Openapi

Generating typed API clients for Stripe’s 588 operations costs $0.07 on Claude Opus. That’s impressive. Then I watched Postmark’s generated client set BASE_URL = "https://api.example.com" — a value the LLM fabricated instead of copying the literal string from the spec. The gap between what LLMs can do and what they actually get wrong is the design problem worth solving.

The problem

AI agents are only as useful as their integrations. Composio catalogs 901 toolkits. Filter to the high-value ones — payment processors, CRMs, communication platforms — and you get about 90 services. At 15 operations each, that’s 1,350 typed functions your agent needs to call correctly.