Add Proxies.sx mobile proxy tools (4G/5G carrier proxies with x402 micropayments)

[bolivian-peru]

Feature Description

Add mobile proxy tools for LangChain agents, providing real 4G/5G carrier IP access with autonomous x402 USDC micropayments. This would join existing proxy-adjacent tools (Hyperbrowser, Scrapeless, Scrapfly) and address the proxy support demand seen in langchain-ai/langchain#16751.

Proposed tools:

• ProxiesSxProxyTool — Acquire a mobile proxy with HTTP/SOCKS5 credentials from 6 countries
• ProxiesSxRotateTool — Rotate IP on an active proxy (triggers real airplane mode toggle on physical modem)
• ProxiesSxBrowserTool — Launch antidetect browser session with auto-allocated mobile proxy and Identity Bundles
• ProxiesSxExtractTool — Extract page content via stealth browser with mobile IP

Use Case

Agents building web research pipelines need real mobile IPs to:

1. Avoid IP bans when scraping at scale (mobile carrier IPs are virtually never blocked)
2. See mobile-specific search results (mobile SERPs differ significantly from desktop)
3. Access geo-restricted content from 6 countries (US, DE, GB, FR, ES, PL)
4. Maintain persistent browser identities with proxy binding via Identity Bundles

Current workarounds involve manually configuring proxies or using MCP adapters, but native LangChain tools would provide a cleaner experience.

Proposed Solution

Option A: langchain-mcp-adapters (works today):

from langchain_mcp_adapters.client import MultiServerMCPClient

async with MultiServerMCPClient({
    "proxies": {
        "command": "npx",
        "args": ["@proxies-sx/mcp-server"]
    },
    "browser": {
        "command": "npx",
        "args": ["@proxies-sx/browser-mcp"]
    }
}) as client:
    tools = client.get_tools()
    agent = create_react_agent(llm, tools)

Option B: Native langchain-proxiess package (proposed):

from langchain_proxiess import ProxiesSxProxyTool

tool = ProxiesSxProxyTool(country="US", tier="shared")
result = tool.invoke({"action": "get_proxy"})
# Returns: {"host": "gw.proxies.sx", "port": 7000, "username": "psx_...", "password": "..."}

Alternatives Considered

• Using PlaywrightURLLoader with manual proxy config — no mobile IPs available
• Hyperbrowser/Scrapeless — datacenter/residential IPs, not mobile carrier
• Raw HTTP requests to Proxies.sx API — no LangChain integration

Additional Context

Infrastructure:

• 155+ real 4G/5G mobile modems across 6 countries (US, DE, GB, FR, ES, PL)
• Pool gateway: HTTP (port 7000) + SOCKS5 (port 7001)
• Antidetect browser with auto-allocated mobile proxy (~$0.005/min)

Payment:

• x402 USDC micropayments on Base and Solana — agents self-provision, no API keys needed
• $4/GB shared, $8/GB private

Published MCP servers:

• @proxies-sx/mcp-server (proxy management, 3 tools)
• @proxies-sx/browser-mcp (browser control, 11 tools)

Related:

• Enhancement: Add Proxy Support to PlaywrightURLLoader Class langchain#16751 (proxy support request for Playwright)
• Existing proxy-adjacent integrations: Hyperbrowser, Scrapeless, Scrapfly

Links:

• Website: https://agents.proxies.sx
• x402 Discovery: https://agents.proxies.sx/.well-known/x402.json
• npm: https://www.npmjs.com/package/@proxies-sx/mcp-server