retention
cohort retention — how much of each signup cohort is still subscribed months later
How to use it
Project documentation lists retention for the Substack MCP MCP server. Add the server to your MCP client (Claude Desktop, Cursor, Windsurf and others), then check which tools your installed version makes available. Tool availability can depend on configuration and credentials. A server handshake does not verify this tool’s behavior. See the full listing for setup details.
Install Substack MCP
npx -y substack-mcp@latestOther tools in Substack MCP (24)
re-adding a tag the post already has answers a bare 400 upstream, so it is
(everyone onlypaid onlyfree founding, optional)
how many countries and US states your subscribers span
other Substacks whose audience overlaps yours — the collaboration shortlist
unsubscribes
signups subscribes foundingsubscribes annualsubscribes monthlysubscribes freetrials freetopaidupgrades signupswithin1day estimatedvalue
ison isafter isonorafter isbefore isonorbefore
(bestfirst mostrecentfirst oldestfirst, optional)
queued sent delivered dropped
, todate (string, optional): YYYY-MM-DD. Used only by the reports covering a
the individual growth events in a window
where new subscribers came from, ranked
what share of subscribers arrived via the Substack network
(asc desc, optional): defaults to desc
paid growth rate, new subscriptions, expirations
what it subscribes to, what is in its inbox and feed — which is a different host and a
opens openrate clicks clickthroughrate views subscribersfinishedpost
headline retention at 1, 6 and 12 months
likes shares restacks engagementrate uniqueengagements
(asc desc, optional): defaults to desc
(drafts published scheduled): which list to read
recent Notes written by your subscribers
(all notes posts, optional): defaults to all
(everyone subscribers onlypaid none, optional): who may comment