Reusable model API contracts, provider adapters, and streaming primitives from Upfyn. The package supports isolated runtime instances; importing it does not register providers globally.

import { createLlmRuntime } from "@upfyn/ai";
import { registerBuiltInApiProviders } from "@upfyn/ai/providers";

const runtime = createLlmRuntime();
registerBuiltInApiProviders(runtime.registry);

Provider-neutral contracts, validation, diagnostics, and event streams are available from the package root and focused subpaths such as @upfyn/ai/event-stream, @upfyn/ai/transports, and @upfyn/ai/validation. No second Upfyn runtime package is required.

Provider ids, credentials, model catalogs, retries, and failover remain application concerns. Upfyn supplies those policies around this package. Host policy (request fetch guarding, secret redaction, strict-tool defaults, provider plugin hooks, and diagnostics logging) can be injected with configureAiTransportHost; the defaults are inert.

The explicit @upfyn/ai/internal/anthropic, openai, retry-after, runtime, and shared subpaths exist for the Upfyn application itself. They carry no semver guarantee and can change or disappear in any release; do not depend on them outside Upfyn.