Brand voice editor Gem that edits drafts to match your pasted style guide and explains each change
A Gemini Gem for marketers, writers and comms teams: upload your style guide once, then paste any draft to get an on-brand edit, a list of the rules applied, and flags for claims that need checking.
Agent in Writing by AISkillHub Library
What it does
Style guides only work if people apply them, and most drafts are written by people who have not read the guide recently. This Gem holds your guide and applies it to every draft you paste, showing which rule drove each change so writers learn the voice over time.
**What it does**
- Reads your brand voice and style guide from the Gem's knowledge: voice traits, words to use and avoid, formatting rules, spelling conventions, product naming. - Edits a pasted draft at the level you choose: **light** (rule fixes only), **standard** (rules plus clarity and rhythm), or **rewrite** (restructure while keeping every fact). - Lists every change with the rule it applies, quoting the guide. - Scores the draft against each voice trait (for example "plain-spoken", "warm", "confident") with one line of evidence. - Flags claims that need evidence or approval: numbers, comparisons, superlatives, guarantees, and anything that sounds like a promise. - Adapts to channel when told: email, landing page, social post, release notes, support macro.
**When to use it**
- Reviewing copy from contributors outside the marketing team - Keeping a consistent voice across product, support and sales materials - Training new writers on the guide with concrete examples
**What it will not do**
- It will not add facts, features, numbers or customer quotes that are not in the draft. - It will not approve legal or regulated claims. It flags them for review. - Without a style guide, it will not invent a brand voice. It asks you to upload one or describe three traits and a few words to avoid, then works from that.
**Example**
Draft: "We're super excited to announce our revolutionary new dashboard which will totally transform how you work!!"
Standard edit with a guide that says "calm and specific, no exclamation marks, avoid hype words": "The new dashboard puts your open tasks, deadlines and team activity on one screen." Change list cites three rules, and a flag notes that "transform how you work" was removed because the draft offered no evidence for it.
How to use it
**Set up as a Gemini Gem** (in the Gemini web app; Gem features depend on your account type).
1. In Gemini, open the Gems manager from the sidebar (Explore Gems) and choose to create a **New Gem**. 2. Name it `Brand Voice Editor`. 3. Paste the full contents of `assistants/brand-voice-editor/instructions.md` into the **Instructions** box. 4. Replace the variables in the pasted text: `{{brand_name}}` and `{{default_level}}` (`light`, `standard` or `rewrite`). 5. In the **Knowledge** section, add files: your brand voice and style guide. If yours is scattered across slides, use `assistants/brand-voice-editor/style-guide-template.md` to consolidate it into one text file first; plain structured text gives more consistent results than a designed PDF. 6. Use the preview panel to test it with a real example, then save. Open the Gem from the sidebar whenever you need it.
**Using it:** paste a draft and optionally a line such as `channel: LinkedIn post, level: light`. Type `rules` to see the rules the Gem extracted from your guide, so you can check it read the guide correctly.
Files
Save each file at the path shown, relative to your project root.