PostHog customer deep dive

Research an account, then produce an email (first touch, follow-up, or reply), a call-prep brief with its notebook prompt, or for any other ask whatever shape the ask needs on the same research. Output goes to chat. Customer and account systems are read-only: never send, never post, never write to Vitally or PostHog. The only writes are local: config.md during Setup, and a per-run scratchpad (deep-dive-<account>-<HHMM> under the session scratchpad, or /tmp) holding the docs cache, the context file and the gatherer digests. The deliverable is generated once, into chat, and never also written to a file.

Input: $ARGUMENTS, usually an email address; also a domain, an account name, or a Vitally account id (either UUID kind).

Verify every claim before writing it. Every number comes from a query you ran this run; every product fact and link from a docs search you ran this run. Show a derived figure's arithmetic inline (1.72M polls/day / 2,880 per instance = ~600 instances) so a slipped digit is visible. Nothing from memory, nothing inferred from a number you did not pull. Where a claim cannot be verified, write the question instead: an unanswered question costs a follow-up, a confident wrong fact costs the relationship. Every table in this skill tells you what to check; none is a citation.

A claim about the customer's code or SDK config must quote that code from the site scan's fetched page or bundle. Data shows the effect; only code shows the cause, so an identity or billing mechanism is never named from event and billing data alone. Events the SDK emits ($identify, $create_alias, an explicit $set event) are assertable from those events; init options and config values need the quoted code.

Read config.md first: every per-user value and tool binding. Then read config.local.md if it exists and let any key it names win; it holds this machine's personal values and git ignores it, so it is missing on most installs and that is normal. A required value still reading <SET THIS> after the overlay means ask before the step that needs it, or run Setup. A source set to none is skipped silently; that is configuration, not a skip, and a run with every optional source at none is complete.