read-file
Read any data file (CSV, JSON, Parquet, Avro, Excel, spatial, SQLite) or remote URL (S3, HTTPS). Use when user references a data file, asks "what's in this file", or wants to preview/profile a dataset. Not for source code.
- Installs
- 1.2K
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- #9298
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/duckdb/duckdb-skills --skill read-file- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads read-file automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
You are helping the user read and analyze a data file using DuckDB.
Filename given: $0
Question: ${1:-describe the data}
Step 1 — Read it
RESOLVED_PATH is $0. If the user gave a bare filename (no /), resolve it to a full path with find first.
Run a single DuckDB command that defines the read_any macro inline and reads the file.
For remote files, prepend the necessary LOAD/SECRET before the macro:
| Protocol | Prepend |
|---|---|
https:// / http:// | LOAD httpfs; |
s3:// | LOAD httpfs; CREATE SECRET (TYPE S3, PROVIDER credential_chain); |
gs:// / gcs:// | LOAD httpfs; CREATE SECRET (TYPE GCS, PROVIDER credential_chain); |
az:// / azure:// / abfss:// | LOAD httpfs; LOAD azure; CREATE SECRET (TYPE AZURE, PROVIDER credential_chain); |
For local files, no prefix needed.
duckdb -csv -c "
CREATE OR REPLACE MACRO read_any(file_name) AS TABLE
WITH json_case AS (FROM read_json_auto(file_name))
, csv_case AS (FROM read_csv(file_name))
, parquet_case AS (FROM read_parquet(file_name))
, avro_case AS (FROM read_avro(file_name))
, blob_case AS (FROM read_blob(file_name))
, spatial_case AS (FROM st_read(file_name))
, excel_case AS (FROM read_xlsx(file_name))
, sqlite_case AS (FROM sqlite_scan(file_name, (SELECT name FROM sqlite_master(file_name) LIMIT 1)))
, ipynb_case AS (
WITH nb AS (FROM read_json_auto(file_name))
SELECT cell_idx, cell.cell_type,
array_to_string(cell.source, '') AS source,
cell.execution_count
FROM nb, UNNEST(cells) WITH ORDINALITY AS t(cell, cell_idx)
ORDER BY cell_idx
)
FROM query_table(
CASE
WHEN file_name ILIKE '%.json' OR file_name ILIKE '%.jsonl' OR file_name ILIKE '%.ndjson' OR file_name ILIKE '%.geojson' OR file_name ILIKE '%.geojsonl' OR file_name ILIKE '%.har' THEN 'json_case'
WHEN file_name ILIKE '%.csv' OR file_name ILIKE '%.tsv' OR file_name ILIKE '%.tab' OR file_name ILIKE '%.txt' THEN 'csv_case'
WHEN file_name ILIKE '%.parquet' OR file_name ILIKE '%.pq' THEN 'parquet_case'
WHEN file_name ILIKE '%.avro' THEN 'avro_case'
WHEN file_name ILIKE '%.xlsx' OR file_name ILIKE '%.xls' THEN 'excel_case'
WHEN file_name ILIKE '%.shp' OR file_name ILIKE '%.gpkg' OR file_name ILIKE '%.fgb' OR file_name ILIKE '%.kml' THEN 'spatial_case'
WHEN file_name ILIKE '%.ipynb' THEN 'ipynb_case'
WHEN file_name ILIKE '%.db' OR file_name ILIKE '%.sqlite' OR file_name ILIKE '%.sqlite3' THEN 'sqlite_case'
ELSE 'blob_case'
END
);
DESCRIBE FROM read_any('RESOLVED_PATH');
SELECT count(*) AS row_count FROM read_any('RESOLVED_PATH');
FROM read_any('RESOLVED_PATH') LIMIT 20;
"
If this fails:
duckdb: command not found→ invoke/duckdb-skills:install-duckdband retry.- Missing extension (e.g. spatial files, xlsx, sqlite) → retry with
INSTALL spatial; LOAD spatial;orINSTALL sqlite_scanner; LOAD sqlite_scanner;prepended before the macro. - Wrong reader / parse error → use the correct
read_*function directly instead ofread_any.
Step 2 — Answer
Using the schema, row count, and sample rows, answer:
${1:-describe the data: summarize column types, row count, and any notable patterns.}
FAQ
What does the read-file skill do?
Read any data file (CSV, JSON, Parquet, Avro, Excel, spatial, SQLite) or remote URL (S3, HTTPS). Use when user references a data file, asks "what's in this file", or wants to preview/profile a dataset. Not for source code.
How do I install read-file?
Run npx skills add https://github.com/duckdb/duckdb-skills --skill read-file in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/read-file/ (personal) or .claude/skills/read-file/ (project).
Which AI agents can use read-file?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is read-file safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains read-file?
It is published by duckdb in duckdb/duckdb-skills. It has 1,229 recorded installs.
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