langchain-pathcourse 0.1.0

LangChain integration for PathCourse Health — autonomous agent inference with USDC billing on Base L2

langchain-pathcourse

PathCourse Health integration for LangChain. Autonomous agent inference with USDC billing on Base L2 — no accounts, no credit cards, no KYC.

Install

pip install langchain-pathcourse

Quick Start

from langchain_pathcourse import ChatPathCourse
from langchain_core.prompts import ChatPromptTemplate

llm = ChatPathCourse(model="pch-fast")   # set PCH_API_KEY env var

prompt = ChatPromptTemplate.from_template("Explain {topic} in one paragraph.")
chain = prompt | llm
print(chain.invoke({"topic": "autonomous agent billing"}))

Drop-in replacement for ChatOpenAI

ChatPathCourse extends ChatOpenAI. Anywhere you use ChatOpenAI in LangChain — chains, agents, tools, memory, callbacks — just swap in ChatPathCourse and your code keeps working.

# Before
from langchain_openai import ChatOpenAI
llm = ChatOpenAI(model="gpt-4o-mini")

# After
from langchain_pathcourse import ChatPathCourse
llm = ChatPathCourse(model="pch-fast")

Embeddings

from langchain_pathcourse import PathCourseEmbeddings
from langchain_community.vectorstores import FAISS

embeddings = PathCourseEmbeddings()
store = FAISS.from_texts(["hello world", "goodbye world"], embeddings)
results = store.similarity_search("greeting")

Models

Model	Rate	Notes
pch-fast	$0.44/M tokens	Fast reasoning, classification, routing
pch-pro	$1.96/M tokens	Deep reasoning, multi-step planning (Bronze+)
pch-coder	$3.50/M tokens	Code generation, debugging
claude-haiku	Common rate	Third-party balanced model (Silver+)
claude-sonnet	Common rate	Third-party long-context model (Gold)

Choosing a model:

• Fast response, simple task → pch-fast
• Complex reasoning, multi-step → pch-pro
• Writing or reviewing code → pch-coder

List all models programmatically:

ChatPathCourse.list_models()

Authentication

Set PCH_API_KEY in your environment, or pass pch_api_key= to the constructor.

export PCH_API_KEY=pch_prod_b_...

Get an API key at pathcoursehealth.com.

Links

• Platform: pathcoursehealth.com
• Python SDK: pypi.org/project/pathcourse-sdk
• JS SDK: npmjs.com/package/@pathcourse/sdk
• Integration examples: github.com/pathcourse-health/pch-integration-examples

License

MIT