RPA Bot HTTP API does not expose array input parameters – is this a limitation?

Hi community,

I’m using MuleSoft Anypoint RPA and ran into a situation with invoking a bot via HTTP API.

• My bot process has two Activity Parameters:
  1. poNumber (string)
  2. lineItems (array of strings)
• The bot also uses user_credentials, but these are configured via the Credential Pool in RPA Manager.
• The bot works perfectly when run locally, including passing the lineItems array (using default values).
• When I publish the bot and try to invoke it via HTTP (Exchange auto-generated API), I noticed:
  • Only poNumber and user_credentials are visible in the InputArguments schema.
  • lineItems does not appear in the OpenAPI spec.
  • If I manually try to include lineItems in the payload, I get a 500 server error: "The server encountered an unexpected error and is unable to handle the request.".
  • With only poNumber request is accepted
• My understanding is that the API only accepts the fields listed in the generated spec.

Question:

Is this a current limitation of MuleSoft RPA (i.e., array-type Activity Parameters cannot be exposed via HTTP API) or am I missing a configuration step to include arrays in the auto-generated spec?

Any insights or best practices on passing array data to a bot via HTTP would be highly appreciated.

Thanks in advance!