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The Belvedir Node SDK auto-instruments the major LLM providers with a single initialize() call.

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Install

Migrating from Fractal? The old packages (@fractalresearch/loop, fractal-loop) still work but are deprecated. Both SDKs run on macOS, Linux, and Windows with no native dependencies: the Node SDK is pure TypeScript (Node 18+), and the Python SDK is pure Python (3.10+). For setting BELVEDIR_API_KEY per operating system, see Environment variables.

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Initialize

The SDK patches your LLM client the moment initialize() runs, so it must run before the LLM SDK is imported. In Next.js use instrumentation.ts at the project root; see the Next.js guide. In a plain CommonJS Node process, call it at the top of your entry file:
In an ESM entry point (.mjs, or "type": "module" in package.json), always pass your LLM SDKs via instrumentModules: static imports hoist above the initialize() call and dynamic import() bypasses the require hook, so auto-instrumentation produces no LLM spans there, with no warning. The same applies to bundled environments. See Configuration.

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Next steps

  • Configuration: every option accepted by initialize(), and the full SDK API.
  • Providers: every LLM provider we auto-instrument.
  • Python SDK: same concepts, snake_case, context managers.