docs(apps): add payload size limit info

Author: masnwilliams

apps/develop.mdx

@@ -56,7 +56,7 @@ app.action("my-action-name", myActionMethod);
 Action methods receive two parameters:
 
 - `runtimeContext`: Contextual information provided by Kernel during execution
-- `payload`: Optional runtime data that you provide when invoking the action. [Read more](/apps/invoke#payload-parameter)
+- `payload`: Optional runtime data that you provide when invoking the action (max 64 KB). [Read more](/apps/invoke#payload-parameter)
 
 <CodeGroup>
 ```typescript Typescript/Javascript

apps/invoke.mdx

@@ -7,7 +7,7 @@ import AsyncInvocation from '/snippets/openapi/post-invocations-async.mdx';
 
 ## Via API
 
-You can invoke your app by making a `POST` request to Kernel's API. **For automations and agents that take longer than 100 seconds, use [async invocations](/apps/invoke#asynchronous-invocations).**
+You can invoke your app by making a `POST` request to Kernel's API or via the CLI. Both support passing a payload. **For automations and agents that take longer than 100 seconds, use [async invocations](/apps/invoke#asynchronous-invocations).**
 
 <Info>Synchronous invocations time out after 100 seconds.</Info>
 
@@ -31,6 +31,10 @@ kernel invoke <app_name> <action_name>
 
 `--payload` allows you to invoke the action with specified parameters. This enables your action to receive and handle dynamic inputs at runtime. For example:
 
+<Info>
+Payloads are stringified JSON and have a maximum size of 64 KB. For larger inputs, store data externally (e.g., object storage or database) and pass a reference (URL or ID) in the payload instead.
+</Info>
+
 ```bash
 kernel invoke <app_name> <action_name>
     --payload '{"tshirt_size": "small", "color": "black", "shipping_address": "2 Mint Plz, San Francisco CA 94103"}'