diff --git a/crates/application/src/plugin/mod.rs b/crates/application/src/plugin/mod.rs
index 7cc52c91..18b01136 100644
--- a/crates/application/src/plugin/mod.rs
+++ b/crates/application/src/plugin/mod.rs
@@ -2443,6 +2443,10 @@ fn workspace_exec_sandbox(
         abs_root: root.as_str().to_owned(),
         access: project_access,
     }];
+    allowed.push(domain::PathGrant {
+        abs_root: "/dev/null".to_owned(),
+        access: domain::PathAccess::RO | domain::PathAccess::RW,
+    });
     for system_root in ["/bin", "/usr", "/lib", "/lib64", "/etc"] {
         allowed.push(domain::PathGrant {
             abs_root: system_root.to_owned(),
@@ -6063,6 +6067,29 @@ mod tests {
         }
     }
 
+    #[test]
+    fn workspace_exec_read_sandbox_grants_dev_null_without_widening_project_access() {
+        let root = ProjectPath::new("/workspace/example").unwrap();
+        let sandbox = workspace_exec_sandbox(&root, PluginWorkspaceExecEffect::Read);
+
+        assert_eq!(
+            sandbox
+                .allowed
+                .iter()
+                .find(|grant| grant.abs_root == root.as_str())
+                .map(|grant| grant.access),
+            Some(domain::PathAccess::RO | domain::PathAccess::EXEC)
+        );
+        assert_eq!(
+            sandbox
+                .allowed
+                .iter()
+                .find(|grant| grant.abs_root == "/dev/null")
+                .map(|grant| grant.access),
+            Some(domain::PathAccess::RO | domain::PathAccess::RW)
+        );
+    }
+
     #[tokio::test]
     async fn workspace_exec_allows_matching_rule_clamps_limits_and_audits_metadata() {
         let (project_id, tool, runner, audit) = workspace_exec_fixture();
diff --git a/crates/infrastructure/src/workspace_tool.rs b/crates/infrastructure/src/workspace_tool.rs
index 0f0d3c25..dbb5ccc6 100644
--- a/crates/infrastructure/src/workspace_tool.rs
+++ b/crates/infrastructure/src/workspace_tool.rs
@@ -263,4 +263,18 @@ mod tests {
         assert!(result.stdout_truncated);
         assert!(!result.stderr_truncated);
     }
+
+    #[cfg(unix)]
+    #[tokio::test]
+    async fn local_runner_allows_cli_to_open_dev_null_for_read_and_write() {
+        let runner = LocalWorkspaceToolRunner::new(Arc::new(crate::sandbox::NoopSandbox));
+        let result = runner
+            .run(spec(&["-c", "exec 3<>/dev/null; printf ok"], 1_000, 32))
+            .await
+            .unwrap();
+
+        assert_eq!(result.exit_code, Some(0));
+        assert_eq!(result.stdout, b"ok");
+        assert!(result.stderr.is_empty());
+    }
 }