@true402.dev/langchain

@true402.dev/langchain

  Stable · production-ready — semver-stable public API (v1.0).

true402 tools for LangChain — give your Base agent pay-per-call on-chain safety and search/SEO data over x402: rug/honeypot checks, address safety, deployer reputation, backlink profiles, and keyword research. No account, no API key — the wallet is the identity (USDC on Base, gas sponsored by the facilitator).

npm i @true402.dev/langchain @langchain/core

import { createTrue402Tools } from '@true402.dev/langchain';

const tools = createTrue402Tools({ payerPrivateKey: process.env.PAYER_PRIVATE_KEY! });
// → add `tools` to any LangChain agent (createReactAgent, AgentExecutor, …)

The agent can now call:

Tool	What it does	~price
true402_token_report	Composite avoid / caution / ok verdict for a Base ERC-20 (buy/sell honeypot sim + liquidity + ownership + rug activity)	$0.01
true402_token_safety	Structural safety score 0–100 + flags	$0.005
true402_address_safety	Profile + risk for any address before you send/approve/call it (proxy detection)	$0.005
true402_tx_preflight	Check an unsigned transaction before signing: does it revert, does it grant an unlimited approval, has the counterparty been draining liquidity. Takes no key and no signature	$0.008
true402_liquidity_history	What already happened to a token's liquidity — every removal with amount/block/tx, plus the tokens drained in the same transaction	$0.005
true402_deployer_check	Deployer reputation — who made the token + their track record	$0.008
true402_backlinks	A domain's backlink profile — referring domains/pages, dofollow split, authority rank, spam score	$0.10
true402_keyword_volume	Search volume/CPC/competition for up to 200 keywords in one call — priced per call, not per keyword	$0.15
true402_ranked_keywords	Keywords a domain already ranks for, with position and the ranking URL — competitor research too	$0.05
true402_keyword_ideas	Related/long-tail keyword ideas for a seed term, with volume and intent	$0.05

payerPrivateKey is a Base wallet holding a little USDC. Without it the stalls still return their HTTP 402 price, so the agent can decide. Override baseUrl / rpcUrl in the options if self-hosting.

Checking tokens by hand? Send any Base token address to @True402bot on Telegram — same on-chain checks, free, no wallet.

Powered by true402 — the machine-native x402 marketplace on Base. Browse every stall at /catalog.

Also available for

MCP (Claude Code / Desktop, Cursor, Hermes) · Hermes Agent · OpenClaw · ElizaOS · LangChain · CrewAI · Vercel AI SDK · Coinbase AgentKit · Virtuals GAME · CLI — same on-chain checks, one install command each: true402.dev/integrations

Paying, exactly

The rules below are the service's, not this package's — they bite whatever client you use, and they are the ones that surprise people writing their own payer.

• Pay the EXACT amount quoted in the 402. Underpaying is rejected. Overpaying is refused with 403 and never credited — settlement submits the signed value and there is no refund path, so a surplus would simply be swept. Equality is also what binds an authorization to the resource it was quoted for.
• One authorization buys exactly one response. A replay is refused, not double-charged.
• You are charged on success only. Settlement is submitted only when the endpoint returns 2xx; if it errors or times out, your signed authorization is never submitted, so there is nothing to refund.
• Some endpoints serve a few free calls per day per client IP, with no wallet. The per-operation description in the OpenAPI spec says which.

Full rules: true402.dev/terms · what is logged and kept: true402.dev/privacy