diff --git a/crates/opy-rs/src/macro_js/tests/isolation.rs b/crates/opy-rs/src/macro_js/tests/isolation.rs
index a5779bb0..b052c13f 100644
--- a/crates/opy-rs/src/macro_js/tests/isolation.rs
+++ b/crates/opy-rs/src/macro_js/tests/isolation.rs
@@ -101,3 +101,151 @@ fn concurrent_runtime_instances_are_independent() {
         }
     });
 }
+
+#[test]
+fn memory_limit_recovery_keeps_each_invocation_bounded() {
+    // An invocation that exhausts the memory limit must neither leak its
+    // allocation accounting nor disable the limit for the next invocation.
+    let limits = Limits {
+        memory_limit_bytes: 2 * 1024 * 1024,
+        ..Limits::default()
+    };
+    let rt = MacroRuntime::new(limits);
+    let allocation_loop =
+        r#"var a = []; for (var i = 0; i < 1000000; i++) { a.push("x".repeat(1024)); }"#;
+
+    for _ in 0..2 {
+        let error = rt.run_macro(allocation_loop, &[], "mem.js").unwrap_err();
+        match error {
+            MacroError::Script(ref script) => assert_eq!(script.message, "out of memory"),
+            ref other => panic!("expected Script error, got {other:?}"),
+        }
+    }
+    let result = rt.run_macro(r#""recovered";"#, &[], "after.js").unwrap();
+    assert_eq!(result.text, "recovered");
+}
+
+#[test]
+fn stack_limit_recovery_keeps_each_invocation_bounded() {
+    let limits = Limits {
+        max_stack_bytes: 128 * 1024,
+        ..Limits::default()
+    };
+    let rt = MacroRuntime::new(limits);
+
+    for _ in 0..2 {
+        let error = rt
+            .run_macro("function f() { return f(); } f();", &[], "stack.js")
+            .unwrap_err();
+        match error {
+            MacroError::Script(ref script) => {
+                assert_eq!(script.message, "Maximum call stack size exceeded")
+            }
+            ref other => panic!("expected Script error, got {other:?}"),
+        }
+    }
+    let result = rt.run_macro(r#""recovered";"#, &[], "after.js").unwrap();
+    assert_eq!(result.text, "recovered");
+}
+
+#[test]
+fn deadline_state_is_re_armed_per_invocation() {
+    // After an interrupted invocation the interrupt handler must be reset:
+    // the next call gets a fresh deadline, not the expired one.
+    let rt = MacroRuntime::new(Limits {
+        macro_time_budget: Duration::from_millis(50),
+        ..Limits::default()
+    });
+    rt.run_macro("while (true) {}", &[], "first.js")
+        .unwrap_err();
+    // Succeeding invocations after the abort get a full fresh budget.
+    for _ in 0..3 {
+        let result = rt
+            .run_macro(
+                r#"var t = Date.now(); while (Date.now() - t < 1) {} "ok";"#,
+                &[],
+                "second.js",
+            )
+            .unwrap();
+        assert_eq!(result.text, "ok");
+    }
+}
+
+#[test]
+fn console_sink_is_rebound_per_invocation() {
+    // `console.log` writes to the invocation's own buffer: a previous call's
+    // sink must not receive or retain lines.
+    let rt = runtime();
+    let first = rt
+        .run_macro(r#"console.log("a"); "ok";"#, &[], "first.js")
+        .unwrap();
+    assert_eq!(first.console_output, vec!["a"]);
+
+    let error = rt
+        .run_macro(r#"console.log("b"); throw new Error("x");"#, &[], "err.js")
+        .unwrap_err();
+    assert!(matches!(error, MacroError::Script(_)));
+
+    let second = rt
+        .run_macro(r#"console.log("c", 1 + 1); "ok";"#, &[], "second.js")
+        .unwrap();
+    assert_eq!(second.console_output, vec!["c 2"]);
+}
+
+#[test]
+fn many_consecutive_invocations_stay_independent() {
+    // Sweep: interleave leaking, throwing, and clean invocations on one
+    // runtime; every result must reflect only its own invocation.
+    let rt = runtime();
+    for i in 0..32 {
+        // Set marker{i} and verify it is visible in the same invocation;
+        // a later script then asserts it is gone again.
+        let leak =
+            format!(r#"globalThis.marker{i} = {i}; (globalThis.marker{i} === {i}).toString();"#);
+        let leaked = rt.run_macro(&leak, &[], "leak.js").unwrap();
+        assert_eq!(leaked.text, "true");
+        let check = rt
+            .run_macro(&format!(r#"typeof globalThis.marker{i};"#), &[], "check.js")
+            .unwrap();
+        assert_eq!(check.text, "undefined");
+        if i > 0 {
+            let previous = rt
+                .run_macro(
+                    &format!(r#"typeof globalThis.marker{};"#, i - 1),
+                    &[],
+                    "check-prev.js",
+                )
+                .unwrap();
+            assert_eq!(previous.text, "undefined");
+        }
+        if i % 3 == 0 {
+            rt.run_macro("throw new Error(\"x\");", &[], "err.js")
+                .unwrap_err();
+        }
+    }
+}
+
+#[test]
+fn builtin_intrinsics_are_fully_reset() {
+    // Mutation of shared-looking intrinsics (Object.prototype, Array methods,
+    // the builtins script's `vect`) must not reach the next invocation.
+    let rt = runtime();
+    rt.run_macro(
+        r#"Array.prototype.push = function() { return -1; };
+           vect = function() { return "tampered"; };
+           Date.now = function() { return 0; };
+           "ok";"#,
+        &[],
+        "poison.js",
+    )
+    .unwrap();
+    let result = rt
+        .run_macro(
+            r#"var a = [1]; a.push(2);
+               (a.length === 2 && typeof vect(1,2,3).x === "number" && Date.now() !== 0).toString();"#,
+            &[],
+            "verify.js",
+        )
+        .unwrap();
+    assert_eq!(result.text, "true");
+}