CSV Inspect

Inspect delimited tables (CSV/TSV) before any analysis: column names, encodings, delimiters, row counts, inferred types, and first/last rows. Use when the user asks to peek a CSV, list headers, show head/tail, preview schema, check dtypes, or before pandas work on .csv/.tsv/.tab files. Use when the user runs /csv-inspect. Do not use for Excel workbooks (.xlsx) or for writing statistical reports — inspect only, then stop or hand off.

Read schema and samples, not the whole file. Do not start analysis until this output exists.

When to use

• User wants headers, preview rows, shape, encoding, or delimiter
• Any later step will parse a .csv / .tsv / .tab / .txt table

Stop after inspect if that was the whole request. For rankings, z-scores, or a written report, inspect first, then use a separate analysis path.

Command

csv-inspect must be on PATH. Run it in the shell. Do not call scripts/csv-inspect. Do not prefix with python3. Do not reimplement this inspect in Python.

bash

csv-inspect /path/to/some.csv
csv-inspect /path/to/some.csv --head 10 --tail 3
csv-inspect /path/to/some.csv --json

Do not cat / read the raw file to "see columns". Do not load the table into pandas just to print columns or head.

What you must take from the output

• names: use these strings exactly (case, spaces, punctuation)
• encoding / delimiter: pass the same when you later open / read_csv
• types: inferred from --scan rows (default 200). date includes YYYY-MM period strings — do not treat them as Excel serials; split or to_datetime explicitly. sample values may come from later rows too.
• rows: data rows only (header excluded unless --no-header)

Hard rules

1. Inspect before any groupby / z-score / report write.
2. Failures must show a traceback. Do not wrap the first parse in except Exception as e: print(e).
3. Never dump a large table into the transcript. --head defaults to 5; raise it only if the user asked for more.
4. If columns is 1 and values contain ; or \t, re-run with the printed delimiter or inspect a larger sample — the sniffer can be wrong on tiny files.
5. After a successful inspect, do not re-inspect in a loop. Proceed or stop.

Done criteria

• csv-inspect was run on the target file via the shell
• Column names in later code match names exactly
• Raw file was not bulk-read into context
• If the user only asked for preview/schema, you stopped after the inspect output