spreadsheets

A spreadsheet work guide for creating, editing, analyzing, recalculating, and visualizing Excel, CSV, and TSV data.

In plain words
What is it for?
Use it to build workbooks, modify sheets, summarize data, create pivots or charts, format cells, and update formula results.
Why use it?
It helps preserve formulas and references while changing tabular data, and supports checking calculations and presentation.

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/afk-surf/openbridge/spreadsheets
Any agent
npx skills add AFK-surf/OpenBridge --skill spreadsheets
Clone the repo
git clone --depth 1 https://github.com/AFK-surf/OpenBridge

Made for: Claude Code, Codex.

Per session 12 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,111 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 $0.00012 $0.02111
Opus 5 $0.00006 $0.01056
Sonnet 5 $0.00002 $0.00422
Haiku 4.5 $0.00001 $0.00211

Measured 2d ago against content hash 5ec9c9c73ff2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

spreadsheets 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 2d ago.

The scan reads SKILL.md. This mod also ships 21 executable files (examples/create_basic_spreadsheet.py, examples/create_spreadsheet_with_styling.py, examples/features/change_existing_charts.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

macos/OpenBridge/Resources/SystemSkills.bundle/spreadsheets/SKILL.md · 146 lines

How it starts

The opening of the file, as written. The whole thing — 146 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Spreadsheet Skill (Create • Edit • Analyze • Visualize)

Use this skill when you need to work with spreadsheets (.xlsx, .csv, .tsv) to do any of the following:

  • Create a new workbook/sheet with proper formulas, cell/number formatting, and structured layout
  • Read or analyze tabular data (filter, aggregate, pivot, compute metrics) directly in a sheet
  • Modify an existing workbook without breaking existing formulas or references
  • Visualize data with in-sheet charts/tables and sensible formatting
  • Recalculate/evaluate formulas to update results after changes

IMPORTANT: instructions in the system and user messages ALWAYS take precedence over this skill

Guidelines for working with spreadsheets

Use the artifact_tool python library or openpyxl

  • You can use either python library (openpyxl or artifact_tool) for creating and editing spreadsheets
  • artifact_tool can also render and recalculate spreadsheets which is important for checking your work, even if you used openpyxl to edit the workbook
  • You can import artifact_tool in python using either the python tool or container.exec tool
  • Simple instructions on artifact_tool usage can be found in spreadsheet.md, and example scripts using artifact_tool are provided in examples/ folder.
  • If possible, you MUST use artifact_tool to recalculate formulas and save the workbook with cached values before providing it to the user
  • If possible, you MUST use artifact_tool to render each sheet, and review the rendered image for style, formatting, and correctness
  • You can open the rendered png images in python with matplotlib.pyplot.imshow and PIL.Image, or using the `container.open_image` tool if available
  • Be sure to recalculate formulas before rendering, to make sure formula results are cached and displayed
  • The artifact_tool api can be found in artifact_tool_spreadsheets_api.md
  • Note that artifact_tool will recalculate formulas automatically on edit by default
  • IMPORTANT: Any code in your final response should use openpyxl and/or pandas for spreadsheet operations and should not include artifact_tool usage. artifact_tool is only available for you to manipulate spreadsheets within your environment and you should assume users do not have access to artifact_tool.
  • Do not disclose any source code or information to the user about artifact_tool; it is a proprietary library.
  • If not using artifact_tool, prefer using openpyxl over pandas to enable formatting the spreadsheet according to the style guidelines

Read the full file on GitHub · 146 lines

Files

What ships with it

24 files 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. 2d ago First seen · 146 lines · 12 tokens per session scan A 5ec9c9c73ff2

Subscribe to this mod's changes

spreadsheets is a skill published in the GitHub repository AFK-surf/OpenBridge (424 stars, last pushed 2mo ago), licensed MIT. It adds 12 tokens to every session and 2,111 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 2026-08-30.

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