feat(hooks): add empty-task-response-detector hook

src/hooks/empty-task-response-detector.ts

@@ -0,0 +1,27 @@
+import type { PluginInput } from "@opencode-ai/plugin"
+
+const EMPTY_RESPONSE_WARNING = `[Task Empty Response Warning]
+
+Task invocation completed but returned no response. This indicates the agent either:
+- Failed to execute properly
+- Did not terminate correctly
+- Returned an empty result
+
+Note: The call has already completed - you are NOT waiting for a response. Proceed accordingly.`
+
+export function createEmptyTaskResponseDetectorHook(_ctx: PluginInput) {
+  return {
+    "tool.execute.after": async (
+      input: { tool: string; sessionID: string; callID: string },
+      output: { title: string; output: string; metadata: unknown }
+    ) => {
+      if (input.tool !== "Task") return
+
+      const responseText = output.output?.trim() ?? ""
+
+      if (responseText === "") {
+        output.output = EMPTY_RESPONSE_WARNING
+      }
+    },
+  }
+}