ml4t-data-export skillA
ml4t-data-export is agent-read markdown (skill) from ml4t/skills: Export financial data in efficient columnar formats with schema enforcement. Use when persisting datasets for reproducible research or cross-pipeline sharing..
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
# Data Export
Saving financial data as CSV loses type information, bloats file size 5-10x, and makes every downstream read parse strings back into numbers - a tax paid on every pipeline run.
## The Problem
CSV is human-readable but machine-hostile: no type information (dates become strings, integers become floats), no compression (a 100MB Parquet file becomes 500MB CSV), no predicate pushdown (you must read the entire file to filter one column), and no schema enforcement (a renamed column breaks silently). For financial data pipelines where the same dataset is read hundreds of times by different notebooks, the cumulative cost of CSV is enormous in both time and correctness.
## The Pattern
### WRONG
```python
import pandas as pd
# CSV: no types, no compression, slow reads, 5x file size
df.to_csv("prices.csv", index=False)
# Every consumer must re-parse types
df = pd.read_csv("prices.csv", parse_dates=["date"]) # Hope the format matches
df["volume"] = df["volume"].astype(int) # Was saved as float because of NaN
```
### CORRECT
```python
import polars as pl
# Enforce schema before writing
SCHEMA = {
"timestamp": pl.Date,
"symbol": pl.Utf8,
"open": pl.Float64,
…Read the whole file at its exact version.
How to install
mdr add ml4t/skills/ml4t-data-export@git:20260901.c415df0mdr add ml4t/skills/ml4t-data-export@sha256:fc229e910bc47d81Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_4hzw6bfklnx22r4k)
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Versions
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260901.c415df0 latest | 2026-09-01 | c415df0 | 4,370 B | A | view · diff |
| git:20260528.303089e | 2026-05-28 | 303089e | 4,380 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4370 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
ml4t/skills · 19 stars · license Apache-2.0 · pushed 2026-09-24 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_4hzw6bfklnx22r4k GET https://markdownregistry.com/api/v1/resolve?ref=ml4t/skills/ml4t-data-export GET https://markdownregistry.com/api/v1/blob/fc229e910bc47d81c7cf3aee5dee272e041de73fe7632964e2ff10ec80ecaeed
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