I’m experimenting with building an AI agent and was wondering how people usually wrap or use existing APIs. For example, if I wanted to interact with X software service using natural language, would I implement a function for each endpoint (turning them into callable functions that get invoked that way), or are there other approaches people typically take?
Is there a resource or methodology I can refer to for quickly integrating with multiple external sources using their existing APIs? Ideally, I’d like my agent to be able to translate a user’s prompt into the appropriate CRUD operations and then return the result.
Great question. There are a few common patterns teams use to let an agent call external APIs from natural-language prompts. Each has trade-offs.
Core patterns
One function per endpoint (“thin wrappers”)
What it is: You implement a callable tool for each concrete API action, e.g., create_ticket, list_tickets, update_ticket_status.
Pros: Very explicit; strong parameter validation; easiest to debug/monitor.
Cons: Lots of boilerplate; changes to the API mean changing code; scaling to many services gets noisy.
Schema-driven tools from OpenAPI
What it is: Ingest an OpenAPI spec and auto-generate tool definitions (JSON Schema) so the agent can select and call them.
Pros: Fast to onboard new services; parameters/types come “for free.”
Cons: Many specs are messy; you still need curation (narrow to safe, high-value actions; add examples); error semantics vary by vendor.
CRUD abstraction layer (capability model)
What it is: Define a small set of generic operations—create(entity), read(entity, filters), update(entity, fields), delete(entity)—and map them to vendor endpoints via config.
Pros: Lets the agent “think” in CRUD; easy to swap vendors; fewer tools to reason about.
Cons: Not all APIs map cleanly to CRUD (workflows, bulk ops, webhooks); you still need per-service adapters.
Domain-specific DSL / intermediate plan
What it is: The agent first emits a concise plan or DSL (e.g., “tickets.search(status='open') -> tickets.update(id, status='closed')”), then an executor translates to API calls.
Pros: Clear separation of planning vs execution; great for review/approvals; easier to test.
Cons: You must design and maintain the DSL and translator.
Unified gateway (GraphQL or API proxy)
What it is: Put a gateway in front of many services; the agent calls the gateway (fewer tools).
Pros: Strong schema; centralized auth/rate-limits; one integration path.
Cons: You must build/operate the gateway; real-time mutations may need careful design.
iPaaS connectors (Zapier/Make/N8N) as tools
What it is: The agent triggers curated “actions” exposed by an integration platform.
Pros: Fastest way to cover many services safely; non-devs can add actions.
Cons: Another dependency; limited to what the connector exposes; may add latency/cost.