Fabric tmdl api

Skill wardawgmalvicious/claude-config/skills/fabric-tmdl-api

Personal Claude Code config — skills, subagents, hooks, and rules for Microsoft Fabric and Power BI workflows on Windows. Cherry-pickable, no semver.

Install

npx -y skills add wardawgmalvicious/claude-config --skill fabric-tmdl-api

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Use for the Fabric Semantic Model Definition API — createItemWithDefinition / getDefinition / updateDefinition. Covers the two-audience rule (Fabric API for definitions, Power BI API for refresh/data sources/permissions), why updateDefinition MUST include ALL parts (modified and unmodified) or they're deleted, why you NEVER include .platform in definition payloads, base64 encoding requirement, LRO polling, required TMDL parts (definition.pbism, database.tmdl, model.tmdl, tables/*.tmdl), the `database` declaration requirement in database.tmdl, and Direct Lake partition configuration (EntityPartitionSource, named expression with AzureStorage.DataLake).

SKILL.md

4.3 KB, as published. Nobody here has run it

Semantic Model Definition API rules

Two audiences: Fabric API (api.fabric.microsoft.com) for CRUD on definitions; Power BI API (analysis.windows.net/powerbi/api) for refresh, data sources, permissions
updateDefinition must include ALL parts — modified AND unmodified. The API replaces the entire definition; omitting parts deletes them.
Never include .platform in updateDefinition payloads — it is Git integration metadata and causes errors
Base64-encode all TMDL content in definition payloads
getDefinition is a POST (not GET) — requires --body '{}'
Poll LRO to completion — createItemWithDefinition, getDefinition, and updateDefinition return 202

Required TMDL Parts

Part Path	Content
`definition.pbism`	Semantic model connection settings (JSON)
`definition/database.tmdl`	`database` declaration + `compatibilityLevel: 1702`
`definition/model.tmdl`	Model properties + `ref` declarations for tables/roles/etc.
`definition/tables/<TableName>.tmdl`	Per-table: measures, columns, partitions

Critical: database.tmdl MUST start with database object declaration, not bare properties. Bare compatibilityLevel: causes InvalidLineType: Property! errors.

model.tmdl Required Properties

model Model
 culture: en-US
 defaultPowerBIDataSourceVersion: powerBI_V3
 discourageImplicitMeasures

defaultPowerBIDataSourceVersion: powerBI_V3 is required for Import-mode models. Without it: Import from JSON supported for V3 models only.

Direct Lake Configuration

ALL partitions must use EntityPartitionSource — no M/Power Query

A named expression pointing to the Lakehouse/Warehouse must be defined before tables:

expression DL_Lakehouse =
    let
        Source = AzureStorage.DataLake("https://onelake.dfs.fabric.microsoft.com/<WorkspaceId>/<LakehouseId>", [HierarchicalNavigation=true])
    in
        Source

Each table partition references the expression:

partition Sales = entity
    mode: directLake
    source
        entityName: Sales
        schemaName: dbo
        expressionSource: DL_Lakehouse

dataType: binary columns are NOT supported in Direct Lake
Columns map directly via sourceColumn — no transforms
Calculated columns / tables (April 2026 preview): Direct Lake on OneLake now supports unmaterialized calculated columns (and calculated tables that reference them). Direct Lake on SQL still does not. User-context-aware DAX (USERCULTURE, USERPRINCIPALNAME, CUSTOMDATA, etc.) requires expressionContext: userContext on the column. See fabric-tmdl REFERENCE for the storage-mode × Expression-Context support matrix.

Reference

Microsoft Learn: Item definition overview (Fabric REST)
Microsoft Learn: SemanticModel definition envelope
Microsoft Learn: Develop Direct Lake semantic models (TMDL partition mode)
Comprehensive MS Learn link bundle (definition envelope / REST CRUD / TMDL language / required parts / Direct Lake configuration / refresh APIs): references/REFERENCE.md