diff --git a/apps/generator/src/lib/render.ts b/apps/generator/src/lib/render.ts
index 179a104..9705179 100644
--- a/apps/generator/src/lib/render.ts
+++ b/apps/generator/src/lib/render.ts
@@ -38,6 +38,15 @@ function renderTool(tool: ToolSpec): string {
     inputSchema: ${schemaShape},
   },
   async (args) => {
+    // The MCP SDK passes the validated tool arguments as the single
+    // parameter. Models trained on OpenAPI / JSON-RPC examples reach
+    // for "params" instead of "args", and "input" shows up too — bind
+    // every common alias to the same object so the generated body
+    // works whichever name the model picked. Without this the runner
+    // crashes with "ReferenceError: params is not defined" at the
+    // first tool call (verified in prod with the wetter server).
+    const params = args;
+    const input = args;
     try {
       ${tool.implementation}
     } catch (err) {
diff --git a/packages/llm/src/index.ts b/packages/llm/src/index.ts
index 1c2c546..a62f155 100644
--- a/packages/llm/src/index.ts
+++ b/packages/llm/src/index.ts
@@ -15,7 +15,7 @@ Output ONE JSON object (no markdown, no prose, no code fences) with this exact s
       "inputSchema": {
         "param_name": { "type": "string|number|boolean|array|object", "description": "short", "required": true }
       },
-      "implementation": "async TS body, return { content: [{ type:'text', text:'...' }] }; secrets via process.env; HTTP via globalThis.fetch with AbortSignal.timeout(10000); try/catch -> { content:[{type:'text',text:'Error: ...'}], isError:true }; no eval/Function/child_process; no imports."
+      "implementation": "async TS body. The tool's validated arguments arrive in the variable named EXACTLY `args` (e.g. args.location, args.query). Return { content: [{ type:'text', text:'...' }] }. Secrets via process.env. HTTP via globalThis.fetch with AbortSignal.timeout(10000). Wrap external calls in try/catch and return { content:[{type:'text',text:'Error: ...'}], isError:true } on failure. No eval/Function/child_process. No import statements."
     }
   ],
   "resources": [],