What is office-customui-xsd?

A reference for Office CustomUI XML, the markup used to define Excel's ribbon, menus, buttons, and related controls.

Use it when creating, editing, reviewing, or validating Excel ribbon toolbars, context menus, the Quick Access Toolbar, or the Backstage screen.

It helps avoid invalid XML structures and attributes that Excel may ignore or reject.

office-customui-xsd — Skill for Claude Code by pyxll

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 pyxll/pyxll-agent-skills --skill office-customui-xsd

Clone the repo

git clone --depth 1 https://github.com/pyxll/pyxll-agent-skills

Made for: Claude Code.

Or install pyxll-agent-skills, the plugin that ships this one along with the rest of its 3 skills.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/pyxll/pyxll-agent-skills/office-customui-xsd/github.svg)](https://agentmods.dev/skills/pyxll/pyxll-agent-skills/office-customui-xsd)

Your own site

<a href="https://agentmods.dev/skills/pyxll/pyxll-agent-skills/office-customui-xsd"><img src="https://agentmods.dev/badge/skills/pyxll/pyxll-agent-skills/office-customui-xsd/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/pyxll/pyxll-agent-skills/office-customui-xsd"><img src="https://agentmods.dev/badge/skills/pyxll/pyxll-agent-skills/office-customui-xsd.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 103 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,267 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.

Model	Per session	Once invoked
Fable 5.1	$0.00103	$0.01267
Opus 5	$0.00051	$0.00633
Sonnet 5	$0.00021	$0.00253
Haiku 4.5	$0.00010	$0.00127

Measured 11d ago against content hash 81932a82ad1e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

office-customui-xsd 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 11d 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.

skills/office-customui-xsd/SKILL.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Office CustomUI XML Reference Skill

How to use this skill

Read resources/index.md — find which reference file covers your task, and check the allowed-controls table before placing any control (not all controls are valid in all locations).
Read the relevant doc(s):
- resources/document-structure.md — root element, namespace, overall XML skeleton
- resources/ribbon.md — tabs, groups, QAT, contextual tabs, PyXLL merge rules
- resources/controls.md — all controls for ribbon groups and menus
- resources/context-menus.md — context menu structure and allowed controls
- resources/attributes.md — complete attribute reference (label, image, callbacks, etc.)
- resources/backstage.md — File menu (Backstage) customisation
If you cannot find what you need in the markdown docs, read the raw XSD: resources/office-customui-2009-07.xsd. Never guess — invalid attributes are silently ignored and invalid nesting causes load errors.
Validate the XML before deploying. Run it through xmllint using the bundled XSD. The XSD is at <SKILL_BASE_DIR>/resources/office-customui-2009-07.xsd — replace <SKILL_BASE_DIR> with the actual base directory path provided when this skill is loaded.
```
xmllint --noout --schema <SKILL_BASE_DIR>/resources/office-customui-2009-07.xsd ribbon.xml
```
Or with Python's lxml: etree.XMLSchema(etree.parse('<SKILL_BASE_DIR>/resources/office-customui-2009-07.xsd')).assertValid(etree.parse('ribbon.xml'))

PyXLL caveat: insertBefore/insertAfter are PyXLL-only merge attributes not in the schema, so they produce expected validation errors. Strip them before validating, or treat those specific attribute errors as false positives.

Rules for AI Agents

These rules are mandatory. Follow them before writing any customUI XML.

Callbacks are module.function strings — e.g. "my_module.on_button_click". All onAction, getLabel, getEnabled, etc. attributes require this format. The module must be importable from the Python path.

Read the full file on GitHub · 112 lines

Files

What ships with it

8 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.

11d ago First seen · 112 lines · 103 tokens per session scan A 81932a82ad1e

Subscribe to this mod's changes

office-customui-xsd is a skill published in the GitHub repository pyxll/pyxll-agent-skills (2 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 103 tokens to every session and 1,267 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 2026-08-31.

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