csv-analysis

A workflow for inspecting a CSV file, calculating basic statistics, and producing a report about its contents and data quality.

In plain words
What is it for?
Use it to profile columns, infer data types, count rows and unique values, calculate numeric summaries, and create a report of findings.
Why use it?
It quickly reveals the file’s structure, missing values, duplicates, inconsistent formats, and unusual numeric values before the data is used.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/codebytes/agent-skills/csv-analysis
Any agent
npx skills add codebytes/agent-skills --skill csv-analysis
Clone the repo
git clone --depth 1 https://github.com/codebytes/agent-skills

Made for: Claude Code, Codex.

Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 417 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00017 $0.00417
Opus 5 $0.00009 $0.00209
Sonnet 5 $0.00003 $0.00083
Haiku 4.5 $0.00002 $0.00042

Measured yesterday against content hash 054f85edbfec, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

csv-analysis scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/csv-analysis/SKILL.md · 50 lines

What it actually says

Instructions

When asked to analyze a CSV file, follow this workflow:

Step 1: Read and Profile

  • Read the first 50 lines of the CSV
  • Identify the delimiter (comma, tab, semicolon, pipe)
  • Count total rows and columns
  • Infer column data types (string, integer, float, date, boolean)

Step 2: Compute Statistics

Run analysis to compute per-column statistics:

  • Count, nulls, unique values
  • Min, max, mean, median, standard deviation for numeric columns
  • Most frequent values for categorical columns

Step 3: Quality Assessment

Check for:

  • Missing or null values (empty strings, "NA", "null", "N/A")
  • Duplicate rows
  • Inconsistent formatting (mixed date formats, case inconsistency)
  • Potential outliers (values beyond 3 standard deviations)

Step 4: Generate Report

Create a markdown report with:

  • Overview: File name, row count, column count
  • Schema table: Column name, type, non-null count, unique count
  • Statistics table: Min, max, mean, median, std dev for numeric columns
  • Quality issues: List of findings with severity (info/warning/error)
  • Key findings: Top 3-5 insights from the data

Output Format

The report should be a well-formatted markdown document suitable for inclusion in project documentation. Use tables for structured data and bullet points for findings.

Error Handling

  • If the file is not valid CSV, report the issue and suggest the correct format
  • If the file is too large (>100MB), sample the first 10,000 rows and note the sampling
  • If encoding errors occur, try UTF-8, Latin-1, and CP1252 in order
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 50 lines · 17 tokens per session scan A 054f85edbfec

Subscribe to this mod's changes

csv-analysis is a skill published in the GitHub repository codebytes/agent-skills (2 stars, last pushed 2mo ago), licensed MIT. It adds 17 tokens to every session and 417 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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