What it does
sepia is an add-on, called a "skill", that AI agents such as Claude Code, Codex, Grok Build and Antigravity can load. It helps the agent write or revise text so it reads less like typical AI writing. It offers four main jobs: write new text, review text without changing it, make small fixes, or fully rewrite it.
For fiction, its makers say it fixes the story's structure before touching word choice. Examples include not spelling out the theme, loosening overly tidy plots, and naming real things. The approach draws on a research study called StoryScope, which looked at how AI-written stories differ from human ones.
For work writing, it has separate rules for release notes, replies on code projects, incident reports, tickets, technical articles and long-form journalism. It also includes optional writing voices, such as a Hemingway-style profile, and a template for creating your own persona.
Who it's for
People who use AI agents to write fiction or professional documents and want the results to read more naturally. It suits writers, developers and technical communicators.
Can I use it without coding?
With some setup. You install it into a compatible AI agent with one command or as a plugin, then use it through simple slash commands. New to this? Start here.
Try it
- Install the skill into your AI agent with the Skills CLI, or install the complete plugin package for Claude Code, Codex, Grok Build, Antigravity or QwenPaw.
- Use the review command to get a diagnosis of a piece of writing without changing it.
- Use the refactor command for small fixes, or the recreate command for a full rewrite.
Before you download
Plain-AyI is an independent guide: we link to each project's official pages, but we don't host, review or endorse the software, and we can't accept responsibility for how it works on your device. Please download and install at your own discretion.
Using Claude Code, Cursor or another AI coding assistant? Paste the prompt and it will walk you through the setup.New to this?
Before you install
- Only download from the official GitHub page or the official download page above. Copies with similar names exist for many popular projects.
- Plain-AyI is an independent guide and doesn't host or review the software it lists. Please check each project's official page before installing.
- License (MIT): Very permissive: free to use, change and share, including for business.
- More on staying safe
Where people are talking about it
- StoryScopeResearch paper · Invalid Date