Update README.md

README.md

@@ -92,6 +92,30 @@ letta -p "run tests" --tools "Bash,Read"         # Only load specific tools
 letta -p "analyze code" --tools ""               # No tools (analysis only)
 ```
 
+Use `--output-format json` to get additional information, including the agent ID ("session_id"):
+```bash
+# regular text output
+$ letta -p "hi there"
+Hi! How can I help you today?
+
+# structured output
+$ letta -p "hi there" --output-format json
+{
+  "type": "result",
+  "subtype": "success",
+  "is_error": false,
+  "duration_ms": 5454,
+  "duration_api_ms": 2098,
+  "num_turns": 1,
+  "result": "Hi! How can I help you today?",
+  "session_id": "agent-8ab431ca-63e0-4ca1-ba83-b64d66d95a0f",
+  "usage": {
+    "input_tokens": 294,
+    "output_tokens": 97
+  }
+}
+```
+
 ### Permissions
 
 **Tool selection** (controls which tools are loaded):