jgravelle/jdatamunch-mcp

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Token-efficient MCP server for tabular data retrieval. Index CSV/Excel files, query rows, aggregate — 99%+ token savings vs raw file reads.

81 ★19 forksPythonUpdated 18d ago

What you need to know

Local-first MCP server that answers questions about CSV, Excel, Parquet, and JSONL files by profiling a dataset once and running column profiles, filtered rows, aggregations, and joins server-side, so a million-row file costs thousands of tokens instead of millions.

Install

claude mcp add jdatamunch -- uvx jdatamunch-mcp
claude mcp add jdatamunch -- uvx --from "jdatamunch-mcp[excel,parquet]" jdatamunch-mcp
uv tool install jdatamunch-mcp
pipx install jdatamunch-mcp

Usage

  • No separate indexing command: ask the agent to index a file and it calls index_local, returning the dataset name, row/column counts, and detected types.
  • Orient with describe_dataset / describe_column, then query without loading rows via get_rows, aggregate, or run_sql.
  • Work across datasets with suggest_joins, suggest_keys, and join_datasets; index CSVs/Excel/Parquet/JSONL straight from GitHub with index_repo.
  • Requires Python 3.10+ and any MCP-compatible client; Excel and Parquet need the matching optional extras.

Key features

  • 39 tools covering orientation, server-side query, data quality (get_dataset_health, get_data_hotspots), schema-drift checks, and semantic search.
  • Aggregations and filters execute against stored data rather than being simulated in the model.
  • Sampled statistics report error bounds (roughly 2% standard error) instead of presenting estimates as exact.
  • Local-first with opt-out anonymous savings counter; no data, column names, file paths, or PII uploaded.
  • Implements the jMRI retrieval spec with token accounting shared across the jMunch suite.

Best for

Analysts and coding agents that need to explore large tabular datasets (CSV/Excel/Parquet/JSONL) without dumping rows into the context window.

Caveats

  • Free for personal use; commercial use requires a paid one-time license (from $39) sold by jMunch LLC.
  • Token savings scale with file size — negligible on small spreadsheets.
  • Excel and Parquet support require optional extras that pull extra dependencies.
  • Does not read code or prose; those belong to the sibling jcodemunch-mcp and jdocmunch-mcp servers.
  • Default describe_column is not labeled offloadable when index freshness is unknown.
Platforms: LocalClients: Claude Code · Claude Desktop · Cursor · Windsurf

Reviewed 2026-08-18

Topics

claudeclaude-codecodexcopilotcsvcursordata-analysisdata-explorationdeveloper-toolsexcelgemini-clillmmcpmcp-servermodel-context-protocolspreadsheetsqltabular-datatoken-optimizationwindsurf
Stars
81★
Forks
19
Language
Python
License
NOASSERTION
Created
2026-03-25
Last push
2026-08-17