solo-metrics-track

使用事件漏斗、KPI 基准和终止/迭代/规模决策阈值设置 PostHog 指标计划。当用户说“设置指标”、“跟踪 KPI”、“PostHog 事件”、“漏斗分析”、“何时终止或扩展”或“成功指标”时使用。请勿用于 SEO 指标（使用 /seo-audit）。

## 概述（中文）

使用事件漏斗、KPI 基准和终止/迭代/规模决策阈值设置 PostHog 指标计划。当用户说“设置指标”、“跟踪 KPI”、“PostHog 事件”、“漏斗分析”、“何时终止或扩展”或“成功指标”时使用。请勿用于 SEO 指标（使用 /seo-audit）。

## 原文

# /metrics-track

Set up a metrics tracking plan for a project. Defines PostHog event funnel, KPI benchmarks, and kill/iterate/scale decision thresholds based on lean startup principles.

## MCP Tools (use if available)

- `kb_search(query)` — find PostHog methodology, analytics patterns

If MCP tools are not available, fall back to Grep + Read.

## Methodology Reference

This skill implements metrics tracking based on lean startup principles:
- **Relative metrics vs niche benchmarks** — compare against your own trajectory, not vanity averages
- **Kill/iterate/scale decision rules** — data-driven thresholds for product decisions (see step 7 below)

## Steps

1. **Parse project** from `$ARGUMENTS`.
   - Read PRD for features, ICP, monetization model.
   - Read CLAUDE.md for stack (iOS/Web/both).
   - If empty: ask via AskUserQuestion.

2. **Detect platform:**
   - iOS app → PostHog iOS SDK events
   - Web app → PostHog JS SDK events
   - Both → cross-platform identity (shared user ID across platforms)

3. **Load PostHog methodology:**
   - If MCP available: `kb_search("PostHog analytics events funnel identity")`
   - Otherwise: check project docs for existing analytics configuration
   - Extract: event naming conventions, identity resolution, funnel pattern

4. **Define event funnel** based on PRD features:

   Standard funnel stages (adapt per product):
   ```
   Awareness → Acquisition → Activation → Revenue → Retention → Referral
   ```

   Map to concrete events:

   | Stage | Event Name | Trigger | Properties |
   |-------|-----------|---------|------------|
   | Awareness | `page_viewed` | Landing page visit | `source`, `utm_*` |
   | Acquisition | `app_installed` or `signed_up` | First install/signup | `platform`, `source` |
   | Activation | `core_action_completed` | First key action | `feature`, `duration_ms` |
   | Revenue | `purchase_completed` | First payment | `plan`, `amount`, `currency` |
   | Retention | `session_started` | Return visit (D1/D7/D30) | `session_number`, `days_since_install` |
   | Referral | `invite_sent` | Shared or referred | `channel`, `referral_code` |

5. **Forced reasoning — metrics selection:**
   Before defining KPIs, write out:
   - **North Star Metric:** The ONE number that matters most (e.g., "weekly active users who completed core action")
   - **Leading indicators:** What predicts the North Star? (e.g., "activation rate D1")
   - **Lagging indicators:** What confirms success? (e.g., "MRR", "retention D30")
   - **Vanity metrics to AVOID:** (e.g., total downloads without activation)

6. **Set KPI benchmarks** per stage:

   | KPI | Target | Kill Threshold | Scale Threshold | Source |
   |-----|--------|---------------|-----------------|--------|
   | Landing → Signup | 3-5% | < 1% | > 8% | Industry avg |
   | Signup → Activation | 20-40% | < 10% | > 50% | Product benchmark |
   | D1 Retention | 25-40% | < 15% | > 50% | Mobile avg |
   | D7 Retention | 10-20% | < 5% | > 25% | Mobile avg |
   | D30 Retention | 5-10% | < 2% | > 15% | Mobile avg |
   | Trial → Paid | 2-5% | < 1% | > 8% | SaaS avg |

   Adjust based on product type (B2C vs B2B, free vs paid, mobile vs web).

7. **Define decision rules** (lean startup kill/iterate/scale):

   ```markdown
   ## Decision Framework

   **Review cadence:** Weekly (Fridays)

   ### KILL signals (any 2 = kill)
   - [ ] Activation rate < {kill_threshold} after 2 weeks
   - [ ] D7 retention < {kill_threshold} after 1 month
   - [ ] Zero organic signups after 2 weeks of distribution
   - [ ] CAC > 3x LTV estimate

   ### ITERATE signals
   - [ ] Metrics between kill and scale thresholds
   - [ ] Qualitative feedback suggests product-market fit issues
   - [ ] One stage of funnel is dramatically worse than others

   ### SCALE signals (all 3 = scale)
   - [ ] Activation rate > {scale_threshold}
   - [ ] D7 retention > {scale_threshold}
   - [ ] Organic growth > 10% week-over-week
   ```

8. **Generate PostHog implementation snippets:**

   ### For iOS (Swift):
   ```swift
   // Event tracking examples
   PostHogSDK.shared.capture("core_action_completed", properties: [
       "feature": "scan_receipt",
       "duration_ms": elapsed
   ])
   ```

   ### For Web (TypeScript):
   ```typescript
   // Event tracking examples
   posthog.capture('signed_up', {
       source: searchParams.get('utm_source') ?? 'direct',
       plan: 'free'
   })
   ```

9. **Write metrics plan** to `docs/metrics-plan.md`:

   ```markdown
   # Metrics Plan: {Project Name}

   **Generated:** {YYYY-MM-DD}
   **Platform:** {iOS / Web / Both}
   **North Star:** {north star metric}

   ## Event Funnel

   | Stage | Event | Properties |
   |-------|-------|------------|
   {event table from step 4}

   ## KPIs & Thresholds

   | KPI | Target | Kill | Scale |
   |-----|--------|------|-------|
   {benchmark table from step 6}

   ## Decision Rules

   {framework from step 7}

   ## Implementation

   ### PostHog Setup
   - Project: {project name} (EU region)
   - SDK: {posthog-ios / posthog-js}
   - Identity: {anonymous → identified on signup}

   ### Code Snippets
   {snippets from step 8}

   ## Dashboard Template
   - Funnel: {stage1} → {stage2} → ... → {stageN}
   - Retention: D1 / D7 / D30 cohort chart
   - Revenue: MRR trend + trial conversion

   ---
   *Generated by /metrics-track. Implement events, then review weekly.*
   ```

10. **Output summary** — North Star metric, key thresholds, first event to implement.

## Notes

- PostHog EU hosting for privacy compliance
- Use `$set` for user properties, `capture` for events
- Identity: start anonymous, `identify()` on signup with user ID
- Cross-platform: same PostHog project, same user ID → unified journey
- Review dashboard weekly, make kill/iterate/scale decision monthly

## Common Issues

### Wrong platform detected
**Cause:** Project has both web and iOS indicators.
**Fix:** Skill checks package manifests. If both exist, it generates cross-platform identity setup. Verify the detected platform in the output.

### KPI thresholds too aggressive
**Cause:** Default thresholds are industry averages.
**Fix:** Adjust thresholds in `docs/metrics-plan.md` based on your niche. B2B typically has lower volume but higher conversion.

### PostHog SDK not in project
**Cause:** Metrics plan generated but SDK not installed.
**Fix:** This skill generates the PLAN only. Install PostHog SDK separately: `pnpm add posthog-js` (web) or add `posthog-ios` via SPM (iOS).