diff --git a/plugin/index.ts b/plugin/index.ts
index 2058c21..3fe19f4 100644
--- a/plugin/index.ts
+++ b/plugin/index.ts
@@ -73,6 +73,30 @@ interface PluginAPI {
   getAgentStatus?: () => Promise<{ status: string } | null>;
 }
 
+/**
+ * Coerce a tool execute() return value into the MCP `{ content: [...] }`
+ * shape that the openclaw Codex tool dispatcher requires.
+ *
+ * Background: openclaw's `convertToolContents()` does `result.content.reduce(...)`
+ * to compute total text length before flattening. Every HF tool here returned a
+ * bare object (`{ running, processing, currentSlot, ... }`) which has no
+ * `.content` field, so `undefined.reduce` threw and every call to
+ * `harborforge_*` from a Codex-harness agent surfaced as the cryptic
+ * `Cannot read properties of undefined (reading 'reduce')`. The fix is to
+ * wrap every tool's execute return; doing it at the `registerTool` boundary
+ * keeps each tool body unchanged.
+ */
+function ensureMcpContentShape(result: unknown): { content: Array<{ type: 'text'; text: string }> } {
+  if (
+    result && typeof result === 'object' &&
+    Array.isArray((result as { content?: unknown }).content)
+  ) {
+    return result as { content: Array<{ type: 'text'; text: string }> };
+  }
+  const text = typeof result === 'string' ? result : JSON.stringify(result, null, 2);
+  return { content: [{ type: 'text', text }] };
+}
+
 function register(api: PluginAPI): void {
     const logger = api.logger || {
       info: (...args: any[]) => console.log('[HarborForge]', ...args),
@@ -81,6 +105,22 @@ function register(api: PluginAPI): void {
       warn: (...args: any[]) => console.warn('[HarborForge]', ...args),
     };
 
+    // Wrap api.registerTool so every tool's execute() return is coerced into
+    // the MCP `{ content: [...] }` shape openclaw expects. See
+    // `ensureMcpContentShape` above.
+    const _origRegisterTool = api.registerTool.bind(api);
+    api.registerTool = (factory: (ctx: any) => any) => {
+      _origRegisterTool((ctx: any) => {
+        const def = factory(ctx);
+        if (!def || typeof def.execute !== 'function') return def;
+        const origExecute = def.execute;
+        return {
+          ...def,
+          execute: async (...args: any[]) => ensureMcpContentShape(await origExecute(...args)),
+        };
+      });
+    };
+
     function resolveConfig() {
       return getPluginConfig(api);
     }