/cja-segment-performance-comparator

name: cja-segment-performance-comparator
description: >
  Compares the performance of two or more audience segments across key metrics
  side by side. Use this skill when someone wants to compare audiences, cohorts,
  or groups — for example, "how do mobile users compare to desktop users on
  conversion," "compare new vs. returning visitors," "show me the difference
  between these two segments," "compare these audiences on our KPIs," or
  "which segment performs better." Also trigger for "segment comparison,"
  "audience comparison," or "cohort comparison."
license: Apache-2.0
metadata:
  author: Adobe
  version: "1.0"

Segment Performance Comparator (Customer Journey Analytics)

Compare 2–5 audience segments across a set of key metrics in a side-by-side matrix. The output tells the user not just what each segment looks like in isolation, but which segment wins or loses on each metric — and which differences are large enough to act on.

This skill answers the question "which audience should we focus on?" with data. Segment comparisons drive product decisions, personalization strategy, and budget allocation — so clarity and actionability matter more than exhaustive data.

---

CJA MCP Tools Used

• `findSegments` — search for segments by name or keyword
• `describeSegment` — understand the logic of candidate segments before using them
• `findMetrics` — resolve base metric IDs
• `findCalculatedMetrics` — include custom KPIs in the comparison
• `listComponentUsage` — identify the most-used metrics as default comparison set
• `runReport` (with `segmentIds` or `adhocSegments`) — pull metric values per segment

---

Phase 0 — Setup

1. Call `findDataViews` to list available data views. 2. If the user hasn't specified a data view, present the list and ask which to use. 3. Call `setDefaultSessionDataViewId` with the chosen ID. 4. Ask the user which segments to compare if not already specified. Confirm the metrics to compare them on.

---

Phase 1 — Identify Segments to Compare

1.1 From user description

If the user named specific segments, resolve them:

findSegments(search: "<segment name>")

For each match, call `describeSegment` to verify it is the correct one:

describeSegment(segmentId: "<id>")

Show the segment definition summary to the user if there is ambiguity: > "I found two segments matching 'mobile users': **Mobile Visitors (All Devices)** > and **Mobile App Users**. Which do you want to compare?"

1.2 From plain-English descriptions

If the user says "compare mobile vs desktop users" but there are no matching segments, offer to create ad hoc segments inline for the comparison: > "I don't see pre-built segments for mobile and desktop. I can create > temporary ad hoc segments for this comparison using device type. Should I > proceed with ad hoc segments, or would you like to create permanent segments > first?"

Ad hoc segments are constructed using `adhocSegments` in `runReport` — no save required for the comparison itself.

1.3 Segment count limit

Maximum 5 segments for a single comparison. More than 5 creates a matrix that is too wide to read meaningfully. If the user requests more, say: > "I'll limit to the 5 most relevant segments for readability. Would you like > me to prioritize by usage count or stick with your list order?"

---

Phase 2 — Identify Metrics to Compare

2.1 From user specification

Resolve named metrics via `findMetrics` and `findCalculatedMetrics`.

2.2 Default metric discovery

If the user did not specify metrics, pull the top metrics by usage. The `listComponentUsage` tool does not support a `limit` parameter — it returns all components ranked by usage count; take the top 6–8 from the result:

listComponentUsage(componentType: "metric")
listComponentUsage(componentType: "calculatedMetric")

Prefer calculated metrics over raw base metrics when they measure the same thing — calculated metrics reflect intentional KPI definitions.

2.3 Metric selection for a comparison

Good comparison metrics should be meaningful across all segments. For example, "Revenue" is meaningful for both mobile and desktop users; "App Installs" is only meaningful for mobile. Remove metrics that would be trivially zero for one segment.

If unsure, ask: "Should I use your standard KPI set, or focus on specific metrics like conversion rate, revenue, and engagement?"

---

Phase 3 — Run the Comparison

For each segment, run a `runReport` with that segment applied and all comparison metrics included. Note that `runReport` takes `metricIds` as a comma-separated string, `startDate`/`endDate` (not `dateRange`), and a `dimensionIds` (required even for summary-only reports — use a low-cardinality dimension like `variables/daterangeday` or `variables/web.webPageDetails.name`). The summary totals for all metrics are in `summaryData.filteredTotals`:

runReport(
  dimensionIds: "variables/web.webPageDetails.name",
  metricIds: "metrics/visits,metrics/revenue_1,metrics/orders_1_1",
  startDate: "<period start>T00:00:00",
  endDate: "<period end>T23:59:59",
  page: 0,
  limit: 1,
  segmentIds: "<segment id>"
)

For ad hoc segments, use the full CJA segment definition object:

runReport(
  dimensionIds: "variables/web.webPageDetails.name",
  metricIds: "metrics/visits,metrics/orders_1_1",
  startDate: "<period start>T00:00:00",
  endDate: "<period end>T23:59:59",
  page: 0,
  limit: 1,
  adhocSegments: [{
    "func": "segment",
    "version": [1, 0, 0],
    "container": {
      "func": "container",
      "context": "visitors",
      "pred": {
        "func": "streq",
        "val": { "func": "attr", "name": "variables/device_type" },
        "str": "Mobile Phone"
      }
    }
  }]
)

Read metric totals from `summaryData.filteredTotals[i]` where `i` is the 0-based index of the metric in the `metricIds` string.

Run one report per segment. Collect all results into a matrix:

• Rows = metrics
• Columns = segments

---

##