MCP CUSIP/ISIN Server

A Model Context Protocol (MCP) server for validating and parsing CUSIP and ISIN security identifiers using check digit algorithms.

Tools (4 total)

| Tool | Description | |------|-------------| | cusip_validate | Validate a 9-character CUSIP using the Luhn-variant check digit algorithm | | cusip_parse | Parse a CUSIP into issuer code, issue number, and check digit | | isin_validate | Validate a 12-character ISIN using the Luhn algorithm | | isin_parse | Parse an ISIN into country code, NSIN, and check digit (extracts embedded CUSIP for US/CA) |

Install

npx @easysolutions906/mcp-cusip-isin

Claude Desktop

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "cusip-isin": {
      "command": "npx",
      "args": ["-y", "@easysolutions906/mcp-cusip-isin"]
    }
  }
}

Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "cusip-isin": {
      "command": "npx",
      "args": ["-y", "@easysolutions906/mcp-cusip-isin"]
    }
  }
}

REST API

Set PORT env var to run as an HTTP server.

• GET /cusip/validate?cusip=037833100 -- validate a CUSIP
• GET /cusip/parse?cusip=037833100 -- parse CUSIP into components
• GET /isin/validate?isin=US0378331005 -- validate an ISIN
• GET /isin/parse?isin=US0378331005 -- parse ISIN into components
• POST /validate/batch -- batch validate multiple CUSIPs and ISINs

Data Source

Pure algorithm -- no external dataset required. CUSIP uses a Luhn-variant checksum; ISIN uses standard Luhn over letter-to-number conversion.

Transport

• stdio (default) -- for local use with Claude Desktop and Cursor
• HTTP -- set PORT env var to start in Streamable HTTP mode on /mcp