PostHog cannot compute retention, stickiness, lifecycle, or cohort insights on profile-less events — exactly the charts growth reporting needs. Lifecycle events (install_*, uninstall_completed, worker_started; ~1-2/day/install) now build a person profile keyed to the anonymous install UUID with $set restricted to whitelisted enums. High-volume operational events stay $process_person_profile:false for cost. Adds plans/2026-06-09-telemetry-metrics-spec.md mapping every event to the growth/retention/activation/reliability metric it powers. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Telemetry Metrics Spec — the story the data must tell
Audience: us, when building the PostHog dashboard and the fundraise narrative. Premise: 82k GitHub stars, zero analytics history. The dataset starts the day this ships, so every chart below is designed to be meaningful within 4–8 weeks of data and to compound from there.
The narrative arc (what a deck slide needs to say)
- Reach — "X installs/week and growing N% w/w, across 12 IDEs."
- Habit — "Installs come back: D30 retention X%, DAU/MAU X%."
- Value loop — "Memory isn't shelfware: X% of installs reach the aha moment, and active installs read memory back X times/day."
- Reliability — "Core pipeline succeeds X% of the time at scale."
Everything below maps an event to one of those four sentences. If a metric doesn't feed a sentence, it doesn't go on the dashboard.
Unit of measure — be precise with VCs
The distinct_id is an install (one machine + one ~/.claude-mem), not a
human. Quote "active installs", never "users". This is the honest dev-tool
convention (Homebrew, VS Code extensions count the same way) and diligence
will check. Reinstalls keep the same ID (uninstall preserves the data dir), so
returning installs are not double-counted.
Always filter is_ci = false on every insight. CI noise inflates everything.
Event → metric map
Reach (growth accounting)
| Metric | Definition |
|---|---|
| New installs/week | unique distinct_id on install_completed where is_update = false |
| Upgrade adoption | install_completed where is_update = true, broken down by version |
| Active installs (WAU/MAU) | unique distinct_id on worker_started (start + daily heartbeat = presence signal) |
| Churn | uninstall_completed count; net growth = new − uninstalls |
| Surface mix | install_completed breakdown by ide, provider, runtime_mode |
Habit (retention — the slide that raises the round)
| Metric | Definition |
|---|---|
| D1/D7/D30 retention | PostHog Retention insight: first install_completed → returning on worker_started. Requires person profiles — that's why lifecycle events set them. |
| Stickiness (DAU/MAU) | PostHog Stickiness insight on worker_started |
| Lifecycle | PostHog Lifecycle insight on worker_started (new / returning / resurrecting / dormant) |
| Retention by segment | same retention insight broken down by person property ide or provider — "Cursor installs retain 2×" is a fundable sentence |
Value loop (activation + engagement)
| Metric | Definition |
|---|---|
| Activation funnel | Funnel: install_completed → first session_compressed → first context_injected. The third step is the aha moment: stored memory actually used. |
| Time-to-value | median time from install_completed to first context_injected |
| Engagement depth | session_compressed count per active install per day; context_injected per active install per day |
| Read/write ratio | context_injected ÷ session_compressed — memory being consumed, not hoarded |
| Feature adoption | search_performed breakdown by endpoint |
Reliability (diligence armor)
| Metric | Definition |
|---|---|
| Compression success rate | session_compressed outcome ok ÷ all, by version and provider |
| Error rate | error_occurred per active install, by error_category and version |
| Latency health | p50/p95 duration_ms on session_compressed, search_performed, context_injected |
| Install success rate | install_completed ÷ (install_completed + install_failed), failures by error_category |
Person-profile design (cost control)
Only lifecycle events (install_*, uninstall_completed, worker_started)
carry person profiles — ~1–2 events/day/install, so profile-priced ingestion
stays bounded even at 100k installs. High-volume operational events are
profile-less (cheaper tier). Person properties are the whitelisted enums only:
version, os, arch, runtime, locale, ide, provider, runtime_mode.
Caveats to state proactively in diligence
- Telemetry is opt-out (
DO_NOT_TRACKhonored, one-command disable); numbers undercount by the opt-out rate. That's the credible direction to undercount. - Data starts ; star history is the pre-telemetry proxy.
- One human can be several installs (work + home). Quote installs.
Dashboard build order (PostHog UI, ~30 min)
- Trends: weekly unique
worker_started(active installs) + weeklyinstall_completedwhereis_update=false(new installs). - Retention:
install_completed→worker_started, weekly, breakdownide. - Funnel:
install_completed→session_compressed→context_injected, 14-day window. - Stickiness + Lifecycle on
worker_started. - Trends:
session_compressedoutcome error ÷ total (reliability), p95duration_ms(latency).