Exception using structured output in 1.16.0

[tonydewan]

Based on my reading of the API documentation, this should work:

params = {
  model: "claude-haiku-4-5",
  max_tokens: 1000,
  messages: [{role: "user", content: "respond with json"}],
  betas: ["structured-outputs-2025-11-13"],
  output_format: {
    type: "json_schema",
    schema: {
      "type" => "object",
      "properties" => {
        "test" => {"type" => "string"}
      },
      "required" => ["test"],
      "additionalProperties" => false
    }
  }
}

response = Anthropic::Client.new.messages.create(**params)
puts response.content[0].text

Worth noting that I also tried:

#...
response = Anthropic::Client.new.beta.messages.create(**params)
puts response.content[0].text

Either way, I get the following exception:

uninitialized constant Anthropic::Helpers::StructuredOutput (NameError)
in {output_format: {schema: Anthropic::Helpers::StructuredOutput::JsonSchemaConverter => model} => output_format}

Looks like the existence of schema in output_format results in a logical branch that references a nonexistent constant.

[ms-jpq]

hihi @cameron-stainless 👋

:D

[cameron-stainless]

Checking on this

[cameron-stainless]

@tonydewan I've created a fix for this. Please also note that yes, you do indeed need to use the beta namespace for now