@minia2a/langchain

The marketplace toolkit for LangChain agents — discover, try, and pay for 1,680+ x402 APIs across crypto, web, AI, and data, plus smart-contract auditing. USDC on Base.

Give your LangChain agent access to the entire minia2a.uk marketplace — live discovery, 5 free trial calls per wallet, and transparent per-call pricing.

Why This Toolkit

| Feature | Other API Tools | This Toolkit | |---------|----------------|-------------| | Services | Usually 1 API at a time | 1,600+ across categories | | Discovery | Hardcoded endpoints | Live marketplace search | | Free trials | Sometimes | 5 free trial calls per wallet | | New services | Wait for tool update | Available instantly | | Provider diversity | Single vendor | Dozens of providers | | Payment | API keys | USDC on Base, no KYC |

Install

npm install @minia2a/langchain zod @langchain/core

Quick Start

import { Minia2aToolkit } from "@minia2a/langchain";
import { ChatOpenAI } from "@langchain/openai";
import { AgentExecutor, createOpenAIFunctionsAgent } from "langchain/agents";
import { ChatPromptTemplate } from "@langchain/core/prompts";

// Create toolkit with auto-trial
const toolkit = new Minia2aToolkit({
  config: {
    autoTrial: true,           // Use free trials automatically
    maxPricePerCall: 0.10,     // Max $0.10 per paid call
  }
});

const llm = new ChatOpenAI({ model: "gpt-4o" });

const prompt = ChatPromptTemplate.fromMessages([
  ["system", "You are a helpful agent with access to the minia2a API marketplace. Use the tools to discover and call APIs for the user."],
  ["human", "{input}"],
  ["placeholder", "{agent_scratchpad}"],
]);

const agent = await createOpenAIFunctionsAgent({
  llm,
  tools: toolkit.getTools(),
  prompt,
});

const executor = new AgentExecutor({
  agent,
  tools: toolkit.getTools(),
  verbose: true,
});

// Use it!
const result = await executor.invoke({
  input: "Find an API that can tell me the current gas price on Ethereum and try it out"
});

console.log(result.output);

Tools

| Tool | What it does | Example query | |------|-------------|---------------| | search_minia2a_apis | Search 1,680+ APIs by keyword | "Find APIs for web scraping" | | call_minia2a_api | Call any endpoint with auto-trial | Call /x402/gas to get gas prices | | list_popular_minia2a_apis | Browse trending services | "What APIs are most popular?" | | audit_smart_contract | Audit contract source ($2 static / $20 AI) | "Audit this Solidity contract for reentrancy" |

search_minia2a_apis

// Search by keyword
await executor.invoke({ input: "Find crypto price APIs" });

// Search by category
await executor.invoke({ input: "What AI services are available?" });

call_minia2a_api

// GET request with auto-trial
await executor.invoke({
  input: "Call /x402/gas to check current Ethereum gas prices"
});

// POST request with body
await executor.invoke({
  input: "Scrape https://example.com using the web-scrape endpoint"
});

list_popular_minia2a_apis

// Browse trending
await executor.invoke({ input: "Show me the most popular APIs on minia2a" });

audit_smart_contract

Give your agent the ability to audit Solidity, Rust, and Move source code — pay per call, no API keys.

// Requires a funded Base wallet in the environment:
//   MINIA2A_PRIVATE_KEY=0x... (signs the x402 payment locally, never sent anywhere)

await executor.invoke({
  input: "Audit this contract for vulnerabilities:\n\n" + contractSource
});

// The agent will call audit_smart_contract with tier 'static' ($2, 10 patterns)
// or tier 'ai' ($20, 3x-sampled deep audit) and act on the findings.

Two tiers:

| Tier | Price | Coverage | |------|-------|----------| | static | $2 / call | 10 deterministic patterns (reentrancy, access-control, integer overflow, tx.origin, delegatecall, selfdestruct, block.timestamp, assert misuse, owner-change) — Solidity only | | ai | $20 / call | 3×-sampled AI deep audit — business-logic, economic, and cross-contract flaws — Solidity, Rust, Move |

Honest limits: output is guidance for manual review, not proof of safety. The AI tier is probabilistic. The audit reads source code, not a deployed address.

Configuration

| Option | Default | Description | |--------|---------|-------------| | baseUrl | https://minia2a.uk | minia2a marketplace URL | | autoTrial | true | Use free trials (5 free trial calls per wallet) | | maxPricePerCall | 0 | Max USD per paid call (0 = trials only) | | timeout | 15000 | Request timeout in ms |

x402 Payment Flow

1. Agent requests endpoint → gets HTTP 402 Payment Required with price + wallet
2. Agent auto-signs USDC on Base (if maxPricePerCall > 0 and wallet configured)
3. Agent retries with signed transaction → receives result
4. Receipt returned for audit trail

Default: trials only. Set maxPricePerCall > 0 and configure wallet for paid calls.

Categories

• 🤖 AI/LLM — text generation, classification, translation, summarization
• 🔗 Web — scraping, search, email verification, DNS, HTTP analysis
• 💰 Crypto — gas prices, wallet intel, token security, DEX data, Polymarket
• 🔐 Security — CAPTCHA solving, domain intel, SSL checks, OSINT
• 📊 Data — enrichment, validation, formatting, CSV/JSON conversion
• 🛠️ Dev Tools — code review, regex, UUID, hashing, JWT decode

Pricing

• Free trial: 5 free trial calls per signed wallet — no registration needed
• Paid calls: Priced per endpoint (typically $0.01–$0.10)
• Platform fee: 5% (transparent)
• Settlement: USDC on Base (eip155:8453) — the only rail the gateway offers. Other chains are recognised but not settleable: /x402/chain/<other>/<id> answers 400 unsupported chain.

LangGraph Integration

import { StateGraph, MessagesAnnotation } from "@langchain/langgraph";
import { ToolNode } from "@langchain/langgraph/prebuilt";
import { Minia2aToolkit } from "@minia2a/langchain";

const toolkit = new Minia2aToolkit();
const tools = toolkit.getTools();
const toolNode = new ToolNode(tools);

const graph = new StateGraph(MessagesAnnotation)
  .addNode("agent", agentNode)
  .addNode("tools", toolNode)
  .addEdge("__start__", "agent")
  .addConditionalEdges("agent", shouldContinue)
  .addEdge("tools", "agent")
  .compile();

Companion Packages

• @minia2a/sdk — CLI for x402 developers
• @minia2a/elizaos-plugin-minia2a — ElizaOS plugin
• minia2a-mcp — MCP server for Claude/Cursor
• minia2a-audit — standalone audit CLI/library (powers audit_smart_contract)

Related

• minia2a.uk — The marketplace (live stats at /api/stats)
• x402.org — The payment protocol
• LangChain Tools — LangChain tool docs

License

MIT