diff --git a/codex-rs/Cargo.lock b/codex-rs/Cargo.lock
index c5846fbe19..67d43f1453 100644
--- a/codex-rs/Cargo.lock
+++ b/codex-rs/Cargo.lock
@@ -2632,6 +2632,7 @@ dependencies = [
 name = "codex-tools"
 version = "0.0.0"
 dependencies = [
+ "codex-protocol",
  "pretty_assertions",
  "rmcp",
  "serde",
diff --git a/codex-rs/core/src/tools/spec.rs b/codex-rs/core/src/tools/spec.rs
index ea85eaacdd..42dbbff98c 100644
--- a/codex-rs/core/src/tools/spec.rs
+++ b/codex-rs/core/src/tools/spec.rs
@@ -46,8 +46,8 @@ use codex_protocol::openai_models::WebSearchToolType;
 use codex_protocol::protocol::SandboxPolicy;
 use codex_protocol::protocol::SessionSource;
 use codex_protocol::protocol::SubAgentSource;
+use codex_tools::parse_dynamic_tool;
 use codex_tools::parse_mcp_tool;
-pub use codex_tools::parse_tool_input_schema;
 use codex_utils_absolute_path::AbsolutePathBuf;
 use serde::Deserialize;
 use serde::Serialize;
@@ -2397,14 +2397,14 @@ pub(crate) fn mcp_tool_to_deferred_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)?;
+    let parsed_tool = parse_dynamic_tool(tool)?;
 
     Ok(ResponsesApiTool {
         name: tool.name.clone(),
-        description: tool.description.clone(),
+        description: parsed_tool.description,
         strict: false,
-        defer_loading: None,
-        parameters: input_schema,
+        defer_loading: parsed_tool.defer_loading.then_some(true),
+        parameters: parsed_tool.input_schema,
         output_schema: None,
     })
 }
diff --git a/codex-rs/core/src/tools/spec_tests.rs b/codex-rs/core/src/tools/spec_tests.rs
index 5b9016ec6a..cd0ffd6f6e 100644
--- a/codex-rs/core/src/tools/spec_tests.rs
+++ b/codex-rs/core/src/tools/spec_tests.rs
@@ -8,6 +8,7 @@ use crate::tools::ToolRouter;
 use crate::tools::registry::ConfiguredToolSpec;
 use crate::tools::router::ToolRouterParams;
 use codex_app_server_protocol::AppInfo;
+use codex_protocol::dynamic_tools::DynamicToolSpec;
 use codex_protocol::openai_models::InputModality;
 use codex_protocol::openai_models::ModelInfo;
 use codex_protocol::openai_models::ModelsResponse;
@@ -126,6 +127,27 @@ fn deferred_responses_api_tool_serializes_with_defer_loading() {
     );
 }
 
+#[test]
+fn dynamic_tool_preserves_defer_loading() {
+    let tool = DynamicToolSpec {
+        name: "lookup_order".to_string(),
+        description: "Look up an order".to_string(),
+        input_schema: serde_json::json!({
+            "type": "object",
+            "properties": {
+                "order_id": {"type": "string"}
+            },
+            "required": ["order_id"],
+            "additionalProperties": false,
+        }),
+        defer_loading: true,
+    };
+
+    let openai_tool = dynamic_tool_to_openai_tool(&tool).expect("convert dynamic tool");
+
+    assert_eq!(openai_tool.defer_loading, Some(true));
+}
+
 fn tool_name(tool: &ToolSpec) -> &str {
     match tool {
         ToolSpec::Function(ResponsesApiTool { name, .. }) => name,
diff --git a/codex-rs/tools/Cargo.toml b/codex-rs/tools/Cargo.toml
index d695336fae..1dc9b1c2fa 100644
--- a/codex-rs/tools/Cargo.toml
+++ b/codex-rs/tools/Cargo.toml
@@ -8,6 +8,7 @@ version.workspace = true
 workspace = true
 
 [dependencies]
+codex-protocol = { workspace = true }
 rmcp = { workspace = true, default-features = false, features = [
     "base64",
     "macros",
diff --git a/codex-rs/tools/README.md b/codex-rs/tools/README.md
index b8780fe7b1..b6f4539ffd 100644
--- a/codex-rs/tools/README.md
+++ b/codex-rs/tools/README.md
@@ -10,6 +10,8 @@ schema primitives that no longer need to live in `core/src/tools/spec.rs`:
 - `JsonSchema`
 - `AdditionalProperties`
 - `parse_tool_input_schema()`
+- `ParsedDynamicTool`
+- `parse_dynamic_tool()`
 - `ParsedMcpTool`
 - `parse_mcp_tool()`
 - `mcp_call_tool_result_output_schema()`
diff --git a/codex-rs/tools/src/dynamic_tool.rs b/codex-rs/tools/src/dynamic_tool.rs
new file mode 100644
index 0000000000..8be6a934a6
--- /dev/null
+++ b/codex-rs/tools/src/dynamic_tool.rs
@@ -0,0 +1,24 @@
+use crate::JsonSchema;
+use crate::parse_tool_input_schema;
+use codex_protocol::dynamic_tools::DynamicToolSpec;
+
+/// Parsed dynamic tool metadata and schemas that can be adapted into a
+/// higher-level tool spec by downstream crates.
+#[derive(Debug, PartialEq)]
+pub struct ParsedDynamicTool {
+    pub description: String,
+    pub input_schema: JsonSchema,
+    pub defer_loading: bool,
+}
+
+pub fn parse_dynamic_tool(tool: &DynamicToolSpec) -> Result<ParsedDynamicTool, serde_json::Error> {
+    Ok(ParsedDynamicTool {
+        description: tool.description.clone(),
+        input_schema: parse_tool_input_schema(&tool.input_schema)?,
+        defer_loading: tool.defer_loading,
+    })
+}
+
+#[cfg(test)]
+#[path = "dynamic_tool_tests.rs"]
+mod tests;
diff --git a/codex-rs/tools/src/dynamic_tool_tests.rs b/codex-rs/tools/src/dynamic_tool_tests.rs
new file mode 100644
index 0000000000..67bb76cc5e
--- /dev/null
+++ b/codex-rs/tools/src/dynamic_tool_tests.rs
@@ -0,0 +1,66 @@
+use super::ParsedDynamicTool;
+use super::parse_dynamic_tool;
+use crate::JsonSchema;
+use codex_protocol::dynamic_tools::DynamicToolSpec;
+use pretty_assertions::assert_eq;
+use std::collections::BTreeMap;
+
+#[test]
+fn parse_dynamic_tool_sanitizes_input_schema() {
+    let tool = DynamicToolSpec {
+        name: "lookup_ticket".to_string(),
+        description: "Fetch a ticket".to_string(),
+        input_schema: serde_json::json!({
+            "properties": {
+                "id": {
+                    "description": "Ticket identifier"
+                }
+            }
+        }),
+        defer_loading: false,
+    };
+
+    assert_eq!(
+        parse_dynamic_tool(&tool).expect("parse dynamic tool"),
+        ParsedDynamicTool {
+            description: "Fetch a ticket".to_string(),
+            input_schema: JsonSchema::Object {
+                properties: BTreeMap::from([(
+                    "id".to_string(),
+                    JsonSchema::String {
+                        description: Some("Ticket identifier".to_string()),
+                    },
+                )]),
+                required: None,
+                additional_properties: None,
+            },
+            defer_loading: false,
+        }
+    );
+}
+
+#[test]
+fn parse_dynamic_tool_preserves_defer_loading() {
+    let tool = DynamicToolSpec {
+        name: "lookup_ticket".to_string(),
+        description: "Fetch a ticket".to_string(),
+        input_schema: serde_json::json!({
+            "type": "object",
+            "properties": {}
+        }),
+        defer_loading: true,
+    };
+
+    assert_eq!(
+        parse_dynamic_tool(&tool).expect("parse dynamic tool"),
+        ParsedDynamicTool {
+            description: "Fetch a ticket".to_string(),
+            input_schema: JsonSchema::Object {
+                properties: BTreeMap::new(),
+                required: None,
+                additional_properties: None,
+            },
+            defer_loading: true,
+        }
+    );
+}
diff --git a/codex-rs/tools/src/lib.rs b/codex-rs/tools/src/lib.rs
index e719d3e23f..2698e83f4f 100644
--- a/codex-rs/tools/src/lib.rs
+++ b/codex-rs/tools/src/lib.rs
@@ -1,8 +1,11 @@
 //! Shared tool-schema parsing primitives that can live outside `codex-core`.
 
+mod dynamic_tool;
 mod json_schema;
 mod mcp_tool;
 
+pub use dynamic_tool::ParsedDynamicTool;
+pub use dynamic_tool::parse_dynamic_tool;
 pub use json_schema::AdditionalProperties;
 pub use json_schema::JsonSchema;
 pub use json_schema::parse_tool_input_schema;