Home / ml4t / skills · data/fetch-data/SKILL.md · GitHub

ml4t-fetch-data skillA

ml4t-fetch-data is agent-read markdown (skill) from ml4t/skills: Reliable data acquisition with provider abstraction and schema validation. Use when ingesting market data from APIs, databases, or files..

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

# Fetch Data

Blindly loading data without validation produces silent schema drift, missing rows, and type errors that surface deep in modeling code.

## The Problem

Financial data providers change schemas, go offline, or return partial results without warning. Loading a CSV and trusting the columns exist, have the right types, and cover the expected date range is the single most common cause of broken pipelines. The failure mode is silent: your model trains on garbage and you only discover it when results make no sense.

## The Pattern

### WRONG
```python
import pandas as pd

# Blind load - no schema check, no gap detection, no type enforcement
df = pd.read_csv("etf_prices.csv")
returns = df["close"].pct_change()  # Might be string column
```

### CORRECT
```python
import polars as pl

EXPECTED_SCHEMA = {
    "timestamp": pl.Date,
    "symbol": pl.Utf8,
    "open": pl.Float64,
    "high": pl.Float64,
    "low": pl.Float64,
    "close": pl.Float64,
    "volume": pl.UInt64,
}

def load_and_validate(path: str) -> pl.DataFrame:
    """Load data with schema enforcement and basic integrity checks."""
    df = pl.read_parquet(path)

    # Schema check
…

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How to install

Latest version
mdr add ml4t/skills/ml4t-fetch-data@git:20260901.c415df0
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Versions

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git:20260901.c415df0 latest2026-09-01 c415df0 4,091 BA view · diff
git:20260528.303089e2026-05-28 303089e 4,101 BA view

Audit of the latest version

A  17 of 17 checks passed. Deterministic, no model, same answer every run.
  • pass: Frontmatter block present
  • pass: Frontmatter declares a name
  • pass: Frontmatter declares a description
  • pass: Size between 200 bytes and 200 KB (4091 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

GitHub

ml4t/skills · 19 stars · license Apache-2.0 · pushed 2026-09-24 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_umdrktgn5my3xixy
GET https://markdownregistry.com/api/v1/resolve?ref=ml4t/skills/ml4t-fetch-data
GET https://markdownregistry.com/api/v1/blob/f38e76e2e900c231cf9046b3e80470501363aea98c415401c5da121e3e55ed09

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