Build a WhatsApp Contact List with Claude, Numbers and Name Fields (2026)
Forty customers in a spreadsheet, and a shop that wants to message them on Saturday. Tell Claude the list, and check the count it gives back.
Daniel Roth5 min read
On this page
- What can Claude do with an audience?
- What do you need before you start?
- The prompt: build the list and read back the count
- How do you write the numbers?
- What are the name fields for?
- What if the numbers do not add up?
- Fix one contact, or drop the list
- What can go wrong?
- Is it safe to let Claude build lists?
- Related guides
- Frequently asked questions
The tulips arrive on Friday. You have forty customers who asked to hear about it, their numbers in a spreadsheet, and no wish to type them into anything twice.
With the Blueticks WhatsApp MCP connector, Claude can build that list for you. In Blueticks a saved list of contacts is called an audience. Claude creates it, adds the numbers with a first name for each, and tells you how many went in. Nothing is sent while you do this. An audience is only a list.
What can Claude do with an audience?
Claude uses the audiences tool. It has eight actions:
| Action | What it does |
|---|---|
create | Makes an empty audience from a name |
append_contacts | Adds contacts: a number, plus optional name fields |
get | Reads one audience, with its first 50 contacts and the total |
list | Lists your audiences |
update | Renames an audience |
update_contact | Changes one contact's number or fields |
remove_contact | Removes one contact |
delete | Deletes the whole audience |
An audience name can be up to 120 characters. One append_contacts call takes up to 1,000 contacts.
What do you need before you start?
A linked WhatsApp number in Blueticks and the connector added to Claude. If you have not done that, how to connect WhatsApp to Claude covers it. The connector URL is https://api.blueticks.co/mcp and you sign in with OAuth.
The connector includes the audiences tool, which is the one this uses. The full list is in the WhatsApp MCP tools guide.
The prompt: build the list and read back the count
Paste this into a normal Claude chat. Put your own rows where the examples are:
Using Blueticks, create an audience called "Tulip customers". Then add these contacts, each with a firstName variable: +447700900101 Maya, +447700900102 Noah, +447700900103 Ella. Before you create anything, show me the name and the rows you will add, and wait for my yes. After adding, tell me how many I gave you, how many were added, and the total in the audience. Do not send any message.
Behind it, Claude makes these calls:
- Pause. Claude reads the plan back and waits for your yes.
- Create.
audiencesrunscreatewith the name. - Add.
append_contactsruns with the audience id and the rows. The answer reports how many were added and how many contacts the audience now holds. - Check. Claude compares those numbers with what you gave it.
A sample answer, with invented numbers:
Created "Tulip customers" You gave me 3 contacts. 3 were added. The audience now holds 3. Nothing was sent.
Pasting forty rows works the same way, straight from the spreadsheet. If a list is bigger than 1,000, Claude adds it in more than one call.
How do you write the numbers?
Each contact needs a number with the + and the country code, or a WhatsApp ID such as 447700900101@c.us. Bare digits without the + are rejected, and so is a name on its own. If all you have is a name, ask Claude to look the person up first with the chats or contacts tool, and to show you the number it found before it adds anything.
A group ID (ending @g.us) or a channel ID (ending @newsletter) is also accepted as a contact.
What are the name fields for?
Each contact can carry fields, called variables. Claude writes firstName in the prompt above, and any key you pick works as long as it starts with a letter or underscore and uses only letters, digits and underscores, up to 32 characters. A contact can have up to 32 of them, each value up to 1,024 characters.
They matter later. In a campaign, a field becomes a {firstName} token in the message text, and the lookup ignores capital letters. Four tokens work without any fields: {whatsappname}, {displayname}, {phone} and {mobile}. If you set a field with one of those names, yours wins.
What if the numbers do not add up?
Compare "added" with the number you gave. A number that is already in the audience is skipped, and so is a repeat inside the same batch, so the gap is usually duplicates. On a list of 50 or fewer, ask Claude to read the audience back with get and name any number you expected that is missing. On a longer list get shows only the first 50, so check a missing number in your spreadsheet.
get returns the first 50 contacts and the total. The tool cannot search or page past 50, so on a long list trust the total, and check a specific number in your own spreadsheet.
Fix one contact, or drop the list
Say it in plain words: "In Tulip customers, change Noah's number to +447700900199" or "remove Ella from Tulip customers." Claude reads the contact id from get and calls update_contact or remove_contact. This works for contacts in the first 50, which is all get shows.
Deleting an audience is refused while a campaign that has not finished uses it. It is flagged as destructive, so Claude may ask you to approve it. Read which audience it names first.
What can go wrong?
- A repeated name. Two audiences can share a name. Ask Claude to use the audience id it created, and to say which one it means.
- A number in the wrong format. Check that each number has its
+and country code before you say yes. - Private details in the list. Whatever Claude reads is shared with Claude. Add only what you need for the message, such as a first name.
Is it safe to let Claude build lists?
Building a list sends nothing. But the connector also holds tools that send messages and start campaigns, so you still decide what runs. Anthropic's custom connector guide says that during Research, Claude can use connector tools without further approval, so do this in a normal chat instead. Read the action name and the audience before you allow a call, and avoid "Allow always" for a connector that can send.
The pause in the prompt ("wait for my yes") is a request to Claude. In a normal chat, your approval of each call is what stops an action.
Related guides
Once the list exists, you can ask Claude to schedule WhatsApp messages. A campaign to a whole audience starts as soon as it is created, so ask Claude to confirm the audience, the text and the timing with you first. To see everything the connector can do, read the WhatsApp MCP tools guide. Plans and prices are on the pricing page, and you can start free.
Frequently asked questions
Can Claude create a WhatsApp contact list? Yes. With the Blueticks connector, Claude can create an audience from a name and add contacts to it, each with a number and optional name fields.
How many contacts can I add at once? Up to 1,000 per call. A longer list goes in more than one call.
Does building the list message anyone? No. An audience is only a list. Sending is a separate step that you approve.
What happens to a number that is already in the list? It is skipped, so adding the same batch twice does not create duplicates. Compare "added" with the number you gave to see how many were skipped.
Can I delete an audience that a campaign is using? Not while a campaign that has not finished uses it. Delete it after the campaign has finished.
