Facebook Custom Audiences
Manage Meta custom audiences — customer lists, members and lookalikes — through the Marketing API, with Meta's required SHA-256 customer-data hashing applied in-app.
About
Facebook Custom Audiences ships in the w6w first-party pack. It declares 9 actions, 2 health checks, and the host runs its code in a sandbox that never sees the credential.
- App id
io.w6w.facebook-custom-audiences- Version
- 0.1.0
- Author
- w6w
- Licence
- MIT
- Categories
- Marketing · Social Media
Overview
Custom audiences are the lists of people an advertiser tells Meta to target — or exclude — in its ads. This app creates and manages them on a Meta ad account through the Marketing API: create an empty customer-list audience, add people to it or remove them, rename or delete it, read back its size and delivery status, and build a lookalike audience from it.
Customer contact data (email, phone, name, date of birth, city and so on) is normalised and SHA-256 hashed inside this app before it leaves, following the rules in Meta’s Customer File Custom Audiences guide, so a workflow can pass a plain email address from a CRM or order system without hand-rolling the hashing. Lists larger than 10,000 people are uploaded in batches that share a session id.
This app manages audiences only. It does not create campaigns or ads, send conversion events (that is the Conversions API app) or read Pages and lead forms. Meta publishes no machine-readable status feed, so the health check reports live rate-limit headroom instead.
Build with Facebook Custom Audiences
Three routes to the same 9 actions. The Workflow tab is generated from Facebook Custom Audiences's own manifest and carries its real ids, so it is copy-pasteable; the Code and CLI examples are the same call for any action on any app, so every app-specific value in them is a blank you fill in.
Add Users to Custom Audience
add-users Add people to a customer-file custom audience from emails, phones, names and other identifiers. Values are normalised and SHA-256 hashed by this app before upload (up to 10,000 per request).
Create Custom Audience
create-custom-audience Create an empty customer-file custom audience on an ad account. Add members afterwards with Add Users.
Create Lookalike Audience
create-lookalike-audience Build a lookalike audience from an existing custom audience of at least 100 people. Population takes 1-6 hours.
Delete Custom Audience
delete-custom-audience Permanently delete a custom audience. Ads using it stop running and cannot be restarted. Fails while lookalikes built from it exist.
Get Custom Audience
get-custom-audience Read one custom audience: size bounds, delivery status (200 = ready) and operation status of the last upload.
List Ad Accounts
list-ad-accounts List the ad accounts the connected Facebook user can access. Use `account_id` (or `id`) as the Ad Account ID of every other action.
List Custom Audiences
list-custom-audiences List the custom audiences (customer lists, website audiences and lookalikes) on an ad account.
Remove Users from Custom Audience
remove-users Remove people from a customer-file custom audience. Identifiers are normalised and SHA-256 hashed exactly as in Add Users, so the same values match.
Update Custom Audience
update-custom-audience Rename a custom audience or change its description, opt-out link or file source.
A workflow step names the app and the action, and the editor fills in the
connection when you pick one. This is the Step shape from the
workflow spec, carrying Facebook Custom Audiences's real ids.
{
"manifestVersion": "2",
"name": "facebook-custom-audiences-example",
"steps": [
{
"id": "add-users",
"uses": {
"app": "io.w6w.facebook-custom-audiences",
"action": "add-users",
"connection": "conn_YOUR_CONNECTION_ID"
},
"with": {
"audienceId": "<audienceId>",
"users": "<users>"
}
}
]
}Here are some of the things you can do
-
Add Users to Custom Audience
performadd-users -
Create Custom Audience
performcreate-custom-audience -
Create Lookalike Audience
performcreate-lookalike-audience -
Get Custom Audience
readget-custom-audience -
List Ad Accounts
readlist-ad-accounts
+4 more actions available
Every app-specific value here is a blank you have to fill in. An
app action is reached through the connection that authenticates it, so the
address is a connection id, not the app id — and connections belong to your account,
so a public page cannot know yours. Create one for Facebook Custom Audiences, then fill in
the three blanks: conn_YOUR_CONNECTION_ID, the action key, and the
parameters that action declares. The call itself is real — the shape is transcribed
from the studio's own snippet builder, which prints the same kind of blanks — but
nothing in it is specific to Facebook Custom Audiences. The Workflow tab is where this app's
real ids are.
npm install @w6w/sdkyarn add @w6w/sdkpnpm add @w6w/sdkdeno add npm:@w6w/sdkimport { W6wClient, isActionRun } from "@w6w/sdk";
// Reads W6W_BASE_URL and W6W_TOKEN from the environment when omitted.
const client = new W6wClient();
const envelope = await client.run({
urn: "conn_YOUR_CONNECTION_ID",
action: "add-users",
payload: {
audienceId: "<value>",
users: "<value>",
// hashing: "<value>",
// sessionId: "<value>",
// batchSeq: "<value>",
// lastBatch: "<value>",
// estimatedTotal: "<value>",
},
});
if (isActionRun(envelope)) console.log(envelope.value);npm install -g @w6w/cliw6w run conn_YOUR_CONNECTION_ID --action add-users --payload '{"audienceId":"<value>","users":"<value>"}'Give an AI agent Facebook Custom Audiences — without giving it Facebook Custom Audiences's credentials. One MCP endpoint exposes every app, function and workflow the caller is entitled to, as tools it can discover and run. Access is granted per team while we onboard.
One tool call{
"name": "w6w_invoke",
"arguments": {
"ref": "app:io.w6w.facebook-custom-audiences#add-users",
"input": {
"audienceId": "<audienceId>",
"users": "<users>"
}
}
}
Every tool names its target with a single ref. The
app: form above doesn't name a connection at all — the
host resolves which of the caller's Facebook Custom Audiences connections to sign
with, and refuses rather than guesses when the answer is ambiguous.
What the agent gets
Credentials it can't read
The token is attached host-side, at the moment of the call. It is never a tool argument, never in the model's context, and never in a transcript — so a prompt injection has nothing to exfiltrate.
A tool surface scoped to the caller
Tools are derived per end user from what that person has actually connected and is entitled to — not one shared bot identity carrying the union of everyone's access.
A durable workflow in one call
Multi-step work runs on the workflow engine and returns a run handle the agent can poll — retries, branching and state survive the conversation that started them.
Health-aware discovery
Facebook Custom Audiences's declared health checks are on the surface too, so an agent can tell "the vendor is down" from "your credential expired" before it burns a retry on either.
The MCP surface is part of the hosted platform. Facebook Custom Audiences itself is MIT, and the runtime that executes it is source-available (FSL).
Health checks
Facebook Custom Audiences declares its own checks, so its health is a property of the app rather than something the host guesses at.
Meta platform status
API usage headroom
Percentage of the app's call-count, CPU-time and total-time allowances consumed, read off `X-App-Usage` and `X-Business-Use-Case-Usage`. Meta throttles when any meter reaches 100.