fix: add plugin load debug shape

src/plugins/loader.ts

@@ -1022,6 +1022,53 @@ function resolvePluginModuleExport(moduleExport: unknown): {
   return {};
 }
 
+function isPluginLoadDebugEnabled(env: NodeJS.ProcessEnv): boolean {
+  const normalized = normalizeLowercaseStringOrEmpty(env.OPENCLAW_PLUGIN_LOAD_DEBUG);
+  return normalized === "1" || normalized === "true" || normalized === "yes" || normalized === "on";
+}
+
+function describePluginModuleExportShape(
+  value: unknown,
+  label = "export",
+  seen: Set<unknown> = new Set(),
+): string[] {
+  if (value === null) {
+    return [`${label}:null`];
+  }
+  if (typeof value !== "object") {
+    return [`${label}:${typeof value}`];
+  }
+  if (seen.has(value)) {
+    return [`${label}:circular`];
+  }
+  seen.add(value);
+
+  const record = value as Record<string, unknown>;
+  const keys = Object.keys(record).toSorted();
+  const visibleKeys = keys.slice(0, 8);
+  const extraCount = keys.length - visibleKeys.length;
+  const keySummary =
+    visibleKeys.length > 0
+      ? `${visibleKeys.join(",")}${extraCount > 0 ? `,+${extraCount}` : ""}`
+      : "none";
+  const details = [`${label}:object keys=${keySummary}`];
+
+  for (const key of ["default", "module", "register", "activate"]) {
+    if (Object.prototype.hasOwnProperty.call(record, key)) {
+      details.push(...describePluginModuleExportShape(record[key], `${label}.${key}`, seen));
+    }
+  }
+  return details;
+}
+
+function formatMissingPluginRegisterError(moduleExport: unknown, env: NodeJS.ProcessEnv): string {
+  const message = "plugin export missing register/activate";
+  if (!isPluginLoadDebugEnabled(env)) {
+    return message;
+  }
+  return `${message} (module shape: ${describePluginModuleExportShape(moduleExport).join("; ")})`;
+}
+
 function mergeChannelPluginSection<T>(
   baseValue: T | undefined,
   overrideValue: T | undefined,
@@ -2511,7 +2558,7 @@ export function loadOpenClawPlugins(options: PluginLoadOptions = {}): PluginRegi
 
       if (typeof register !== "function") {
         logger.error(`[plugins] ${record.id} missing register/activate export`);
-        pushPluginLoadError("plugin export missing register/activate");
+        pushPluginLoadError(formatMissingPluginRegisterError(mod, env));
         continue;
       }
 
@@ -2934,7 +2981,7 @@ export async function loadOpenClawPluginCliRegistry(
 
     if (typeof register !== "function") {
       logger.error(`[plugins] ${record.id} missing register/activate export`);
-      pushPluginLoadError("plugin export missing register/activate");
+      pushPluginLoadError(formatMissingPluginRegisterError(mod, env));
       continue;
     }