Isbn MCP runs on your own machine — the client starts it, so there is no endpoint to ping. 557 installs a week from npm. Last commit 28 Oct 2026.
Validate and convert ISBN-10 and ISBN-13 numbers, with checksum maths - fully local.
Today is the operative word: we check Isbn MCP every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add isbn-mcp -- npx -y @mrfentmen/isbn-mcp
{
"mcpServers": {
"isbn-mcp": {
"command": "npx",
"args": [
"-y",
"@mrfentmen/isbn-mcp"
]
}
}
}
[mcp_servers.isbn-mcp]
command = "npx"
args = ["-y", "@mrfentmen/isbn-mcp"]
{
"mcpServers": {
"isbn-mcp": {
"command": "npx",
"args": [
"-y",
"@mrfentmen/isbn-mcp"
]
}
}
}
{
"servers": {
"isbn-mcp": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@mrfentmen/isbn-mcp"
]
}
}
}
Validate and format international phone numbers locally. No network and no key.
Validate and format IBAN bank account numbers locally. No network and no key.
Validate EU VAT numbers against the official VIES service with a local pre-check.
Compress, convert and resize images locally, with marketplace presets and rule rechecks.
Validate IBANs offline with the official length table and mod-97 checksum, country by country
Validate EU VAT numbers in VIES and check Peppol e-invoicing, with source and date on every fact
Compute file and text checksums locally with sha and md5. No network and no key.
Validate IBAN, EU VAT, card numbers, ISBN, BIC, EAN and postcodes
Answers built from our own checks of this server.