Feature request to integrate SiaMesh as a LangChain tool for secure web scraping with x402 micro-payments. The proposed solution adds a new SiaMeshTool class that wraps the public endpoint, enabling agents to scrape URLs while handling payment and anti-prompt-injection sanitization.
LangChain currently lacks a built-in tool for SiaMesh/x402-based scraping. Developers must manually implement a BaseTool subclass, manage HTTP requests, handle payment-required responses (402), and parse sanitized JSON, leading to duplicated effort and potential inconsistencies.
1. Attempt to find a SiaMesh tool in LangChain; none exists. 2. Try to use a generic HTTP tool to scrape a URL with x402 payment; it fails because standard tools do not handle 402 or sanitize responses. 3. Manually implement a custom BaseTool, which is error-prone and not reusable.
Fixing Code Block
import requests
from typing import Optional, Type
from pydantic import BaseModel, Field
from langchain_core.tools import BaseTool
class SiaMeshInput(BaseModel):
url: str = Field(description="Target URL to scrape")
class SiaMeshTool(BaseTool):
name: str = "siamesh_scraper"
description: str = "Scrape a URL using SiaMesh secure scraper with x402 micro-payments and anti-prompt-injection sanitization. Returns clean JSON."
args_schema: Type[BaseModel] = SiaMeshInput
endpoint: str = "https://black-hall-4823.serkhankilicer57.workers.dev/scrape"
def _run(self, url: str) -> str:
"""Use the tool."""
try:
params = {"url": url}
response = requests.get(self.endpoint, params=params, timeout=10)
if response.status_code == 402:
return "Payment required (x402). Please ensure wallet has USDC and approve micro-payment."
response.raise_for_status()
return response.text
except requests.exceptions.RequestException as e:
return f"Error scraping URL: {e}"
async def _arun(self, url: str) -> str:
"""Use the tool asynchronously."""
import aiohttp
async with aiohttp.ClientSession() as session:
async with session.get(self.endpoint, params={"url": url}, timeout=10) as response:
if response.status == 402:
return "Payment required (x402). Please ensure wallet has USDC and approve micro-payment."
response.raise_for_status()
return await response.text()
The code defines a SiaMeshTool class inheriting from BaseTool. It uses Pydantic for input validation (URL string). The _run method performs a synchronous GET request to the SiaMesh endpoint with the target URL as a query parameter. It handles HTTP 402 (payment required) by returning an instruction message, and other errors by catching RequestException. The _arun method provides an equivalent asynchronous implementation using aiohttp. Both methods return the raw response text (expected to be sanitized JSON).
Edge Case Audit
This integration relies on a third-party service (SiaMesh endpoint) that may be unavailable, rate-limited, or change without notice. The endpoint accepts arbitrary URLs, introducing potential SSRF if used with untrusted input. x402 micro-payments require a configured Solana wallet; without it, requests will fail with 402. Payments could accumulate unexpectedly, leading to unexpected costs. Production usage should add URL allowlisting, request timeout tuning, rate limiting, and explicit user confirmation for payments. Rollback: simply remove the SiaMeshTool instance from the agent's tool list; no core LangChain components are affected.
