diff --git a/codex-rs/app-server-protocol/src/protocol.rs b/codex-rs/app-server-protocol/src/protocol.rs
index 78adcbfdbd..2734c21c65 100644
--- a/codex-rs/app-server-protocol/src/protocol.rs
+++ b/codex-rs/app-server-protocol/src/protocol.rs
@@ -10,12 +10,12 @@ use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::config_types::SandboxMode;
 use codex_protocol::config_types::Verbosity;
 use codex_protocol::protocol::AskForApproval;
+use codex_protocol::protocol::DisabledTool;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::FileChange;
 use codex_protocol::protocol::ReviewDecision;
 use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::TurnAbortReason;
-use codex_protocol::protocol::default_disabled_tools;
 use paste::paste;
 use serde::Deserialize;
 use serde::Serialize;
@@ -551,8 +551,8 @@ pub struct SendUserTurnParams {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub effort: Option<ReasoningEffort>,
     pub summary: ReasoningSummary,
-    #[serde(default = "default_disabled_tools")]
-    pub disabled_tools: Vec<String>,
+    #[serde(default = "DisabledTool::defaults")]
+    pub disabled_tools: Vec<DisabledTool>,
 }
 
 #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, TS)]
diff --git a/codex-rs/app-server/tests/suite/codex_message_processor_flow.rs b/codex-rs/app-server/tests/suite/codex_message_processor_flow.rs
index ce9302d22f..6403459559 100644
--- a/codex-rs/app-server/tests/suite/codex_message_processor_flow.rs
+++ b/codex-rs/app-server/tests/suite/codex_message_processor_flow.rs
@@ -27,10 +27,10 @@ use codex_core::protocol_config_types::ReasoningEffort;
 use codex_core::protocol_config_types::ReasoningSummary;
 use codex_core::spawn::CODEX_SANDBOX_NETWORK_DISABLED_ENV_VAR;
 use codex_protocol::config_types::SandboxMode;
+use codex_protocol::protocol::DisabledTool;
 use codex_protocol::protocol::Event;
 use codex_protocol::protocol::EventMsg;
 use codex_protocol::protocol::InputMessageKind;
-use codex_protocol::protocol::default_disabled_tools;
 use pretty_assertions::assert_eq;
 use std::env;
 use tempfile::TempDir;
@@ -346,7 +346,7 @@ async fn test_send_user_turn_changes_approval_policy_behavior() {
             model: "mock-model".to_string(),
             effort: Some(ReasoningEffort::Medium),
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .expect("send sendUserTurn");
@@ -485,7 +485,7 @@ async fn test_send_user_turn_updates_sandbox_and_cwd_between_turns() {
             model: model.clone(),
             effort: Some(ReasoningEffort::Medium),
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .expect("send first sendUserTurn");
@@ -516,7 +516,7 @@ async fn test_send_user_turn_updates_sandbox_and_cwd_between_turns() {
             model: model.clone(),
             effort: Some(ReasoningEffort::Medium),
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .expect("send second sendUserTurn");
diff --git a/codex-rs/core/src/client.rs b/codex-rs/core/src/client.rs
index 9b4538ced8..78d8c101c4 100644
--- a/codex-rs/core/src/client.rs
+++ b/codex-rs/core/src/client.rs
@@ -239,8 +239,7 @@ impl ModelClient {
             instructions: &full_instructions,
             input: &input_with_instructions,
             tools: &tools_json,
-            allowed_tools: prompt.allowed_tools.as_slice(),
-            tool_choice: "auto",
+            tool_choice: prompt.tool_choice(),
             parallel_tool_calls: prompt.parallel_tool_calls,
             reasoning,
             store: azure_workaround,
diff --git a/codex-rs/core/src/client_common.rs b/codex-rs/core/src/client_common.rs
index e67f9e4ff8..3a7e04b4ec 100644
--- a/codex-rs/core/src/client_common.rs
+++ b/codex-rs/core/src/client_common.rs
@@ -43,7 +43,7 @@ pub struct Prompt {
     pub output_schema: Option<Value>,
 
     /// The set of tools that are allowed to be used by the model.
-    pub(crate) allowed_tools: Vec<Value>,
+    pub(crate) allowed_tools: Option<Vec<Value>>,
 }
 
 impl Prompt {
@@ -88,10 +88,17 @@ impl Prompt {
 
         input
     }
-}
 
-fn json_slice_is_empty(values: &[Value]) -> bool {
-    values.is_empty()
+    pub(crate) fn tool_choice(&self) -> ToolChoice<'_> {
+        match &self.allowed_tools {
+            Some(tools) => ToolChoice::AllowedTools(AllowedToolsChoice {
+                choice_type: "allowed_tools",
+                mode: "auto",
+                tools,
+            }),
+            None => ToolChoice::Auto("auto"),
+        }
+    }
 }
 
 fn reserialize_shell_outputs(items: &mut [ResponseItem]) {
@@ -275,9 +282,7 @@ pub(crate) struct ResponsesApiRequest<'a> {
     // separate enum for serialization.
     pub(crate) input: &'a Vec<ResponseItem>,
     pub(crate) tools: &'a [serde_json::Value],
-    #[serde(skip_serializing_if = "json_slice_is_empty")]
-    pub(crate) allowed_tools: &'a [serde_json::Value],
-    pub(crate) tool_choice: &'static str,
+    pub(crate) tool_choice: ToolChoice<'a>,
     pub(crate) parallel_tool_calls: bool,
     pub(crate) reasoning: Option<Reasoning>,
     pub(crate) store: bool,
@@ -289,6 +294,21 @@ pub(crate) struct ResponsesApiRequest<'a> {
     pub(crate) text: Option<TextControls>,
 }
 
+#[derive(Debug, Serialize)]
+#[serde(untagged)]
+pub(crate) enum ToolChoice<'a> {
+    Auto(&'static str),
+    AllowedTools(AllowedToolsChoice<'a>),
+}
+
+#[derive(Debug, Serialize)]
+pub(crate) struct AllowedToolsChoice<'a> {
+    #[serde(rename = "type")]
+    pub(crate) choice_type: &'static str,
+    pub(crate) mode: &'static str,
+    pub(crate) tools: &'a [Value],
+}
+
 pub(crate) mod tools {
     use crate::openai_tools::JsonSchema;
     use serde::Deserialize;
@@ -466,8 +486,7 @@ mod tests {
             instructions: "i",
             input: &input,
             tools: &tools,
-            allowed_tools: &[],
-            tool_choice: "auto",
+            tool_choice: ToolChoice::Auto("auto"),
             parallel_tool_calls: true,
             reasoning: None,
             store: false,
@@ -508,8 +527,7 @@ mod tests {
             instructions: "i",
             input: &input,
             tools: &tools,
-            allowed_tools: &[],
-            tool_choice: "auto",
+            tool_choice: ToolChoice::Auto("auto"),
             parallel_tool_calls: true,
             reasoning: None,
             store: false,
@@ -545,8 +563,7 @@ mod tests {
             instructions: "i",
             input: &input,
             tools: &tools,
-            allowed_tools: &[],
-            tool_choice: "auto",
+            tool_choice: ToolChoice::Auto("auto"),
             parallel_tool_calls: true,
             reasoning: None,
             store: false,
@@ -573,8 +590,11 @@ mod tests {
             instructions: "i",
             input: &input,
             tools: &tools,
-            allowed_tools: allowed.as_slice(),
-            tool_choice: "auto",
+            tool_choice: ToolChoice::AllowedTools(AllowedToolsChoice {
+                choice_type: "allowed_tools",
+                mode: "auto",
+                tools: allowed.as_slice(),
+            }),
             parallel_tool_calls: true,
             reasoning: None,
             store: false,
@@ -585,17 +605,21 @@ mod tests {
         };
 
         let v = serde_json::to_value(&req).expect("json");
+        let choice = v.get("tool_choice").expect("tool_choice field");
         assert_eq!(
-            v.get("allowed_tools")
-                .and_then(|val| val.as_array())
-                .map(std::vec::Vec::len),
-            Some(1)
+            choice.get("type"),
+            Some(&serde_json::Value::String("allowed_tools".into()))
         );
-        let first = v
-            .get("allowed_tools")
+        assert_eq!(
+            choice.get("mode"),
+            Some(&serde_json::Value::String("auto".into()))
+        );
+        let tools_array = choice
+            .get("tools")
             .and_then(|val| val.as_array())
-            .and_then(|arr| arr.first())
-            .expect("allowed tool entry");
+            .expect("tools array");
+        assert_eq!(tools_array.len(), 1);
+        let first = &tools_array[0];
         assert_eq!(
             first.get("type"),
             Some(&serde_json::Value::String("function".into()))
diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index 9d0e8b17ee..c0b699e08b 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -16,6 +16,7 @@ use async_channel::Sender;
 use codex_apply_patch::ApplyPatchAction;
 use codex_protocol::ConversationId;
 use codex_protocol::protocol::ConversationPathResponseEvent;
+use codex_protocol::protocol::DisabledTool;
 use codex_protocol::protocol::ExitedReviewModeEvent;
 use codex_protocol::protocol::ReviewRequest;
 use codex_protocol::protocol::RolloutItem;
@@ -23,7 +24,6 @@ use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::TaskStartedEvent;
 use codex_protocol::protocol::TurnAbortReason;
 use codex_protocol::protocol::TurnContextItem;
-use codex_protocol::protocol::default_disabled_tools;
 use futures::future::BoxFuture;
 use futures::prelude::*;
 use futures::stream::FuturesOrdered;
@@ -265,7 +265,7 @@ pub(crate) struct TurnContext {
     pub(crate) tools_config: ToolsConfig,
     pub(crate) is_review_mode: bool,
     pub(crate) final_output_json_schema: Option<Value>,
-    pub(crate) disabled_tools: Vec<String>,
+    pub(crate) disabled_tools: Vec<DisabledTool>,
 }
 
 impl TurnContext {
@@ -461,7 +461,7 @@ impl Session {
             cwd,
             is_review_mode: false,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         };
         let services = SessionServices {
             mcp_connection_manager,
@@ -1211,7 +1211,7 @@ async fn submission_loop(
                     cwd: new_cwd.clone(),
                     is_review_mode: false,
                     final_output_json_schema: None,
-                    disabled_tools: disabled_tools.unwrap_or_else(default_disabled_tools),
+                    disabled_tools: disabled_tools.unwrap_or_else(DisabledTool::defaults),
                 };
 
                 // Install the new persistent context for subsequent tasks/turns.
@@ -1586,7 +1586,7 @@ async fn spawn_review_thread(
         cwd: parent_turn_context.cwd.clone(),
         is_review_mode: true,
         final_output_json_schema: None,
-        disabled_tools: default_disabled_tools(),
+        disabled_tools: DisabledTool::defaults(),
     };
 
     // Seed the child task with the review prompt as the initial user message.
@@ -1953,20 +1953,29 @@ async fn run_turn(
         .get_model_family()
         .supports_parallel_tool_calls;
     let parallel_tool_calls = model_supports_parallel;
-    let allowed_tools = router
-        .allowed_tools()
-        .into_iter()
-        .filter(|tool| {
-            tool.get("name")
-                .and_then(|val| val.as_str())
-                .is_none_or(|name| {
-                    !turn_context
-                        .disabled_tools
-                        .iter()
-                        .any(|disabled| disabled == name)
-                })
-        })
-        .collect::<Vec<_>>();
+    let mut allowed_tools = Vec::new();
+    let mut restricted_tool_choice = false;
+    for tool in router.allowed_tools() {
+        let is_disabled = tool
+            .get("name")
+            .and_then(|val| val.as_str())
+            .is_some_and(|name| {
+                turn_context
+                    .disabled_tools
+                    .iter()
+                    .any(|disabled| disabled.matches_tool_name(name))
+            });
+        if is_disabled {
+            restricted_tool_choice = true;
+            continue;
+        }
+        allowed_tools.push(tool);
+    }
+    let allowed_tools = if restricted_tool_choice {
+        Some(allowed_tools)
+    } else {
+        None
+    };
     let prompt = Prompt {
         input,
         tools: router.specs(),
@@ -2781,7 +2790,7 @@ mod tests {
             tools_config,
             is_review_mode: false,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         };
         let services = SessionServices {
             mcp_connection_manager: McpConnectionManager::default(),
@@ -2850,7 +2859,7 @@ mod tests {
             tools_config,
             is_review_mode: false,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         });
         let services = SessionServices {
             mcp_connection_manager: McpConnectionManager::default(),
diff --git a/codex-rs/core/src/features.rs b/codex-rs/core/src/features.rs
index b8314b0c14..6357e1af25 100644
--- a/codex-rs/core/src/features.rs
+++ b/codex-rs/core/src/features.rs
@@ -245,6 +245,6 @@ pub const FEATURES: &[FeatureSpec] = &[
         id: Feature::WebSearchRequest,
         key: "web_search_request",
         stage: Stage::Stable,
-        default_enabled: false,
+        default_enabled: true,
     },
 ];
diff --git a/codex-rs/core/tests/suite/compact_resume_fork.rs b/codex-rs/core/tests/suite/compact_resume_fork.rs
index 2c35268de1..5ba5c87bcf 100644
--- a/codex-rs/core/tests/suite/compact_resume_fork.rs
+++ b/codex-rs/core/tests/suite/compact_resume_fork.rs
@@ -124,7 +124,7 @@ async fn compact_resume_and_fork_preserve_model_history_view() {
         .unwrap_or_default()
         .to_string();
     let tool_calls = requests[0]["tools"].clone();
-    let allowed_tools = requests[0]["allowed_tools"].clone();
+    let tool_choice = requests[0]["tool_choice"].clone();
     let prompt_cache_key = requests[0]["prompt_cache_key"]
         .as_str()
         .unwrap_or_default()
@@ -171,8 +171,7 @@ async fn compact_resume_and_fork_preserve_model_history_view() {
         }
       ],
       "tools": tool_calls,
-      "allowed_tools": allowed_tools,
-      "tool_choice": "auto",
+      "tool_choice": tool_choice,
       "parallel_tool_calls": false,
       "reasoning": {
         "summary": "auto"
@@ -241,8 +240,7 @@ async fn compact_resume_and_fork_preserve_model_history_view() {
         }
       ],
       "tools": [],
-      "allowed_tools": allowed_tools,
-      "tool_choice": "auto",
+      "tool_choice": tool_choice,
       "parallel_tool_calls": false,
       "reasoning": {
         "summary": "auto"
@@ -307,8 +305,7 @@ SUMMARY_ONLY_CONTEXT"
         }
       ],
       "tools": tool_calls,
-      "allowed_tools": allowed_tools,
-      "tool_choice": "auto",
+      "tool_choice": tool_choice,
       "parallel_tool_calls": false,
       "reasoning": {
         "summary": "auto"
@@ -393,8 +390,7 @@ SUMMARY_ONLY_CONTEXT"
         }
       ],
       "tools": tool_calls,
-      "allowed_tools": allowed_tools,
-      "tool_choice": "auto",
+      "tool_choice": tool_choice,
       "parallel_tool_calls": false,
       "reasoning": {
         "summary": "auto"
@@ -479,8 +475,7 @@ SUMMARY_ONLY_CONTEXT"
         }
       ],
       "tools": tool_calls,
-      "allowed_tools": allowed_tools,
-      "tool_choice": "auto",
+      "tool_choice": tool_choice,
       "parallel_tool_calls": false,
       "reasoning": {
         "summary": "auto"
diff --git a/codex-rs/core/tests/suite/grep_files.rs b/codex-rs/core/tests/suite/grep_files.rs
index 5a83d6831f..3f35c22257 100644
--- a/codex-rs/core/tests/suite/grep_files.rs
+++ b/codex-rs/core/tests/suite/grep_files.rs
@@ -3,11 +3,11 @@
 use anyhow::Result;
 use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses;
 use core_test_support::responses::ev_assistant_message;
@@ -160,7 +160,7 @@ async fn submit_turn(test: &TestCodex, prompt: &str) -> Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/json_result.rs b/codex-rs/core/tests/suite/json_result.rs
index 568a6df28e..294c7e9058 100644
--- a/codex-rs/core/tests/suite/json_result.rs
+++ b/codex-rs/core/tests/suite/json_result.rs
@@ -1,11 +1,11 @@
 #![cfg(not(target_os = "windows"))]
 
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses;
 use core_test_support::skip_if_no_network;
@@ -85,7 +85,7 @@ async fn codex_returns_json_result(model: String) -> anyhow::Result<()> {
             model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/list_dir.rs b/codex-rs/core/tests/suite/list_dir.rs
index 4d5c5cbf71..f98316e38f 100644
--- a/codex-rs/core/tests/suite/list_dir.rs
+++ b/codex-rs/core/tests/suite/list_dir.rs
@@ -1,11 +1,11 @@
 #![cfg(not(target_os = "windows"))]
 
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses;
 use core_test_support::responses::ev_assistant_message;
@@ -77,7 +77,7 @@ async fn list_dir_tool_returns_entries() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -183,7 +183,7 @@ async fn list_dir_tool_depth_one_omits_children() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -296,7 +296,7 @@ async fn list_dir_tool_depth_two_includes_children_only() -> anyhow::Result<()>
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -412,7 +412,7 @@ async fn list_dir_tool_depth_three_includes_grandchildren() -> anyhow::Result<()
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/prompt_caching.rs b/codex-rs/core/tests/suite/prompt_caching.rs
index 336406bba8..cf3cd18275 100644
--- a/codex-rs/core/tests/suite/prompt_caching.rs
+++ b/codex-rs/core/tests/suite/prompt_caching.rs
@@ -8,11 +8,11 @@ use codex_core::config::OPENAI_DEFAULT_MODEL;
 use codex_core::features::Feature;
 use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_core::protocol_config_types::ReasoningEffort;
 use codex_core::protocol_config_types::ReasoningSummary;
 use codex_core::shell::Shell;
@@ -579,7 +579,7 @@ async fn per_turn_overrides_keep_cached_prefix_and_key_constant() {
             effort: Some(ReasoningEffort::High),
             summary: ReasoningSummary::Detailed,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .unwrap();
@@ -691,7 +691,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() {
             effort: default_effort,
             summary: default_summary,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .unwrap();
@@ -709,7 +709,7 @@ async fn send_user_turn_with_no_changes_does_not_send_environment_context() {
             effort: default_effort,
             summary: default_summary,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .unwrap();
@@ -807,7 +807,7 @@ async fn send_user_turn_with_changes_sends_environment_context() {
             effort: default_effort,
             summary: default_summary,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .unwrap();
@@ -825,7 +825,7 @@ async fn send_user_turn_with_changes_sends_environment_context() {
             effort: Some(ReasoningEffort::High),
             summary: ReasoningSummary::Detailed,
             final_output_json_schema: None,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await
         .unwrap();
diff --git a/codex-rs/core/tests/suite/read_file.rs b/codex-rs/core/tests/suite/read_file.rs
index 293621b4c2..8ba7bccc84 100644
--- a/codex-rs/core/tests/suite/read_file.rs
+++ b/codex-rs/core/tests/suite/read_file.rs
@@ -1,11 +1,11 @@
 #![cfg(not(target_os = "windows"))]
 
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses;
 use core_test_support::responses::ev_assistant_message;
@@ -75,7 +75,7 @@ async fn read_file_tool_returns_requested_lines() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/rmcp_client.rs b/codex-rs/core/tests/suite/rmcp_client.rs
index 8af9f90ff3..54b3bf8c24 100644
--- a/codex-rs/core/tests/suite/rmcp_client.rs
+++ b/codex-rs/core/tests/suite/rmcp_client.rs
@@ -12,11 +12,11 @@ use codex_core::config_types::McpServerTransportConfig;
 use codex_core::features::Feature;
 
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses;
 use core_test_support::responses::mount_sse_once_match;
@@ -111,7 +111,7 @@ async fn stdio_server_round_trip() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -261,7 +261,7 @@ async fn streamable_http_tool_call_round_trip() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -443,7 +443,7 @@ async fn streamable_http_with_oauth_round_trip() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/shell_serialization.rs b/codex-rs/core/tests/suite/shell_serialization.rs
index f07dc6f887..89cec293ee 100644
--- a/codex-rs/core/tests/suite/shell_serialization.rs
+++ b/codex-rs/core/tests/suite/shell_serialization.rs
@@ -4,11 +4,11 @@ use anyhow::Result;
 use codex_core::features::Feature;
 use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::assert_regex_match;
 use core_test_support::responses::ev_apply_patch_function_call;
@@ -46,7 +46,7 @@ async fn submit_turn(test: &TestCodex, prompt: &str, sandbox_policy: SandboxPoli
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/tool_harness.rs b/codex-rs/core/tests/suite/tool_harness.rs
index 277e677bb8..05923d1d9e 100644
--- a/codex-rs/core/tests/suite/tool_harness.rs
+++ b/codex-rs/core/tests/suite/tool_harness.rs
@@ -6,11 +6,11 @@ use assert_matches::assert_matches;
 use codex_core::features::Feature;
 use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use codex_protocol::plan_tool::StepStatus;
 use core_test_support::assert_regex_match;
@@ -85,7 +85,7 @@ async fn shell_tool_executes_command_and_streams_output() -> anyhow::Result<()>
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -155,7 +155,7 @@ async fn update_plan_tool_emits_plan_update_event() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -239,7 +239,7 @@ async fn update_plan_tool_rejects_malformed_payload() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -338,7 +338,7 @@ async fn apply_patch_tool_executes_and_emits_patch_events() -> anyhow::Result<()
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -440,7 +440,7 @@ async fn apply_patch_reports_parse_diagnostics() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/tool_parallelism.rs b/codex-rs/core/tests/suite/tool_parallelism.rs
index 65f082cfd1..4120e73e3b 100644
--- a/codex-rs/core/tests/suite/tool_parallelism.rs
+++ b/codex-rs/core/tests/suite/tool_parallelism.rs
@@ -6,11 +6,11 @@ use std::time::Instant;
 
 use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses::ev_assistant_message;
 use core_test_support::responses::ev_completed;
@@ -39,7 +39,7 @@ async fn run_turn(test: &TestCodex, prompt: &str) -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/tools.rs b/codex-rs/core/tests/suite/tools.rs
index ee35f2515d..4e6b321bec 100644
--- a/codex-rs/core/tests/suite/tools.rs
+++ b/codex-rs/core/tests/suite/tools.rs
@@ -5,11 +5,12 @@ use anyhow::Result;
 use codex_core::features::Feature;
 use codex_core::model_family::find_family_for_model;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
+use codex_core::protocol::DisabledToolKind;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::assert_regex_match;
 use core_test_support::responses::ev_assistant_message;
@@ -49,7 +50,7 @@ async fn submit_turn(
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -410,6 +411,163 @@ async fn shell_timeout_includes_timeout_prefix_and_metadata() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn web_search_allowed_when_other_tool_disabled() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let mock = mount_sse_once(
+        &server,
+        sse(vec![
+            ev_response_created("resp-1"),
+            ev_assistant_message("msg-1", "done"),
+            ev_completed("resp-1"),
+        ]),
+    )
+    .await;
+
+    let mut builder = test_codex().with_config(|config| {
+        config.model = "gpt-5".to_string();
+        config.model_family = find_family_for_model("gpt-5").expect("gpt-5 family");
+        config.features.enable(Feature::WebSearchRequest);
+    });
+    let test = builder.build(&server).await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![InputItem::Text {
+                text: "hello codex".into(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd.path().to_path_buf(),
+            approval_policy: AskForApproval::Never,
+            sandbox_policy: SandboxPolicy::DangerFullAccess,
+            model: test.session_configured.model.clone(),
+            effort: None,
+            summary: ReasoningSummary::Auto,
+            disabled_tools: vec![DisabledToolKind::ViewImage.into()],
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |event| {
+        matches!(event, EventMsg::TaskComplete(_))
+    })
+    .await;
+
+    let body = mock.single_request().body_json();
+    let choice = body
+        .get("tool_choice")
+        .expect("tool_choice field should be present");
+    assert!(
+        choice.is_object(),
+        "expected tool_choice to be an object when tools are restricted: {choice:?}"
+    );
+    assert_eq!(
+        choice.get("type").and_then(Value::as_str),
+        Some("allowed_tools")
+    );
+    assert_eq!(choice.get("mode").and_then(Value::as_str), Some("auto"));
+
+    let allowed = choice
+        .get("tools")
+        .and_then(Value::as_array)
+        .cloned()
+        .expect("allowed tools array");
+    assert!(
+        allowed
+            .iter()
+            .any(|tool| tool.get("name").and_then(Value::as_str) == Some("web_search")),
+        "expected web_search to remain allowed: {allowed:?}"
+    );
+    assert!(
+        !allowed
+            .iter()
+            .any(|tool| tool.get("name").and_then(Value::as_str) == Some("view_image")),
+        "expected view_image to be excluded: {allowed:?}"
+    );
+    let tools = tool_names(&body);
+    assert!(
+        tools.iter().any(|name| name == "web_search"),
+        "expected tools list to include web_search: {tools:?}"
+    );
+
+    Ok(())
+}
+
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn override_enables_web_search() -> Result<()> {
+    skip_if_no_network!(Ok(()));
+
+    let server = start_mock_server().await;
+    let mock = mount_sse_once(
+        &server,
+        sse(vec![
+            ev_response_created("resp-1"),
+            ev_assistant_message("msg-1", "done"),
+            ev_completed("resp-1"),
+        ]),
+    )
+    .await;
+
+    let mut builder = test_codex().with_config(|config| {
+        config.model = "gpt-5".to_string();
+        config.model_family = find_family_for_model("gpt-5").expect("gpt-5 family");
+        config.features.enable(Feature::WebSearchRequest);
+    });
+    let test = builder.build(&server).await?;
+
+    test.codex
+        .submit(Op::OverrideTurnContext {
+            cwd: None,
+            approval_policy: None,
+            sandbox_policy: None,
+            model: None,
+            effort: None,
+            summary: None,
+            disabled_tools: Some(vec![]),
+        })
+        .await?;
+
+    test.codex
+        .submit(Op::UserTurn {
+            items: vec![InputItem::Text {
+                text: "hello after override".into(),
+            }],
+            final_output_json_schema: None,
+            cwd: test.cwd.path().to_path_buf(),
+            approval_policy: AskForApproval::Never,
+            sandbox_policy: SandboxPolicy::DangerFullAccess,
+            model: test.session_configured.model.clone(),
+            effort: None,
+            summary: ReasoningSummary::Auto,
+            disabled_tools: vec![],
+        })
+        .await?;
+
+    wait_for_event(&test.codex, |event| {
+        matches!(event, EventMsg::TaskComplete(_))
+    })
+    .await;
+
+    let body = mock.single_request().body_json();
+    let choice = body
+        .get("tool_choice")
+        .expect("tool_choice field should be present");
+    assert_eq!(
+        choice.as_str(),
+        Some("auto"),
+        "expected unrestricted tool choice to be auto: {choice:?}"
+    );
+
+    let tools = tool_names(&body);
+    assert!(
+        tools.iter().any(|name| name == "web_search"),
+        "expected tools list to include web_search: {tools:?}"
+    );
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn shell_spawn_failure_truncates_exec_error() -> Result<()> {
     skip_if_no_network!(Ok(()));
diff --git a/codex-rs/core/tests/suite/unified_exec.rs b/codex-rs/core/tests/suite/unified_exec.rs
index 230a88e992..17d1108f7c 100644
--- a/codex-rs/core/tests/suite/unified_exec.rs
+++ b/codex-rs/core/tests/suite/unified_exec.rs
@@ -5,11 +5,11 @@ use std::collections::HashMap;
 use anyhow::Result;
 use codex_core::features::Feature;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses::ev_assistant_message;
 use core_test_support::responses::ev_completed;
@@ -129,7 +129,7 @@ async fn unified_exec_reuses_session_via_stdin() -> Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -266,7 +266,7 @@ PY
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -373,7 +373,7 @@ async fn unified_exec_timeout_and_followup_poll() -> Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/core/tests/suite/view_image.rs b/codex-rs/core/tests/suite/view_image.rs
index 6749de3b92..160175f633 100644
--- a/codex-rs/core/tests/suite/view_image.rs
+++ b/codex-rs/core/tests/suite/view_image.rs
@@ -3,11 +3,11 @@
 use base64::Engine;
 use base64::engine::general_purpose::STANDARD as BASE64_STANDARD;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SandboxPolicy;
-use codex_core::protocol::default_disabled_tools;
 use codex_protocol::config_types::ReasoningSummary;
 use core_test_support::responses;
 use core_test_support::responses::ev_assistant_message;
@@ -101,7 +101,7 @@ async fn view_image_tool_attaches_local_image() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -201,7 +201,7 @@ async fn view_image_tool_errors_when_path_is_directory() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
@@ -267,7 +267,7 @@ async fn view_image_tool_errors_when_file_missing() -> anyhow::Result<()> {
             model: session_model,
             effort: None,
             summary: ReasoningSummary::Auto,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
 
diff --git a/codex-rs/exec/src/lib.rs b/codex-rs/exec/src/lib.rs
index 7d8466a8c8..dfdbf589b2 100644
--- a/codex-rs/exec/src/lib.rs
+++ b/codex-rs/exec/src/lib.rs
@@ -19,13 +19,13 @@ use codex_core::config::Config;
 use codex_core::config::ConfigOverrides;
 use codex_core::git_info::get_git_repo_root;
 use codex_core::protocol::AskForApproval;
+use codex_core::protocol::DisabledTool;
 use codex_core::protocol::Event;
 use codex_core::protocol::EventMsg;
 use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use codex_core::protocol::SessionSource;
 use codex_core::protocol::TaskCompleteEvent;
-use codex_core::protocol::default_disabled_tools;
 use codex_ollama::DEFAULT_OSS_MODEL;
 use codex_protocol::config_types::SandboxMode;
 use event_processor_with_human_output::EventProcessorWithHumanOutput;
@@ -349,7 +349,7 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
             effort: default_effort,
             summary: default_summary,
             final_output_json_schema: output_schema,
-            disabled_tools: default_disabled_tools(),
+            disabled_tools: DisabledTool::defaults(),
         })
         .await?;
     info!("Sent prompt with event ID: {initial_prompt_task_id}");
diff --git a/codex-rs/protocol/src/protocol.rs b/codex-rs/protocol/src/protocol.rs
index 8927dd2335..eae1c7b3e9 100644
--- a/codex-rs/protocol/src/protocol.rs
+++ b/codex-rs/protocol/src/protocol.rs
@@ -37,9 +37,67 @@ pub const ENVIRONMENT_CONTEXT_OPEN_TAG: &str = "<environment_context>";
 pub const ENVIRONMENT_CONTEXT_CLOSE_TAG: &str = "</environment_context>";
 pub const USER_MESSAGE_BEGIN: &str = "## My request for Codex:";
 
-/// Default disabled tools used when clients do not explicitly supply one.
-pub fn default_disabled_tools() -> Vec<String> {
-    vec!["web_search".to_string()]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, TS)]
+#[serde(rename_all = "snake_case")]
+pub enum DisabledToolKind {
+    WebSearch,
+    ViewImage,
+    UnifiedExec,
+    UpdatePlan,
+    Shell,
+    ApplyPatch,
+    GrepFiles,
+    ReadFile,
+    ListDir,
+    LocalShell,
+}
+
+impl DisabledToolKind {
+    pub fn raw_name(self) -> &'static str {
+        match self {
+            DisabledToolKind::WebSearch => "web_search",
+            DisabledToolKind::ViewImage => "view_image",
+            DisabledToolKind::UnifiedExec => "unified_exec",
+            DisabledToolKind::UpdatePlan => "update_plan",
+            DisabledToolKind::Shell => "shell",
+            DisabledToolKind::ApplyPatch => "apply_patch",
+            DisabledToolKind::GrepFiles => "grep_files",
+            DisabledToolKind::ReadFile => "read_file",
+            DisabledToolKind::ListDir => "list_dir",
+            DisabledToolKind::LocalShell => "local_shell",
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, TS)]
+#[serde(untagged)]
+pub enum DisabledTool {
+    Known(DisabledToolKind),
+    Other(String),
+}
+
+impl From<DisabledToolKind> for DisabledTool {
+    fn from(kind: DisabledToolKind) -> Self {
+        DisabledTool::Known(kind)
+    }
+}
+
+impl DisabledTool {
+    /// Default disabled tools used when clients do not explicitly supply one.
+    pub fn defaults() -> Vec<Self> {
+        vec![DisabledToolKind::WebSearch.into()]
+    }
+
+    pub fn raw_name(&self) -> &str {
+        match self {
+            DisabledTool::Known(kind) => kind.raw_name(),
+            DisabledTool::Other(name) => name.as_str(),
+        }
+    }
+
+    pub fn matches_tool_name(&self, tool_name: &str) -> bool {
+        self.raw_name() == tool_name
+    }
 }
 
 /// Submission Queue Entry - requests from user
@@ -96,8 +154,8 @@ pub enum Op {
         // The JSON schema to use for the final assistant message
         final_output_json_schema: Option<Value>,
         // disables tools
-        #[serde(default = "default_disabled_tools")]
-        disabled_tools: Vec<String>,
+        #[serde(default = "DisabledTool::defaults")]
+        disabled_tools: Vec<DisabledTool>,
     },
 
     /// Override parts of the persistent turn context for subsequent turns.
@@ -136,7 +194,7 @@ pub enum Op {
 
         /// Updated disabled tools.
         #[serde(skip_serializing_if = "Option::is_none")]
-        disabled_tools: Option<Vec<String>>,
+        disabled_tools: Option<Vec<DisabledTool>>,
     },
 
     /// Approve a command execution