ecom -- Ecommerce Business Review Toolkit

D2C ecommerce analytics system. The Python backend computes KPIs, runs health checks, and scores performance from order transaction data; you (Claude) interpret the numbers and write the human-readable report.

Input: Order transaction data only (CSV).

Quick Reference

Command	What it does	Output
/ecom review	Full business review (auto-selects periods from data)	REVIEW.md
/ecom review 30d	Focused on the last 30 days	REVIEW_30D.md
/ecom review 90d	Focused on the last 90 days	REVIEW_90D.md
/ecom review 365d	Focused on the last 365 days	REVIEW_365D.md
/ecom review [question]	Answers a specific question from the data	Inline response

One command. Two modes: full report or focused answer.

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Response Modes

Mode 1: Full Review (default)

Triggered when: no natural-language question in the user's input. Output: REVIEW.md (or REVIEW_{PERIOD}.md for period-specific runs) following the full 6-part structure defined below.

Examples: /ecom review, /ecom review 30d, /ecom review 365d

Mode 2: Focused Query

Triggered when: user's input includes a natural-language question or topic. Output: inline conversational response (no file creation).

Examples:

• "how was last month?" → extract from monthly_trend
• "how was last year?" → 365d data
• "how was Q4 last year?" → extract from monthly_trend
• "how's retention looking?" → customer metrics focus

Query-to-Period Mapping

Query pattern	Data source
last 30 days	--period 30d
last 3 months / last 90 days	--period 90d
last year / this year	--period 365d
last month / specific month name	full run, extract from monthly_trend
Q1-Q4 / specific quarter	full run, extract from monthly_trend

Calendar-month questions ("last month", "January") use the 365d monthly_trend, NOT a 30d trailing window. Use --period 30d only when the user explicitly asks for "last 30 days".

Fallback when 365d coverage is unavailable: Calendar-month and quarter queries require 365d monthly_trend data. If 365d coverage is missing (data < 400 days):

• Answer from the best available trailing window data
• State that exact calendar-month/quarter breakdown is not available
• Suggest running a full review for deeper analysis

monthly_trend limitation: no year-over-year comparison by month/quarter monthly_trend covers only the most recent 12 months. Comparing "Q4 this year vs Q4 last year" is not possible. Instead:

• Present absolute values (revenue, orders) for the requested period
• Calculate its share of annual revenue (seasonality concentration)
• Compare against Q1-Q3 average for relative scale
• Add 365d overall YoY growth rate as context
• Do not mention the absence of YoY comparison (follow Handling Incomplete Data rules — omit what you can't measure)

If the query doesn't map to a clear period, run full (no --period flag) and answer from the most relevant data.

Focused Query Response Format

1. Direct answer (2-3 sentences with key numbers from review.json)
2. Supporting context (1-2 observations that add nuance — tensions, comparisons)
3. One actionable takeaway (if warranted by the data)

Total: 10-30 lines. Headings, KPI tree, and Finding format are NOT required. Use whatever structure best fits the answer. For example, "what's the new vs returning split?" is clearest as a partial KPI tree. Apply the same data rules: all numbers from review.json only, match user's language. Do NOT create a REVIEW.md file.

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Data Input

Order transaction data (CSV). Each row = one order or line item.

Required columns:

• Order ID, Order date, Customer ID (or email)
• Revenue (after discounts, before tax/shipping)
• Quantity, SKU/Product ID
• Discount amount (if available)

~/.claude/skills/ecom/bin/ecom review orders.csv --output <output-dir>
~/.claude/skills/ecom/bin/ecom review orders.csv --period 90d --output <output-dir>

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Workflow

Phase 1: Compute (Python)

~/.claude/skills/ecom/bin/ecom review orders.csv --output <output-dir>

The engine internally:

1. Period analysis -- computes KPIs for each time period (30d, 90d, 365d) with prior-period comparisons, decompositions, and trend detection.
2. Health checks -- evaluates ~30 checks across Revenue, Customer, and Product. Each check produces a pass/watch/fail signal with severity weighting. These power the 🟢/🟡/🔴 markers in the KPI tree.

Output: review.json (or review_{period}.json for period-specific runs). See Schema section below.

Phase 2: Interpret (You -- Claude)

1. Read review.json (or review_{period}.json for period-specific runs)
2. Load reference files on demand (see Reference Files below)
3. Write REVIEW.md (or REVIEW_{PERIOD}.md) following the Output Format below

Your job is to weave trends and diagnostics into one coherent story. Period analysis tells you where things are heading. Health checks tell you what's broken right now. The report combines both.

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review.json Schema

This is the data contract between Python and Claude. Every field below is guaranteed to exist in the output. Claude reads this structure; Claude does NOT invent data that isn't here.

{
  "version": "0.1.0",

  // --- Metadata ---
  "metadata": {
    "generated_at": "2026-03-05T18:00:00Z",
    "data_start": "2025-01-01",
    "data_end": "2025-12-31",
    "total_orders": 5784,
    "total_customers": 2765,
    "total_revenue": 1383651,
    "currency": "USD",
    "revenue_definition": "Net sales after discounts, before tax and shipping"
  },

  // --- Data quality warnings (empty array = no issues) ---
  "data_quality": [
    // Example entries (only present when issues detected):
    // { "type": "partial_period", "period": "2026-02", "days_with_data": 3,
    //   "message": "Latest month (2026-02) has only 3 days of data. MoM comparisons use prior complete months." }
    // { "type": "short_data_span", "days": 45, "message": "Data spans only 45 days..." }
    // { "type": "limited_data_span", "days": 200, "message": "Data spans 200 days (<1 year)..." }
  ],

  // --- Data coverage: which periods are available ---
  "data_coverage": {
    "30d": true,       // true if >=45 days of data exist
    "90d": true,       // true if >=120 days of data exist
    "365d": true       // true if >=400 days of data exist
  },

  // --- Period metrics (one block per available period) ---
  "periods": {
    "30d": {
      "summary": {
        "revenue": 98000,
        "revenue_change": -0.003,       // vs prior 30d
        "orders": 412,
        "orders_change": -0.03,
        "aov": 238,
        "aov_change": -0.001,
        "customers": 287,
        "customers_change": -0.05
      },
      "kpi_tree": {
        "new_customer_revenue": 38000,
        "new_customer_revenue_share": 0.388,
        "new_customers": 95,
        "new_customers_change": -0.08,
        "new_customer_aov": 400,
        "returning_customer_revenue": 60000,
        "returning_customer_revenue_share": 0.612,
        "returning_customers": 192,
        "returning_customers_change": -0.03,
        "returning_customer_aov": 312
      },
      "drivers": {
        "aov_effect": 1200,            // revenue change attributable to AOV
        "volume_effect": -1500,         // revenue change attributable to order count
        "mix_effect": 0                 // revenue change attributable to new/returning mix shift
      }
    },
    "90d": { /* same structure */ },
    "365d": {
      /* same structure as 30d (summary, kpi_tree, drivers) plus: */
      "repeat_purchase_rate": 0.38,   // only in 365d block
      "monthly_trend": [
        { "month": "2025-01", "revenue": 95000, "orders": 420, "aov": 226, "customers": 310, "new_customers": 180, "returning_customers": 130, "days_with_data": 31 },
        // ... only months with actual data (no zero-fill for future months)
        { "month": "2025-12", "revenue": 12000, "orders": 45, "aov": 267, "customers": 38, "new_customers": 10, "returning_customers": 28, "days_with_data": 3, "partial": true }
      ]
    }
  },

  // --- Health checks (powers 🟢/🟡/🔴 markers) ---
  "health": {
    "checks": [
      {
        "id": "monthly_revenue_trend",   // internal only, never expose
        "category": "revenue",
        "severity": "high",
        "result": "watch",              // pass | watch | fail
        "message": "MoM revenue growth: -3.8%",
        "value": -0.038,
        "threshold": 0.0
      }
      // ... more checks
    ],
    "top_issues": [
      // Pre-sorted by severity * impact. Max 10.
      {
        "id": "multi_item_order_rate",
        "category": "product",
        "severity": "high",
        "result": "fail",
        "message": "Multi-item order rate: 0.0%",
        "estimated_annual_impact": 77573
      }
      // ...
    ]
  },

  // --- Pre-computed action candidates ---
  "action_candidates": [
    {
      "action": "Introduce product bundles to increase multi-item orders",
      "source_check": "multi_item_order_rate",  // internal reference
      "severity": "high",
      "estimated_annual_impact": 77573,
      "timeline": "this_month"
    }
    // ... max 10 candidates, sorted by impact
  ]
}

Schema Rules

• periods only contains keys for periods where data_coverage is true
• All _change fields are proportional change vs prior period (e.g., 0.08 = +8%)
• health.checks contains every check result; health.top_issues is a filtered/sorted subset (fail and watch only, max 10, sorted by severity × impact)
• action_candidates are suggestions from Python; Claude refines, merges, and rewrites them in business language for the report
• monthly_trend contains only months with actual order data (no zero-fill for future months)
• monthly_trend entries with "partial": true have less than half the month's days with data
• When data_quality is non-empty, mention relevant warnings in Data Notes

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Reference Files

Load on-demand -- do NOT load all at startup.

Path: references/

• review-narratives.md -- Narrative templates by health level and growth trajectory, finding templates, period-specific guidance. Always load.
• finding-clusters.md -- Cluster model for grouping related issues into themes. Load to identify themes.
• recommended-actions.md -- Actionable recommendations per check with timeline and impact range. Load for watch/fail checks.
• impact-formulas.md -- Revenue impact formulas with worked examples. Load when estimating impact.
• health-checks.md -- Check definitions (R/C/P) with thresholds and interpretation.
• benchmarks.md -- D2C ecommerce KPI benchmarks.

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Output Format: REVIEW.md / REVIEW_{PERIOD}.md

The following structure applies to Full Review mode only. See Response Modes for Focused Query.

One report. Three parts. Target: ~150 lines. Tighter is better.

Report Construction Checklist (MANDATORY)

Before writing, verify your report contains ALL sections in this exact order. Missing or reordered sections are a format violation.

1. Executive Summary -- narrative blockquote (4-6 lines) + Scoreboard table
2. 30d Pulse section (if data available) -- KPI tree + max 1 finding
3. 90d Momentum section (if data available) -- KPI tree + drivers + max 2 findings
4. 365d Structure section (if data available) -- KPI tree + drivers + max 3 findings
5. Action Plan -- max 5 items grouped by time horizon + Guardrails
6. Data Notes -- 2-4 lines

Structural rules:

• Sections MUST appear in this order. Do NOT reorganize by theme.
• Period sections MUST use the KPI tree format with emoji markers.
• Do NOT create standalone sections like "What's Working Well" or "Issues to Address".
• Positive signals belong in Executive Summary narrative and KPI tree markers.

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Part 1: Executive Summary

Narrative (4-6 lines, blockquote)

Synthesize across all available periods. Structure:

[North Star result + trend across periods]
[What's working: 1-2 strengths confirmed by data -- 80/20 rule]
[What needs attention: the key tension/risk, with data]
[Most important action, with timeline]

Example:

Revenue reached $1.38M for the year (+25.7% YoY), but growth is decelerating -- the last 90 days grew only 8% vs prior 90 days, and last month was flat (+0.3%). Growth depends on existing customer AOV increases (+14.8%), while new customer acquisition has stalled (share: 42.3%, unchanged). Reallocate 20% of retention budget to acquisition channels by end of this month, targeting CPA below $XX.

Scoreboard

          30d Pulse     90d Momentum    365d Structure
Revenue   $98K (= flat) $340K (+ 8%)    $1.38M (+ 26%)
Orders    412 (- 3%)    1,280 (+ 5%)    5,784 (+ 10%)
AOV       $238 (= flat) $266 (+ 12%)    $239 (+ 15%)
Customers 287 (- 5%)    812 (+ 3%)      2,765 (+ 10%)

+ improving, - deteriorating, = stable. Only show periods that data supports.

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Part 2: Period Sections

CRITICAL: Each period gets its own heading and its own KPI tree. Do NOT merge periods into thematic sections.

All periods use the same skeleton. But they are not equal length:

Period	Depth	Findings cap	Role
30d Pulse	Shallow -- KPI tree + 1-2 sentences + max 1 finding	1	Flag fires only
90d Momentum	Medium -- KPI tree + drivers + max 2 findings	2	Main analytical body
365d Structure	Deep -- KPI tree + drivers + max 3 findings	3	Strategic narrative

If only one period is available, give it the full depth (3 findings).

The total across all periods must not exceed 5-7 findings. If a theme appears in multiple periods, state it once at the most structural level and reference supporting signals from shorter periods.

Skeleton

[Period Name]: [One-line headline -- the "so what"]

KPI Tree:

Revenue $X (vs prior period: +X%)
|-- 🟢 New Customer Revenue $X (X% of total)
|   |-- New Customers: X (+X%)
|   |-- New Customer AOV: $X (+X%)
|-- 🟡 Existing Customer Revenue $X (X% of total)
    |-- Returning Customers: X (+X%)
    |-- Returning AOV: $X (+X%)
    |-- Repeat Purchase Rate: X% -- first-to-second purchase conversion (365d only)

🟢 healthy / 🟡 watch / 🔴 problem (driven by health check results).

Growth Drivers (1-2 sentences, 90d and 365d only):

Was the change volume-driven or price-driven? Connect to KPI tree nodes.

Findings (within period cap):

Each follows Finding Quality Standards. Findings should weave trend data and health check diagnostics together, not present them separately. Use this format:

[Finding title]

What is: [1 sentence, quantitative fact]

Why it matters: [Data-backed tension with "however"/"despite"/"but"]

What to do: [Direction only — 1 sentence. Details go in Action Plan.]

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Part 3: Action Plan (unified, max 5 items)

Hard cap: 5 action items. Exceeding 5 is a format violation.

Action Plan is the single source of truth for deadlines and success metrics. Findings point to the problem and direction; Action Plan specifies the execution.

One list synthesizing across all periods. Group by time horizon:

Immediate (from 30d signals)
1. ...

This Month (from 90d findings)
2. ...

This Quarter (from 365d insights)
3. ...

For each item:

• What (one concrete sentence)
• Why (reference specific data)
• When (specific deadline)
• Success metric (measurable)

End with (REQUIRED -- omitting Guardrails is a format violation):

Guardrails: [2-3 metrics that must not deteriorate while executing above actions]

Example: AOV must stay above $X | Repeat purchase rate must not drop below X% | Discount rate must stay under X%

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Data Notes (2-4 lines)

Always include:

• Revenue definition (from metadata.revenue_definition)
• Data period and order count
• Periods included/omitted

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Period Interaction Rules

• Confirm or contradict across periods. Don't let periods exist in isolation.
• Zoom in: If 90d shows a break, check 30d for continuation.
• Never repeat a finding across periods. State once at the structural level.
• Executive Summary synthesizes, does not summarize sequentially.

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Finding Quality Standards

Every finding follows: What is → Why it matters → What to do

• What is: 1 sentence. Quantitative fact. No interpretation.
• Why it matters: Data-backed tension. Must show contrast ("despite", "however"). Abstract concerns like "growth must be validated" are PROHIBITED.
• What to do: Direction and rationale only — 1 sentence. Deadlines and success metrics belong in the Action Plan. "Consider", "improve", "optimize", "explore" are PROHIBITED.

Good:

What is:       Annual revenue grew 25.7% YoY.
Why it matters: However, despite a 25.4% reduction in discount rate, new customer
               revenue share remains at 42.3% -- growth depends entirely on
               existing customer AOV increases (+14.8%).
What to do:    Reallocate retention budget toward acquisition channels to diversify growth sources.

Bad (PROHIBITED):

What is:       Revenue grew 25.7%.
Why it matters: Rapid growth must be validated. <-- no data, no tension
What to do:    Consider improving acquisition. <-- banned verb, no deadline

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Handling Incomplete Data

• Omit what you can't measure. No N/A, no empty sections.
• Don't apologize. Never say "unfortunately..."
• Shorter data = shorter report.
• All gaps noted in Data Notes only.

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Language and Data Scope Rules

Language

• Write entire report in ONE language (match user's prompt/store language)
• Data Notes follows same language as body

Data Scope: review.json Only

• All numbers MUST come from review.json or be derived from its values
• Do NOT reference external sources (Shopify Analytics, GA, etc.)
• If additional data would help, note as recommended investigation in "What to do"
• PROHIBITED: "CVR from Shopify shows 2.1%" (CVR not in review.json)
• ALLOWED: "Investigate CVR in Shopify Analytics to determine root cause"

data_quality Warnings

• When data_quality array is non-empty, mention relevant warnings in Data Notes
• Do NOT present partial-month MoM as real performance signals

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Quality Gates

• Never present numbers without interpretation
• Always explain why, not just the value
• Specific, actionable recommendations only
• Business language, not jargon (explain terms on first use)
• Connect related findings into systemic patterns
• No internal check IDs in the report
• No check counts in the report
• No repeated findings across sections
• Finding Quality Standards on every finding
• Guardrails on every action plan
• 80/20 rule: ~80% confirmation (builds trust), ~20% surprise (drives action)

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Internal: Health Check Engine

Each check returns pass / watch / fail. These power the 🟢🟡🔴 KPI tree markers. Check definitions in references/health-checks.md. Do NOT use numeric scores, letter grades, or percentage-based health ratings.

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Runtime

The skill uses a local Python runtime installed in ~/.claude/skills/ecom/.venv/. Use the wrapper command:

~/.claude/skills/ecom/bin/ecom review orders.csv --output <output-dir>
~/.claude/skills/ecom/bin/ecom review orders.csv --period 90d --output <output-dir>

Modules: loader, metrics, decomposition, cohort, product, checks, report, review_engine, config, normalize, periods.