Bluefeather in ChatGPT
A plugin that measures your writing and checks every rewrite against your own voice. Type @Bluefeather in any chat.
Free. Needs ChatGPT Free, Go, Plus, or Pro. One account works on the web, in ChatGPT, and in Claude.
I am writing to inform you that, after careful consideration, we have decided to postpone the launch until next week in order to ensure all outstanding issues are fully resolved.
Quick one: we're pushing the launch a week. A few bugs are still open and I'd rather fix them than ship with them. More on Monday.Shorter sentences, contractions, no em dash. Same facts.
Set up in two minutes
Add Bluefeather
Open chatgpt.com/plugins and search for Bluefeather. Until it is listed, choose Add custom MCP server, paste the address below, pick OAuth, and create it as a plugin.
https://mcp.bluefeather.ai/mcp
Sign in with Google
The first time you use it, ChatGPT opens a Bluefeather page that names the app asking for access. Continue with Google, or enter an email and password. Takes a few seconds.
Teach it your voice
Say teach Bluefeather my voice and paste two or three things you wrote: an email, a message, a post. Forty words or more each. Or add them on the web; same account.
Edit
Paste any draft and say what you want. The plugin measures, ChatGPT rewrites, the plugin checks the result, and it goes another round if the match is low.
What you will see on the sign-in page
ChatGPT wants to use your Bluefeather account to measure drafts and read your voice profile. Published by chatgpt.com.
You can revoke access any time from ChatGPT's plugin settings. Doing so deletes nothing; your samples stay in your account.
Things to say
Bluefeather comes with four skills: get-started, humanize, match-my-voice, and tighten. These prompts trigger them.
Teach it your voice
“Teach Bluefeather my voice. Here are three emails I wrote: …”
Humanize
“@Bluefeather humanize this so it reads like a person wrote it”
Match your voice
“@Bluefeather rewrite this in my voice”
Tighten
“@Bluefeather tighten this to 120 words without losing the ask”
Check only
“@Bluefeather score this and tell me what gives it away”
Your type
“@Bluefeather what kind of writer am I?”
What the plugin can do
Seven tools. Each one does exactly what its name says, and the assistant asks before anything is deleted.
analyze_text | Scores a draft, underlines the tells, draws its writing web. | Reads only |
get_voice_profile | Returns how you write: rhythm, contractions, punctuation, favourite words, your type. | Reads only |
compare_to_voice | Overlays a draft on your web and lists what to change. | Reads only |
save_voice_sample | Stores a piece of your own writing in your account. | Writes |
list_voice_samples | Shows what you have saved, without the text. | Reads only |
delete_voice_sample | Removes one sample. The assistant asks first. | Deletes |
delete_all_voice_samples | Erases everything. The assistant asks first. | Deletes |
What it will not do
- Write from scratch. It measures and checks; ChatGPT does the writing.
- Store drafts. Text sent to analyze or compare is measured in memory and discarded.
- Read your conversation. It only receives the text ChatGPT sends to a tool.
- Evaluate or promise anything about third-party detection tools. It scores readability and voice, nothing else.
- Save text as a sample unless you wrote it yourself and asked for it to be saved.
Questions
Which Google account should I use?
Any. Use the same one on the web, in ChatGPT, and in Claude so your samples are in one place.
ChatGPT says I have no voice profile.
Save two or three samples first, in the chat or on the web.
Does it work in Codex?
Yes. Plugins are shared between ChatGPT and Codex, so the same install works in both.
How do I delete my data?
Say “delete all my writing samples”, or do it on the web. For the account itself, email hello@bluefeather.ai from your account address.