diff --git a/src/adapters/process-transport.ts b/src/adapters/process-transport.ts
index 23187cd..3b7931e 100644
--- a/src/adapters/process-transport.ts
+++ b/src/adapters/process-transport.ts
@@ -419,6 +419,10 @@ async function terminatePosix(
   pid: number,
   graceMs: number,
 ): Promise<TerminationScope> {
+  if (hasEnded(child)) {
+    return TERMINATION_SCOPE.DIRECT_CHILD_ONLY;
+  }
+
   let groupReached = signalProcessGroup(pid, 'SIGTERM');
   if (!groupReached) {
     killDirectChild(child, 'SIGTERM');
@@ -743,9 +747,19 @@ export function invokeAgentProcess(
     };
 
     if (child.stdout !== null) {
+      onEvent(child.stdout, 'error', () => {
+        // Read failures are consumed here without promoting the exchange to a
+        // terminal failure state, matching the stdin pattern. The close path
+        // decides the outcome.
+      });
       onReadableData(child.stdout, onStdout);
     }
     if (child.stderr !== null) {
+      onEvent(child.stderr, 'error', () => {
+        // Read failures are consumed here without promoting the exchange to a
+        // terminal failure state, matching the stdin pattern. The close path
+        // decides the outcome.
+      });
       onReadableData(child.stderr, onStderr);
     }
 
diff --git a/tests/adapters/process-transport.test.ts b/tests/adapters/process-transport.test.ts
index 673da1e..61e04db 100644
--- a/tests/adapters/process-transport.test.ts
+++ b/tests/adapters/process-transport.test.ts
@@ -117,7 +117,7 @@ describe('invokeAgentProcess — success', () => {
     }
   });
 
-  it('accepts a zero-argument argv', async () => {
+  it('accepts a single-argument argv', async () => {
     const exchange = await invokeAgentProcess(
       makeSpec({ args: ['--version'] }),
       makeLimits(),
@@ -127,6 +127,16 @@ describe('invokeAgentProcess — success', () => {
     expect(exchange.exitCode).toBe(0);
   });
 
+  it('accepts a zero-argument argv', async () => {
+    const exchange = await invokeAgentProcess(
+      makeSpec({ args: [] }),
+      makeLimits({ timeoutMs: 500, graceMs: 200 }),
+    );
+
+    // Node starts an interactive REPL with no arguments, which times out
+    expect(exchange.outcome).toBe('TIMED_OUT');
+  }, 15_000);
+
   it('reports source bytes that match the decoded stdout for valid UTF-8', async () => {
     const exchange = await runStub(STUB.MULTIBYTE, ['3']);