ArtifactPlan missing structuredOutputIds field

[Frikster]

Assistants with structured outputs cannot be used with the iOS SDK. Current workaround is to disable structured outputs in the dashboard.

Something like this is missing:

public struct ArtifactPlan: Decodable {
      public let videoRecordingEnabled: Bool?
      public let structuredOutputIds: [String]?
  }

[Frikster]

Vapi changed their API response format so disabling structured outputs no longer seems to work. I pulled the code locally and fixed it. Seems no other way.

The fix is a single Bool → Bool? change on line 11 of WebCallResponse.swift.

This iOS SDK appears completely unmaintained by the vapi team. Multiple PRs have been sitting unmerged since mid-2025 and if they saw my issue above posted a month ago this probably could have been avoided.

Our core product is an iOS app with voice AI and this caused all calls to simply and suddenly stop working with obscure logs (silent failure). This experience will likely cause us to migrate away from Vapi (looking at Retell, Livekit, Pipecat now) and I'd recommend anyone specifically building an iOS app using Vapi to consider the same.

For a hobby project this would all be annoying. For a production iOS app where voice calls are the core experience, this is entirely unacceptable. Vapi represents one of our company's big expenses making this even more unacceptable.