feat(worker): enforce bounded bash timeouts via pi extension

apps/worker/src/ai/extensions/bash-timeout/index.ts

@@ -0,0 +1,47 @@
+/**
+ * pi extension: enforce a bounded timeout on every `bash` tool call.
+ *
+ * pi's built-in bash tool accepts an optional `timeout` (in seconds) but applies
+ * NO default and NO upper bound — an unbounded command (e.g. a `playwright-cli`
+ * browser action that never returns) hangs the agent indefinitely. This extension
+ * registers a `tool_call` pre-execution handler that blocks any `bash` invocation
+ * that omits `timeout` or sets it above the maximum, returning a message that tells
+ * the model how to re-run the command correctly.
+ */
+
+import type { ExtensionAPI, ToolCallEvent, ToolCallEventResult } from '@earendil-works/pi-coding-agent';
+import { isToolCallEventType } from '@earendil-works/pi-coding-agent';
+
+/** Recommended timeout (seconds) suggested to the model when it omits one. */
+const DEFAULT_TIMEOUT_SECONDS = 120;
+
+/** Hard upper bound (seconds) a single bash command may run. */
+const MAX_TIMEOUT_SECONDS = 600;
+
+function evaluateBashTimeout(timeout: number | undefined): ToolCallEventResult | undefined {
+  const hasValidTimeout = typeof timeout === 'number' && Number.isFinite(timeout) && timeout > 0;
+  if (!hasValidTimeout) {
+    return {
+      block: true,
+      reason: `Set bash 'timeout' (seconds). Default ${DEFAULT_TIMEOUT_SECONDS}s, max ${MAX_TIMEOUT_SECONDS}s.`,
+    };
+  }
+
+  if (timeout > MAX_TIMEOUT_SECONDS) {
+    return {
+      block: true,
+      reason: `bash 'timeout' ${timeout}s exceeds max ${MAX_TIMEOUT_SECONDS}s. Default ${DEFAULT_TIMEOUT_SECONDS}s, max ${MAX_TIMEOUT_SECONDS}s.`,
+    };
+  }
+
+  return undefined;
+}
+
+export default function bashTimeoutExtension(pi: ExtensionAPI): void {
+  pi.on('tool_call', (event: ToolCallEvent): ToolCallEventResult | undefined => {
+    if (!isToolCallEventType('bash', event)) {
+      return undefined;
+    }
+    return evaluateBashTimeout(event.input.timeout);
+  });
+}