llm-connect/contracts/functional/costs.md

Cost Estimates

llm_connect.costs converts token estimates or observed token counts into USD estimates using ModelRateRegistry.

Contract

from llm_connect import estimate_cost

estimate = estimate_cost("openai/gpt-4o-mini", 28_000, 7_500)

For known models the result is:

• cost_usd: prompt plus completion estimate.
• prompt_cost_usd: prompt-token component.
• completion_cost_usd: completion-token component.
• cost_source: rate_table:<model_id>.

Unknown models return CostEstimate(cost_usd=None, cost_source="unknown"). Missing rates are never silently treated as zero cost.

The module also exposes CostModel(registry=...) for callers that prefer to carry a registry object and call model.estimate_cost(...).