a fresh thread when you need a new Codex conversation.
 { "method": "thread/started", "params": { "thread": { … } } }
 ```
 
-To continue a stored session, call `thread/resume` with the `thread.id` you previously recorded. The response shape matches `thread/start`, and no additional notifications are emitted:
+To continue a stored session, call `thread/resume` with the `thread.id` you previously recorded. The response shape matches `thread/start`, and no additional notifications are emitted. You can also pass the same configuration overrides supported by `thread/start`, such as `personality`:
 
 ```json
-{ "method": "thread/resume", "id": 11, "params": { "threadId": "thr_123" } }
+{ "method": "thread/resume", "id": 11, "params": {
+    "threadId": "thr_123",
+    "personality": "friendly"
+} }
 { "id": 11, "result": { "thread": { "id": "thr_123", … } } }
 ```
 
@@ -231,6 +235,7 @@ You can optionally specify config overrides on the new turn. If specified, these
     "model": "gpt-5.1-codex",
     "effort": "medium",
     "summary": "concise",
+    "personality": "friendly",
     // Optional JSON Schema to constrain the final assistant message for this turn.
     "outputSchema": {
         "type": "object",
diff --git a/codex-rs/app-server/src/codex_message_processor.rs b/codex-rs/app-server/src/codex_message_processor.rs
index 62fceb34db..daf0fb3d73 100644
--- a/codex-rs/app-server/src/codex_message_processor.rs
+++ b/codex-rs/app-server/src/codex_message_processor.rs
@@ -169,6 +169,7 @@ use codex_login::ShutdownHandle;
 use codex_login::run_login_server;
 use codex_protocol::ThreadId;
 use codex_protocol::config_types::ForcedLoginMethod;
+use codex_protocol::config_types::Personality;
 use codex_protocol::items::TurnItem;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::protocol::GitInfo as CoreGitInfo;
@@ -1405,6 +1406,7 @@ impl CodexMessageProcessor {
             params.sandbox,
             params.base_instructions,
             params.developer_instructions,
+            params.personality,
         );
 
         let config =
@@ -1518,6 +1520,7 @@ impl CodexMessageProcessor {
         sandbox: Option<SandboxMode>,
         base_instructions: Option<String>,
         developer_instructions: Option<String>,
+        personality: Option<Personality>,
     ) -> ConfigOverrides {
         ConfigOverrides {
             model,
@@ -1529,6 +1532,7 @@ impl CodexMessageProcessor {
             codex_linux_sandbox_exe: self.codex_linux_sandbox_exe.clone(),
             base_instructions,
             developer_instructions,
+            model_personality: personality,
             ..Default::default()
         }
     }
@@ -1836,6 +1840,7 @@ impl CodexMessageProcessor {
             config: request_overrides,
             base_instructions,
             developer_instructions,
+            personality,
         } = params;
 
         let thread_history = if let Some(history) = history {
@@ -1921,6 +1926,7 @@ impl CodexMessageProcessor {
             sandbox,
             base_instructions,
             developer_instructions,
+            personality,
         );
 
         // Derive a Config using the same logic as new conversation, honoring overrides if provided.
@@ -2105,6 +2111,7 @@ impl CodexMessageProcessor {
             sandbox,
             base_instructions,
             developer_instructions,
+            None,
         );
         // Derive a Config using the same logic as new conversation, honoring overrides if provided.
         let config = match derive_config_for_cwd(
@@ -3615,7 +3622,8 @@ impl CodexMessageProcessor {
             || params.model.is_some()
             || params.effort.is_some()
             || params.summary.is_some()
-            || params.collaboration_mode.is_some();
+            || params.collaboration_mode.is_some()
+            || params.personality.is_some();
 
         // If any overrides are provided, update the session turn context first.
         if has_any_overrides {
@@ -3628,7 +3636,7 @@ impl CodexMessageProcessor {
                     effort: params.effort.map(Some),
                     summary: params.summary,
                     collaboration_mode: params.collaboration_mode,
-                    personality: None,
+                    personality: params.personality,
                 })
                 .await;
         }
diff --git a/codex-rs/app-server/tests/suite/v2/thread_resume.rs b/codex-rs/app-server/tests/suite/v2/thread_resume.rs
index 2865d73649..183532ea7d 100644
--- a/codex-rs/app-server/tests/suite/v2/thread_resume.rs
+++ b/codex-rs/app-server/tests/suite/v2/thread_resume.rs
@@ -11,18 +11,23 @@ use codex_app_server_protocol::ThreadResumeParams;
 use codex_app_server_protocol::ThreadResumeResponse;
 use codex_app_server_protocol::ThreadStartParams;
 use codex_app_server_protocol::ThreadStartResponse;
+use codex_app_server_protocol::TurnStartParams;
 use codex_app_server_protocol::TurnStatus;
 use codex_app_server_protocol::UserInput;
+use codex_protocol::config_types::Personality;
 use codex_protocol::models::ContentItem;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::user_input::ByteRange;
 use codex_protocol::user_input::TextElement;
+use core_test_support::responses;
+use core_test_support::skip_if_no_network;
 use pretty_assertions::assert_eq;
 use std::path::PathBuf;
 use tempfile::TempDir;
 use tokio::time::timeout;
 
 const DEFAULT_READ_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(10);
+const DEFAULT_BASE_INSTRUCTIONS: &str = "You are Codex, based on GPT-5. You are running as a coding agent in the Codex CLI on a user's computer.";
 
 #[tokio::test]
 async fn thread_resume_returns_original_thread() -> Result<()> {
@@ -248,6 +253,91 @@ async fn thread_resume_supports_history_and_overrides() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn thread_resume_accepts_personality_override_v2() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = responses::start_mock_server().await;
+    let body = responses::sse(vec![
+        responses::ev_response_created("resp-1"),
+        responses::ev_assistant_message("msg-1", "Done"),
+        responses::ev_completed("resp-1"),
+    ]);
+    let response_mock = responses::mount_sse_once(&server, body).await;
+
+    let codex_home = TempDir::new()?;
+    create_config_toml(codex_home.path(), &server.uri())?;
+
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
+
+    let start_id = mcp
+        .send_thread_start_request(ThreadStartParams {
+            model: Some("gpt-5.2-codex".to_string()),
+            ..Default::default()
+        })
+        .await?;
+    let start_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(start_id)),
+    )
+    .await??;
+    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(start_resp)?;
+
+    let resume_id = mcp
+        .send_thread_resume_request(ThreadResumeParams {
+            thread_id: thread.id.clone(),
+            model: Some("gpt-5.2-codex".to_string()),
+            personality: Some(Personality::Friendly),
+            ..Default::default()
+        })
+        .await?;
+    let resume_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(resume_id)),
+    )
+    .await??;
+    let _resume: ThreadResumeResponse = to_response::<ThreadResumeResponse>(resume_resp)?;
+
+    let turn_id = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id,
+            input: vec![UserInput::Text {
+                text: "Hello".to_string(),
+                text_elements: Vec::new(),
+            }],
+            ..Default::default()
+        })
+        .await?;
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_id)),
+    )
+    .await??;
+
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let request = response_mock.single_request();
+    let developer_texts = request.message_input_texts("developer");
+    assert!(
+        !developer_texts
+            .iter()
+            .any(|text| text.contains("<personality_spec>")),
+        "did not expect a personality update message in developer input, got {developer_texts:?}"
+    );
+    let instructions_text = request.instructions_text();
+    assert!(
+        instructions_text.contains(DEFAULT_BASE_INSTRUCTIONS),
+        "expected default base instructions from history, got {instructions_text:?}"
+    );
+
+    Ok(())
+}
+
 // Helper to create a config.toml pointing at the mock model server.
 fn create_config_toml(codex_home: &std::path::Path, server_uri: &str) -> std::io::Result<()> {
     let config_toml = codex_home.join("config.toml");
@@ -261,6 +351,9 @@ sandbox_mode = "read-only"
 
 model_provider = "mock_provider"
 
+[features]
+remote_models = false
+
 [model_providers.mock_provider]
 name = "Mock provider for test"
 base_url = "{server_uri}/v1"
diff --git a/codex-rs/app-server/tests/suite/v2/turn_start.rs b/codex-rs/app-server/tests/suite/v2/turn_start.rs
index c465444709..bf04eaf252 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -34,13 +34,17 @@ use codex_app_server_protocol::TurnStartResponse;
 use codex_app_server_protocol::TurnStartedNotification;
 use codex_app_server_protocol::TurnStatus;
 use codex_app_server_protocol::UserInput as V2UserInput;
+use codex_core::features::FEATURES;
+use codex_core::features::Feature;
 use codex_core::protocol_config_types::ReasoningSummary;
 use codex_protocol::config_types::CollaborationMode;
+use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::Settings;
 use codex_protocol::openai_models::ReasoningEffort;
 use core_test_support::responses;
 use core_test_support::skip_if_no_network;
 use pretty_assertions::assert_eq;
+use std::collections::BTreeMap;
 use std::path::Path;
 use tempfile::TempDir;
 use tokio::time::timeout;
@@ -54,7 +58,12 @@ async fn turn_start_sends_originator_header() -> Result<()> {
     let server = create_mock_responses_server_sequence_unchecked(responses).await;
 
     let codex_home = TempDir::new()?;
-    create_config_toml(codex_home.path(), &server.uri(), "never")?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(
@@ -124,7 +133,12 @@ async fn turn_start_emits_user_message_item_with_text_elements() -> Result<()> {
     let server = create_mock_responses_server_sequence_unchecked(responses).await;
 
     let codex_home = TempDir::new()?;
-    create_config_toml(codex_home.path(), &server.uri(), "never")?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -211,7 +225,12 @@ async fn turn_start_emits_notifications_and_accepts_model_override() -> Result<(
     let server = create_mock_responses_server_sequence_unchecked(responses).await;
 
     let codex_home = TempDir::new()?;
-    create_config_toml(codex_home.path(), &server.uri(), "never")?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -321,13 +340,19 @@ async fn turn_start_accepts_collaboration_mode_override_v2() -> Result<()> {
     let response_mock = responses::mount_sse_once(&server, body).await;
 
     let codex_home = TempDir::new()?;
-    create_config_toml(codex_home.path(), &server.uri(), "never")?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
 
     let thread_req = mcp
         .send_thread_start_request(ThreadStartParams {
+            model: Some("gpt-5.2-codex".to_string()),
             ..Default::default()
         })
         .await?;
@@ -379,6 +404,81 @@ async fn turn_start_accepts_collaboration_mode_override_v2() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test]
+async fn turn_start_accepts_personality_override_v2() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = responses::start_mock_server().await;
+    let body = responses::sse(vec![
+        responses::ev_response_created("resp-1"),
+        responses::ev_assistant_message("msg-1", "Done"),
+        responses::ev_completed("resp-1"),
+    ]);
+    let response_mock = responses::mount_sse_once(&server, body).await;
+
+    let codex_home = TempDir::new()?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
+
+    let mut mcp = McpProcess::new(codex_home.path()).await?;
+    timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
+
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            model: Some("gpt-5.2-codex".to_string()),
+            ..Default::default()
+        })
+        .await?;
+    let thread_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(thread_req)),
+    )
+    .await??;
+    let ThreadStartResponse { thread, .. } = to_response::<ThreadStartResponse>(thread_resp)?;
+
+    let turn_req = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id.clone(),
+            input: vec![V2UserInput::Text {
+                text: "Hello".to_string(),
+                text_elements: Vec::new(),
+            }],
+            personality: Some(Personality::Friendly),
+            ..Default::default()
+        })
+        .await?;
+    let turn_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
+    )
+    .await??;
+    let _turn: TurnStartResponse = to_response::<TurnStartResponse>(turn_resp)?;
+
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let request = response_mock.single_request();
+    let developer_texts = request.message_input_texts("developer");
+    if developer_texts.is_empty() {
+        eprintln!("request body: {}", request.body_json());
+    }
+    assert!(
+        developer_texts
+            .iter()
+            .any(|text| text.contains("<personality_spec>")),
+        "expected personality update message in developer input, got {developer_texts:?}"
+    );
+
+    Ok(())
+}
+
 #[tokio::test]
 async fn turn_start_accepts_local_image_input() -> Result<()> {
     // Two Codex turns hit the mock model (session start + turn/start).
@@ -391,7 +491,12 @@ async fn turn_start_accepts_local_image_input() -> Result<()> {
     let server = create_mock_responses_server_sequence_unchecked(responses).await;
 
     let codex_home = TempDir::new()?;
-    create_config_toml(codex_home.path(), &server.uri(), "never")?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -466,7 +571,12 @@ async fn turn_start_exec_approval_toggle_v2() -> Result<()> {
     ];
     let server = create_mock_responses_server_sequence(responses).await;
     // Default approval is untrusted to force elicitation on first turn.
-    create_config_toml(codex_home.as_path(), &server.uri(), "untrusted")?;
+    create_config_toml(
+        codex_home.as_path(),
+        &server.uri(),
+        "untrusted",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.as_path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -591,7 +701,12 @@ async fn turn_start_exec_approval_decline_v2() -> Result<()> {
         create_final_assistant_message_sse_response("done")?,
     ];
     let server = create_mock_responses_server_sequence(responses).await;
-    create_config_toml(codex_home.as_path(), &server.uri(), "untrusted")?;
+    create_config_toml(
+        codex_home.as_path(),
+        &server.uri(),
+        "untrusted",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.as_path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -738,7 +853,12 @@ async fn turn_start_updates_sandbox_and_cwd_between_turns_v2() -> Result<()> {
         create_final_assistant_message_sse_response("done second")?,
     ];
     let server = create_mock_responses_server_sequence(responses).await;
-    create_config_toml(&codex_home, &server.uri(), "untrusted")?;
+    create_config_toml(
+        &codex_home,
+        &server.uri(),
+        "untrusted",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(&codex_home).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -776,6 +896,7 @@ async fn turn_start_updates_sandbox_and_cwd_between_turns_v2() -> Result<()> {
             model: Some("mock-model".to_string()),
             effort: Some(ReasoningEffort::Medium),
             summary: Some(ReasoningSummary::Auto),
+            personality: None,
             output_schema: None,
             collaboration_mode: None,
         })
@@ -806,6 +927,7 @@ async fn turn_start_updates_sandbox_and_cwd_between_turns_v2() -> Result<()> {
             model: Some("mock-model".to_string()),
             effort: Some(ReasoningEffort::Medium),
             summary: Some(ReasoningSummary::Auto),
+            personality: None,
             output_schema: None,
             collaboration_mode: None,
         })
@@ -876,7 +998,12 @@ async fn turn_start_file_change_approval_v2() -> Result<()> {
         create_final_assistant_message_sse_response("patch applied")?,
     ];
     let server = create_mock_responses_server_sequence(responses).await;
-    create_config_toml(&codex_home, &server.uri(), "untrusted")?;
+    create_config_toml(
+        &codex_home,
+        &server.uri(),
+        "untrusted",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(&codex_home).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -1053,7 +1180,12 @@ async fn turn_start_file_change_approval_accept_for_session_persists_v2() -> Res
         create_final_assistant_message_sse_response("patch 2 applied")?,
     ];
     let server = create_mock_responses_server_sequence(responses).await;
-    create_config_toml(&codex_home, &server.uri(), "untrusted")?;
+    create_config_toml(
+        &codex_home,
+        &server.uri(),
+        "untrusted",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(&codex_home).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -1229,7 +1361,12 @@ async fn turn_start_file_change_approval_decline_v2() -> Result<()> {
         create_final_assistant_message_sse_response("patch declined")?,
     ];
     let server = create_mock_responses_server_sequence(responses).await;
-    create_config_toml(&codex_home, &server.uri(), "untrusted")?;
+    create_config_toml(
+        &codex_home,
+        &server.uri(),
+        "untrusted",
+        &BTreeMap::default(),
+    )?;
 
     let mut mcp = McpProcess::new(&codex_home).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -1369,16 +1506,12 @@ async fn command_execution_notifications_include_process_id() -> Result<()> {
     ];
     let server = create_mock_responses_server_sequence(responses).await;
     let codex_home = TempDir::new()?;
-    create_config_toml(codex_home.path(), &server.uri(), "never")?;
-    let config_toml = codex_home.path().join("config.toml");
-    let mut config_contents = std::fs::read_to_string(&config_toml)?;
-    config_contents.push_str(
-        r#"
-[features]
-unified_exec = true
-"#,
-    );
-    std::fs::write(&config_toml, config_contents)?;
+    create_config_toml(
+        codex_home.path(),
+        &server.uri(),
+        "never",
+        &BTreeMap::from([(Feature::UnifiedExec, true)]),
+    )?;
 
     let mut mcp = McpProcess::new(codex_home.path()).await?;
     timeout(DEFAULT_READ_TIMEOUT, mcp.initialize()).await??;
@@ -1502,7 +1635,24 @@ fn create_config_toml(
     codex_home: &Path,
     server_uri: &str,
     approval_policy: &str,
+    feature_flags: &BTreeMap<Feature, bool>,
 ) -> std::io::Result<()> {
+    let mut features = BTreeMap::from([(Feature::RemoteModels, false)]);
+    for (feature, enabled) in feature_flags {
+        features.insert(*feature, *enabled);
+    }
+    let feature_entries = features
+        .into_iter()
+        .map(|(feature, enabled)| {
+            let key = FEATURES
+                .iter()
+                .find(|spec| spec.id == feature)
+                .map(|spec| spec.key)
+                .unwrap_or_else(|| panic!("missing feature key for {feature:?}"));
+            format!("{key} = {enabled}")
+        })
+        .collect::<Vec<_>>()
+        .join("\n");
     let config_toml = codex_home.join("config.toml");
     std::fs::write(
         config_toml,
@@ -1514,6 +1664,9 @@ sandbox_mode = "read-only"
 
 model_provider = "mock_provider"
 
+[features]
+{feature_entries}
+
 [model_providers.mock_provider]
 name = "Mock provider for test"
 base_url = "{server_uri}/v1"
diff --git a/codex-rs/core/src/config/mod.rs b/codex-rs/core/src/config/mod.rs
index ca2f79edf2..ada42663bf 100644
--- a/codex-rs/core/src/config/mod.rs
+++ b/codex-rs/core/src/config/mod.rs
@@ -1141,6 +1141,7 @@ pub struct ConfigOverrides {
     pub codex_linux_sandbox_exe: Option<PathBuf>,
     pub base_instructions: Option<String>,
     pub developer_instructions: Option<String>,
+    pub model_personality: Option<Personality>,
     pub compact_prompt: Option<String>,
     pub include_apply_patch_tool: Option<bool>,
     pub show_raw_agent_reasoning: Option<bool>,
@@ -1228,6 +1229,7 @@ impl Config {
             codex_linux_sandbox_exe,
             base_instructions,
             developer_instructions,
+            model_personality,
             compact_prompt,
             include_apply_patch_tool: include_apply_patch_tool_override,
             show_raw_agent_reasoning,
@@ -1433,6 +1435,9 @@ impl Config {
             Self::try_read_non_empty_file(model_instructions_path, "model instructions file")?;
         let base_instructions = base_instructions.or(file_base_instructions);
         let developer_instructions = developer_instructions.or(cfg.developer_instructions);
+        let model_personality = model_personality
+            .or(config_profile.model_personality)
+            .or(cfg.model_personality);
 
         let experimental_compact_prompt_path = config_profile
             .experimental_compact_prompt_file
@@ -1482,7 +1487,7 @@ impl Config {
             notify: cfg.notify,
             user_instructions,
             base_instructions,
-            model_personality: config_profile.model_personality.or(cfg.model_personality),
+            model_personality,
             developer_instructions,
             compact_prompt,
             // The config.toml omits "_mode" because it's a config file. However, "_mode"
diff --git a/codex-rs/exec/src/lib.rs b/codex-rs/exec/src/lib.rs
index ccd10355b7..d5fb0f6ed2 100644
--- a/codex-rs/exec/src/lib.rs
+++ b/codex-rs/exec/src/lib.rs
@@ -211,6 +211,7 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
         codex_linux_sandbox_exe,
         base_instructions: None,
         developer_instructions: None,
+        model_personality: None,
         compact_prompt: None,
         include_apply_patch_tool: None,
         show_raw_agent_reasoning: oss.then_some(true),