How to send a real letter with Meta Muse

Muse cannot put paper in a mailbox on its own. Connect it to No Errands Mail once and then you can say "mail my landlord a letter saying the heat is out" and a real printed letter goes out in the post. Set-up takes about five minutes. A one-page black-and-white letter costs $2.49, including printing, the envelope, and the stamp. United States addresses only.

What you need

• A Muse account.
• The recipient's full mailing address.
• What you want the letter to say. A rough idea is fine; Muse can draft it.
• A card to buy credits with.

Step 1: Get a key

Go to https://noerrands.com/get-key, enter your email, and leave the choice on read and write so Muse is allowed to send. You get one key that looks like ne_live_....

The key is shown once. Leave that tab open until step 3.

Step 2: Paste this prompt into Muse

Copy the whole block and paste it into Muse as one message.

Build a custom connector for No Errands. One API key covers three services:
printed mail (letters and postcards), fax, and appointment booking.

1. Read these three connector briefs and follow them exactly:
   https://noerrands.com/connectors/muse.md
   https://noerrands.com/connectors/fax/muse.md
   https://noerrands.com/connectors/booking/muse.md

2. Store my API key in the Secure Credentials Store as NOERRANDS_API_KEY.
   The same key works for all three. Never print, log, echo, or repeat it,
   not even partially.
   Send it as the header: Authorization: Bearer <NOERRANDS_API_KEY>

3. Prefer the MCP endpoints (streamable HTTP):
   https://api.noerrands.com/c/mail/mcp
   https://api.noerrands.com/c/fax/mcp
   https://api.noerrands.com/c/booking/mcp
   If you use the REST APIs instead, each brief links its OpenAPI document.

4. Before you mail anything, fax anything, or book anything, show me exactly
   what will happen, what it costs, and who it goes to, and wait for my
   explicit approval. Never act without asking me first.

5. Save this as a reusable skill called "Mail, fax and bookings".

Muse will read our connector brief, write its own code to talk to us, test it, and save it as a reusable skill. This takes a minute or two. Muse will also ask you to approve network access to our domain the first time. Say yes.

You will see a caution notice, because this is a custom connector that Meta has not reviewed. That is normal for every custom connector.

Step 3: Paste your key into the Secure Credentials Store

Muse will ask for your API key and open its Secure Credentials Store.

Paste the key into that box. Do not paste it into the chat.

The Secure Credentials Store is the point of the whole thing: Muse's agent never sees the real key. It works with a stand-in token, and the real value is swapped in at the network edge. A web page that tries to trick Muse into revealing your key gets nothing.

Step 4: Add credits

Your balance starts at $0.00. Say:

Add credits to my mail account.

Muse gives you a checkout link. You pay in your own browser. Packs are $10.00, $25.00, $50.00. Nothing about your card touches Muse or us.

Step 5: Ask Muse to send the letter

Now just ask. For example:

Mail a letter to Ada Lovelace, 1 Main St, Austin TX 78701, from me, saying that the kitchen tap has been leaking since Monday and I would like it fixed this week.

Muse will:

1. check the address against postal records and correct the formatting;
2. get an exact price;
3. show you the recipient, a summary of the letter, the page count, and the total;
4. wait for you to say yes.

Nothing is printed until you approve. After you approve, Muse reports a mail ID and the expected delivery date. Later you can ask:

Where is the letter I sent to Ada?

What it costs

Item	Price
Letter, first page, black and white	$2.49
Each additional page	$0.25
Color printing, per letter	$0.50
Certified mail	$7.50

Checking an address and getting a quote are free. See full pricing.

Questions people ask

Is my key safe?

Yes, as long as you paste it into Muse's Secure Credentials Store and not into a chat message. Muse's agent only ever handles a stand-in token; the real key is inserted at the network edge, outside the agent's reach. We store only a hash of your key, so even we cannot read it back.

If you think a key leaked, email support@noerrands.com and we will revoke it.

Can Muse send a letter without asking me?

No. The connector brief tells Muse to check the address, get a price, show you the recipient and a content summary, and get your explicit approval before every single send. Sending is a separate, consequential call, and Muse's own permission layer treats it that way.

If you want a hard guarantee, ask for a read-only key on the key page. A read-only key can check addresses and prices but is refused by the server if it ever tries to send.

What if I run out of credits?

The send stops before anything is printed. Muse tells you how much you are short and hands you a top-up link. It will not retry on its own and it will not send a partial letter. Add credits, then ask again.

Can I mail outside the US?

Not yet. United States addresses only.

Can I cancel a letter?

Only before you approve it. Once it is handed to the print partner it is on its way. If our side fails after charging you, the credits go straight back to your balance.

---

Next: send a postcard with Muse.