Per tool call cost visibility in tool execution responses

[Flux690]

Hi
I'm building a SaaS platform where I'm integrating Arcade as the tool execution layer. The challenge I'm running into is billing. I want to pass through Arcade tool execution costs to my users charging them differently for standard vs. pro tool calls, since the cost difference is significant ($0.01 vs $0.50).

After reading the full OpenAPI spec, I can't find any field in the POST /v1/tools/execute response that indicates the tool's pricing tier or what a specific call cost. ExecuteToolResponse and tool.ResponseOutput don't appear to expose a cost, tier, or billing metadata field. The tool.Classification schema only contains service_domains.

A few specific questions:

1. Is there a response field, header, or separate billing endpoint I've missed that tells me whether a given execution was standard or pro (or what it cost)?
2. If there's genuinely no runtime signal, what do other SaaS builders using Arcade do for per-user billing passthrough?

Thanks for your time