SQL CSV Chomper

A VS Code extension and MCP server for querying and editing CSV/TSV files using SQL, powered by DuckDB.

Install from VS Code Marketplace

Features

• Custom CSV Editor — Open delimited files in VS Code with a full SQL IDE layout
• Full SQL Support — Write and execute DuckDB SQL against your CSV files
• Format Preservation — The source delimiter, quoting and header are detected on load and reused on save, so a pipe- or tab-delimited file is never silently rewritten as comma-delimited
• Load Options — Override the column delimiter, row delimiter, header, quoting or encoding when detection gets it wrong, and re-read the file in place
• Virtual Scrolling — Handles 500K+ rows with chunked loading
• Resizable Columns — Drag any column edge; double-click the handle to auto-fit
• Column Filtering — Excel-style filter panels with value checkboxes, search, date histograms
• Column Profiling — Distinct, null, whitespace-only and max-length stats per column
• Inline Editing — Double-click cells to edit, save back to disk
• Column Operations — Rename, insert, delete columns via right-click
• Find & Replace — Regex and case-sensitive search across columns
• Save As — Export with custom delimiter, quoting, row numbers
• Multi-Table Support — Load multiple files and JOIN across them
• MCP Server — Expose CSV querying, profiling and table diffing to Claude, Copilot, and other AI assistants

Project Structure

packages/
extension/ # VS Code extension (custom editor provider)
webapp/ # React editor UI (Monaco, TanStack Table, DuckDB WASM)
mcp-server/ # MCP server for LLM integration (native DuckDB)

Development

npm install
npm run build # Build all packages
npm run dev # Run webapp standalone for development

Press F5 in VS Code to launch the Extension Development Host for testing.

Publishing

cd packages/extension
npx @vscode/vsce publish --no-dependencies

MCP Server

The MCP server lets AI assistants load, query, edit, and save CSV files via SQL. It auto-installs the native DuckDB binary on first run.

See the extension README for full setup instructions (Claude Code, Copilot, terminal).

Quick setup (Claude Code)

claude mcp add sql-csv-chomper --scope user -- npx -y sql-csv-chomper-mcp

Available MCP Tools

Tool	Description
load_csv / unload_csv	Load a delimited file as a named table (dialect detected and overridable), or drop it
execute_sql	Run SQL queries against loaded tables
list_tables / list_columns / get_schema	Inspect loaded data
profile_table / profile_file	Column stats, or scan a file before loading it
diff_tables	Schema-aware diff of two tables on a key column
update_rows / insert_row / delete_rows	Edit data
save_table	Write a table back out, in its original dialect by default
list_remembered_tables / reload_remembered_tables	Re-load tables from a previous session
set_editor_sql / run_editor_query	Push SQL into the VS Code editor

See the MCP server README for details, including a note on how DuckDB treats empty CSV fields as NULL.

License

MIT