Reject non-boolean child gate results

bin/aas.mjs

@@ -133,6 +133,14 @@ export function parseJsonOutput(text, label) {
   throw new Error(`${label} did not return JSON: ${parseError.message}`);
 }
 
+function booleanField(payload, field, label) {
+  if (!payload || typeof payload !== "object" || Array.isArray(payload)
+    || typeof payload[field] !== "boolean") {
+    throw new Error(`${label} did not return a boolean ${field} field`);
+  }
+  return payload[field];
+}
+
 function pythonCandidates() {
   if (process.platform === "win32") {
     return [["py", ["-3"]], ["python", []], ["python3", []]];
@@ -195,7 +203,7 @@ export function runDecide(
       throw childProcessError("decide", result);
     }
     const evaluation = parseJsonOutput(result.stdout, "decide");
-    return { ok: Boolean(evaluation.passed), raw: evaluation, status: 0 };
+    return { ok: booleanField(evaluation, "passed", "decide"), raw: evaluation, status: 0 };
   }
   throw new Error(`Python not found for decide stage${lastError ? ` (${lastError.code ?? "spawn-error"})` : ""}`);
 }
@@ -231,7 +239,7 @@ export function runProve(
   );
   if (result.status !== 0) throw childProcessError("prove", result);
   const payload = parseJsonOutput(result.stdout, "prove");
-  return { ok: Boolean(payload.ok), raw: payload, status: 0 };
+  return { ok: booleanField(payload, "ok", "prove"), raw: payload, status: 0 };
 }
 
 export function createRunId(now = new Date(), nonce = randomUUID()) {

test/stack.test.mjs

@@ -10,7 +10,9 @@ import {
   persistRunBundle,
   resolveComponentProvenance,
   runAct,
+  runDecide,
   runDemo,
+  runProve,
   writeAtomicFile,
 } from "../bin/aas.mjs";
 
@@ -140,6 +142,17 @@ test("act rejects a zero-exit payload without a valid outcome", () => {
   );
 });
 
+test("decide and prove reject non-boolean success fields", () => {
+  const runner = () => ({
+    status: 0,
+    stdout: '{"passed":"false","ok":"false"}\n',
+    stderr: "",
+    error: null,
+  });
+  assert.throws(() => runDecide("unused", { runner }), /boolean passed field/);
+  assert.throws(() => runProve("unused", { runner }), /boolean ok field/);
+});
+
 test("child output parser accepts logged pretty-printed JSON", () => {
   assert.deepEqual(
     parseJsonOutput('starting child\n{\n  "ok": true,\n  "result": { "count": 2 }\n}\n', "fixture"),