Assay MCP MCP server

A read-only MCP server that verifies crypto payment settlement across 20 chains. It allows agents to confirm the actual amount received versus the stated amount, preventing credit errors due to settlement failures, without requiring API keys or accounts.

Endpoint and access

No sign-in: your client connects and lists tools immediately, with no account or key.

No sign-inEndpoint checked 2026-10-05Operated by FOMOx

MCP endpoint (Streamable HTTP)

https://fomox.io/api/assay/mcp

Vendor documentation

What you can do with it

Verify if a crypto payment has settled
Check the actual amount received on-chain
Test payment verification with sandbox cases

Tools advertised by the last live check:

verify_payment
list_chains
list_failure_modes
evaluate_spend_policy
run_sandbox_case
check_sandbox_answer

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers a Streamable HTTP server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http assay-mcp https://fomox.io/api/assay/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add assay-mcp --url https://fomox.io/api/assay/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable assay-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "assay-mcp": {
      "url": "https://fomox.io/api/assay/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure). The type must be streamableHttp for a remote HTTP server.

Cline configuration

{
  "mcpServers": {
    "assay-mcp": {
      "type": "streamableHttp",
      "url": "https://fomox.io/api/assay/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start assay-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "assay-mcp": {
      "type": "http",
      "url": "https://fomox.io/api/assay/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http assay-mcp https://fomox.io/api/assay/mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.

Claude Desktop configuration

{
  "mcpServers": {
    "assay-mcp": {
      "url": "https://fomox.io/api/assay/mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "assay-mcp": {
      "serverUrl": "https://fomox.io/api/assay/mcp"
    }
  }
}

See all 128

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