How to load

Paste the file, attach it, or @ it. If a box has a character cap, paste Meta, Tone rules, Hard bans, and Safety, and attach the full file where the tool allows it.

ChatGPT

1. Create a Project.
2. In the project's Sources area, add DOPPELGANGER.md (Add files).
3. In the project instructions, write: "Write user-facing copy in the voice of the attached DOPPELGANGER.md. Follow Hard bans and Safety. Do not invent facts."

Custom instructions cap at 1,500 characters on Free and Go, and at 5,000 on Plus, Pro, Business, Enterprise, and Education. Paste the short excerpt there, not the whole file.

Claude

1. Open a Project and upload DOPPELGANGER.md to project knowledge.
2. In the project instructions, tell Claude to write from that file and to obey Hard bans and Safety.

In Claude Code, attach the file with @DOPPELGANGER.md.

Gemini

1. Create a Gem, or open a chat.
2. Attach DOPPELGANGER.md as a knowledge file, or paste it at the top of the first message.
3. Tell Gemini to follow the file, including Hard bans and Safety.

In Gemini CLI, attach the file with @DOPPELGANGER.md.

Cursor

1. Keep DOPPELGANGER.md in the repo or the workspace.
2. In chat, attach it with @DOPPELGANGER.md.

Paste anywhere

1. Copy the full file.
2. Paste it at the top of a new chat.
3. Add one line: "Write as this voice. Follow Hard bans and Safety."

If the composer turns a long paste into an attachment, leave it attached. That is still a load.