Split the jobs: what goes in a Gemini skill, and what doesn't
Gemini skills save your instructions so you don't retype them. Google's skills page lists what you need to use them, and one line matters: "Have Keep Activity on." On a personal Google account, that's the setting under which Google says "a subset of chats are reviewed by human reviewers". So split the work: skills for jobs with no client data, a temporary chat for the rest.
What you need
A personal Google account, signed in to the Gemini app, 18 or over
Keep Activity on (Google's requirement for skills)
The list: skill jobs that never need client data
Give a skill the how, not the who. Each of these works with no names, numbers or contracts in it:
Your writing style. Tone, sentence length, words you never use, how you sign off.
Agendas. The headings, the order, how long each item gets, what goes in the follow-up.
Report layouts. Sections, the table columns you always want, the summary on top.
Checklists. Your steps for a proposal, a handover, a month-end close, a new hire's first week.
Email templates. The structure of a quote follow-up or a meeting recap, with blanks where the details go.
Formatting rules. Date format, currency, file naming, how you want lists and tables.
What stays out of skills
Client names, numbers and contracts. Google's own line for when Keep Activity is on: "don’t enter data that’s confidential or that you wouldn’t want a reviewer to see or Google to use to improve its services."
For those, use a temporary chat. Google: temporary chats "are not used to improve Google AI with help from human reviewers." Google also says it still uses temporary chats to respond to you and to keep people safe, so they're not a vault either.
On a work account
If your company uses Google Workspace, Google says: "Your content is not human reviewed or otherwise used for Generative AI model training outside your domain without permission." Skills are coming to work and school accounts "soon", according to Google.
The mistake to avoid
Building one skill that does everything for a client, with their name, prices and contract terms inside it. Put the method in the skill and paste the client details into a temporary chat when you need them.
Check your setting
Go to the Gemini Apps Activity page. The card is called "Keep activity". On means skills work. Off means they don't.
Sources: Gemini Apps Help, "Create & manage skills for Gemini Apps" and "Gemini Apps Privacy Hub" (updated 23 Oct 2026); Google Workspace Help, "Generative AI in Google Workspace Privacy Hub". Read 27 Oct 2026.