“Week four ate two evenings I had promised to a release. The contract survived the release; the release notes did not mention D7, which was the point.”
Flagship · six weeks
Cohort Craft
A seminar for people who are tired of D7 as a personality. You will write retention in sentences, then draw the windows that those sentences require.
What you leave with
An event contract covering install, first success, return, and paid conversion — written so a new teammate can implement it without a hallway conversation.
A cohort map with every window labelled in English, plus a one-page list of default charts you are retiring and the date you retired them.
A packet diary habit. We check it. If the diary is empty, the certificate of attendance is also empty; we do not issue vendor badges in any case.
Who it is for
Product managers, analysts, and the occasional staff engineer who has inherited a schema that looks like a junk drawer. You should already be able to export a CSV of events. We will not teach SQL from zero.
Designers are welcome when they own a listing or an onboarding flow. Founders are welcome when they can tolerate being told a favourite metric is a silent refresh.
Modules
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Week 1 — The sentence test
Every event is read aloud as “who did what, where, after which state.” Properties that cannot finish the sentence are parked. Homework: twenty raw rows from your app, annotated.
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Week 2 — Time is a product decision
Billing cycles, puzzle weeks, commute hours. You draft three candidate windows and kill two of them in critique. No “industry standard D7” without a calendar defence.
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Week 3 — Ghosts in the open
Background fetch, token refresh, webview double-counts. The grocery case on our voices page is the specimen. You hunt ghosts in your own log.
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Week 4 — The contract
A two-page event contract, versioned. This week is heavier than the fee page implies; several alumni have said so. Bring a colleague if your schema has more than one owner.
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Week 5 — Steering versus the lab
You split charts into a lab notebook and a single steering page. The steering page may hold four figures. If you need a fifth, one of the four leaves.
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Week 6 — Public reading
Each seat presents the contract and the map. The room is allowed to ask “what packet is missing?” once. You answer with silence or with a date you will instrument it.
Instructor
Rhiannon Blake
Rhiannon spent eleven years inside mobile telemetry at two UK consumer apps, then got tired of explaining the same ghost-open problem in different canteens. She writes the journal essays on naming and teaches Cohort Craft from Cashel, with a visiting critique in week four from a privacy counsel who is not on the marketing roster.
Informational fee
Base Studio lists Cohort Craft at £1,140 for one learner. Packet Desk recordings are included. Foundry Circle can place three colleagues across the year; see fees. Nothing on this page is a checkout.
To sit a cohort, send the one-page sketch. We reply with dates and an invoice if there is a seat.
Notes from the room
Questions we actually get
Do I need Mixpanel, Amplitude, or a particular SDK?
No. Bring whatever currently emits events. We work from exports. If your tool cannot export twenty rows, that is the first problem and we will say so early.
Will this get my team certified?
No. Packagepacketbase does not issue vendor certification, and Cohort Craft will not prepare you for a multiple-choice exam. The artefact is the contract.
What will you not cover?
We do not teach server-side tagging in Firebase, nor SKAdNetwork engineering, nor building a data warehouse from scratch. If your wound lives there, this syllabus will only get you as far as a clearer question for the engineer who does that work. That limitation is intentional; pretending otherwise wastes a Tuesday evening.
Can my whole squad sit together?
Two seats in the same cohort is fine. Three or more belongs on Foundry Circle so the critique does not become an internal meeting with an audience.