io.github.Nero-Engine/dataset-join-merge

repo:https://github.com/nero-engine/dataset-join-merge-mcp

Join two lists of JSON rows on a key, like SQL or VLOOKUP: left, inner, full, anti joins, union.

transport:: remote
credential class:: self-provisionable
repo:: https://github.com/Nero-Engine/dataset-join-merge-mcp

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Tools

join_rows
Joins two lists of JSON rows on a shared key, like a SQL join or a spreadsheet VLOOKUP, and returns the combined rows plus a summary: how many rows matched on each side, match rates, and warnings for duplicate keys, rows missing the key and key fields that exist on no row. Use it to enrich a list with fields from a lookup table (left join), keep only the overlap (inner), combine two sources into one table (full), find rows in one list that are missing from the other (leftAnti or rightAnti), or stack two same-shape lists (union). Keys match case-insensitively with whitespace trimmed by default, and the key can have a different name on each side (email on the left, contact_email on the right). Input and output rows are capped per call; a many-to-many join that would exceed the output cap is refused with the predicted row count, never truncated. Call list_capabilities for the exact limits.
shallow
list_capabilities
Returns every join type, key matching mode, conflict strategy and fan-out mode this server supports, the fields it adds to each row, and the input and output row limits per call. Free, processes no data.
shallow

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