@cgaravitoq/open-langchain-ts

Native LangChain BaseChatModel adapters for coding-agent subscriptions — no Pi, no API key:

• ChatClaudeCode — Anthropic Messages API billed against your Claude Code OAuth subscription.
• ChatCodex — OpenAI Codex (ChatGPT Plus/Pro) over the responses API.
• ChatOpencode — OpenCode Zen, an OpenAI-compatible endpoint.

Tool calling and streaming work across all three. The TypeScript half of a pair; a Python twin (open-langchain) ships the same models.

Install

npm install @cgaravitoq/open-langchain-ts @langchain/core

@langchain/core is a peer dependency (^1.1.44). ESM-only, Node >= 22.19.0.

Usage

createChat routes by provider:

import { createChat } from "@cgaravitoq/open-langchain-ts";

const free = createChat({ provider: "opencode", model: "deepseek-v4-flash-free" }); // no key
const go = createChat({ provider: "opencode-go", model: "glm-5", apiKey: "..." });
const codex = createChat({ provider: "openai-codex", model: "gpt-5.3-codex-spark" });
const claude = createChat({ provider: "claude-code", model: "claude-sonnet-4-6" });

Unknown providers throw. Or import a model directly from its subpath (/claude-code, /codex, /opencode).

Tool calling & streaming

import { tool } from "@langchain/core/tools";
import { z } from "zod";

const getWeather = tool(({ city }) => `Sunny in ${city}.`, {
  name: "get_weather",
  description: "Get the weather for a city.",
  schema: z.object({ city: z.string() }),
});

const model = createChat({ provider: "claude-code", model: "claude-sonnet-4-6" });
const withTools = model.bindTools([getWeather]);

for await (const chunk of await model.stream("Write a haiku.")) {
  process.stdout.write(chunk.content as string);
}

Claude Code (Anthropic subscription)

import { ChatClaudeCode } from "@cgaravitoq/open-langchain-ts/claude-code";

const opus = new ChatClaudeCode({ model: "claude-opus-4-8", reasoning: "medium" });

Reads the Claude Code OAuth session at ~/.claude/.credentials.json (log in once with the claude CLI). Models: claude-opus-4-8, claude-opus-4-7, claude-sonnet-4-6, claude-haiku-4-5. Adaptive thinking on Opus 4.8/4.7; the 1M-context beta is opt-in via longContext: true. The native Claude Code stack (OAuth refresh, signed billing header, betas, payload transforms) lives in @cgaravitoq/claude-code-core.

OpenAI Codex (ChatGPT subscription)

import { ChatCodex } from "@cgaravitoq/open-langchain-ts/codex";

const codex = new ChatCodex({ model: "gpt-5.4", reasoning: "low" });

Reads the Codex OAuth session at ~/.pi/agent/auth.json (sign in via pi or the Python twin's codex-login). Models: gpt-5.2, gpt-5.3-codex, gpt-5.3-codex-spark, gpt-5.4, gpt-5.4-mini, gpt-5.5.

OpenCode Zen

import { ChatOpencode } from "@cgaravitoq/open-langchain-ts/opencode";

const free = new ChatOpencode({ model: "deepseek-v4-flash-free" }); // no key
const paid = new ChatOpencode({ model: "glm-5" }); // OPENCODE_API_KEY or apiKey

Notes

Using a subscription OAuth session from a third-party app may violate the provider's terms and risk your account. See the pi-claude-code-auth README for the Claude Code caveats.

License

MIT