# Dtdiff

> Use when the user asks to compare, diff, or find differences between two tabular data files (CSV, TSV, Parquet, Arrow, JSON, NDJSON, Excel). Also use when the user mentions data diff, file comparison, or wants to know what changed between two data files of the same format.

- **Type:** Skill
- **Install:** `agentstack add skill-louloulibs-claude-skills-dtdiff`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [LouLouLibs](https://agentstack.voostack.com/s/louloulibs)
- **Installs:** 0
- **Category:** [Data & Analytics](https://agentstack.voostack.com/c/data-and-analytics)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [LouLouLibs](https://github.com/LouLouLibs)
- **Source:** https://github.com/LouLouLibs/claude-skills/tree/main/skills/dtdiff

## Install

```sh
agentstack add skill-louloulibs-claude-skills-dtdiff
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# dtdiff — Tabular Data Comparison

Compare two tabular data files of the same format and report added, removed, and modified rows.

## Quick Reference

```bash
# Compare two CSV files (positional mode)
dtdiff old.csv new.csv

# Compare by key column
dtdiff old.parquet new.parquet --key ID

# Composite key
dtdiff old.csv new.csv --key Date,Ticker

# Float tolerance (differences ` | auto | Override format detection (applies to both files) |
| `--sheet ` | first | Select sheet (Excel only) |
| `--key ` | *(none)* | Key columns for matching (comma-separated names) |
| `--tolerance ` | `1e-10` | Float comparison tolerance |
| `--json` | false | Output as JSON |
| `--csv` | false | Output as CSV |
| `--no-color` | false | Disable ANSI colors |

## Exit Codes (diff convention)

| Code | Meaning |
|------|---------|
| 0 | No differences |
| 1 | Differences found |
| 2 | Error |

## Workflow

1. Identify the two files to compare (must be same format)
2. Use `--key` if rows have a natural identity column (ID, date, etc.)
3. Use `--tolerance` for financial/scientific data with float rounding
4. Use `--json` for structured output, default text for quick review

## Common Patterns

**What changed between versions:**
```bash
dtdiff old.csv new.csv --key ID
```

**Ignore small rounding differences:**
```bash
dtdiff old.parquet new.parquet --key ID --tolerance 0.001
```

**Pipe structured results for processing:**
```bash
dtdiff a.csv b.csv --key ID --json | jq '.modified'
```

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [LouLouLibs](https://github.com/LouLouLibs)
- **Source:** [LouLouLibs/claude-skills](https://github.com/LouLouLibs/claude-skills)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-louloulibs-claude-skills-dtdiff
- Seller: https://agentstack.voostack.com/s/louloulibs
- Browse the marketplace: https://agentstack.voostack.com/browse

---
Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.