Office Tells
A behavioral overlay on top of the pptx, docx, and xlsx skills. It does not replace them, it constrains them. The format skill handles how to build the file; Office Tells strips the signals that mark a document as machine-generated before it ships: pipe separators, em dashes, accent lines under slide titles, beige or default-blue or default-grey color choices, zebra table banding, excessive conditional formatting, Sheet1 names, library-default file metadata, hardcoded totals where a formula belongs, and boilerplate section names. The file type alone is the trigger, no anti-AI wording required. The final step renders the file to images and inspects the metadata, because the visual rules cannot be enforced without actually looking at the output. Running prose voice is delegated to the human-tone skill.
Simple install — no setup required
Download the skill file below
Add it to Claude — pick your platform:
Claude desktop app
- Open the Claude desktop app
- Go to Code, then Customize
- Click Create a new skill
- Upload the skill file you downloaded
claude.ai (web)
- Go to Customize, then Skills
- Click +, then Create a new skill
- Upload the skill file you downloaded
Say a trigger phrase to activate it
What Claude does with this skill
The following is the exact SKILL.md content Claude reads when this skill is
active. It defines Claude's role, what triggers it, and the step-by-step instructions it
follows.
Office Tells
This skill is a behavioral overlay, not a document generator. It sits on top of the pptx, docx, and xlsx skills and constrains them. The format skill tells Claude how to build the file; Office Tells strips the signals that give it away as machine-generated before it ships.
What it does
Claude can build a clean .pptx, .docx, or .xlsx and still leave fingerprints all over it: a thin accent line under every slide title, a beige default background, zebra-striped table rows, a sheet called Sheet1, file metadata that names the python library, totals typed in as values instead of =SUM() formulas. None of those survive someone who actually looks. Office Tells is the gate that catches them.
The file type is the trigger. Ask Claude to make a deck, write a report, build a budget, or produce any Office file, and this skill loads first, before a single line of code or content is written. The user does not have to say “make it look human” for it to fire.
The three formats
Each format has its own tells, and the skill carries a rule set for each one:
- PowerPoint: no accent lines under titles, no repeated layouts, varied bullet counts and lengths, real typographic hierarchy, no generic corporate blue or beige defaults.
- Word: no Introduction-Overview-Conclusion boilerplate, no zebra table banding, at most two accent colors, roomy cell padding, a single thin grey rule instead of rainbow dividers.
- Excel: specific human sheet names, frozen headers, live formulas for every total, restrained conditional formatting, deliberate header colors instead of the openpyxl default grey.
Across all three, the universal rules ban pipe separators and em dashes, require real file metadata with a plausible author and a created time that differs from modified, and push for lumpy, realistic example data instead of suspiciously round numbers.
Render and look
The last rule matters most. Claude generates these files blind through python libraries and cannot trust that the visual rules held. So the final step is to convert the file to images, view them, and check them against a delivery list, then confirm the metadata is set. The visual rules are unenforceable without that step, so the skill refuses to skip it.
Voice is delegated
Office Tells owns structural language: slide titles, section headers, sheet names, table labels, callouts. Sentence-level prose voice is handed off to the human-tone skill, which runs on any paragraph or body copy. The two skills stack cleanly, one shapes the structure, the other shapes the sentences.