Read File

You are helping the user read and analyze a data file using DuckDB.

Filename given: $0 Question: ${1:-describe the data}

Follow these steps in order, stopping and reporting clearly if any step fails.

Step 1 — Locate DuckDB (requires ≥ v1.5.0)

DUCKDB=$(command -v duckdb)

• Not found → invoke /duckdb-claude-skills:install-duckdb (no arguments) to install DuckDB, then re-check.
• Found but version < 1.5.0 → tell the user the installed version is too old, then invoke /duckdb-claude-skills:install-duckdb --update to upgrade.
• Found and version ≥ 1.5.0 → continue.

CURRENT=$(duckdb --version | grep -oE '[0-9]+\.[0-9]+\.[0-9]+')

Step 2 — Resolve the filename to a full path

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

• Zero results → tell the user the file was not found and stop.
• More than one result → list all matches, ask the user to re-run with a fuller path, and stop.
• Exactly one result → use that full path for all subsequent steps (RESOLVED_PATH).

Step 3 — Attempt to read the file (optimistic)

Try a sandboxed read without loading any extra extensions — this succeeds immediately for built-in formats (CSV, plain text):

"$DUCKDB" :memory: -csv -c "LOAD magic; SET allowed_paths=['RESOLVED_PATH']; SET enable_external_access=false; SET allow_persistent_secrets=false; SET lock_configuration=true; SELECT column_name FROM (DESCRIBE FROM read_any('RESOLVED_PATH')); SELECT count(*) AS row_count FROM read_any('RESOLVED_PATH'); FROM read_any('RESOLVED_PATH') LIMIT 10;"

If this succeeds → skip to Step 5 (Answer).

If this fails (missing extension, or magic not found) → continue to Step 4.

Notes:

• All LOAD statements must precede SET enable_external_access=false.
• Spatial files: st_read globs for sidecar files using the filename stem. For spatial formats add a stem-wildcard to allowed_paths: SET allowed_paths=['RESOLVED_PATH', 'RESOLVED_PATH_WITHOUT_EXTENSION.*']

Step 4 — Install required extensions and retry

Detect which extensions are needed, install them, then re-run the read:

# 4a — detect (also installs magic if missing)
"$DUCKDB" :memory: -csv -c "INSTALL magic FROM community; LOAD magic; SELECT magic_required_extensions('RESOLVED_PATH') AS required_exts;"

# 4b — install all required extensions in one call (skip if list is empty)
"$DUCKDB" :memory: -c "INSTALL <ext1>; INSTALL <ext2>;"

# 4c — retry the sandboxed read with all extensions loaded
"$DUCKDB" :memory: -csv -c "LOAD magic; LOAD <ext1>; LOAD <ext2>; SET allowed_paths=['RESOLVED_PATH']; SET enable_external_access=false; SET allow_persistent_secrets=false; SET lock_configuration=true; SELECT column_name FROM (DESCRIBE FROM read_any('RESOLVED_PATH')); SELECT count(*) AS row_count FROM read_any('RESOLVED_PATH'); FROM read_any('RESOLVED_PATH') LIMIT 10;"

The three SELECT statements in 4c produce three result sets printed sequentially in CSV format.

Step 5 — Answer the question

Using the schema, row count, and sample rows gathered above, answer:

${1:-describe the data: summarize column types, row count, and any notable patterns.}