convert-file

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha eaf479591fd1 · 21 Oct 2026Report an issue or request a re-scan

• Publisherduckdb GitHub organizationOwner of the repository this skill is read from
• Source folderduckdb/duckdb-skills/skills/convert-fileThe exact folder we audited
• LicenceMITAs the repository states it
• Commit pinned for this verdicteaf479591fd1A new audit runs when the source changes
• Repository statusNot archivedLast push 180 days ago
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: 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…

---
name: convert-file
description: >
  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.
argument-hint: <input-file> [output-file]
allowed-tools: Bash
---

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

Excerpt, first 2,877 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

git clone https://github.com/duckdb/duckdb-skills
git -C duckdb-skills checkout eaf479591fd1

Works in

1. 2026-10-21
   ✓SAFE B 89 / 100

   first audit · source eaf479591fd1

Questions about convert-file

• github.com/duckdb/duckdb-skills/tree/main/skills/convert-file — the audited source at commit eaf479591fd1 and every finding aboveObserved · 21 Oct 2026

Spotted something wrong? Report a correction · Methodology