venkatv-hub/powerbi-dashboard-builder

Power BI Dashboard Builder

Turns a dashboard spec (see bi-dashboard-design/references/dashboard-spec.md) into a working Power BI artifact. Domain knowledge comes from the domain skill; layout and styling rules come from bi-dashboard-design. This skill covers the Power BI specifics.

Choose the build mode first

Check what is available and tell the user which mode you are using:

Mode	When	What you produce
A. Live model via MCP/CLI	The Power BI Modeling MCP server (@microsoft/powerbi-modeling-mcp) or pbi-cli is connected and Power BI Desktop has the model open	Tables, relationships, measures created directly in the open model; report built as PBIR files
B. PBIP project files	You can write files but have no live connection	A .pbip project folder: <Name>.SemanticModel/definition/*.tmdl and <Name>.Report/definition/ (PBIR) the user opens in Power BI Desktop
C. Build kit	Neither files nor tools are practical (e.g. chat-only)	DAX measure script, TMDL snippets, theme JSON and a page-by-page build sheet a developer follows

Prefer A, then B. In mode B, remind the user to enable the PBIP save option and "Store semantic model using TMDL format" in Power BI Desktop preview features if their version still has them as previews.

Workflow

1. Read the spec and the domain metrics file. Every measure you create must match a definition in the domain skill's <domain-skill>/references/metrics.md.
2. Model the star schema (references/tmdl-patterns.md):
   • One fact table per grain in the spec; dimensions conformed across facts.
   • A dedicated Date table marked as a date table, continuous, covering all fact dates, with fiscal columns when the domain uses a fiscal calendar.
   • Single-direction one-to-many relationships from dimension to fact. Use bidirectional only with a written reason. Role-playing dates (invoice vs due vs paid date): one active relationship, the others inactive and activated with USERELATIONSHIP in measures.
   • Hide foreign keys and raw numeric columns that are replaced by measures; set summarizeBy: none on keys, IDs and year/month numbers.
   • Sort-by columns for month names and for bucket labels (aging, bands).
3. Write measures (references/dax-patterns.md): a _Measures table, display folders per theme (e.g. 01 Revenue, 02 Margin), a format string and a description on every measure. Build base measures first, then ratios, then time intelligence, then display helpers (delta %, arrow, status color).
4. Build report pages (references/report-pbir.md): map each spec component to a visual, place it on the 1280×720 canvas using the grid mapping, apply the theme from bi-dashboard-design/references/theme-tokens.md, add drill-through pages and a reset bookmark.
5. Security: if the spec has row_level, create the RLS role with a DAX filter on the relevant dimension and document how to assign members in the Service.
6. Verify: run the DAX checks in references/dax-patterns.md#verification (totals match source, time intelligence returns values for the latest period, no blank KPIs), then run the bi-dashboard-design acceptance checklist. Report what you could not verify.

Grid mapping (1280 × 720 canvas)

• Margins 16 px; usable width 1248 px; 12 columns of 88 px with 16 px gutters.
• Column span c → width c*88 + (c-1)*16 px; x = 16 + col_index*104.
• One height unit = 56 px with 16 px gutters (header row ≈ 64 px).
• Long pages: prefer a second page over vertical scrolling for L1/L2; L3 detail pages may use a taller canvas (1280 × 1440) for tables.

Visual mapping

Spec component	Power BI visual	Notes
kpi_card	Card (new) / KPI	Reference label for comparison; conditional color via measure
trend_line	Line chart	Target as second measure or constant line; 13 months via relative date filter or measure window
ranked_bar	Clustered bar	Top N filter + "Other" via a dynamic segmentation measure if needed
variance_bar	Clustered bar on variance measure	Color by rule on Var sign × direction
waterfall	Waterfall	Breakdown field = driver dimension
stacked_bar	100% stacked bar
matrix	Matrix	Rows hierarchy, values Actual/Budget/Var/Var%, cell elements on Var%
exception_table	Table	Top N or severity filter, conditional icons, drill-through enabled
aging_buckets	Clustered column	Bucket column sorted by bucket order column
funnel	Funnel or bar	Bar sorted by stage order is more readable
map	Azure Map / filled map	Only if the tenant allows maps
slicer	Slicer (dropdown or tile)	Sync slicers across pages for Period and Org

Guardrails

• Never hard-code dates like "2026-10-31" in measures; derive "latest complete period" from the data or a parameter.
• Use DIVIDE() for every ratio. Never average a ratio over rows.
• Prefer measures over calculated columns; prefer Power Query / warehouse transforms over DAX calculated tables.
• Do not import sensitive columns (SSN, patient name, salary detail) unless the spec asks and RLS/OLS is in place.
• Keep Auto date/time off; it bloats the model and conflicts with the Date table.

Reference files

• references/tmdl-patterns.md – TMDL syntax for tables, columns, relationships, Date table, roles. Read in mode A/B.
• references/dax-patterns.md – reusable DAX: ratios, time intelligence, semi-additive snapshots, aging buckets, top N + Other, display helpers, verification queries.
• references/report-pbir.md – PBIR folder layout, visual JSON essentials, drill-through, bookmarks, and the build-sheet format for mode C.