Produce documented data cleaning scripts that log every transformation with N before/after each step, generate a CONSORT-style exclusion flow diagram, create decision log entries for every subjective choice, compute scale reliability and composites, and write cleaned data to data/processed/. Never modifies raw data.
SkillScore77Maintained
Automatic
◆Data Engineer pack
Last verified 8/8/2026
What it changes
Passed 17 of 22 test cases with the skill, and 11 of 22 without it.
Without skill50%
With skill77%
Checks it passed that the model alone missed
Stores R cleaning functions in R/02_clean.R.
Saves cleaned dataset outputs in Parquet format.
Places Python cleaning functions in python/02_clean.py.
and 5 more in the full report
6 fixed11 passed either way5 still failing0 broke
Pass-rate lift
+27 pp
Tokens
+10%
Agent turns
0%
Response time
-25%
Model gemini-3.6-flashMeasured 8/8/2026v117 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 6 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 6
Prompt
In which file path should Python cleaning functions be placed within the project layout?
What was checked, without and with the skill
Checked
Without skill
With skill
Places Python cleaning functions in python/02_clean.py.
Missed
Passed
case-19 · gemini-3.6-flash · 8/8/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md86 lines3 files
/data-clean — Documented Data Cleaning
You produce cleaning scripts that are as rigorous as the analysis itself. Every transformation is logged. Every exclusion is counted. Every subjective choice is documented. The cleaned data is a traceable, reproducible derivation of the raw data.
You never touch data/raw/. You write to data/processed/. The raw-data-guard hook enforces this, but you enforce it in principle too.
How to run cleaning
Step 1 — Read context
Follow _shared/project-discovery.md to find the project.
Read:
Validation report (from /data-validate) — what issues were found?
Codebook — what are the variables, types, scales?
Pre-registration — what exclusion criteria were pre-specified?
Decision log — any prior cleaning decisions already made?
Step 2 — Load principles and rubric
Read references/principles.md and references/criteria.md.
Step 3 — Plan the cleaning pipeline
Before writing any code, outline the cleaning steps in order:
Type corrections (convert strings to numeric, parse dates, etc.)
Missing value recoding (convert -99, 999, "N/A" to proper NA)
Use when collecting data for a research project, downloading time series, building a dataset, accessing economic or social data APIs, or scraping data from a non-API source. Handles source discovery, respectful collection, local caching, and manifest documentation.