convert-file

Original：🇺🇸 English

Translated

Convert any data file to another format: CSV, Parquet, JSON, Excel, GeoJSON, and more. Use when the user says "convert to parquet", "save as xlsx", "export as JSON", "make this a CSV", "turn into parquet", or any variation of format-to-format conversion for data files. Also triggers when the user wants to write Parquet, Excel, or other binary formats that Claude cannot produce natively.

2installs

Sourceduckdb/duckdb-skills

Added on2026-05-21

NPX Install

npx skill4agent add duckdb/duckdb-skills convert-file

SKILL.md Content

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You are helping the user convert a data file from one format to another using DuckDB.

Input file:

$0

Output file:

${1:-}

Step 1 — Resolve input and output

Input:

$0

. If it's a bare filename (no

), resolve to a full path with

find "$PWD" -name "$0" -not -path '*/.git/*' 2>/dev/null | head -1

.

Output: If

$1

is provided, use it as the output path. If not, default to the same stem as the input with a

.parquet

extension (e.g.,

data.csv

→

data.parquet

).

Infer the output format from the output file extension:

Extension	Format clause
`.parquet` , `.pq`	(default, no clause needed)
`.csv`	`(FORMAT csv, HEADER)`
`.tsv`	`(FORMAT csv, HEADER, DELIMITER '\t')`
`.json`	`(FORMAT json, ARRAY true)`
`.jsonl` , `.ndjson`	`(FORMAT json, ARRAY false)`
`.xlsx`	`(FORMAT xlsx)` — requires `INSTALL excel; LOAD excel;`
`.geojson`	`(FORMAT GDAL, DRIVER 'GeoJSON')` — requires `LOAD spatial;`
`.gpkg`	`(FORMAT GDAL, DRIVER 'GPKG')` — requires `LOAD spatial;`
`.shp`	`(FORMAT GDAL, DRIVER 'ESRI Shapefile')` — requires `LOAD spatial;`

Step 2 — Convert

Run a single DuckDB command. Prepend extension loads as needed based on both the input and output formats.

bash

duckdb -c "
<EXTENSION_LOADS>
COPY (FROM '<INPUT_PATH>') TO '<OUTPUT_PATH>' <FORMAT_CLAUSE>;
"

For remote inputs (

s3://

,

https://

, etc.), prepend the same protocol setup as

read-file

:

Protocol	Prepend
`s3://`	`LOAD httpfs; CREATE SECRET (TYPE S3, PROVIDER credential_chain);`
`gs://` / `gcs://`	`LOAD httpfs; CREATE SECRET (TYPE GCS, PROVIDER credential_chain);`
`https://` / `http://`	`LOAD httpfs;`

If the user mentions partitioning (e.g., "partition by year"), add

PARTITION_BY (col)

to the format clause. This only works with Parquet and CSV output.

If the user mentions compression (e.g., "use zstd"), add

CODEC 'zstd'

for Parquet output.

Step 3 — Report

On success, report:

Input file and detected format
Output file, format, and size (
```
ls -lh
```
)
Row count if quick to compute

On failure:

duckdb: command not found
→ delegate to

/duckdb-skills:install-duckdb

Missing extension → install it and retry
Input parse error → suggest the user check the input format or try
```
/duckdb-skills:read-file
```
first to inspect it