MCP server

Blackwall X402 Guardrail

com.blackwalltier/blackwall-x402-guardrail

Checked 26 Oct 2026, 08:29 UTC · Connected to it and listed its tools

Keyless hosted MCP: pre-signature x402 payment verdict (GO/HOLD/STOP) with a signed receipt.

Website Source

At a glance

Type

MCP server

Publisher

blackwalltier.com (verified by the MCP Registry)

Status

Working at last check

Tools

1

Token cost

About 303 tokens per request

Sets up in

Claude Code, Claude Desktop, Codex, Gemini CLI, Cursor, VS Code, Antigravity, ChatGPT, OpenAI API, Grok

Last checked

26 Oct 2026, 08:29 UTC

Connect it to your agent

Add to CursorAdd to VS CodeVS Code Insiders

Opens the app, which shows the server and asks you to confirm. For other apps, copy the setup below.

Claude Code

claude mcp add --transport http blackwall-x402-guardrail https://mcp.blackwalltier.com

Claude Desktop

Settings → Connectors → Add custom connector, and paste the URL.

Codex (config.toml)

[mcp_servers.blackwall-x402-guardrail]
url = "https://mcp.blackwalltier.com"

Gemini CLI

{"mcpServers":{"blackwall-x402-guardrail":{"httpUrl":"https://mcp.blackwalltier.com"}}}

Cursor

{"mcpServers":{"blackwall-x402-guardrail":{"url":"https://mcp.blackwalltier.com"}}}

VS Code

{"servers":{"blackwall-x402-guardrail":{"type":"http","url":"https://mcp.blackwalltier.com"}}}

Antigravity

agy mcp add blackwall-x402-guardrail https://mcp.blackwalltier.com

ChatGPT

Settings → Apps & Connectors → Advanced settings: turn on Developer mode, then Create a connector and paste the URL. Which plans can do this varies.

OpenAI API (Responses tools)

{"type":"mcp","server_label":"blackwall-x402-guardrail","server_url":"https://mcp.blackwalltier.com","require_approval":"always"}

Grok (xAI API tools)

{"type":"mcp","server_label":"blackwall-x402-guardrail","server_url":"https://mcp.blackwalltier.com"}

Tools

• forecast_payment ~303 tokens
  Pre-signature x402 payment verdict: GO / HOLD / STOP for paying a counterparty, from settlement reputation, price-anomaly (quoted vs the payee's own median), and OFAC sanctions — with a third-party-verifiable Ed25519 signed receipt. Verdict only; never takes custody. Free under $10 at risk; over tha

Browse

• Payments

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Badge for your README

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