docs: PZERO ChatOpenAI configuration.baseURL example

[cursor]

Checklist

• I added a very descriptive title to this issue.
• I included a link to the documentation page I am referring to (if applicable).

Issue with current documentation:

The Custom URLs section on https://docs.langchain.com/oss/javascript/integrations/chat/openai shows configuration.baseURL with a placeholder. People looking for prepaid, privacy-first inference still have to guess the host, key format, and that the catalog id is passed as model (no openai/ prefix on this class).

Search for pzero in this repo returned none. Python LangChain already has a sibling docs issue: langchain-ai/docs#5740

Idea or request for content:

A named PZERO example under Custom URLs. No first-party @langchain/pzero package required.

import { ChatOpenAI } from "@langchain/openai";

const llm = new ChatOpenAI({
  model: "deepseek-v4-flash",
  apiKey: process.env.PZERO_API_KEY,
  configuration: {
    baseURL: "https://api.pzero.studio/v1",
  },
});

await llm.invoke("Hello from PZERO");

configuration.baseURL is the /v1 root, not /v1/chat/completions. Pass the catalog id as model. Do not prefix openai/ here.

Get a key: https://pzero.studio/agents (sign-in free; min top-up 1 USDC on Base; no starter credits). Live text ids: GET https://api.pzero.studio/v1/models (public, no key). Default landing model: deepseek-v4-flash.

Smoke against the same host LangChain.js will call:

curl -sS -X POST "https://api.pzero.studio/v1/chat/completions" \
  -H "Authorization: Bearer $PZERO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"deepseek-v4-flash","messages":[{"role":"user","content":"Hello from PZERO"}],"stream":false}'

I am not asking for a bundled provider package. The existing Custom URLs seam is enough. Do not start implementation on my behalf until the board says Ready; the snippet is for users today.

Every AI Credit is at least 20% off $1 list. Usage is paid.