diff --git a/codex-rs/app-server-protocol/src/protocol/common.rs b/codex-rs/app-server-protocol/src/protocol/common.rs
index fcc35a60dd..75acf96f2a 100644
--- a/codex-rs/app-server-protocol/src/protocol/common.rs
+++ b/codex-rs/app-server-protocol/src/protocol/common.rs
@@ -524,6 +524,12 @@ server_request_definitions! {
         response: v2::ToolRequestUserInputResponse,
     },
 
+    /// Execute a dynamic tool call on the client.
+    DynamicToolCall => "item/tool/call" {
+        params: v2::DynamicToolCallParams,
+        response: v2::DynamicToolCallResponse,
+    },
+
     /// DEPRECATED APIs below
     /// Request to approve a patch.
     /// This request is used for Turns started via the legacy APIs (i.e. SendUserTurn, SendUserMessage).
diff --git a/codex-rs/app-server-protocol/src/protocol/v2.rs b/codex-rs/app-server-protocol/src/protocol/v2.rs
index e282e924fc..65648bbdb0 100644
--- a/codex-rs/app-server-protocol/src/protocol/v2.rs
+++ b/codex-rs/app-server-protocol/src/protocol/v2.rs
@@ -325,6 +325,15 @@ pub struct ToolsV2 {
     pub view_image: Option<bool>,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct DynamicToolSpec {
+    pub name: String,
+    pub description: String,
+    pub input_schema: JsonValue,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "snake_case")]
 #[ts(export_to = "v2/")]
@@ -905,6 +914,8 @@ pub struct Model {
     pub description: String,
     pub supported_reasoning_efforts: Vec<ReasoningEffortOption>,
     pub default_reasoning_effort: ReasoningEffort,
+    #[serde(default)]
+    pub supports_personality: bool,
     // Only one model should be marked as default.
     pub is_default: bool,
 }
@@ -1088,6 +1099,7 @@ pub struct ThreadStartParams {
     pub developer_instructions: Option<String>,
     pub personality: Option<Personality>,
     pub ephemeral: Option<bool>,
+    pub dynamic_tools: Option<Vec<DynamicToolSpec>>,
     /// If true, opt into emitting raw response items on the event stream.
     ///
     /// This is for internal use only (e.g. Codex Cloud).
@@ -2372,6 +2384,25 @@ pub struct FileChangeRequestApprovalResponse {
     pub decision: FileChangeApprovalDecision,
 }
 
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct DynamicToolCallParams {
+    pub thread_id: String,
+    pub turn_id: String,
+    pub call_id: String,
+    pub tool: String,
+    pub arguments: JsonValue,
+}
+
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+#[ts(export_to = "v2/")]
+pub struct DynamicToolCallResponse {
+    pub output: String,
+    pub success: bool,
+}
+
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
 #[serde(rename_all = "camelCase")]
 #[ts(export_to = "v2/")]
diff --git a/codex-rs/app-server/README.md b/codex-rs/app-server/README.md
index 659e2bf72c..a4860ea512 100644
--- a/codex-rs/app-server/README.md
+++ b/codex-rs/app-server/README.md
@@ -114,7 +114,20 @@ Start a fresh thread when you need a new Codex conversation.
     "cwd": "/Users/me/project",
     "approvalPolicy": "never",
     "sandbox": "workspaceWrite",
-    "personality": "friendly"
+    "personality": "friendly",
+    "dynamicTools": [
+        {
+            "name": "lookup_ticket",
+            "description": "Fetch a ticket by id",
+            "inputSchema": {
+                "type": "object",
+                "properties": {
+                    "id": { "type": "string" }
+                },
+                "required": ["id"]
+            }
+        }
+    ],
 } }
 { "id": 10, "result": {
     "thread": {
diff --git a/codex-rs/app-server/src/bespoke_event_handling.rs b/codex-rs/app-server/src/bespoke_event_handling.rs
index 68e233b843..0cb6fb1bc6 100644
--- a/codex-rs/app-server/src/bespoke_event_handling.rs
+++ b/codex-rs/app-server/src/bespoke_event_handling.rs
@@ -25,6 +25,7 @@ use codex_app_server_protocol::CommandExecutionRequestApprovalResponse;
 use codex_app_server_protocol::CommandExecutionStatus;
 use codex_app_server_protocol::ContextCompactedNotification;
 use codex_app_server_protocol::DeprecationNoticeNotification;
+use codex_app_server_protocol::DynamicToolCallParams;
 use codex_app_server_protocol::ErrorNotification;
 use codex_app_server_protocol::ExecCommandApprovalParams;
 use codex_app_server_protocol::ExecCommandApprovalResponse;
@@ -85,6 +86,7 @@ use codex_core::protocol::TurnDiffEvent;
 use codex_core::review_format::format_review_findings_block;
 use codex_core::review_prompts;
 use codex_protocol::ThreadId;
+use codex_protocol::dynamic_tools::DynamicToolResponse as CoreDynamicToolResponse;
 use codex_protocol::plan_tool::UpdatePlanArgs;
 use codex_protocol::protocol::ReviewOutputEvent;
 use codex_protocol::request_user_input::RequestUserInputAnswer as CoreRequestUserInputAnswer;
@@ -318,6 +320,40 @@ pub(crate) async fn apply_bespoke_event_handling(
                 }
             }
         }
+        EventMsg::DynamicToolCallRequest(request) => {
+            if matches!(api_version, ApiVersion::V2) {
+                let call_id = request.call_id;
+                let params = DynamicToolCallParams {
+                    thread_id: conversation_id.to_string(),
+                    turn_id: request.turn_id,
+                    call_id: call_id.clone(),
+                    tool: request.tool,
+                    arguments: request.arguments,
+                };
+                let rx = outgoing
+                    .send_request(ServerRequestPayload::DynamicToolCall(params))
+                    .await;
+                tokio::spawn(async move {
+                    crate::dynamic_tools::on_call_response(call_id, rx, conversation).await;
+                });
+            } else {
+                error!(
+                    "dynamic tool calls are only supported on api v2 (call_id: {})",
+                    request.call_id
+                );
+                let call_id = request.call_id;
+                let _ = conversation
+                    .submit(Op::DynamicToolResponse {
+                        id: call_id.clone(),
+                        response: CoreDynamicToolResponse {
+                            call_id,
+                            output: "dynamic tool calls require api v2".to_string(),
+                            success: false,
+                        },
+                    })
+                    .await;
+            }
+        }
         // TODO(celia): properly construct McpToolCall TurnItem in core.
         EventMsg::McpToolCallBegin(begin_event) => {
             let notification = construct_mcp_tool_call_notification(
diff --git a/codex-rs/app-server/src/codex_message_processor.rs b/codex-rs/app-server/src/codex_message_processor.rs
index d0b8c7f949..ab2f31fc51 100644
--- a/codex-rs/app-server/src/codex_message_processor.rs
+++ b/codex-rs/app-server/src/codex_message_processor.rs
@@ -31,6 +31,7 @@ use codex_app_server_protocol::CollaborationModeListResponse;
 use codex_app_server_protocol::CommandExecParams;
 use codex_app_server_protocol::ConversationGitInfo;
 use codex_app_server_protocol::ConversationSummary;
+use codex_app_server_protocol::DynamicToolSpec as ApiDynamicToolSpec;
 use codex_app_server_protocol::ExecOneOffCommandResponse;
 use codex_app_server_protocol::FeedbackUploadParams;
 use codex_app_server_protocol::FeedbackUploadResponse;
@@ -171,6 +172,7 @@ 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::dynamic_tools::DynamicToolSpec as CoreDynamicToolSpec;
 use codex_protocol::items::TurnItem;
 use codex_protocol::models::ResponseItem;
 use codex_protocol::protocol::AgentStatus;
@@ -1411,35 +1413,81 @@ impl CodexMessageProcessor {
     }
 
     async fn thread_start(&mut self, request_id: RequestId, params: ThreadStartParams) {
+        let ThreadStartParams {
+            model,
+            model_provider,
+            cwd,
+            approval_policy,
+            sandbox,
+            config,
+            base_instructions,
+            developer_instructions,
+            dynamic_tools,
+            experimental_raw_events,
+            personality,
+            ephemeral,
+        } = params;
         let mut typesafe_overrides = self.build_thread_config_overrides(
-            params.model,
-            params.model_provider,
-            params.cwd,
-            params.approval_policy,
-            params.sandbox,
-            params.base_instructions,
-            params.developer_instructions,
-            params.personality,
+            model,
+            model_provider,
+            cwd,
+            approval_policy,
+            sandbox,
+            base_instructions,
+            developer_instructions,
+            personality,
         );
-        typesafe_overrides.ephemeral = Some(params.ephemeral.unwrap_or_default());
+        typesafe_overrides.ephemeral = ephemeral;
 
-        let config =
-            match derive_config_from_params(&self.cli_overrides, params.config, typesafe_overrides)
-                .await
-            {
-                Ok(config) => config,
-                Err(err) => {
-                    let error = JSONRPCErrorError {
-                        code: INVALID_REQUEST_ERROR_CODE,
-                        message: format!("error deriving config: {err}"),
-                        data: None,
-                    };
-                    self.outgoing.send_error(request_id, error).await;
-                    return;
-                }
-            };
+        let config = match derive_config_from_params(
+            &self.cli_overrides,
+            config,
+            typesafe_overrides,
+        )
+        .await
+        {
+            Ok(config) => config,
+            Err(err) => {
+                let error = JSONRPCErrorError {
+                    code: INVALID_REQUEST_ERROR_CODE,
+                    message: format!("error deriving config: {err}"),
+                    data: None,
+                };
+                self.outgoing.send_error(request_id, error).await;
+                return;
+            }
+        };
 
-        match self.thread_manager.start_thread(config).await {
+        let dynamic_tools = dynamic_tools.unwrap_or_default();
+        let core_dynamic_tools = if dynamic_tools.is_empty() {
+            Vec::new()
+        } else {
+            let snapshot = collect_mcp_snapshot(&config).await;
+            let mcp_tool_names = snapshot.tools.keys().cloned().collect::<HashSet<_>>();
+            if let Err(message) = validate_dynamic_tools(&dynamic_tools, &mcp_tool_names) {
+                let error = JSONRPCErrorError {
+                    code: INVALID_REQUEST_ERROR_CODE,
+                    message,
+                    data: None,
+                };
+                self.outgoing.send_error(request_id, error).await;
+                return;
+            }
+            dynamic_tools
+                .into_iter()
+                .map(|tool| CoreDynamicToolSpec {
+                    name: tool.name,
+                    description: tool.description,
+                    input_schema: tool.input_schema,
+                })
+                .collect()
+        };
+
+        match self
+            .thread_manager
+            .start_thread_with_tools(config, core_dynamic_tools)
+            .await
+        {
             Ok(new_conv) => {
                 let NewThread {
                     thread_id,
@@ -1489,7 +1537,7 @@ impl CodexMessageProcessor {
                 if let Err(err) = self
                     .attach_conversation_listener(
                         thread_id,
-                        params.experimental_raw_events,
+                        experimental_raw_events,
                         ApiVersion::V2,
                     )
                     .await
@@ -4322,6 +4370,41 @@ fn errors_to_info(
         .collect()
 }
 
+fn validate_dynamic_tools(
+    tools: &[ApiDynamicToolSpec],
+    mcp_tool_names: &HashSet<String>,
+) -> Result<(), String> {
+    let mut seen = HashSet::new();
+    for tool in tools {
+        let name = tool.name.trim();
+        if name.is_empty() {
+            return Err("dynamic tool name must not be empty".to_string());
+        }
+        if name != tool.name {
+            return Err(format!(
+                "dynamic tool name has leading/trailing whitespace: {}",
+                tool.name
+            ));
+        }
+        if name == "mcp" || name.starts_with("mcp__") {
+            return Err(format!("dynamic tool name is reserved: {name}"));
+        }
+        if mcp_tool_names.contains(name) {
+            return Err(format!("dynamic tool name conflicts with MCP tool: {name}"));
+        }
+        if !seen.insert(name.to_string()) {
+            return Err(format!("duplicate dynamic tool name: {name}"));
+        }
+
+        if let Err(err) = codex_core::parse_tool_input_schema(&tool.input_schema) {
+            return Err(format!(
+                "dynamic tool input schema is not supported for {name}: {err}"
+            ));
+        }
+    }
+    Ok(())
+}
+
 /// Derive the effective [`Config`] by layering three override sources.
 ///
 /// Precedence (lowest to highest):
@@ -4602,6 +4685,28 @@ mod tests {
     use serde_json::json;
     use tempfile::TempDir;
 
+    #[test]
+    fn validate_dynamic_tools_rejects_unsupported_input_schema() {
+        let tools = vec![ApiDynamicToolSpec {
+            name: "my_tool".to_string(),
+            description: "test".to_string(),
+            input_schema: json!({"type": "null"}),
+        }];
+        let err = validate_dynamic_tools(&tools, &HashSet::new()).expect_err("invalid schema");
+        assert!(err.contains("my_tool"), "unexpected error: {err}");
+    }
+
+    #[test]
+    fn validate_dynamic_tools_accepts_sanitizable_input_schema() {
+        let tools = vec![ApiDynamicToolSpec {
+            name: "my_tool".to_string(),
+            description: "test".to_string(),
+            // Missing `type` is common; core sanitizes these to a supported schema.
+            input_schema: json!({"properties": {}}),
+        }];
+        validate_dynamic_tools(&tools, &HashSet::new()).expect("valid schema");
+    }
+
     #[test]
     fn extract_conversation_summary_prefers_plain_user_messages() -> Result<()> {
         let conversation_id = ThreadId::from_string("3f941c35-29b3-493b-b0a4-e25800d9aeb0")?;
diff --git a/codex-rs/app-server/src/dynamic_tools.rs b/codex-rs/app-server/src/dynamic_tools.rs
new file mode 100644
index 0000000000..a1b424d0ee
--- /dev/null
+++ b/codex-rs/app-server/src/dynamic_tools.rs
@@ -0,0 +1,58 @@
+use codex_app_server_protocol::DynamicToolCallResponse;
+use codex_core::CodexThread;
+use codex_protocol::dynamic_tools::DynamicToolResponse as CoreDynamicToolResponse;
+use codex_protocol::protocol::Op;
+use std::sync::Arc;
+use tokio::sync::oneshot;
+use tracing::error;
+
+pub(crate) async fn on_call_response(
+    call_id: String,
+    receiver: oneshot::Receiver<serde_json::Value>,
+    conversation: Arc<CodexThread>,
+) {
+    let response = receiver.await;
+    let value = match response {
+        Ok(value) => value,
+        Err(err) => {
+            error!("request failed: {err:?}");
+            let fallback = CoreDynamicToolResponse {
+                call_id: call_id.clone(),
+                output: "dynamic tool request failed".to_string(),
+                success: false,
+            };
+            if let Err(err) = conversation
+                .submit(Op::DynamicToolResponse {
+                    id: call_id.clone(),
+                    response: fallback,
+                })
+                .await
+            {
+                error!("failed to submit DynamicToolResponse: {err}");
+            }
+            return;
+        }
+    };
+
+    let response = serde_json::from_value::<DynamicToolCallResponse>(value).unwrap_or_else(|err| {
+        error!("failed to deserialize DynamicToolCallResponse: {err}");
+        DynamicToolCallResponse {
+            output: "dynamic tool response was invalid".to_string(),
+            success: false,
+        }
+    });
+    let response = CoreDynamicToolResponse {
+        call_id: call_id.clone(),
+        output: response.output,
+        success: response.success,
+    };
+    if let Err(err) = conversation
+        .submit(Op::DynamicToolResponse {
+            id: call_id,
+            response,
+        })
+        .await
+    {
+        error!("failed to submit DynamicToolResponse: {err}");
+    }
+}
diff --git a/codex-rs/app-server/src/lib.rs b/codex-rs/app-server/src/lib.rs
index fde208106d..c6d943ae46 100644
--- a/codex-rs/app-server/src/lib.rs
+++ b/codex-rs/app-server/src/lib.rs
@@ -40,6 +40,7 @@ use tracing_subscriber::util::SubscriberInitExt;
 mod bespoke_event_handling;
 mod codex_message_processor;
 mod config_api;
+mod dynamic_tools;
 mod error_code;
 mod fuzzy_file_search;
 mod message_processor;
diff --git a/codex-rs/app-server/src/models.rs b/codex-rs/app-server/src/models.rs
index b0798b11ba..4189435c05 100644
--- a/codex-rs/app-server/src/models.rs
+++ b/codex-rs/app-server/src/models.rs
@@ -28,6 +28,7 @@ fn model_from_preset(preset: ModelPreset) -> Model {
             preset.supported_reasoning_efforts,
         ),
         default_reasoning_effort: preset.default_reasoning_effort,
+        supports_personality: preset.supports_personality,
         is_default: preset.is_default,
     }
 }
diff --git a/codex-rs/app-server/tests/suite/v2/dynamic_tools.rs b/codex-rs/app-server/tests/suite/v2/dynamic_tools.rs
new file mode 100644
index 0000000000..dc985ac49f
--- /dev/null
+++ b/codex-rs/app-server/tests/suite/v2/dynamic_tools.rs
@@ -0,0 +1,286 @@
+use anyhow::Context;
+use anyhow::Result;
+use app_test_support::McpProcess;
+use app_test_support::create_final_assistant_message_sse_response;
+use app_test_support::create_mock_responses_server_sequence_unchecked;
+use app_test_support::to_response;
+use codex_app_server_protocol::DynamicToolCallParams;
+use codex_app_server_protocol::DynamicToolCallResponse;
+use codex_app_server_protocol::DynamicToolSpec;
+use codex_app_server_protocol::JSONRPCResponse;
+use codex_app_server_protocol::RequestId;
+use codex_app_server_protocol::ServerRequest;
+use codex_app_server_protocol::ThreadStartParams;
+use codex_app_server_protocol::ThreadStartResponse;
+use codex_app_server_protocol::TurnStartParams;
+use codex_app_server_protocol::TurnStartResponse;
+use codex_app_server_protocol::UserInput as V2UserInput;
+use core_test_support::responses;
+use pretty_assertions::assert_eq;
+use serde_json::Value;
+use serde_json::json;
+use std::path::Path;
+use std::time::Duration;
+use tempfile::TempDir;
+use tokio::time::timeout;
+use wiremock::MockServer;
+
+const DEFAULT_READ_TIMEOUT: Duration = Duration::from_secs(10);
+
+/// Ensures dynamic tool specs are serialized into the model request payload.
+#[tokio::test]
+async fn thread_start_injects_dynamic_tools_into_model_requests() -> Result<()> {
+    let responses = vec![create_final_assistant_message_sse_response("Done")?];
+    let server = create_mock_responses_server_sequence_unchecked(responses).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??;
+
+    // Use a minimal JSON schema so we can assert the tool payload round-trips.
+    let input_schema = json!({
+        "type": "object",
+        "properties": {
+            "city": { "type": "string" }
+        },
+        "required": ["city"],
+        "additionalProperties": false,
+    });
+    let dynamic_tool = DynamicToolSpec {
+        name: "demo_tool".to_string(),
+        description: "Demo dynamic tool".to_string(),
+        input_schema: input_schema.clone(),
+    };
+
+    // Thread start injects dynamic tools into the thread's tool registry.
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            dynamic_tools: Some(vec![dynamic_tool.clone()]),
+            ..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)?;
+
+    // Start a turn so a model request is issued.
+    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(),
+            }],
+            ..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??;
+
+    // Inspect the captured model request to assert the tool spec made it through.
+    let bodies = responses_bodies(&server).await?;
+    let body = bodies
+        .first()
+        .context("expected at least one responses request")?;
+    let tool = find_tool(body, &dynamic_tool.name)
+        .context("expected dynamic tool to be injected into request")?;
+
+    assert_eq!(
+        tool.get("description"),
+        Some(&Value::String(dynamic_tool.description.clone()))
+    );
+    assert_eq!(tool.get("parameters"), Some(&input_schema));
+
+    Ok(())
+}
+
+/// Exercises the full dynamic tool call path (server request, client response, model output).
+#[tokio::test]
+async fn dynamic_tool_call_round_trip_sends_output_to_model() -> Result<()> {
+    let call_id = "dyn-call-1";
+    let tool_name = "demo_tool";
+    let tool_args = json!({ "city": "Paris" });
+    let tool_call_arguments = serde_json::to_string(&tool_args)?;
+
+    // First response triggers a dynamic tool call, second closes the turn.
+    let responses = vec![
+        responses::sse(vec![
+            responses::ev_response_created("resp-1"),
+            responses::ev_function_call(call_id, tool_name, &tool_call_arguments),
+            responses::ev_completed("resp-1"),
+        ]),
+        create_final_assistant_message_sse_response("Done")?,
+    ];
+    let server = create_mock_responses_server_sequence_unchecked(responses).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 dynamic_tool = DynamicToolSpec {
+        name: tool_name.to_string(),
+        description: "Demo dynamic tool".to_string(),
+        input_schema: json!({
+            "type": "object",
+            "properties": {
+                "city": { "type": "string" }
+            },
+            "required": ["city"],
+            "additionalProperties": false,
+        }),
+    };
+
+    let thread_req = mcp
+        .send_thread_start_request(ThreadStartParams {
+            dynamic_tools: Some(vec![dynamic_tool]),
+            ..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)?;
+
+    // Start a turn so the tool call is emitted.
+    let turn_req = mcp
+        .send_turn_start_request(TurnStartParams {
+            thread_id: thread.id.clone(),
+            input: vec![V2UserInput::Text {
+                text: "Run the tool".to_string(),
+                text_elements: Vec::new(),
+            }],
+            ..Default::default()
+        })
+        .await?;
+    let turn_resp: JSONRPCResponse = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_response_message(RequestId::Integer(turn_req)),
+    )
+    .await??;
+    let TurnStartResponse { turn } = to_response::<TurnStartResponse>(turn_resp)?;
+
+    // Read the tool call request from the app server.
+    let request = timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_request_message(),
+    )
+    .await??;
+    let (request_id, params) = match request {
+        ServerRequest::DynamicToolCall { request_id, params } => (request_id, params),
+        other => panic!("expected DynamicToolCall request, got {other:?}"),
+    };
+
+    let expected = DynamicToolCallParams {
+        thread_id: thread.id,
+        turn_id: turn.id,
+        call_id: call_id.to_string(),
+        tool: tool_name.to_string(),
+        arguments: tool_args.clone(),
+    };
+    assert_eq!(params, expected);
+
+    // Respond to the tool call so the model receives a function_call_output.
+    let response = DynamicToolCallResponse {
+        output: "dynamic-ok".to_string(),
+        success: true,
+    };
+    mcp.send_response(request_id, serde_json::to_value(response)?)
+        .await?;
+
+    timeout(
+        DEFAULT_READ_TIMEOUT,
+        mcp.read_stream_until_notification_message("turn/completed"),
+    )
+    .await??;
+
+    let bodies = responses_bodies(&server).await?;
+    let output = bodies
+        .iter()
+        .find_map(|body| function_call_output_text(body, call_id))
+        .context("expected function_call_output in follow-up request")?;
+    assert_eq!(output, "dynamic-ok");
+
+    Ok(())
+}
+
+async fn responses_bodies(server: &MockServer) -> Result<Vec<Value>> {
+    let requests = server
+        .received_requests()
+        .await
+        .context("failed to fetch received requests")?;
+
+    requests
+        .into_iter()
+        .filter(|req| req.url.path().ends_with("/responses"))
+        .map(|req| {
+            req.body_json::<Value>()
+                .context("request body should be JSON")
+        })
+        .collect()
+}
+
+fn find_tool<'a>(body: &'a Value, name: &str) -> Option<&'a Value> {
+    body.get("tools")
+        .and_then(Value::as_array)
+        .and_then(|tools| {
+            tools
+                .iter()
+                .find(|tool| tool.get("name").and_then(Value::as_str) == Some(name))
+        })
+}
+
+fn function_call_output_text(body: &Value, call_id: &str) -> Option<String> {
+    body.get("input")
+        .and_then(Value::as_array)
+        .and_then(|items| {
+            items.iter().find(|item| {
+                item.get("type").and_then(Value::as_str) == Some("function_call_output")
+                    && item.get("call_id").and_then(Value::as_str) == Some(call_id)
+            })
+        })
+        .and_then(|item| item.get("output"))
+        .and_then(Value::as_str)
+        .map(str::to_string)
+}
+
+fn create_config_toml(codex_home: &Path, server_uri: &str) -> std::io::Result<()> {
+    let config_toml = codex_home.join("config.toml");
+    std::fs::write(
+        config_toml,
+        format!(
+            r#"
+model = "mock-model"
+approval_policy = "never"
+sandbox_mode = "read-only"
+
+model_provider = "mock_provider"
+
+[model_providers.mock_provider]
+name = "Mock provider for test"
+base_url = "{server_uri}/v1"
+wire_api = "responses"
+request_max_retries = 0
+stream_max_retries = 0
+"#
+        ),
+    )
+}
diff --git a/codex-rs/app-server/tests/suite/v2/mod.rs b/codex-rs/app-server/tests/suite/v2/mod.rs
index 95ec61f20a..4d9e105147 100644
--- a/codex-rs/app-server/tests/suite/v2/mod.rs
+++ b/codex-rs/app-server/tests/suite/v2/mod.rs
@@ -3,6 +3,7 @@ mod analytics;
 mod app_list;
 mod collaboration_mode_list;
 mod config_rpc;
+mod dynamic_tools;
 mod initialize;
 mod model_list;
 mod output_schema;
diff --git a/codex-rs/app-server/tests/suite/v2/model_list.rs b/codex-rs/app-server/tests/suite/v2/model_list.rs
index c98da19345..a496e4a590 100644
--- a/codex-rs/app-server/tests/suite/v2/model_list.rs
+++ b/codex-rs/app-server/tests/suite/v2/model_list.rs
@@ -72,6 +72,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
                 },
             ],
             default_reasoning_effort: ReasoningEffort::Medium,
+            supports_personality: false,
             is_default: true,
         },
         Model {
@@ -99,6 +100,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
                 },
             ],
             default_reasoning_effort: ReasoningEffort::Medium,
+            supports_personality: false,
             is_default: false,
         },
         Model {
@@ -118,6 +120,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
                 },
             ],
             default_reasoning_effort: ReasoningEffort::Medium,
+            supports_personality: false,
             is_default: false,
         },
         Model {
@@ -151,6 +154,7 @@ async fn list_models_returns_all_models_with_large_limit() -> Result<()> {
                 },
             ],
             default_reasoning_effort: ReasoningEffort::Medium,
+            supports_personality: false,
             is_default: false,
         },
     ];
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 d375a2db2f..3abe73e2e9 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -433,7 +433,7 @@ async fn turn_start_accepts_personality_override_v2() -> Result<()> {
 
     let thread_req = mcp
         .send_thread_start_request(ThreadStartParams {
-            model: Some("gpt-5.2-codex".to_string()),
+            model: Some("exp-codex-personality".to_string()),
             ..Default::default()
         })
         .await?;
diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index 9fc2bae165..8a66fca0e1 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -38,6 +38,8 @@ use codex_protocol::approvals::ExecPolicyAmendment;
 use codex_protocol::config_types::ModeKind;
 use codex_protocol::config_types::Settings;
 use codex_protocol::config_types::WebSearchMode;
+use codex_protocol::dynamic_tools::DynamicToolResponse;
+use codex_protocol::dynamic_tools::DynamicToolSpec;
 use codex_protocol::items::TurnItem;
 use codex_protocol::items::UserMessageItem;
 use codex_protocol::models::BaseInstructions;
@@ -236,6 +238,7 @@ fn maybe_push_chat_wire_api_deprecation(
 
 impl Codex {
     /// Spawn a new [`Codex`] and initialize the session.
+    #[allow(clippy::too_many_arguments)]
     pub(crate) async fn spawn(
         config: Config,
         auth_manager: Arc<AuthManager>,
@@ -244,16 +247,12 @@ impl Codex {
         conversation_history: InitialHistory,
         session_source: SessionSource,
         agent_control: AgentControl,
+        dynamic_tools: Vec<DynamicToolSpec>,
     ) -> CodexResult<CodexSpawnOk> {
         let (tx_sub, rx_sub) = async_channel::bounded(SUBMISSION_CHANNEL_CAPACITY);
         let (tx_event, rx_event) = async_channel::unbounded();
 
         let loaded_skills = skills_manager.skills_for_config(&config);
-        // let loaded_skills = if config.features.enabled(Feature::Skills) {
-        //     Some(skills_manager.skills_for_config(&config))
-        // } else {
-        //     None
-        // };
 
         for err in &loaded_skills.errors {
             error!(
@@ -320,6 +319,7 @@ impl Codex {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             session_source,
+            dynamic_tools,
         };
 
         // Generate a unique ID for the lifetime of this Codex session.
@@ -443,6 +443,7 @@ pub(crate) struct TurnContext {
     pub(crate) codex_linux_sandbox_exe: Option<PathBuf>,
     pub(crate) tool_call_gate: Arc<ReadinessFlag>,
     pub(crate) truncation_policy: TruncationPolicy,
+    pub(crate) dynamic_tools: Vec<DynamicToolSpec>,
 }
 
 impl TurnContext {
@@ -500,6 +501,7 @@ pub(crate) struct SessionConfiguration {
     original_config_do_not_use: Arc<Config>,
     /// Source of the session (cli, vscode, exec, mcp, ...)
     session_source: SessionSource,
+    dynamic_tools: Vec<DynamicToolSpec>,
 }
 
 impl SessionConfiguration {
@@ -616,6 +618,7 @@ impl Session {
             codex_linux_sandbox_exe: per_turn_config.codex_linux_sandbox_exe.clone(),
             tool_call_gate: Arc::new(ReadinessFlag::new()),
             truncation_policy: model_info.truncation_policy.into(),
+            dynamic_tools: session_configuration.dynamic_tools.clone(),
         }
     }
 
@@ -1495,6 +1498,27 @@ impl Session {
         }
     }
 
+    pub async fn notify_dynamic_tool_response(&self, call_id: &str, response: DynamicToolResponse) {
+        let entry = {
+            let mut active = self.active_turn.lock().await;
+            match active.as_mut() {
+                Some(at) => {
+                    let mut ts = at.turn_state.lock().await;
+                    ts.remove_pending_dynamic_tool(call_id)
+                }
+                None => None,
+            }
+        };
+        match entry {
+            Some(tx_response) => {
+                tx_response.send(response).ok();
+            }
+            None => {
+                warn!("No pending dynamic tool call found for call_id: {call_id}");
+            }
+        }
+    }
+
     pub async fn notify_approval(&self, sub_id: &str, decision: ReviewDecision) {
         let entry = {
             let mut active = self.active_turn.lock().await;
@@ -2156,6 +2180,9 @@ async fn submission_loop(sess: Arc<Session>, config: Arc<Config>, rx_sub: Receiv
             Op::UserInputAnswer { id, response } => {
                 handlers::request_user_input_response(&sess, id, response).await;
             }
+            Op::DynamicToolResponse { id, response } => {
+                handlers::dynamic_tool_response(&sess, id, response).await;
+            }
             Op::AddToHistory { text } => {
                 handlers::add_to_history(&sess, &config, text).await;
             }
@@ -2252,6 +2279,7 @@ mod handlers {
     use codex_protocol::config_types::CollaborationMode;
     use codex_protocol::config_types::ModeKind;
     use codex_protocol::config_types::Settings;
+    use codex_protocol::dynamic_tools::DynamicToolResponse;
     use codex_protocol::user_input::UserInput;
     use codex_rmcp_client::ElicitationAction;
     use codex_rmcp_client::ElicitationResponse;
@@ -2489,6 +2517,14 @@ mod handlers {
         sess.notify_user_input_response(&id, response).await;
     }
 
+    pub async fn dynamic_tool_response(
+        sess: &Arc<Session>,
+        id: String,
+        response: DynamicToolResponse,
+    ) {
+        sess.notify_dynamic_tool_response(&id, response).await;
+    }
+
     pub async fn add_to_history(sess: &Arc<Session>, config: &Arc<Config>, text: String) {
         let id = sess.conversation_id;
         let config = Arc::clone(config);
@@ -2826,6 +2862,7 @@ async fn spawn_review_thread(
         final_output_json_schema: None,
         codex_linux_sandbox_exe: parent_turn_context.codex_linux_sandbox_exe.clone(),
         tool_call_gate: Arc::new(ReadinessFlag::new()),
+        dynamic_tools: parent_turn_context.dynamic_tools.clone(),
         truncation_policy: model_info.truncation_policy.into(),
     };
 
@@ -3162,6 +3199,7 @@ async fn run_sampling_request(
                 .map(|(name, tool)| (name, tool.tool))
                 .collect(),
         ),
+        turn_context.dynamic_tools.as_slice(),
     ));
 
     let model_supports_parallel = turn_context
@@ -3942,6 +3980,7 @@ mod tests {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             session_source: SessionSource::Exec,
+            dynamic_tools: Vec::new(),
         };
 
         let mut state = SessionState::new(session_configuration);
@@ -4021,6 +4060,7 @@ mod tests {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             session_source: SessionSource::Exec,
+            dynamic_tools: Vec::new(),
         };
 
         let mut state = SessionState::new(session_configuration);
@@ -4284,6 +4324,7 @@ mod tests {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             session_source: SessionSource::Exec,
+            dynamic_tools: Vec::new(),
         };
         let per_turn_config = Session::build_per_turn_config(&session_configuration);
         let model_info = ModelsManager::construct_model_info_offline(
@@ -4392,6 +4433,7 @@ mod tests {
             cwd: config.cwd.clone(),
             original_config_do_not_use: Arc::clone(&config),
             session_source: SessionSource::Exec,
+            dynamic_tools: Vec::new(),
         };
         let per_turn_config = Session::build_per_turn_config(&session_configuration);
         let model_info = ModelsManager::construct_model_info_offline(
@@ -4712,6 +4754,7 @@ mod tests {
                     .map(|(name, tool)| (name, tool.tool))
                     .collect(),
             ),
+            turn_context.dynamic_tools.as_slice(),
         );
         let item = ResponseItem::CustomToolCall {
             id: None,
diff --git a/codex-rs/core/src/codex_delegate.rs b/codex-rs/core/src/codex_delegate.rs
index 9a94f988d5..5e1de2ef1f 100644
--- a/codex-rs/core/src/codex_delegate.rs
+++ b/codex-rs/core/src/codex_delegate.rs
@@ -57,6 +57,7 @@ pub(crate) async fn run_codex_thread_interactive(
         initial_history.unwrap_or(InitialHistory::New),
         SessionSource::SubAgent(SubAgentSource::Review),
         parent_session.services.agent_control.clone(),
+        Vec::new(),
     )
     .await?;
     let codex = Arc::new(codex);
diff --git a/codex-rs/core/src/config/edit.rs b/codex-rs/core/src/config/edit.rs
index 9c12272d94..b99fde92bf 100644
--- a/codex-rs/core/src/config/edit.rs
+++ b/codex-rs/core/src/config/edit.rs
@@ -4,6 +4,7 @@ use crate::config::types::Notice;
 use crate::path_utils::resolve_symlink_write_paths;
 use crate::path_utils::write_atomically;
 use anyhow::Context;
+use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::TrustLevel;
 use codex_protocol::openai_models::ReasoningEffort;
 use std::collections::BTreeMap;
@@ -24,6 +25,8 @@ pub enum ConfigEdit {
         model: Option<String>,
         effort: Option<ReasoningEffort>,
     },
+    /// Update the active (or default) model personality.
+    SetModelPersonality { personality: Option<Personality> },
     /// Toggle the acknowledgement flag under `[notice]`.
     SetNoticeHideFullAccessWarning(bool),
     /// Toggle the Windows world-writable directories warning acknowledgement flag.
@@ -269,6 +272,10 @@ impl ConfigDocument {
                 );
                 mutated
             }),
+            ConfigEdit::SetModelPersonality { personality } => Ok(self.write_profile_value(
+                &["model_personality"],
+                personality.map(|personality| value(personality.to_string())),
+            )),
             ConfigEdit::SetNoticeHideFullAccessWarning(acknowledged) => Ok(self.write_value(
                 Scope::Global,
                 &[Notice::TABLE_KEY, "hide_full_access_warning"],
@@ -712,6 +719,12 @@ impl ConfigEditsBuilder {
         self
     }
 
+    pub fn set_model_personality(mut self, personality: Option<Personality>) -> Self {
+        self.edits
+            .push(ConfigEdit::SetModelPersonality { personality });
+        self
+    }
+
     pub fn set_hide_full_access_warning(mut self, acknowledged: bool) -> Self {
         self.edits
             .push(ConfigEdit::SetNoticeHideFullAccessWarning(acknowledged));
diff --git a/codex-rs/core/src/lib.rs b/codex-rs/core/src/lib.rs
index 2042e330ef..7e1d80ace5 100644
--- a/codex-rs/core/src/lib.rs
+++ b/codex-rs/core/src/lib.rs
@@ -126,6 +126,7 @@ pub use safety::get_platform_sandbox;
 pub use safety::is_windows_elevated_sandbox_enabled;
 pub use safety::set_windows_elevated_sandbox_enabled;
 pub use safety::set_windows_sandbox_enabled;
+pub use tools::spec::parse_tool_input_schema;
 // Re-export the protocol types from the standalone `codex-protocol` crate so existing
 // `codex_core::protocol::...` references continue to work across the workspace.
 pub use codex_protocol::protocol;
diff --git a/codex-rs/core/src/models_manager/model_info.rs b/codex-rs/core/src/models_manager/model_info.rs
index 8fb77e29e4..c07c144c11 100644
--- a/codex-rs/core/src/models_manager/model_info.rs
+++ b/codex-rs/core/src/models_manager/model_info.rs
@@ -169,6 +169,16 @@ pub(crate) fn find_model_info_for_slug(slug: &str) -> ModelInfo {
         model_info!(
             slug,
             base_instructions: GPT_5_2_CODEX_INSTRUCTIONS.to_string(),
+            model_instructions_template: Some(ModelInstructionsTemplate {
+                template: GPT_5_2_CODEX_INSTRUCTIONS_TEMPLATE.to_string(),
+                personality_messages: Some(PersonalityMessages(BTreeMap::from([(
+                    Personality::Friendly,
+                    PERSONALITY_FRIENDLY.to_string(),
+                ), (
+                    Personality::Pragmatic,
+                    PERSONALITY_PRAGMATIC.to_string(),
+                )]))),
+            }),
             apply_patch_tool_type: Some(ApplyPatchToolType::Freeform),
             shell_type: ConfigShellToolType::ShellCommand,
             supports_parallel_tool_calls: true,
@@ -203,16 +213,6 @@ pub(crate) fn find_model_info_for_slug(slug: &str) -> ModelInfo {
             truncation_policy: TruncationPolicyConfig::tokens(10_000),
             context_window: Some(CONTEXT_WINDOW_272K),
             supported_reasoning_levels: supported_reasoning_level_low_medium_high_xhigh(),
-            model_instructions_template: Some(ModelInstructionsTemplate {
-                template: GPT_5_2_CODEX_INSTRUCTIONS_TEMPLATE.to_string(),
-                personality_messages: Some(PersonalityMessages(BTreeMap::from([(
-                    Personality::Friendly,
-                    PERSONALITY_FRIENDLY.to_string(),
-                ), (
-                    Personality::Pragmatic,
-                    PERSONALITY_PRAGMATIC.to_string(),
-                )]))),
-            }),
         )
     } else if slug.starts_with("gpt-5.1-codex-max") {
         model_info!(
diff --git a/codex-rs/core/src/models_manager/model_presets.rs b/codex-rs/core/src/models_manager/model_presets.rs
index e60b229ec7..a8f4931f8d 100644
--- a/codex-rs/core/src/models_manager/model_presets.rs
+++ b/codex-rs/core/src/models_manager/model_presets.rs
@@ -36,6 +36,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Extra high reasoning depth for complex problems".to_string(),
                 },
             ],
+            supports_personality: true,
             is_default: true,
             upgrade: None,
             show_in_picker: true,
@@ -65,6 +66,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Extra high reasoning depth for complex problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: true,
@@ -87,6 +89,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                         .to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: true,
@@ -116,6 +119,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Extra high reasoning depth for complex problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: true,
@@ -145,6 +149,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Extra high reasoning depth for complex problems".to_string(),
                 },
             ],
+            supports_personality: true,
             is_default: false,
             upgrade: None,
             show_in_picker: false,
@@ -174,6 +179,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Extra high reasoning depth for complex problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: None,
             show_in_picker: false,
@@ -200,6 +206,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Maximizes reasoning depth for complex or ambiguous problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: false,
@@ -221,6 +228,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Maximizes reasoning depth for complex or ambiguous problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: false,
@@ -247,6 +255,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                         .to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: false,
@@ -276,6 +285,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Maximizes reasoning depth for complex or ambiguous problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: false,
@@ -301,6 +311,7 @@ static PRESETS: Lazy<Vec<ModelPreset>> = Lazy::new(|| {
                     description: "Maximizes reasoning depth for complex or ambiguous problems".to_string(),
                 },
             ],
+            supports_personality: false,
             is_default: false,
             upgrade: Some(gpt_52_codex_upgrade()),
             show_in_picker: false,
diff --git a/codex-rs/core/src/rollout/policy.rs b/codex-rs/core/src/rollout/policy.rs
index 2d4a79cc22..2d263c0539 100644
--- a/codex-rs/core/src/rollout/policy.rs
+++ b/codex-rs/core/src/rollout/policy.rs
@@ -68,6 +68,7 @@ pub(crate) fn should_persist_event_msg(ev: &EventMsg) -> bool {
         | EventMsg::ExecCommandEnd(_)
         | EventMsg::ExecApprovalRequest(_)
         | EventMsg::RequestUserInput(_)
+        | EventMsg::DynamicToolCallRequest(_)
         | EventMsg::ElicitationRequest(_)
         | EventMsg::ApplyPatchApprovalRequest(_)
         | EventMsg::BackgroundEvent(_)
diff --git a/codex-rs/core/src/state/turn.rs b/codex-rs/core/src/state/turn.rs
index 66e2f694e9..ccc50d066b 100644
--- a/codex-rs/core/src/state/turn.rs
+++ b/codex-rs/core/src/state/turn.rs
@@ -8,6 +8,7 @@ use tokio::sync::Notify;
 use tokio_util::sync::CancellationToken;
 use tokio_util::task::AbortOnDropHandle;
 
+use codex_protocol::dynamic_tools::DynamicToolResponse;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::request_user_input::RequestUserInputResponse;
 use tokio::sync::oneshot;
@@ -70,6 +71,7 @@ impl ActiveTurn {
 pub(crate) struct TurnState {
     pending_approvals: HashMap<String, oneshot::Sender<ReviewDecision>>,
     pending_user_input: HashMap<String, oneshot::Sender<RequestUserInputResponse>>,
+    pending_dynamic_tools: HashMap<String, oneshot::Sender<DynamicToolResponse>>,
     pending_input: Vec<ResponseInputItem>,
 }
 
@@ -92,6 +94,7 @@ impl TurnState {
     pub(crate) fn clear_pending(&mut self) {
         self.pending_approvals.clear();
         self.pending_user_input.clear();
+        self.pending_dynamic_tools.clear();
         self.pending_input.clear();
     }
 
@@ -110,6 +113,21 @@ impl TurnState {
         self.pending_user_input.remove(key)
     }
 
+    pub(crate) fn insert_pending_dynamic_tool(
+        &mut self,
+        key: String,
+        tx: oneshot::Sender<DynamicToolResponse>,
+    ) -> Option<oneshot::Sender<DynamicToolResponse>> {
+        self.pending_dynamic_tools.insert(key, tx)
+    }
+
+    pub(crate) fn remove_pending_dynamic_tool(
+        &mut self,
+        key: &str,
+    ) -> Option<oneshot::Sender<DynamicToolResponse>> {
+        self.pending_dynamic_tools.remove(key)
+    }
+
     pub(crate) fn push_pending_input(&mut self, input: ResponseInputItem) {
         self.pending_input.push(input);
     }
diff --git a/codex-rs/core/src/thread_manager.rs b/codex-rs/core/src/thread_manager.rs
index bc5cd4f19e..9b633ded37 100644
--- a/codex-rs/core/src/thread_manager.rs
+++ b/codex-rs/core/src/thread_manager.rs
@@ -196,12 +196,21 @@ impl ThreadManager {
     }
 
     pub async fn start_thread(&self, config: Config) -> CodexResult<NewThread> {
+        self.start_thread_with_tools(config, Vec::new()).await
+    }
+
+    pub async fn start_thread_with_tools(
+        &self,
+        config: Config,
+        dynamic_tools: Vec<codex_protocol::dynamic_tools::DynamicToolSpec>,
+    ) -> CodexResult<NewThread> {
         self.state
             .spawn_thread(
                 config,
                 InitialHistory::New,
                 Arc::clone(&self.state.auth_manager),
                 self.agent_control(),
+                dynamic_tools,
             )
             .await
     }
@@ -224,7 +233,13 @@ impl ThreadManager {
         auth_manager: Arc<AuthManager>,
     ) -> CodexResult<NewThread> {
         self.state
-            .spawn_thread(config, initial_history, auth_manager, self.agent_control())
+            .spawn_thread(
+                config,
+                initial_history,
+                auth_manager,
+                self.agent_control(),
+                Vec::new(),
+            )
             .await
     }
 
@@ -262,6 +277,7 @@ impl ThreadManager {
                 history,
                 Arc::clone(&self.state.auth_manager),
                 self.agent_control(),
+                Vec::new(),
             )
             .await
     }
@@ -330,6 +346,7 @@ impl ThreadManagerState {
             Arc::clone(&self.auth_manager),
             agent_control,
             session_source,
+            Vec::new(),
         )
         .await
     }
@@ -341,6 +358,7 @@ impl ThreadManagerState {
         initial_history: InitialHistory,
         auth_manager: Arc<AuthManager>,
         agent_control: AgentControl,
+        dynamic_tools: Vec<codex_protocol::dynamic_tools::DynamicToolSpec>,
     ) -> CodexResult<NewThread> {
         self.spawn_thread_with_source(
             config,
@@ -348,6 +366,7 @@ impl ThreadManagerState {
             auth_manager,
             agent_control,
             self.session_source.clone(),
+            dynamic_tools,
         )
         .await
     }
@@ -359,6 +378,7 @@ impl ThreadManagerState {
         auth_manager: Arc<AuthManager>,
         agent_control: AgentControl,
         session_source: SessionSource,
+        dynamic_tools: Vec<codex_protocol::dynamic_tools::DynamicToolSpec>,
     ) -> CodexResult<NewThread> {
         let CodexSpawnOk {
             codex, thread_id, ..
@@ -370,6 +390,7 @@ impl ThreadManagerState {
             initial_history,
             session_source,
             agent_control,
+            dynamic_tools,
         )
         .await?;
         self.finalize_thread_spawn(codex, thread_id).await
diff --git a/codex-rs/core/src/tools/handlers/dynamic.rs b/codex-rs/core/src/tools/handlers/dynamic.rs
new file mode 100644
index 0000000000..a68c70b98d
--- /dev/null
+++ b/codex-rs/core/src/tools/handlers/dynamic.rs
@@ -0,0 +1,98 @@
+use crate::codex::Session;
+use crate::codex::TurnContext;
+use crate::function_tool::FunctionCallError;
+use crate::tools::context::ToolInvocation;
+use crate::tools::context::ToolOutput;
+use crate::tools::context::ToolPayload;
+use crate::tools::handlers::parse_arguments;
+use crate::tools::registry::ToolHandler;
+use crate::tools::registry::ToolKind;
+use async_trait::async_trait;
+use codex_protocol::dynamic_tools::DynamicToolCallRequest;
+use codex_protocol::dynamic_tools::DynamicToolResponse;
+use codex_protocol::protocol::EventMsg;
+use serde_json::Value;
+use tokio::sync::oneshot;
+use tracing::warn;
+
+pub struct DynamicToolHandler;
+
+#[async_trait]
+impl ToolHandler for DynamicToolHandler {
+    fn kind(&self) -> ToolKind {
+        ToolKind::Function
+    }
+
+    async fn is_mutating(&self, _invocation: &ToolInvocation) -> bool {
+        true
+    }
+
+    async fn handle(&self, invocation: ToolInvocation) -> Result<ToolOutput, FunctionCallError> {
+        let ToolInvocation {
+            session,
+            turn,
+            call_id,
+            tool_name,
+            payload,
+            ..
+        } = invocation;
+
+        let arguments = match payload {
+            ToolPayload::Function { arguments } => arguments,
+            _ => {
+                return Err(FunctionCallError::RespondToModel(
+                    "dynamic tool handler received unsupported payload".to_string(),
+                ));
+            }
+        };
+
+        let args: Value = parse_arguments(&arguments)?;
+        let response = request_dynamic_tool(&session, turn.as_ref(), call_id, tool_name, args)
+            .await
+            .ok_or_else(|| {
+                FunctionCallError::RespondToModel(
+                    "dynamic tool call was cancelled before receiving a response".to_string(),
+                )
+            })?;
+
+        Ok(ToolOutput::Function {
+            content: response.output,
+            content_items: None,
+            success: Some(response.success),
+        })
+    }
+}
+
+async fn request_dynamic_tool(
+    session: &Session,
+    turn_context: &TurnContext,
+    call_id: String,
+    tool: String,
+    arguments: Value,
+) -> Option<DynamicToolResponse> {
+    let _sub_id = turn_context.sub_id.clone();
+    let (tx_response, rx_response) = oneshot::channel();
+    let event_id = call_id.clone();
+    let prev_entry = {
+        let mut active = session.active_turn.lock().await;
+        match active.as_mut() {
+            Some(at) => {
+                let mut ts = at.turn_state.lock().await;
+                ts.insert_pending_dynamic_tool(call_id.clone(), tx_response)
+            }
+            None => None,
+        }
+    };
+    if prev_entry.is_some() {
+        warn!("Overwriting existing pending dynamic tool call for call_id: {event_id}");
+    }
+
+    let event = EventMsg::DynamicToolCallRequest(DynamicToolCallRequest {
+        call_id,
+        turn_id: turn_context.sub_id.clone(),
+        tool,
+        arguments,
+    });
+    session.send_event(turn_context, event).await;
+    rx_response.await.ok()
+}
diff --git a/codex-rs/core/src/tools/handlers/mod.rs b/codex-rs/core/src/tools/handlers/mod.rs
index 8b63c9567f..a00c6eba51 100644
--- a/codex-rs/core/src/tools/handlers/mod.rs
+++ b/codex-rs/core/src/tools/handlers/mod.rs
@@ -1,5 +1,6 @@
 pub mod apply_patch;
 pub(crate) mod collab;
+mod dynamic;
 mod grep_files;
 mod list_dir;
 mod mcp;
@@ -18,6 +19,7 @@ use serde::Deserialize;
 use crate::function_tool::FunctionCallError;
 pub use apply_patch::ApplyPatchHandler;
 pub use collab::CollabHandler;
+pub use dynamic::DynamicToolHandler;
 pub use grep_files::GrepFilesHandler;
 pub use list_dir::ListDirHandler;
 pub use mcp::McpHandler;
diff --git a/codex-rs/core/src/tools/router.rs b/codex-rs/core/src/tools/router.rs
index 2bc19ddd03..b1f41923bc 100644
--- a/codex-rs/core/src/tools/router.rs
+++ b/codex-rs/core/src/tools/router.rs
@@ -10,6 +10,7 @@ use crate::tools::registry::ConfiguredToolSpec;
 use crate::tools::registry::ToolRegistry;
 use crate::tools::spec::ToolsConfig;
 use crate::tools::spec::build_specs;
+use codex_protocol::dynamic_tools::DynamicToolSpec;
 use codex_protocol::models::LocalShellAction;
 use codex_protocol::models::ResponseInputItem;
 use codex_protocol::models::ResponseItem;
@@ -34,8 +35,9 @@ impl ToolRouter {
     pub fn from_config(
         config: &ToolsConfig,
         mcp_tools: Option<HashMap<String, mcp_types::Tool>>,
+        dynamic_tools: &[DynamicToolSpec],
     ) -> Self {
-        let builder = build_specs(config, mcp_tools);
+        let builder = build_specs(config, mcp_tools, dynamic_tools);
         let (specs, registry) = builder.build();
 
         Self { registry, specs }
diff --git a/codex-rs/core/src/tools/spec.rs b/codex-rs/core/src/tools/spec.rs
index e330d93a03..c3ff4354a8 100644
--- a/codex-rs/core/src/tools/spec.rs
+++ b/codex-rs/core/src/tools/spec.rs
@@ -10,6 +10,7 @@ use crate::tools::handlers::collab::DEFAULT_WAIT_TIMEOUT_MS;
 use crate::tools::handlers::collab::MAX_WAIT_TIMEOUT_MS;
 use crate::tools::registry::ToolRegistryBuilder;
 use codex_protocol::config_types::WebSearchMode;
+use codex_protocol::dynamic_tools::DynamicToolSpec;
 use codex_protocol::models::VIEW_IMAGE_TOOL_NAME;
 use codex_protocol::openai_models::ApplyPatchToolType;
 use codex_protocol::openai_models::ConfigShellToolType;
@@ -87,7 +88,7 @@ impl ToolsConfig {
 /// Generic JSON‑Schema subset needed for our tool definitions
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 #[serde(tag = "type", rename_all = "lowercase")]
-pub(crate) enum JsonSchema {
+pub enum JsonSchema {
     Boolean {
         #[serde(skip_serializing_if = "Option::is_none")]
         description: Option<String>,
@@ -123,7 +124,7 @@ pub(crate) enum JsonSchema {
 /// Whether additional properties are allowed, and if so, any required schema
 #[derive(Debug, Clone, Serialize, Deserialize, PartialEq)]
 #[serde(untagged)]
-pub(crate) enum AdditionalProperties {
+pub enum AdditionalProperties {
     Boolean(bool),
     Schema(Box<JsonSchema>),
 }
@@ -1101,6 +1102,26 @@ pub(crate) fn mcp_tool_to_openai_tool(
     })
 }
 
+fn dynamic_tool_to_openai_tool(
+    tool: &DynamicToolSpec,
+) -> Result<ResponsesApiTool, serde_json::Error> {
+    let input_schema = parse_tool_input_schema(&tool.input_schema)?;
+
+    Ok(ResponsesApiTool {
+        name: tool.name.clone(),
+        description: tool.description.clone(),
+        strict: false,
+        parameters: input_schema,
+    })
+}
+
+/// Parse the tool input_schema or return an error for invalid schema
+pub fn parse_tool_input_schema(input_schema: &JsonValue) -> Result<JsonSchema, serde_json::Error> {
+    let mut input_schema = input_schema.clone();
+    sanitize_json_schema(&mut input_schema);
+    serde_json::from_value::<JsonSchema>(input_schema)
+}
+
 /// Sanitize a JSON Schema (as serde_json::Value) so it can fit our limited
 /// JsonSchema enum. This function:
 /// - Ensures every schema object has a "type". If missing, infers it from
@@ -1216,9 +1237,11 @@ fn sanitize_json_schema(value: &mut JsonValue) {
 pub(crate) fn build_specs(
     config: &ToolsConfig,
     mcp_tools: Option<HashMap<String, mcp_types::Tool>>,
+    dynamic_tools: &[DynamicToolSpec],
 ) -> ToolRegistryBuilder {
     use crate::tools::handlers::ApplyPatchHandler;
     use crate::tools::handlers::CollabHandler;
+    use crate::tools::handlers::DynamicToolHandler;
     use crate::tools::handlers::GrepFilesHandler;
     use crate::tools::handlers::ListDirHandler;
     use crate::tools::handlers::McpHandler;
@@ -1239,6 +1262,7 @@ pub(crate) fn build_specs(
     let unified_exec_handler = Arc::new(UnifiedExecHandler);
     let plan_handler = Arc::new(PlanHandler);
     let apply_patch_handler = Arc::new(ApplyPatchHandler);
+    let dynamic_tool_handler = Arc::new(DynamicToolHandler);
     let view_image_handler = Arc::new(ViewImageHandler);
     let mcp_handler = Arc::new(McpHandler);
     let mcp_resource_handler = Arc::new(McpResourceHandler);
@@ -1384,6 +1408,23 @@ pub(crate) fn build_specs(
         }
     }
 
+    if !dynamic_tools.is_empty() {
+        for tool in dynamic_tools {
+            match dynamic_tool_to_openai_tool(tool) {
+                Ok(converted_tool) => {
+                    builder.push_spec(ToolSpec::Function(converted_tool));
+                    builder.register_handler(tool.name.clone(), dynamic_tool_handler.clone());
+                }
+                Err(e) => {
+                    tracing::error!(
+                        "Failed to convert dynamic tool {:?} to OpenAI tool: {e:?}",
+                        tool.name
+                    );
+                }
+            }
+        }
+    }
+
     builder
 }
 
@@ -1496,7 +1537,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Live),
         });
-        let (tools, _) = build_specs(&config, None).build();
+        let (tools, _) = build_specs(&config, None, &[]).build();
 
         // Build actual map name -> spec
         use std::collections::BTreeMap;
@@ -1560,7 +1601,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Cached),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
         assert_contains_tool_names(
             &tools,
             &["spawn_agent", "send_input", "wait", "close_agent"],
@@ -1578,7 +1619,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Cached),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
         assert!(
             !tools.iter().any(|t| t.spec.name() == "request_user_input"),
             "request_user_input should be disabled when collaboration_modes feature is off"
@@ -1590,7 +1631,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Cached),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
         assert_contains_tool_names(&tools, &["request_user_input"]);
     }
 
@@ -1607,7 +1648,7 @@ mod tests {
             features,
             web_search_mode,
         });
-        let (tools, _) = build_specs(&tools_config, Some(HashMap::new())).build();
+        let (tools, _) = build_specs(&tools_config, Some(HashMap::new()), &[]).build();
         let tool_names = tools.iter().map(|t| t.spec.name()).collect::<Vec<_>>();
         assert_eq!(&tool_names, &expected_tools,);
     }
@@ -1623,7 +1664,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Cached),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
 
         let tool = find_tool(&tools, "web_search");
         assert_eq!(
@@ -1645,7 +1686,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Live),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
 
         let tool = find_tool(&tools, "web_search");
         assert_eq!(
@@ -1891,7 +1932,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Live),
         });
-        let (tools, _) = build_specs(&tools_config, Some(HashMap::new())).build();
+        let (tools, _) = build_specs(&tools_config, Some(HashMap::new()), &[]).build();
 
         // Only check the shell variant and a couple of core tools.
         let mut subset = vec!["exec_command", "write_stdin", "update_plan"];
@@ -1913,7 +1954,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Cached),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
 
         assert!(!find_tool(&tools, "exec_command").supports_parallel_tool_calls);
         assert!(!find_tool(&tools, "write_stdin").supports_parallel_tool_calls);
@@ -1932,7 +1973,7 @@ mod tests {
             features: &features,
             web_search_mode: Some(WebSearchMode::Cached),
         });
-        let (tools, _) = build_specs(&tools_config, None).build();
+        let (tools, _) = build_specs(&tools_config, None, &[]).build();
 
         assert!(
             tools
@@ -1999,6 +2040,7 @@ mod tests {
                     description: Some("Do something cool".to_string()),
                 },
             )])),
+            &[],
         )
         .build();
 
@@ -2108,7 +2150,7 @@ mod tests {
             ),
         ]);
 
-        let (tools, _) = build_specs(&tools_config, Some(tools_map)).build();
+        let (tools, _) = build_specs(&tools_config, Some(tools_map), &[]).build();
 
         // Only assert that the MCP tools themselves are sorted by fully-qualified name.
         let mcp_names: Vec<_> = tools
@@ -2157,6 +2199,7 @@ mod tests {
                     description: Some("Search docs".to_string()),
                 },
             )])),
+            &[],
         )
         .build();
 
@@ -2212,6 +2255,7 @@ mod tests {
                     description: Some("Pagination".to_string()),
                 },
             )])),
+            &[],
         )
         .build();
 
@@ -2266,6 +2310,7 @@ mod tests {
                     description: Some("Tags".to_string()),
                 },
             )])),
+            &[],
         )
         .build();
 
@@ -2322,6 +2367,7 @@ mod tests {
                     description: Some("AnyOf Value".to_string()),
                 },
             )])),
+            &[],
         )
         .build();
 
@@ -2459,6 +2505,7 @@ Examples of valid command strings:
                     description: Some("Do something cool".to_string()),
                 },
             )])),
+            &[],
         )
         .build();
 
diff --git a/codex-rs/core/tests/suite/list_models.rs b/codex-rs/core/tests/suite/list_models.rs
index 1791d28b01..f6db54af7b 100644
--- a/codex-rs/core/tests/suite/list_models.rs
+++ b/codex-rs/core/tests/suite/list_models.rs
@@ -94,6 +94,7 @@ fn gpt_52_codex() -> ModelPreset {
                 "Extra high reasoning depth for complex problems",
             ),
         ],
+        supports_personality: false,
         is_default: true,
         upgrade: None,
         show_in_picker: true,
@@ -126,6 +127,7 @@ fn gpt_5_1_codex_max() -> ModelPreset {
                 "Extra high reasoning depth for complex problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5.1-codex-max",
@@ -160,6 +162,7 @@ fn gpt_5_1_codex_mini() -> ModelPreset {
                 "Maximizes reasoning depth for complex or ambiguous problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5.1-codex-mini",
@@ -204,6 +207,7 @@ fn gpt_5_2() -> ModelPreset {
                 "Extra high reasoning for complex problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5.2",
@@ -246,6 +250,7 @@ fn bengalfox() -> ModelPreset {
                 "Extra high reasoning depth for complex problems",
             ),
         ],
+        supports_personality: true,
         is_default: false,
         upgrade: None,
         show_in_picker: false,
@@ -278,6 +283,7 @@ fn boomslang() -> ModelPreset {
                 "Extra high reasoning depth for complex problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: None,
         show_in_picker: false,
@@ -306,6 +312,7 @@ fn gpt_5_codex() -> ModelPreset {
                 "Maximizes reasoning depth for complex or ambiguous problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5-codex",
@@ -340,6 +347,7 @@ fn gpt_5_codex_mini() -> ModelPreset {
                 "Maximizes reasoning depth for complex or ambiguous problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5-codex-mini",
@@ -378,6 +386,7 @@ fn gpt_5_1_codex() -> ModelPreset {
                 "Maximizes reasoning depth for complex or ambiguous problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5.1-codex",
@@ -420,6 +429,7 @@ fn gpt_5() -> ModelPreset {
                 "Maximizes reasoning depth for complex or ambiguous problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5",
@@ -458,6 +468,7 @@ fn gpt_5_1() -> ModelPreset {
                 "Maximizes reasoning depth for complex or ambiguous problems",
             ),
         ],
+        supports_personality: false,
         is_default: false,
         upgrade: Some(gpt52_codex_upgrade(
             "gpt-5.1",
diff --git a/codex-rs/core/tests/suite/personality.rs b/codex-rs/core/tests/suite/personality.rs
index c17994cbca..410ca08e4e 100644
--- a/codex-rs/core/tests/suite/personality.rs
+++ b/codex-rs/core/tests/suite/personality.rs
@@ -122,7 +122,7 @@ async fn config_personality_some_sets_instructions_template() -> anyhow::Result<
     let server = start_mock_server().await;
     let resp_mock = mount_sse_once(&server, sse_completed("resp-1")).await;
     let mut builder = test_codex()
-        .with_model("gpt-5.2-codex")
+        .with_model("exp-codex-personality")
         .with_config(|config| {
             config.model_personality = Some(Personality::Friendly);
             config.features.disable(Feature::RemoteModels);
@@ -179,7 +179,7 @@ async fn user_turn_personality_some_adds_update_message() -> anyhow::Result<()>
     )
     .await;
     let mut builder = test_codex()
-        .with_model("gpt-5.2-codex")
+        .with_model("exp-codex-personality")
         .with_config(|config| {
             config.features.disable(Feature::RemoteModels);
         });
diff --git a/codex-rs/docs/codex_mcp_interface.md b/codex-rs/docs/codex_mcp_interface.md
index 1aa5aa12ae..2c8e124c1f 100644
--- a/codex-rs/docs/codex_mcp_interface.md
+++ b/codex-rs/docs/codex_mcp_interface.md
@@ -94,6 +94,7 @@ Each response yields:
     - `reasoningEffort` – one of `minimal|low|medium|high`
     - `description` – human-friendly label for the effort
   - `defaultReasoningEffort` – suggested effort for the UI
+  - `supportsPersonality` – whether the model supports personality-specific instructions
   - `isDefault` – whether the model is recommended for most users
 - `nextCursor` – pass into the next request to continue paging (optional)
 
diff --git a/codex-rs/exec/src/event_processor_with_human_output.rs b/codex-rs/exec/src/event_processor_with_human_output.rs
index c4a5c27d9c..76c22caa75 100644
--- a/codex-rs/exec/src/event_processor_with_human_output.rs
+++ b/codex-rs/exec/src/event_processor_with_human_output.rs
@@ -607,7 +607,8 @@ impl EventProcessor for EventProcessorWithHumanOutput {
             | EventMsg::UndoCompleted(_)
             | EventMsg::UndoStarted(_)
             | EventMsg::ThreadRolledBack(_)
-            | EventMsg::RequestUserInput(_) => {}
+            | EventMsg::RequestUserInput(_)
+            | EventMsg::DynamicToolCallRequest(_) => {}
         }
         CodexStatus::Running
     }
diff --git a/codex-rs/mcp-server/src/codex_tool_runner.rs b/codex-rs/mcp-server/src/codex_tool_runner.rs
index b400b4cc79..dcaf8a89e6 100644
--- a/codex-rs/mcp-server/src/codex_tool_runner.rs
+++ b/codex-rs/mcp-server/src/codex_tool_runner.rs
@@ -360,6 +360,7 @@ async fn run_codex_tool_session_inner(
                     | EventMsg::UndoCompleted(_)
                     | EventMsg::ExitedReviewMode(_)
                     | EventMsg::RequestUserInput(_)
+                    | EventMsg::DynamicToolCallRequest(_)
                     | EventMsg::ContextCompacted(_)
                     | EventMsg::ThreadRolledBack(_)
                     | EventMsg::CollabAgentSpawnBegin(_)
diff --git a/codex-rs/protocol/src/config_types.rs b/codex-rs/protocol/src/config_types.rs
index ae956797ea..ba6b12aadf 100644
--- a/codex-rs/protocol/src/config_types.rs
+++ b/codex-rs/protocol/src/config_types.rs
@@ -2,6 +2,7 @@ use schemars::JsonSchema;
 use serde::Deserialize;
 use serde::Serialize;
 use strum_macros::Display;
+use strum_macros::EnumIter;
 use ts_rs::TS;
 
 use crate::openai_models::ReasoningEffort;
@@ -78,6 +79,7 @@ pub enum SandboxMode {
     TS,
     PartialOrd,
     Ord,
+    EnumIter,
 )]
 #[serde(rename_all = "lowercase")]
 #[strum(serialize_all = "lowercase")]
diff --git a/codex-rs/protocol/src/dynamic_tools.rs b/codex-rs/protocol/src/dynamic_tools.rs
new file mode 100644
index 0000000000..e55d372d8e
--- /dev/null
+++ b/codex-rs/protocol/src/dynamic_tools.rs
@@ -0,0 +1,30 @@
+use schemars::JsonSchema;
+use serde::Deserialize;
+use serde::Serialize;
+use serde_json::Value as JsonValue;
+use ts_rs::TS;
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct DynamicToolSpec {
+    pub name: String,
+    pub description: String,
+    pub input_schema: JsonValue,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct DynamicToolCallRequest {
+    pub call_id: String,
+    pub turn_id: String,
+    pub tool: String,
+    pub arguments: JsonValue,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, JsonSchema, TS)]
+#[serde(rename_all = "camelCase")]
+pub struct DynamicToolResponse {
+    pub call_id: String,
+    pub output: String,
+    pub success: bool,
+}
diff --git a/codex-rs/protocol/src/lib.rs b/codex-rs/protocol/src/lib.rs
index 69d09da089..60b01bbd73 100644
--- a/codex-rs/protocol/src/lib.rs
+++ b/codex-rs/protocol/src/lib.rs
@@ -4,6 +4,7 @@ pub use thread_id::ThreadId;
 pub mod approvals;
 pub mod config_types;
 pub mod custom_prompts;
+pub mod dynamic_tools;
 pub mod items;
 pub mod message_history;
 pub mod models;
diff --git a/codex-rs/protocol/src/openai_models.rs b/codex-rs/protocol/src/openai_models.rs
index ac030a303b..3f29484ffd 100644
--- a/codex-rs/protocol/src/openai_models.rs
+++ b/codex-rs/protocol/src/openai_models.rs
@@ -78,6 +78,9 @@ pub struct ModelPreset {
     pub default_reasoning_effort: ReasoningEffort,
     /// Supported reasoning effort options.
     pub supported_reasoning_efforts: Vec<ReasoningEffortPreset>,
+    /// Whether this model supports personality-specific instructions.
+    #[serde(default)]
+    pub supports_personality: bool,
     /// Whether this is the default model for new users.
     pub is_default: bool,
     /// recommended upgrade model
@@ -214,6 +217,12 @@ impl ModelInfo {
         })
     }
 
+    pub fn supports_personality(&self) -> bool {
+        self.model_instructions_template
+            .as_ref()
+            .is_some_and(ModelInstructionsTemplate::supports_personality)
+    }
+
     pub fn get_model_instructions(&self, personality: Option<Personality>) -> String {
         if let Some(personality) = personality
             && let Some(template) = &self.model_instructions_template
@@ -249,6 +258,13 @@ impl ModelInstructionsTemplate {
     fn has_personality_placeholder(&self) -> bool {
         self.template.contains(PERSONALITY_PLACEHOLDER)
     }
+
+    fn supports_personality(&self) -> bool {
+        self.has_personality_placeholder()
+            && self.personality_messages.as_ref().is_some_and(|messages| {
+                Personality::iter().all(|personality| messages.0.contains_key(&personality))
+            })
+    }
 }
 
 // serializes as a dictionary from personality to message
@@ -280,6 +296,7 @@ pub struct ModelsResponse {
 // convert ModelInfo to ModelPreset
 impl From<ModelInfo> for ModelPreset {
     fn from(info: ModelInfo) -> Self {
+        let supports_personality = info.supports_personality();
         ModelPreset {
             id: info.slug.clone(),
             model: info.slug.clone(),
@@ -289,6 +306,7 @@ impl From<ModelInfo> for ModelPreset {
                 .default_reasoning_level
                 .unwrap_or(ReasoningEffort::None),
             supported_reasoning_efforts: info.supported_reasoning_levels.clone(),
+            supports_personality,
             is_default: false, // default is the highest priority available model
             upgrade: info.upgrade.as_ref().map(|upgrade| ModelUpgrade {
                 id: upgrade.model.clone(),
diff --git a/codex-rs/protocol/src/protocol.rs b/codex-rs/protocol/src/protocol.rs
index 7bf3c90eab..e9cb8147d7 100644
--- a/codex-rs/protocol/src/protocol.rs
+++ b/codex-rs/protocol/src/protocol.rs
@@ -17,6 +17,8 @@ use crate::config_types::CollaborationMode;
 use crate::config_types::Personality;
 use crate::config_types::ReasoningSummary as ReasoningSummaryConfig;
 use crate::custom_prompts::CustomPrompt;
+use crate::dynamic_tools::DynamicToolCallRequest;
+use crate::dynamic_tools::DynamicToolResponse;
 use crate::items::TurnItem;
 use crate::message_history::HistoryEntry;
 use crate::models::BaseInstructions;
@@ -216,6 +218,14 @@ pub enum Op {
         response: RequestUserInputResponse,
     },
 
+    /// Resolve a dynamic tool call request.
+    DynamicToolResponse {
+        /// Call id for the in-flight request.
+        id: String,
+        /// Tool output payload.
+        response: DynamicToolResponse,
+    },
+
     /// Append an entry to the persistent cross-session message history.
     ///
     /// Note the entry is not guaranteed to be logged if the user has
@@ -750,6 +760,8 @@ pub enum EventMsg {
 
     RequestUserInput(RequestUserInputEvent),
 
+    DynamicToolCallRequest(DynamicToolCallRequest),
+
     ElicitationRequest(ElicitationRequestEvent),
 
     ApplyPatchApprovalRequest(ApplyPatchApprovalRequestEvent),
diff --git a/codex-rs/tui/src/app.rs b/codex-rs/tui/src/app.rs
index 1d53f5d70d..d3185adf34 100644
--- a/codex-rs/tui/src/app.rs
+++ b/codex-rs/tui/src/app.rs
@@ -60,6 +60,7 @@ use codex_core::protocol::SkillErrorInfo;
 use codex_core::protocol::TokenUsage;
 use codex_otel::OtelManager;
 use codex_protocol::ThreadId;
+use codex_protocol::config_types::Personality;
 use codex_protocol::items::TurnItem;
 use codex_protocol::openai_models::ModelPreset;
 use codex_protocol::openai_models::ModelUpgrade;
@@ -932,14 +933,10 @@ impl App {
 
         let auth = auth_manager.auth().await;
         let auth_ref = auth.as_ref();
-        let model_info = thread_manager
-            .get_models_manager()
-            .get_model_info(model.as_str(), &config)
-            .await;
         let otel_manager = OtelManager::new(
             ThreadId::new(),
             model.as_str(),
-            model_info.slug.as_str(),
+            model.as_str(),
             auth_ref.and_then(CodexAuth::get_account_id),
             auth_ref.and_then(CodexAuth::get_account_email),
             auth_ref.map(|auth| auth.mode),
@@ -1505,6 +1502,9 @@ impl App {
             AppEvent::UpdateCollaborationMode(mask) => {
                 self.chat_widget.set_collaboration_mask(mask);
             }
+            AppEvent::UpdatePersonality(personality) => {
+                self.on_update_personality(personality);
+            }
             AppEvent::OpenReasoningPopup { model } => {
                 self.chat_widget.open_reasoning_popup(model);
             }
@@ -1758,6 +1758,41 @@ impl App {
                     }
                 }
             }
+            AppEvent::PersistPersonalitySelection { personality } => {
+                let profile = self.active_profile.as_deref();
+                match ConfigEditsBuilder::new(&self.config.codex_home)
+                    .with_profile(profile)
+                    .set_model_personality(Some(personality))
+                    .apply()
+                    .await
+                {
+                    Ok(()) => {
+                        let label = Self::personality_label(personality);
+                        let mut message = format!("Personality set to {label}");
+                        if let Some(profile) = profile {
+                            message.push_str(" for ");
+                            message.push_str(profile);
+                            message.push_str(" profile");
+                        }
+                        self.chat_widget.add_info_message(message, None);
+                    }
+                    Err(err) => {
+                        tracing::error!(
+                            error = %err,
+                            "failed to persist personality selection"
+                        );
+                        if let Some(profile) = profile {
+                            self.chat_widget.add_error_message(format!(
+                                "Failed to save personality for profile `{profile}`: {err}"
+                            ));
+                        } else {
+                            self.chat_widget.add_error_message(format!(
+                                "Failed to save default personality: {err}"
+                            ));
+                        }
+                    }
+                }
+            }
             AppEvent::UpdateAskForApprovalPolicy(policy) => {
                 self.runtime_approval_policy_override = Some(policy);
                 if let Err(err) = self.config.approval_policy.set(policy) {
@@ -2074,9 +2109,23 @@ impl App {
                 return Ok(());
             }
         };
+        let config_snapshot = thread.config_snapshot().await;
         let event = Event {
             id: String::new(),
-            msg: EventMsg::SessionConfigured(self.session_configured_for_thread(thread_id)),
+            msg: EventMsg::SessionConfigured(SessionConfiguredEvent {
+                session_id: thread_id,
+                forked_from_id: None,
+                model: config_snapshot.model,
+                model_provider_id: config_snapshot.model_provider_id,
+                approval_policy: config_snapshot.approval_policy,
+                sandbox_policy: config_snapshot.sandbox_policy,
+                cwd: config_snapshot.cwd,
+                reasoning_effort: config_snapshot.reasoning_effort,
+                history_log_id: 0,
+                history_entry_count: 0,
+                initial_messages: None,
+                rollout_path: thread.rollout_path(),
+            }),
         };
         let channel =
             ThreadEventChannel::new_with_session_configured(THREAD_EVENT_CHANNEL_CAPACITY, event);
@@ -2106,33 +2155,6 @@ impl App {
         Ok(())
     }
 
-    fn session_configured_for_thread(&self, thread_id: ThreadId) -> SessionConfiguredEvent {
-        let mut session_configured =
-            self.primary_session_configured
-                .clone()
-                .unwrap_or_else(|| SessionConfiguredEvent {
-                    session_id: thread_id,
-                    forked_from_id: None,
-                    model: self.chat_widget.current_model().to_string(),
-                    model_provider_id: self.config.model_provider_id.clone(),
-                    approval_policy: *self.config.approval_policy.get(),
-                    sandbox_policy: self.config.sandbox_policy.get().clone(),
-                    cwd: self.config.cwd.clone(),
-                    reasoning_effort: None,
-                    history_log_id: 0,
-                    history_entry_count: 0,
-                    initial_messages: None,
-                    rollout_path: Some(PathBuf::new()),
-                });
-        session_configured.session_id = thread_id;
-        session_configured.forked_from_id = None;
-        session_configured.history_log_id = 0;
-        session_configured.history_entry_count = 0;
-        session_configured.initial_messages = None;
-        session_configured.rollout_path = Some(PathBuf::new());
-        session_configured
-    }
-
     fn reasoning_label(reasoning_effort: Option<ReasoningEffortConfig>) -> &'static str {
         match reasoning_effort {
             Some(ReasoningEffortConfig::Minimal) => "minimal",
@@ -2162,6 +2184,18 @@ impl App {
         self.chat_widget.set_reasoning_effort(effort);
     }
 
+    fn on_update_personality(&mut self, personality: Personality) {
+        self.config.model_personality = Some(personality);
+        self.chat_widget.set_personality(personality);
+    }
+
+    fn personality_label(personality: Personality) -> &'static str {
+        match personality {
+            Personality::Friendly => "Friendly",
+            Personality::Pragmatic => "Pragmatic",
+        }
+    }
+
     async fn launch_external_editor(&mut self, tui: &mut tui::Tui) {
         let editor_cmd = match external_editor::resolve_editor_command() {
             Ok(cmd) => cmd,
diff --git a/codex-rs/tui/src/app_event.rs b/codex-rs/tui/src/app_event.rs
index 9a2d979f1c..f1ec28f3f1 100644
--- a/codex-rs/tui/src/app_event.rs
+++ b/codex-rs/tui/src/app_event.rs
@@ -24,6 +24,7 @@ use codex_core::features::Feature;
 use codex_core::protocol::AskForApproval;
 use codex_core::protocol::SandboxPolicy;
 use codex_protocol::config_types::CollaborationModeMask;
+use codex_protocol::config_types::Personality;
 use codex_protocol::openai_models::ReasoningEffort;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -106,12 +107,20 @@ pub(crate) enum AppEvent {
     /// Update the active collaboration mask in the running app and widget.
     UpdateCollaborationMode(CollaborationModeMask),
 
+    /// Update the current personality in the running app and widget.
+    UpdatePersonality(Personality),
+
     /// Persist the selected model and reasoning effort to the appropriate config.
     PersistModelSelection {
         model: String,
         effort: Option<ReasoningEffort>,
     },
 
+    /// Persist the selected personality to the appropriate config.
+    PersistPersonalitySelection {
+        personality: Personality,
+    },
+
     /// Open the reasoning selection popup after picking a model.
     OpenReasoningPopup {
         model: ModelPreset,
diff --git a/codex-rs/tui/src/bottom_pane/chat_composer.rs b/codex-rs/tui/src/bottom_pane/chat_composer.rs
index d1f8d691a2..c4fba97f65 100644
--- a/codex-rs/tui/src/bottom_pane/chat_composer.rs
+++ b/codex-rs/tui/src/bottom_pane/chat_composer.rs
@@ -235,6 +235,7 @@ pub(crate) struct ChatComposer {
     steer_enabled: bool,
     collaboration_modes_enabled: bool,
     collaboration_mode_indicator: Option<CollaborationModeIndicator>,
+    personality_command_enabled: bool,
 }
 
 #[derive(Clone, Debug)]
@@ -296,6 +297,7 @@ impl ChatComposer {
             steer_enabled: false,
             collaboration_modes_enabled: false,
             collaboration_mode_indicator: None,
+            personality_command_enabled: false,
         };
         // Apply configuration via the setter to keep side-effects centralized.
         this.set_disable_paste_burst(disable_paste_burst);
@@ -327,6 +329,10 @@ impl ChatComposer {
         self.collaboration_mode_indicator = indicator;
     }
 
+    pub fn set_personality_command_enabled(&mut self, enabled: bool) {
+        self.personality_command_enabled = enabled;
+    }
+
     fn layout_areas(&self, area: Rect) -> [Rect; 3] {
         let footer_props = self.footer_props();
         let footer_hint_height = self
@@ -1631,9 +1637,11 @@ impl ChatComposer {
         if let Some((name, _rest, _rest_offset)) = parse_slash_name(&text) {
             let treat_as_plain_text = input_starts_with_space || name.contains('/');
             if !treat_as_plain_text {
-                let is_builtin =
-                    Self::built_in_slash_commands_for_input(self.collaboration_modes_enabled)
-                        .any(|(command_name, _)| command_name == name);
+                let is_builtin = Self::built_in_slash_commands_for_input(
+                    self.collaboration_modes_enabled,
+                    self.personality_command_enabled,
+                )
+                .any(|(command_name, _)| command_name == name);
                 let prompt_prefix = format!("{PROMPTS_CMD_PREFIX}:");
                 let is_known_prompt = name
                     .strip_prefix(&prompt_prefix)
@@ -1798,9 +1806,11 @@ impl ChatComposer {
         let first_line = self.textarea.text().lines().next().unwrap_or("");
         if let Some((name, rest, _rest_offset)) = parse_slash_name(first_line)
             && rest.is_empty()
-            && let Some((_n, cmd)) =
-                Self::built_in_slash_commands_for_input(self.collaboration_modes_enabled)
-                    .find(|(n, _)| *n == name)
+            && let Some((_n, cmd)) = Self::built_in_slash_commands_for_input(
+                self.collaboration_modes_enabled,
+                self.personality_command_enabled,
+            )
+            .find(|(n, _)| *n == name)
         {
             self.textarea.set_text_clearing_elements("");
             Some(InputResult::Command(cmd))
@@ -1820,9 +1830,11 @@ impl ChatComposer {
             if let Some((name, rest, _rest_offset)) = parse_slash_name(&text)
                 && !rest.is_empty()
                 && !name.contains('/')
-                && let Some((_n, cmd)) =
-                    Self::built_in_slash_commands_for_input(self.collaboration_modes_enabled)
-                        .find(|(command_name, _)| *command_name == name)
+                && let Some((_n, cmd)) = Self::built_in_slash_commands_for_input(
+                    self.collaboration_modes_enabled,
+                    self.personality_command_enabled,
+                )
+                .find(|(command_name, _)| *command_name == name)
                 && cmd == SlashCommand::Review
             {
                 self.textarea.set_text_clearing_elements("");
@@ -2253,9 +2265,11 @@ impl ChatComposer {
             return rest_after_name.is_empty();
         }
 
-        let builtin_match =
-            Self::built_in_slash_commands_for_input(self.collaboration_modes_enabled)
-                .any(|(cmd_name, _)| fuzzy_match(cmd_name, name).is_some());
+        let builtin_match = Self::built_in_slash_commands_for_input(
+            self.collaboration_modes_enabled,
+            self.personality_command_enabled,
+        )
+        .any(|(cmd_name, _)| fuzzy_match(cmd_name, name).is_some());
 
         if builtin_match {
             return true;
@@ -2308,10 +2322,12 @@ impl ChatComposer {
             _ => {
                 if is_editing_slash_command_name {
                     let collaboration_modes_enabled = self.collaboration_modes_enabled;
+                    let personality_command_enabled = self.personality_command_enabled;
                     let mut command_popup = CommandPopup::new(
                         self.custom_prompts.clone(),
                         CommandPopupFlags {
                             collaboration_modes_enabled,
+                            personality_command_enabled,
                         },
                     );
                     command_popup.on_composer_text_change(first_line.to_string());
@@ -2323,12 +2339,16 @@ impl ChatComposer {
 
     fn built_in_slash_commands_for_input(
         collaboration_modes_enabled: bool,
+        personality_command_enabled: bool,
     ) -> impl Iterator<Item = (&'static str, SlashCommand)> {
         let allow_elevate_sandbox = windows_degraded_sandbox_active();
         built_in_slash_commands()
             .into_iter()
             .filter(move |(_, cmd)| allow_elevate_sandbox || *cmd != SlashCommand::ElevateSandbox)
             .filter(move |(_, cmd)| collaboration_modes_enabled || *cmd != SlashCommand::Collab)
+            .filter(move |(_, cmd)| {
+                personality_command_enabled || *cmd != SlashCommand::Personality
+            })
     }
 
     pub(crate) fn set_custom_prompts(&mut self, prompts: Vec<CustomPrompt>) {
diff --git a/codex-rs/tui/src/bottom_pane/command_popup.rs b/codex-rs/tui/src/bottom_pane/command_popup.rs
index f2c178dfa2..d0805707fa 100644
--- a/codex-rs/tui/src/bottom_pane/command_popup.rs
+++ b/codex-rs/tui/src/bottom_pane/command_popup.rs
@@ -39,6 +39,7 @@ pub(crate) struct CommandPopup {
 #[derive(Clone, Copy, Debug, Default)]
 pub(crate) struct CommandPopupFlags {
     pub(crate) collaboration_modes_enabled: bool,
+    pub(crate) personality_command_enabled: bool,
 }
 
 impl CommandPopup {
@@ -48,6 +49,9 @@ impl CommandPopup {
             .into_iter()
             .filter(|(_, cmd)| allow_elevate_sandbox || *cmd != SlashCommand::ElevateSandbox)
             .filter(|(_, cmd)| flags.collaboration_modes_enabled || *cmd != SlashCommand::Collab)
+            .filter(|(_, cmd)| {
+                flags.personality_command_enabled || *cmd != SlashCommand::Personality
+            })
             .collect();
         // Exclude prompts that collide with builtin command names and sort by name.
         let exclude: HashSet<String> = builtins.iter().map(|(n, _)| (*n).to_string()).collect();
@@ -216,6 +220,7 @@ impl CommandPopup {
                     display_shortcut: None,
                     description: Some(description),
                     wrap_indent: None,
+                    is_disabled: false,
                     disabled_reason: None,
                 }
             })
@@ -466,6 +471,7 @@ mod tests {
             Vec::new(),
             CommandPopupFlags {
                 collaboration_modes_enabled: true,
+                personality_command_enabled: true,
             },
         );
         popup.on_composer_text_change("/collab".to_string());
@@ -475,4 +481,46 @@ mod tests {
             other => panic!("expected collab to be selected for exact match, got {other:?}"),
         }
     }
+
+    #[test]
+    fn personality_command_hidden_when_disabled() {
+        let mut popup = CommandPopup::new(
+            Vec::new(),
+            CommandPopupFlags {
+                collaboration_modes_enabled: true,
+                personality_command_enabled: false,
+            },
+        );
+        popup.on_composer_text_change("/pers".to_string());
+
+        let cmds: Vec<&str> = popup
+            .filtered_items()
+            .into_iter()
+            .filter_map(|item| match item {
+                CommandItem::Builtin(cmd) => Some(cmd.command()),
+                CommandItem::UserPrompt(_) => None,
+            })
+            .collect();
+        assert!(
+            !cmds.contains(&"personality"),
+            "expected '/personality' to be hidden when disabled, got {cmds:?}"
+        );
+    }
+
+    #[test]
+    fn personality_command_visible_when_enabled() {
+        let mut popup = CommandPopup::new(
+            Vec::new(),
+            CommandPopupFlags {
+                collaboration_modes_enabled: true,
+                personality_command_enabled: true,
+            },
+        );
+        popup.on_composer_text_change("/personality".to_string());
+
+        match popup.selected_item() {
+            Some(CommandItem::Builtin(cmd)) => assert_eq!(cmd.command(), "personality"),
+            other => panic!("expected personality to be selected for exact match, got {other:?}"),
+        }
+    }
 }
diff --git a/codex-rs/tui/src/bottom_pane/file_search_popup.rs b/codex-rs/tui/src/bottom_pane/file_search_popup.rs
index 48de1cff54..e0a0cc2f49 100644
--- a/codex-rs/tui/src/bottom_pane/file_search_popup.rs
+++ b/codex-rs/tui/src/bottom_pane/file_search_popup.rs
@@ -132,6 +132,7 @@ impl WidgetRef for &FileSearchPopup {
                     display_shortcut: None,
                     description: None,
                     wrap_indent: None,
+                    is_disabled: false,
                     disabled_reason: None,
                 })
                 .collect()
diff --git a/codex-rs/tui/src/bottom_pane/list_selection_view.rs b/codex-rs/tui/src/bottom_pane/list_selection_view.rs
index 40787a9c25..7591b99326 100644
--- a/codex-rs/tui/src/bottom_pane/list_selection_view.rs
+++ b/codex-rs/tui/src/bottom_pane/list_selection_view.rs
@@ -42,6 +42,7 @@ pub(crate) struct SelectionItem {
     pub selected_description: Option<String>,
     pub is_current: bool,
     pub is_default: bool,
+    pub is_disabled: bool,
     pub actions: Vec<SelectionAction>,
     pub dismiss_on_select: bool,
     pub search_value: Option<String>,
@@ -217,12 +218,14 @@ impl ListSelectionView {
                         .flatten()
                         .or_else(|| item.description.clone());
                     let wrap_indent = description.is_none().then_some(wrap_prefix_width);
+                    let is_disabled = item.is_disabled || item.disabled_reason.is_some();
                     GenericDisplayRow {
                         name: display_name,
                         display_shortcut: item.display_shortcut,
                         match_indices: None,
                         description,
                         wrap_indent,
+                        is_disabled,
                         disabled_reason: item.disabled_reason.clone(),
                     }
                 })
@@ -247,19 +250,27 @@ impl ListSelectionView {
     }
 
     fn accept(&mut self) {
-        if let Some(idx) = self.state.selected_idx
-            && let Some(actual_idx) = self.filtered_indices.get(idx)
-            && let Some(item) = self.items.get(*actual_idx)
+        let selected_item = self
+            .state
+            .selected_idx
+            .and_then(|idx| self.filtered_indices.get(idx))
+            .and_then(|actual_idx| self.items.get(*actual_idx));
+        if let Some(item) = selected_item
             && item.disabled_reason.is_none()
+            && !item.is_disabled
         {
-            self.last_selected_actual_idx = Some(*actual_idx);
+            if let Some(idx) = self.state.selected_idx
+                && let Some(actual_idx) = self.filtered_indices.get(idx)
+            {
+                self.last_selected_actual_idx = Some(*actual_idx);
+            }
             for act in &item.actions {
                 act(&self.app_event_tx);
             }
             if item.dismiss_on_select {
                 self.complete = true;
             }
-        } else {
+        } else if selected_item.is_none() {
             self.complete = true;
         }
     }
@@ -286,7 +297,7 @@ impl ListSelectionView {
                 && self
                     .items
                     .get(*actual_idx)
-                    .is_some_and(|item| item.disabled_reason.is_some())
+                    .is_some_and(|item| item.disabled_reason.is_some() || item.is_disabled)
             {
                 self.state.move_down_wrap(len);
             } else {
@@ -303,7 +314,7 @@ impl ListSelectionView {
                 && self
                     .items
                     .get(*actual_idx)
-                    .is_some_and(|item| item.disabled_reason.is_some())
+                    .is_some_and(|item| item.disabled_reason.is_some() || item.is_disabled)
             {
                 self.state.move_up_wrap(len);
             } else {
@@ -395,7 +406,7 @@ impl BottomPaneView for ListSelectionView {
                     && self
                         .items
                         .get(idx)
-                        .is_some_and(|item| item.disabled_reason.is_none())
+                        .is_some_and(|item| item.disabled_reason.is_none() && !item.is_disabled)
                 {
                     self.state.selected_idx = Some(idx);
                     self.accept();
diff --git a/codex-rs/tui/src/bottom_pane/mod.rs b/codex-rs/tui/src/bottom_pane/mod.rs
index e772a60215..a570bfb384 100644
--- a/codex-rs/tui/src/bottom_pane/mod.rs
+++ b/codex-rs/tui/src/bottom_pane/mod.rs
@@ -215,6 +215,11 @@ impl BottomPane {
         self.request_redraw();
     }
 
+    pub fn set_personality_command_enabled(&mut self, enabled: bool) {
+        self.composer.set_personality_command_enabled(enabled);
+        self.request_redraw();
+    }
+
     pub fn status_widget(&self) -> Option<&StatusIndicatorWidget> {
         self.status.as_ref()
     }
diff --git a/codex-rs/tui/src/bottom_pane/selection_popup_common.rs b/codex-rs/tui/src/bottom_pane/selection_popup_common.rs
index c1675b01aa..c9ca076d60 100644
--- a/codex-rs/tui/src/bottom_pane/selection_popup_common.rs
+++ b/codex-rs/tui/src/bottom_pane/selection_popup_common.rs
@@ -23,7 +23,8 @@ pub(crate) struct GenericDisplayRow {
     pub match_indices: Option<Vec<usize>>, // indices to bold (char positions)
     pub description: Option<String>,       // optional grey text after the name
     pub disabled_reason: Option<String>,   // optional disabled message
-    pub wrap_indent: Option<usize>,        // optional indent for wrapped lines
+    pub is_disabled: bool,
+    pub wrap_indent: Option<usize>, // optional indent for wrapped lines
 }
 
 pub(crate) fn wrap_styled_line<'a>(line: &'a Line<'a>, width: u16) -> Vec<Line<'a>> {
@@ -282,13 +283,18 @@ pub(crate) fn render_rows(
         }
 
         let mut full_line = build_full_line(row, desc_col);
-        if Some(i) == state.selected_idx {
+        if Some(i) == state.selected_idx && !row.is_disabled {
             // Match previous behavior: cyan + bold for the selected row.
             // Reset the style first to avoid inheriting dim from keyboard shortcuts.
             full_line.spans.iter_mut().for_each(|span| {
                 span.style = Style::default().fg(Color::Cyan).bold();
             });
         }
+        if row.is_disabled {
+            full_line.spans.iter_mut().for_each(|span| {
+                span.style = span.style.dim();
+            });
+        }
 
         // Wrap with subsequent indent aligned to the description column.
         use crate::wrapping::RtOptions;
@@ -364,11 +370,16 @@ pub(crate) fn render_rows_single_line(
         }
 
         let mut full_line = build_full_line(row, desc_col);
-        if Some(i) == state.selected_idx {
+        if Some(i) == state.selected_idx && !row.is_disabled {
             full_line.spans.iter_mut().for_each(|span| {
                 span.style = Style::default().fg(Color::Cyan).bold();
             });
         }
+        if row.is_disabled {
+            full_line.spans.iter_mut().for_each(|span| {
+                span.style = span.style.dim();
+            });
+        }
 
         let full_line = truncate_line_with_ellipsis_if_overflow(full_line, area.width as usize);
         full_line.render(
diff --git a/codex-rs/tui/src/bottom_pane/skill_popup.rs b/codex-rs/tui/src/bottom_pane/skill_popup.rs
index 44afb1ff0b..4736953208 100644
--- a/codex-rs/tui/src/bottom_pane/skill_popup.rs
+++ b/codex-rs/tui/src/bottom_pane/skill_popup.rs
@@ -96,6 +96,7 @@ impl SkillPopup {
                     match_indices: indices,
                     display_shortcut: None,
                     description: Some(description),
+                    is_disabled: false,
                     disabled_reason: None,
                     wrap_indent: None,
                 }
diff --git a/codex-rs/tui/src/chatwidget.rs b/codex-rs/tui/src/chatwidget.rs
index ce87b33eed..aa420a3ea9 100644
--- a/codex-rs/tui/src/chatwidget.rs
+++ b/codex-rs/tui/src/chatwidget.rs
@@ -95,6 +95,7 @@ use codex_protocol::approvals::ElicitationRequestEvent;
 use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::CollaborationModeMask;
 use codex_protocol::config_types::ModeKind;
+use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::Settings;
 use codex_protocol::models::local_image_label_text;
 use codex_protocol::parse_command::ParsedCommand;
@@ -738,6 +739,7 @@ impl ChatWidget {
             None,
         );
         self.refresh_model_display();
+        self.sync_personality_command_enabled();
         let session_info_cell = history_cell::new_session_info(
             &self.config,
             &model_for_header,
@@ -2023,6 +2025,7 @@ impl ChatWidget {
         widget.bottom_pane.set_collaboration_modes_enabled(
             widget.config.features.enabled(Feature::CollaborationModes),
         );
+        widget.sync_personality_command_enabled();
         widget.update_collaboration_mode_indicator();
 
         widget
@@ -2147,6 +2150,7 @@ impl ChatWidget {
         widget.bottom_pane.set_collaboration_modes_enabled(
             widget.config.features.enabled(Feature::CollaborationModes),
         );
+        widget.sync_personality_command_enabled();
 
         widget
     }
@@ -2272,6 +2276,7 @@ impl ChatWidget {
         widget.bottom_pane.set_collaboration_modes_enabled(
             widget.config.features.enabled(Feature::CollaborationModes),
         );
+        widget.sync_personality_command_enabled();
         widget.update_collaboration_mode_indicator();
 
         widget
@@ -2507,6 +2512,9 @@ impl ChatWidget {
             SlashCommand::Model => {
                 self.open_model_popup();
             }
+            SlashCommand::Personality => {
+                self.open_personality_popup();
+            }
             SlashCommand::Collab => {
                 if self.collaboration_modes_enabled() {
                     self.open_collaboration_modes_popup();
@@ -2830,6 +2838,10 @@ impl ChatWidget {
         } else {
             None
         };
+        let personality = self
+            .config
+            .model_personality
+            .filter(|_| self.current_model_supports_personality());
         let op = Op::UserTurn {
             items,
             cwd: self.config.cwd.clone(),
@@ -2840,7 +2852,7 @@ impl ChatWidget {
             summary: self.config.model_reasoning_summary,
             final_output_json_schema: None,
             collaboration_mode,
-            personality: None,
+            personality,
         };
 
         self.codex_op_tx.send(op).unwrap_or_else(|e| {
@@ -3031,7 +3043,8 @@ impl ChatWidget {
             | EventMsg::ItemCompleted(_)
             | EventMsg::AgentMessageContentDelta(_)
             | EventMsg::ReasoningContentDelta(_)
-            | EventMsg::ReasoningRawContentDelta(_) => {}
+            | EventMsg::ReasoningRawContentDelta(_)
+            | EventMsg::DynamicToolCallRequest(_) => {}
         }
     }
 
@@ -3382,6 +3395,76 @@ impl ChatWidget {
         self.open_model_popup_with_presets(presets);
     }
 
+    pub(crate) fn open_personality_popup(&mut self) {
+        if !self.is_session_configured() {
+            self.add_info_message(
+                "Personality selection is disabled until startup completes.".to_string(),
+                None,
+            );
+            return;
+        }
+        self.open_personality_popup_for_current_model();
+    }
+
+    fn open_personality_popup_for_current_model(&mut self) {
+        let current_model = self.current_model();
+        let current_personality = self.config.model_personality;
+        let personalities = [Personality::Friendly, Personality::Pragmatic];
+        let supports_personality = self.current_model_supports_personality();
+        let disabled_message = (!supports_personality).then(|| {
+            format!(
+                "Current model ({current_model}) doesn't support personalities. Try /model to switch to a newer model."
+            )
+        });
+
+        let items: Vec<SelectionItem> = personalities
+            .into_iter()
+            .map(|personality| {
+                let name = Self::personality_label(personality).to_string();
+                let description = Some(Self::personality_description(personality).to_string());
+                let actions: Vec<SelectionAction> = vec![Box::new(move |tx| {
+                    tx.send(AppEvent::CodexOp(Op::OverrideTurnContext {
+                        cwd: None,
+                        approval_policy: None,
+                        sandbox_policy: None,
+                        model: None,
+                        effort: None,
+                        summary: None,
+                        collaboration_mode: None,
+                        personality: Some(personality),
+                    }));
+                    tx.send(AppEvent::UpdatePersonality(personality));
+                    tx.send(AppEvent::PersistPersonalitySelection { personality });
+                })];
+                SelectionItem {
+                    name,
+                    description,
+                    is_current: current_personality == Some(personality),
+                    is_disabled: !supports_personality,
+                    actions,
+                    dismiss_on_select: true,
+                    ..Default::default()
+                }
+            })
+            .collect();
+
+        let mut header = ColumnRenderable::new();
+        header.push(Line::from("Select Personality".bold()));
+        header.push(Line::from(
+            "Choose a communication style for future responses.".dim(),
+        ));
+        if let Some(message) = disabled_message {
+            header.push(Line::from(message.red()));
+        }
+
+        self.bottom_pane.show_selection_view(SelectionViewParams {
+            header: Box::new(header),
+            footer_hint: Some(standard_popup_hint_line()),
+            items,
+            ..Default::default()
+        });
+    }
+
     fn model_menu_header(&self, title: &str, subtitle: &str) -> Box<dyn Renderable> {
         let title = title.to_string();
         let subtitle = subtitle.to_string();
@@ -4608,6 +4691,11 @@ impl ChatWidget {
         }
     }
 
+    /// Set the personality in the widget's config copy.
+    pub(crate) fn set_personality(&mut self, personality: Personality) {
+        self.config.model_personality = Some(personality);
+    }
+
     /// Set the model in the widget's config copy and stored collaboration mode.
     pub(crate) fn set_model(&mut self, model: &str) {
         self.current_collaboration_mode =
@@ -4619,6 +4707,7 @@ impl ChatWidget {
             mask.model = Some(model.to_string());
         }
         self.refresh_model_display();
+        self.sync_personality_command_enabled();
     }
 
     pub(crate) fn current_model(&self) -> &str {
@@ -4631,6 +4720,25 @@ impl ChatWidget {
             .unwrap_or_else(|| self.current_collaboration_mode.model())
     }
 
+    fn sync_personality_command_enabled(&mut self) {
+        self.bottom_pane
+            .set_personality_command_enabled(self.current_model_supports_personality());
+    }
+
+    fn current_model_supports_personality(&self) -> bool {
+        let model = self.current_model();
+        self.models_manager
+            .try_list_models(&self.config)
+            .ok()
+            .and_then(|models| {
+                models
+                    .into_iter()
+                    .find(|preset| preset.model == model)
+                    .map(|preset| preset.supports_personality)
+            })
+            .unwrap_or(false)
+    }
+
     #[allow(dead_code)] // Used in tests
     pub(crate) fn current_collaboration_mode(&self) -> &CollaborationMode {
         &self.current_collaboration_mode
@@ -4746,6 +4854,20 @@ impl ChatWidget {
         self.bottom_pane.set_collaboration_mode_indicator(indicator);
     }
 
+    fn personality_label(personality: Personality) -> &'static str {
+        match personality {
+            Personality::Friendly => "Friendly",
+            Personality::Pragmatic => "Pragmatic",
+        }
+    }
+
+    fn personality_description(personality: Personality) -> &'static str {
+        match personality {
+            Personality::Friendly => "Warm, collaborative, and helpful.",
+            Personality::Pragmatic => "Concise, task-focused, and direct.",
+        }
+    }
+
     /// Cycle to the next collaboration mode variant (Plan -> Code -> Plan).
     fn cycle_collaboration_mode(&mut self) {
         if !self.collaboration_modes_enabled() {
diff --git a/codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__personality_selection_popup.snap b/codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__personality_selection_popup.snap
new file mode 100644
index 0000000000..6df7d5ad6b
--- /dev/null
+++ b/codex-rs/tui/src/chatwidget/snapshots/codex_tui__chatwidget__tests__personality_selection_popup.snap
@@ -0,0 +1,11 @@
+---
+source: tui/src/chatwidget/tests.rs
+expression: popup
+---
+  Select Personality
+  Choose a communication style for future responses.
+
+› 1. Friendly   Warm, collaborative, and helpful.
+  2. Pragmatic  Concise, task-focused, and direct.
+
+  Press enter to confirm or esc to go back
diff --git a/codex-rs/tui/src/chatwidget/tests.rs b/codex-rs/tui/src/chatwidget/tests.rs
index e76abdbd7a..fab175edcf 100644
--- a/codex-rs/tui/src/chatwidget/tests.rs
+++ b/codex-rs/tui/src/chatwidget/tests.rs
@@ -65,6 +65,7 @@ use codex_protocol::ThreadId;
 use codex_protocol::account::PlanType;
 use codex_protocol::config_types::CollaborationMode;
 use codex_protocol::config_types::ModeKind;
+use codex_protocol::config_types::Personality;
 use codex_protocol::config_types::Settings;
 use codex_protocol::openai_models::ModelPreset;
 use codex_protocol::openai_models::ReasoningEffortPreset;
@@ -788,7 +789,7 @@ async fn make_chatwidget_manual(
         },
     };
     let current_collaboration_mode = base_mode;
-    let widget = ChatWidget {
+    let mut widget = ChatWidget {
         app_event_tx,
         codex_op_tx: op_tx,
         bottom_pane: bottom,
@@ -800,7 +801,7 @@ async fn make_chatwidget_manual(
         auth_manager,
         models_manager,
         otel_manager,
-        session_header: SessionHeader::new(resolved_model),
+        session_header: SessionHeader::new(resolved_model.clone()),
         initial_user_message: None,
         token_info: None,
         rate_limit_snapshot: None,
@@ -844,6 +845,7 @@ async fn make_chatwidget_manual(
         current_rollout_path: None,
         external_editor_state: ExternalEditorState::Closed,
     };
+    widget.set_model(&resolved_model);
     (widget, rx, op_rx)
 }
 
@@ -2416,6 +2418,25 @@ async fn collab_mode_enabling_keeps_custom_until_selected() {
     assert_eq!(chat.current_collaboration_mode().mode, ModeKind::Custom);
 }
 
+#[tokio::test]
+async fn user_turn_includes_personality_from_config() {
+    let (mut chat, _rx, mut op_rx) = make_chatwidget_manual(Some("bengalfox")).await;
+    chat.thread_id = Some(ThreadId::new());
+    chat.set_model("bengalfox");
+    chat.set_personality(Personality::Friendly);
+
+    chat.bottom_pane
+        .set_composer_text("hello".to_string(), Vec::new(), Vec::new());
+    chat.handle_key_event(KeyEvent::from(KeyCode::Enter));
+    match next_submit_op(&mut op_rx) {
+        Op::UserTurn {
+            personality: Some(Personality::Friendly),
+            ..
+        } => {}
+        other => panic!("expected Op::UserTurn with friendly personality, got {other:?}"),
+    }
+}
+
 #[tokio::test]
 async fn slash_quit_requests_exit() {
     let (mut chat, mut rx, _op_rx) = make_chatwidget_manual(None).await;
@@ -2960,6 +2981,16 @@ async fn model_selection_popup_snapshot() {
     assert_snapshot!("model_selection_popup", popup);
 }
 
+#[tokio::test]
+async fn personality_selection_popup_snapshot() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("bengalfox")).await;
+    chat.thread_id = Some(ThreadId::new());
+    chat.open_personality_popup();
+
+    let popup = render_bottom_popup(&chat, 80);
+    assert_snapshot!("personality_selection_popup", popup);
+}
+
 #[tokio::test]
 async fn model_picker_hides_show_in_picker_false_models_from_cache() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual(Some("test-visible-model")).await;
@@ -2974,6 +3005,7 @@ async fn model_picker_hides_show_in_picker_false_models_from_cache() {
             effort: ReasoningEffortConfig::Medium,
             description: "medium".to_string(),
         }],
+        supports_personality: false,
         is_default: false,
         upgrade: None,
         show_in_picker,
@@ -3186,6 +3218,7 @@ async fn single_reasoning_option_skips_selection() {
         description: "".to_string(),
         default_reasoning_effort: ReasoningEffortConfig::High,
         supported_reasoning_efforts: single_effort,
+        supports_personality: false,
         is_default: false,
         upgrade: None,
         show_in_picker: true,
diff --git a/codex-rs/tui/src/slash_command.rs b/codex-rs/tui/src/slash_command.rs
index 2562d5e689..28d27d2301 100644
--- a/codex-rs/tui/src/slash_command.rs
+++ b/codex-rs/tui/src/slash_command.rs
@@ -13,6 +13,7 @@ pub enum SlashCommand {
     // DO NOT ALPHA-SORT! Enum order is presentation order in the popup, so
     // more frequently used commands should be listed first.
     Model,
+    Personality,
     Approvals,
     Permissions,
     #[strum(serialize = "setup-elevated-sandbox")]
@@ -60,6 +61,7 @@ impl SlashCommand {
             SlashCommand::Status => "show current session configuration and token usage",
             SlashCommand::Ps => "list background terminals",
             SlashCommand::Model => "choose what model and reasoning effort to use",
+            SlashCommand::Personality => "choose a communication style for responses",
             SlashCommand::Collab => "change collaboration mode (experimental)",
             SlashCommand::Agent => "switch the active agent thread",
             SlashCommand::Approvals => "choose what Codex can do without approval",
@@ -89,6 +91,7 @@ impl SlashCommand {
             | SlashCommand::Compact
             // | SlashCommand::Undo
             | SlashCommand::Model
+            | SlashCommand::Personality
             | SlashCommand::Approvals
             | SlashCommand::Permissions
             | SlashCommand::ElevateSandbox
diff --git a/codex-rs/tui/src/tooltips.rs b/codex-rs/tui/src/tooltips.rs
index 402a18ba2b..8acfcce892 100644
--- a/codex-rs/tui/src/tooltips.rs
+++ b/codex-rs/tui/src/tooltips.rs
@@ -104,7 +104,12 @@ pub(crate) mod announcement {
     }
 
     fn blocking_init_announcement_tip() -> Option<String> {
-        let response = reqwest::blocking::Client::new()
+        // Avoid system proxy detection to prevent macOS system-configuration panics (#8912).
+        let client = reqwest::blocking::Client::builder()
+            .no_proxy()
+            .build()
+            .ok()?;
+        let response = client
             .get(ANNOUNCEMENT_TIP_URL)
             .timeout(Duration::from_millis(2000))
             .send()