TokenUsage

class TokenUsage(CamelModel):
    prompt_tokens: int
    completion_tokens: int
    total_tokens: int

from rdk.models import TokenUsage

usage = TokenUsage(
    prompt_tokens=150,
    completion_tokens=75,
    total_tokens=225
)

from anthropic import Anthropic
from rdk import observe

@observe(name="chat")
def chat(message: str):
    client = Anthropic()
    response = client.messages.create(
        model="claude-sonnet-4-6",
        max_tokens=1024,
        messages=[{"role": "user", "content": message}]
    )
    # Token usage is automatically captured in the span
    return response.content[0].text

# Example cost calculation (rates vary by model)
COST_PER_1K_INPUT = 0.003   # $3 per 1M input tokens
COST_PER_1K_OUTPUT = 0.015  # $15 per 1M output tokens

def estimate_cost(usage: TokenUsage) -> float:
    input_cost = (usage.prompt_tokens / 1000) * COST_PER_1K_INPUT
    output_cost = (usage.completion_tokens / 1000) * COST_PER_1K_OUTPUT
    return input_cost + output_cost

{
  "promptTokens": 150,
  "completionTokens": 75,
  "totalTokens": 225
}