diff --git a/codex-rs/core/src/tasks/user_shell.rs b/codex-rs/core/src/tasks/user_shell.rs
index f0922a070c..5b5bd7043b 100644
--- a/codex-rs/core/src/tasks/user_shell.rs
+++ b/codex-rs/core/src/tasks/user_shell.rs
@@ -106,7 +106,7 @@ impl SessionTask for UserShellCommandTask {
             // default timeout now that cancellation is wired through ExecExpiration.
             expiration: ExecExpiration::from_timeout_ms(
                 Some(USER_SHELL_TIMEOUT_MS),
-                cancellation_token.clone(),
+                cancellation_token.child_token(),
             ),
             sandbox: SandboxType::None,
             sandbox_permissions: SandboxPermissions::UseDefault,
diff --git a/codex-rs/core/src/tools/handlers/apply_patch.rs b/codex-rs/core/src/tools/handlers/apply_patch.rs
index 2223099892..8a4951969b 100644
--- a/codex-rs/core/src/tools/handlers/apply_patch.rs
+++ b/codex-rs/core/src/tools/handlers/apply_patch.rs
@@ -145,7 +145,7 @@ impl ToolHandler for ApplyPatchHandler {
                             turn: turn.as_ref(),
                             call_id: call_id.clone(),
                             tool_name: tool_name.to_string(),
-                            cancellation_token: cancellation_token.clone(),
+                            cancellation_token: cancellation_token.child_token(),
                         };
                         let out = orchestrator
                             .run(&mut runtime, &req, &tool_ctx, &turn, turn.approval_policy)
diff --git a/codex-rs/core/src/tools/handlers/shell.rs b/codex-rs/core/src/tools/handlers/shell.rs
index 67f8f5cd5d..bf6229f6f6 100644
--- a/codex-rs/core/src/tools/handlers/shell.rs
+++ b/codex-rs/core/src/tools/handlers/shell.rs
@@ -115,7 +115,7 @@ impl ToolHandler for ShellHandler {
             ToolPayload::Function { arguments } => {
                 let params: ShellToolCallParams = parse_arguments(&arguments)?;
                 let exec_params =
-                    Self::to_exec_params(params, turn.as_ref(), cancellation_token.clone());
+                    Self::to_exec_params(params, turn.as_ref(), cancellation_token.child_token());
                 Self::run_exec_like(
                     tool_name.as_str(),
                     exec_params,
@@ -126,7 +126,7 @@ impl ToolHandler for ShellHandler {
             }
             ToolPayload::LocalShell { params } => {
                 let exec_params =
-                    Self::to_exec_params(params, turn.as_ref(), cancellation_token.clone());
+                    Self::to_exec_params(params, turn.as_ref(), cancellation_token.child_token());
                 Self::run_exec_like(
                     tool_name.as_str(),
                     exec_params,
@@ -188,7 +188,7 @@ impl ToolHandler for ShellCommandHandler {
             params,
             session.as_ref(),
             turn.as_ref(),
-            cancellation_token.clone(),
+            cancellation_token.child_token(),
         );
         ShellHandler::run_exec_like(
             tool_name.as_str(),
@@ -265,7 +265,7 @@ impl ShellHandler {
             Some(&tracker),
             &call_id,
             tool_name,
-            cancellation_token.clone(),
+            cancellation_token.child_token(),
         )
         .await?
         {
diff --git a/codex-rs/core/src/tools/handlers/unified_exec.rs b/codex-rs/core/src/tools/handlers/unified_exec.rs
index e71fb315e4..9474a2a92b 100644
--- a/codex-rs/core/src/tools/handlers/unified_exec.rs
+++ b/codex-rs/core/src/tools/handlers/unified_exec.rs
@@ -164,7 +164,7 @@ impl ToolHandler for UnifiedExecHandler {
                     Some(&tracker),
                     &context.call_id,
                     tool_name.as_str(),
-                    context.cancellation_token.clone(),
+                    context.cancellation_token.child_token(),
                 )
                 .await?
                 {
diff --git a/codex-rs/core/src/tools/parallel.rs b/codex-rs/core/src/tools/parallel.rs
index d1e5875341..30ca574cca 100644
--- a/codex-rs/core/src/tools/parallel.rs
+++ b/codex-rs/core/src/tools/parallel.rs
@@ -64,7 +64,7 @@ impl ToolCallRuntime {
 
         let handle: AbortOnDropHandle<Result<ResponseInputItem, FunctionCallError>> =
             AbortOnDropHandle::new(tokio::spawn(async move {
-                let dispatch_cancellation = cancellation_token.clone();
+                let dispatch_cancellation = cancellation_token.child_token();
                 let mut dispatch_future = Box::pin(async {
                     let _guard = if supports_parallel {
                         Either::Left(lock.read().await)
diff --git a/codex-rs/core/src/tools/runtimes/apply_patch.rs b/codex-rs/core/src/tools/runtimes/apply_patch.rs
index 8f4e4745c3..c1d6c7f479 100644
--- a/codex-rs/core/src/tools/runtimes/apply_patch.rs
+++ b/codex-rs/core/src/tools/runtimes/apply_patch.rs
@@ -154,7 +154,7 @@ impl ToolRuntime<ApplyPatchRequest, ExecToolCallOutput> for ApplyPatchRuntime {
         attempt: &SandboxAttempt<'_>,
         ctx: &ToolCtx<'_>,
     ) -> Result<ExecToolCallOutput, ToolError> {
-        let spec = Self::build_command_spec(req, ctx.cancellation_token.clone())?;
+        let spec = Self::build_command_spec(req, ctx.cancellation_token.child_token())?;
         let env = attempt
             .env_for(spec)
             .map_err(|err| ToolError::Codex(err.into()))?;
diff --git a/codex-rs/core/src/tools/runtimes/shell.rs b/codex-rs/core/src/tools/runtimes/shell.rs
index 95f303ad79..3db0f89bba 100644
--- a/codex-rs/core/src/tools/runtimes/shell.rs
+++ b/codex-rs/core/src/tools/runtimes/shell.rs
@@ -157,7 +157,7 @@ impl ToolRuntime<ShellRequest, ExecToolCallOutput> for ShellRuntime {
         };
 
         let expiration =
-            ExecExpiration::from_timeout_ms(req.timeout_ms, ctx.cancellation_token.clone());
+            ExecExpiration::from_timeout_ms(req.timeout_ms, ctx.cancellation_token.child_token());
         let spec = build_command_spec(
             &command,
             &req.cwd,
diff --git a/codex-rs/core/src/tools/runtimes/unified_exec.rs b/codex-rs/core/src/tools/runtimes/unified_exec.rs
index bf1f008054..682c7e4acc 100644
--- a/codex-rs/core/src/tools/runtimes/unified_exec.rs
+++ b/codex-rs/core/src/tools/runtimes/unified_exec.rs
@@ -180,7 +180,7 @@ impl<'a> ToolRuntime<UnifiedExecRequest, UnifiedExecProcess> for UnifiedExecRunt
             &command,
             &req.cwd,
             &req.env,
-            ExecExpiration::default(ctx.cancellation_token.clone()),
+            ExecExpiration::default(ctx.cancellation_token.child_token()),
             req.sandbox_permissions,
             req.justification.clone(),
         )
diff --git a/codex-rs/core/src/unified_exec/process_manager.rs b/codex-rs/core/src/unified_exec/process_manager.rs
index d363edeb2f..59c711e082 100644
--- a/codex-rs/core/src/unified_exec/process_manager.rs
+++ b/codex-rs/core/src/unified_exec/process_manager.rs
@@ -543,7 +543,7 @@ impl UnifiedExecProcessManager {
             turn: context.turn.as_ref(),
             call_id: context.call_id.clone(),
             tool_name: "exec_command".to_string(),
-            cancellation_token: context.cancellation_token.clone(),
+            cancellation_token: context.cancellation_token.child_token(),
         };
         orchestrator
             .run(
diff --git a/codex-rs/core/tests/suite/abort_tasks.rs b/codex-rs/core/tests/suite/abort_tasks.rs
index 985280533a..e44cb6bfa5 100644
--- a/codex-rs/core/tests/suite/abort_tasks.rs
+++ b/codex-rs/core/tests/suite/abort_tasks.rs
@@ -29,7 +29,7 @@ fn long_running_exec_command_with_output() -> (String, Option<&'static str>) {
         )
     } else {
         (
-            "sleep 0.2; printf 'partial output\\n'; sleep 60".to_string(),
+            "sleep 0.2; printf 'partial output\\n' >&2; sleep 60".to_string(),
             None,
         )
     }
@@ -47,7 +47,7 @@ fn long_running_shell_command_with_output() -> Vec<String> {
         vec![
             "/bin/sh".to_string(),
             "-c".to_string(),
-            "sleep 0.2; printf 'partial output\\n'; sleep 60".to_string(),
+            "sleep 0.2; printf 'partial output\\n' >&2; sleep 60".to_string(),
         ]
     }
 }
@@ -64,7 +64,7 @@ fn long_running_local_shell_call_with_output() -> Vec<&'static str> {
         vec![
             "/bin/sh",
             "-c",
-            "sleep 0.2; printf 'partial output\\n'; sleep 60",
+            "sleep 0.2; printf 'partial output\\n' >&2; sleep 60",
         ]
     }
 }