dax

# DAX Skills and references for writing, debugging, and optimizing DAX in semantic models. ## Optimization For systematic DAX query performance optimization, read the workflow reference first: **[`references/dax-performance-optimization.md`](./references/dax-performance-optimization.md)** — Tiered framework (4 tiers), phased workflow, decision guide, and error handling. Detailed reference files (progressive disclosure — consult as directed by the workflow): - **[`references/engine-internals.md`](./references/engine-internals.md)** — FE/SE architecture, xmSQL, compression/segments, SE fusion, trace diagnostics - **[`references/dax-patterns.md`](./references/dax-patterns.md)** — Tier 1 DAX patterns (DAX001–DAX021) + Tier 2 query structure (QRY001–QRY004) - **[`references/model-optimization.md`](./references/model-optimization.md)** — Tier 3 model patterns (MDL001–MDL010) + Tier 4 Direct Lake (DL001–DL002) Trace capture and performance profiling: - **Local models (Power BI Desktop):** Use the [`connect-pbid` skill](../../../pbi-desktop/skills/connect-pbid/) — specifically `performance-profiling.md` for FE/SE timing and `evaluateandlog-debugging.md` for intermediate result inspection. - **Remote models (Fabric Service / XMLA):** Use the [`powerbi-modeling-mcp`](https://marketplace.visualstudio.com/items?itemName=analysis-services.powerbi-modeling-mcp) VS Code extension for trace and query operations. Install: `code --install-extension analysis-services.powerbi-modeling-mc...