Overview

from tokensense.router import Router, Rule

router = Router(
    tiers={
        "small":  ["claude-haiku-4-5"],
        "large":  ["claude-sonnet-4-6"],
    },
    rules=[
        Rule(if_context_tokens_gt=4000, deny_tiers=["small"]),
        Rule(if_task="legal-review", pin_tier="large"),
    ],
    on_failure="escalate",
)

messages = [{"role": "user", "content": "Summarise this contract..."}]

decision = router.route(
    messages=messages,
    task_hint="legal-review",
)

print(decision.model)   # claude-sonnet-4-6
print(decision.tier)    # large
print(decision.reason)  # pinned to large by rule

client = observe(anthropic.Anthropic())

decision = router.route(messages=messages, task_hint="summarise")

response = client.messages.create(
    model=decision.model,
    max_tokens=1024,
    messages=messages,
)

tiers={
    "small":  ["claude-haiku-4-5", "groq/llama3-8b"],  # tried left to right
    "medium": ["gpt-4o-mini"],
    "large":  ["claude-sonnet-4-6", "gpt-4o"],
}