@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) | $0.008 | | 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. It is required: the tools sign each payment with it, and every call is refused above a $0.25 cap. 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.

Guides

• Add a rug check to a LangChain agent
• Token price and rug risk in one call
• The x402 protocol, explained

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 402 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