langchain-agent-margin-router

LangChain integration for the Agent Margin Router.

Give your LangChain agents instant access to 39 paid API endpoints — real-time market data, on-chain reads, best-price gas routing, news, web search, and developer tools — through one pay-per-call backend. Billing is handled with USDC on Base via x402 or an API key, with 3 free calls per wallet so you can try every tool with no signup.

pip install langchain-agent-margin-router

This package is a thin wrapper around the official agent-margin-router SDK: it turns every SDK endpoint into a ready-to-use LangChain StructuredTool, with the argument schema and description inferred automatically from the SDK's typed methods — so the tools always stay in sync with the API.

Quickstart

from langchain_agent_margin_router import get_tools

# 3 free calls per wallet, no signup
tools = get_tools(wallet="0xYourWallet000000000000000000000000000000")

print(len(tools))            # 39
print([t.name for t in tools][:5])
# ['extract_clean', 'market_spread', 'gas_fees', 'best_price', 'token_price']

Pass tools straight into any LangChain agent:

from langchain.chat_models import init_chat_model
from langgraph.prebuilt import create_react_agent

llm = init_chat_model("openai:gpt-4o-mini")
agent = create_react_agent(llm, tools)

result = agent.invoke({
    "messages": [("user", "What's the median ETH price and the cheapest gas on Base right now?")]
})
print(result["messages"][-1].content)

Or bind them to a model directly:

llm_with_tools = llm.bind_tools(tools)

Selecting a subset

Most agents only need a handful of endpoints. Keep the tool list tight:

tools = get_tools(
    wallet="0x...",
    only=["token_price", "best_price", "news_search", "web_search"],
)

Or exclude a few:

tools = get_tools(wallet="0x...", exclude=["pdf_text", "youtube_transcript"])

Add a prefix to avoid name collisions with your other tools:

tools = get_tools(wallet="0x...", name_prefix="amr_")
# tool names become amr_token_price, amr_best_price, ...

Authentication

Pick one:

Payment behaviour. When the free tier is exhausted and no payment is attached, the API returns HTTP 402. The tool does not perform an automatic on-chain payment; instead it returns a structured error payload including the accepts block (asset, network, price, payTo, facilitator) so your application can settle the x402 payment out of band or top up an API key.

Toolkit class

from langchain_agent_margin_router import AgentMarginRouterToolkit

toolkit = AgentMarginRouterToolkit(wallet="0x...")
tools = toolkit.get_tools()

Available endpoints

All 39 endpoints of the SDK are exposed, including:

• Market & crypto: token_price, market_spread, crypto_ohlcv, dex_price, fear_greed
• On-chain: best_price, gas_fees, wallet_balance, erc20_balance, tx_status, ens_resolve, contract_info, agent_wallet_snapshot
• DeFi: defi_yields, defi_tvl
• News & search: news_search, web_search, hn_search, reddit_search, rss_feed, wikipedia_summary, arxiv_search
• Web & content: extract_clean, html_to_markdown, web_crawl, url_status, pdf_text, youtube_transcript, seo_check
• Developer & data: github_repo_summary, npm_package, pypi_package, dns_lookup, dns_whois, domain_rdap, email_validate, geo_ip, geocode, currency_convert

See the full reference at https://agentmarginrouter.com/docs.

License

MIT © NovaNest