read-file

name read-file description 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. argument-hint <filename or URL> [question about the data] allowed-tools Bash 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-duckdb and retry. Missing extension (e.g. spatial files, xlsx, sqlite) → retry with INSTALL spatial; LOAD spatial; or INSTALL sqlite_scanner; LOAD sqlite_scanner; prepended before the macro. Wrong reader / parse error → use the correct read_* function directly instead of read_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.}