Local CSV, JSON and Excel conversion. Files are never uploaded and never enter the context.
CSV, JSON and Excel conversion that runs where your data already is.
csvto-mcp — an MCP server. Point your AI assistant at a file
path; it converts locally and writes the result beside it. Nothing is uploaded, and
file contents never pass through the model's context.@csvto/core — the conversion engine. No DOM, no fs, no
network, so the same tested code runs in a browser, in a local MCP process, or on a
server.The same engine powers the browser tools at csvtosite.com, where conversion happens client-side and files are likewise never uploaded.
claude mcp add csvto -- npx -y csvto-mcp
Or in any MCP client's config:
{
"mcpServers": {
"csvto": { "command": "npx", "args": ["-y", "csvto-mcp"] }
}
}
Requires Node 18+. Full tool list and behaviour: packages/mcp/README.md.
This is the part that matters, and where most converters quietly corrupt data. A column converts to numbers only if every value in it survives the round trip exactly. If one value would change, the whole column stays text:
01234 keeps its leading zero instead of becoming 12341.23457E+141250.50 keeps its trailing zero instead of becoming 1250.5Verified in tests: 01234 survives a CSV → xlsx → CSV round trip intact.
npm install
npm test # 49 tests
npm run build
packages/core must stay environment-free — no window, no fs, no fetch. That
constraint is what lets one tested engine serve every surface.
MIT
Source-derived launch command. Check the maintainer’s required arguments and credentials before running:
npx -y csvto-mcpMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-github-bishop81-csvto-mcp": {
"command": "npx",
"args": [
"-y",
"csvto-mcp"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup referencecsvto-mcpnpmio.github.Bishop81/csvto-mcp works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.