Excel / XLSX

Excel / XLSX is a skill for Claude Code, Codex from waterfeet/DoroPet_V3. It costs 90 tokens per session (1,457 once invoked), scanned A, original, Apache-2.0.

A set of instructions for creating, reading, analysing, and editing Microsoft Excel workbooks and other spreadsheet files such as XLSX, XLSM, XLS, CSV, and TSV.

In plain words
What is it for?
It is for analysing tabular data, preserving or editing existing workbooks, writing live Excel formulas, and creating or formatting spreadsheet files.
Why use it?
It helps avoid common spreadsheet problems involving formulas, dates, data types, formatting, workbook structure, and compatibility between spreadsheet programs.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It is for analysing tabular data, preserving or editing existing workbooks, writing live Excel formulas, and creating or formatting spreadsheet files.

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Install with agentmods
npx agentmods add skills/waterfeet/doropet_v3/excel-xlsx
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.

Any agent
npx skills add waterfeet/DoroPet_V3 --skill excel-xlsx
Clone the repo
git clone --depth 1 https://github.com/waterfeet/DoroPet_V3

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for Excel / XLSX

README.md
[![agentmods](https://agentmods.dev/badge/skills/waterfeet/doropet_v3/excel-xlsx/github.svg)](https://agentmods.dev/skills/waterfeet/doropet_v3/excel-xlsx)
Your own site
<a href="https://agentmods.dev/skills/waterfeet/doropet_v3/excel-xlsx"><img src="https://agentmods.dev/badge/skills/waterfeet/doropet_v3/excel-xlsx/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for Excel / XLSX

Your own site · 80×15
<a href="https://agentmods.dev/skills/waterfeet/doropet_v3/excel-xlsx"><img src="https://agentmods.dev/badge/skills/waterfeet/doropet_v3/excel-xlsx.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,457 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00090 $0.01457
Opus 5 $0.00045 $0.00728
Sonnet 5 $0.00018 $0.00291
Haiku 4.5 $0.00009 $0.00146

Measured 12d ago against content hash 52421d9fba8f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

Excel / XLSX 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 12d ago.

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.

opendoro/src/skills/excel-xlsx/SKILL.md · 104 lines

How it starts

The opening of the file, as written. The whole thing — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to Use

Use when the main artifact is a Microsoft Excel workbook or spreadsheet file, especially when formulas, dates, formatting, merged cells, workbook structure, or cross-platform behavior matter.

Core Rules

1. Choose the workflow by job, not by habit

  • Use pandas for analysis, reshaping, and CSV-like tasks.
  • Use openpyxl when formulas, styles, sheets, comments, merged cells, or workbook preservation matter.
  • Treat CSV as plain data exchange, not as an Excel feature-complete format.
  • Reading values, preserving a live workbook, and building a model from scratch are different spreadsheet jobs.

2. Dates are serial numbers with legacy quirks

  • Excel stores dates as serial numbers, not real date objects.
  • The 1900 date system includes the false leap-day bug, and some workbooks use the 1904 system.
  • Time is fractional day data, so formatting and conversion both matter.
  • Date correctness is not enough if the number format still displays the wrong thing to the user.

3. Keep calculations in Excel when the workbook should stay live

  • Write formulas into cells instead of hardcoding derived results from Python.
  • Use references to assumption cells instead of magic numbers inside formulas.
  • Cached formula values can be stale, so do not trust them blindly after edits.
  • Check copied formulas for wrong ranges, wrong sheets, and silent off-by-one drift before delivery.
  • Absolute and relative references are part of the logic, so copied formulas can be wrong even when they still "work".
  • Test new formulas on a few representative cells before filling them across a whole block.
  • Verify denominators, named ranges, and precedent cells before shipping formulas that depend on them.
  • A workbook should ship with zero formula errors, not with known #REF!, #DIV/0!, #VALUE!, #NAME?, or circular-reference fallout left for the user to fix.
  • For model-style work, document non-obvious hardcodes, assumptions, or source inputs in comments or nearby notes.

Read the full file on GitHub · 104 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 12d ago First seen · 104 lines · 90 tokens per session scan A 52421d9fba8f

Subscribe to this mod's changes

Excel / XLSX is a skill published in the GitHub repository waterfeet/DoroPet_V3 (30 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 90 tokens to every session and 1,457 once invoked, about $0.0005 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 2026-08-30.