How to Connect Flyletter to Claude with the MCP Connector

So you want Claude to write in your brand voice? Well, until recently, you've had two options. Paste a wall of instructions into every new chat, or drop a brand voice file into a project and hope it sticks.

Turns out neither one actually holds.

Claude doesn't reliably follow a voice profile in your project files. It reads it, sort of gets the gist, then drifts halfway through the second paragraph. The voice profile itself is usually thin too, a rough sketch of your voice rather than the real thing.

But now there's a third option: Flyletter.

Flyletter is built different. The 54-dimension brand profile is more robust, and it runs on a three-layer prompt architecture that tells the model exactly how to write like you. No drift. No re-teaching. Just your voice, time-after-time.

Flyletter has a Claude MCP connector that loads your brand profile directly into Claude so it always writes in your voice. Setup takes about three minutes, and after that you never have to think about it again.

Let me show you how it works.

What the MCP Connector Actually Does

The Claude connector gives you three things:

• First, brand voice: Claude reads your Flyletter brand profile and writes in your voice automatically, including your audience, unique differentiator, tone, and more.
• Second, read tools: you can query live data from Flyletter right inside Claude, like how many newsletters you have scheduled or how many ideas are saved.
• Third, write tools: you can save newsletter ideas from Claude straight back into Flyletter without leaving the chat.

It works in both Claude browser and Claude desktop, and it runs on the same architecture and instructions Flyletter itself is built on. This is a native connection, not a bolt-on.

Way better than dropping a JSON file into a project and hoping for the best.

Step-by-Step Setup

Run through these six steps to set it up:

1. Open Flyletter and copy your connector URL from your account settings.
2. Go to Claude settings and navigate to Connectors, then Customize.
3. Click the + button, then Add custom connector.
4. Name it Flyletter and paste the connector URL you copied. Click Add.
5. Connect and authorize your Flyletter profile when prompted.
6. Click Allow to grant permissions.

That's it. You're connected.

Claude now has live access to your brand profile. Authorization is done, but there's one optional setting that removes the last bit of friction from every future session.

Set Permissions to Always Allow

When Claude first uses a connector tool, it may ask for permission before each action.

If this happens to you, find the Always allow option in the connector permissions setting and enable it. Now Claude can read your brand data and save your ideas without interrupting the conversation to ask.

Do this once, and Claude stops asking. Your brand voice will work with every chat.

Brand Voice in Action

Open a new Claude chat and invoke Flyletter.

Try it by typing a simple prompt: Write a cold email in my Flyletter brand voice.

Claude reads your Flyletter profile, understands your audience and your differentiator, and writes in your tone automatically.

The same workflow applies to anything you write. Website copy, long-form content, a love letter to your spouse, whatever you need.

No instructions pasted over-and-over again. No project files. Just your voice, already there.

And it doesn't just write. It reads and saves too.

Query and Save Ideas

This is the part that turns the connector from a one-time novelty into a daily tool.

The read direction pulls live data. Ask Claude how many newsletters you have scheduled, how many ideas are saved, what's sitting in your pipeline, and it pulls the answer straight from Flyletter. Try it: How many ideas do I have saved in Flyletter? Claude returns the live count.

The write direction pushes data back. If Claude surfaces a good newsletter idea mid-conversation, you save it without leaving the chat. Type Save this as a newsletter idea in Flyletter and it lands in your account instantly.

Your Claude chat and your Flyletter account are the same workspace now.

Why This Beats Every Workaround

Pasting a JSON file into a project is a workaround. This is the architecture.

JSON drops and project file instructions are approximations. They degrade, they get forgotten, they vary from session to session. You're basically re-teaching Claude who you are every time and hoping the copy-paste holds.

The MCP connector reads your Flyletter profile directly, the same way Flyletter itself reads it. Your brand voice stays consistent because the source of truth is always your live account, not a stale block of text you pasted three weeks ago.

Every new Claude chat starts with your voice already loaded. The reset problem is gone. Not patched, not worked around. Gone.

The integration is persistent by design, not by repetition.

Your voice is always there. You never have to think about it again.

Get Set Up in Three Minutes

You know the friction. Every new chat, back to zero, pasting and hoping.

So fix it right now while it's fresh. Head to Flyletter, copy your connector URL, and run through the seven steps above. Three minutes, start to finish.

Your brand voice lives in Claude from here on out.