Module: Rubino::Output::Cost

Defined in:
lib/rubino/output/cost.rb

Overview

Best-effort USD cost for a turn’s token usage, for the machine-readable ‘total_cost_usd` field (Claude-Code-aligned).

Pricing is sourced from ruby_llm’s model registry when the model is known there (input/output price per million tokens). Most self-hosted / MiniMax deployments are NOT in that registry, so there is no price to apply — in that case we return nil and the serializer emits ‘total_cost_usd: null` rather than a fabricated number. This is the honest counterpart to Claude Code, which always has its own pricing table.

Class Method Summary collapse

Class Method Details

.for_usage(model_id:, input_tokens:, output_tokens:) ⇒ Float?

Returns USD cost, or nil when the model’s pricing is unknown.

Returns:

  • (Float, nil) —

    USD cost, or nil when the model’s pricing is unknown.



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# File 'lib/rubino/output/cost.rb', line 18

def for_usage(model_id:, input_tokens:, output_tokens:)
  return nil if model_id.to_s.empty?

  model = lookup(model_id)
  return nil unless model

  in_price  = price(model, :input_price_per_million)
  out_price = price(model, :output_price_per_million)
  return nil if in_price.nil? && out_price.nil?

  cost = (input_tokens.to_i / 1_000_000.0 * in_price.to_f) +
         (output_tokens.to_i / 1_000_000.0 * out_price.to_f)
  cost.round(6)
rescue StandardError
  # A pricing lookup detail must never fail the run or corrupt the JSON.
  nil
end

.lookup(model_id) ⇒ Object 



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# File 'lib/rubino/output/cost.rb', line 36

def lookup(model_id)
  return nil unless defined?(RubyLLM)

  RubyLLM.models.find(model_id)
rescue StandardError
  nil
end

.price(model, method_name) ⇒ Object 



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# File 'lib/rubino/output/cost.rb', line 44

def price(model, method_name)
  return nil unless model.respond_to?(method_name)

  value = model.public_send(method_name)
  value&.to_f
end