token-police-langchain

The LangChain companion for the TokenPolice Node.js SDK. Install it alongside token-police to capture tokens for LangChain apps.

npm install token-police token-police-langchain

That's it — there's no API to call. token-police's init() detects this package automatically and starts capturing LangChain calls:

import * as tp from 'token-police';

tp.init({
  // apiKey: 'tp_sk_...',   // or set TOKENPOLICE_API_KEY
  firewall: 'dry_run',      // watch first; 'enforce' when your rules look right
});
// LangChain calls (OpenAI / Anthropic / Google, etc.) are now tracked & enforced.

Everything else — sessions, rules, blocked calls — is configured through token-police; see its README and the LangChain integration guide.

Why a separate package?

LangChain support pulls in a comparatively heavy dependency tree, so it's kept opt-in rather than bundled into the base token-police install. Apps that don't use LangChain pay nothing; LangChain apps add this one package and get full capture.

token-police (>= 1.0.0) is a peer dependency — install both.

Supported LangChain versions

@langchain/core 0.3.x and 1.x (tested with langchain 0.3 and @langchain/langgraph 1.x). The package declares @langchain/core >=0.3.0 <2.0.0 as an optional peer dependency, so no package manager can fail an install on it.

On @langchain/core 0.3, pnpm may print an unmet-peer warning from a bundled dependency. It is expected and safe — token capture works on 0.3 exactly as on 1.x. npm prints nothing.

Requirements

• Node.js >= 20
• token-police >= 1.0.0

Support

• Docs: tokenpolice.ai/docs
• Issues: github.com/tokenpolice/token-police-langchain-node/issues
• Email: [email protected]

License

Apache-2.0