connect-pbid

# Connect to Power BI Desktop (Local Analysis Services)

> **CRITICAL:** Record mistakes, surprises, and model-specific nuances encountered while using this skill in `.claude/rules/connect-pbid.md`. This file must begin with "Learnings from Claude about connecting to semantic models via the connect-pbid skill". Write only active reference notes (e.g. "QueryGroup property returns an object; access .Folder for the name string"); do not log a changelog or history of events. Omit anything already documented in the skill or its references. Keep the file under 1500 characters at all times; prune stale entries when adding new ones. Do not over-attend to this file; update it only when something genuinely unexpected is discovered.

> **Note:** No MCP server required; do not use this skill with MCP servers or CLI tools. Use this skill to execute PowerShell commands directly via Bash to connect to Power BI Desktop's local Analysis Services instance.

Expert guidance for connecting to Power BI Desktop's local tabular model via the Tabular Object Model (TOM) and ADOMD.NET in PowerShell. Covers connection, enumeration, DAX queries, query traces, and full model modification.


## When to Use This Skill

Activate only when the Tabular Editor CLI or a Power BI MCP server is unavailable. TOM is more reliable than direct TMDL editing because it validates changes against the engine and applies them atomically.

**WARNING:** This skill does NOT support remote models via the XMLA endpoint. For Direct Lake models or models hosted in Fabric, use the Tabular Editor CLI or a Power BI MCP server instead; the local Analysis Services proxy does not expose Direct Lake databases to external TOM/ADOMD.NET connections.

## Model and report: routing

Power BI Desktop exposes the model and the report as two separate local surfaces. This skill owns the model surface and report-canvas verification, and routes report authoring to the right skill:

- **Model** (tables, columns, measures, relationships, roles, calculation groups, refresh): this skill, via TOM/ADOMD over the local Analysis Services instance. For model edits, prefer the `te` CLI or a model MCP when available; fall back to this skill's TOM when they are not (see "When to Use This Skill").
- **Report-canvas verification** (reload after edits, screenshot pages): this skill, the raw Desktop Bridge named-pipe API (section 13).
- **Report authoring** (visuals, pages, formatting, filters, bookmarks, themes): the `pbir-cli` skill in the reports plugin (it drives the `pbir` CLI). The Desktop Bridge here only reloads and screenshots; it never edits visuals. Route every visual or page change to `pbir-cli`.
- **Report JSON edited directly** (only when `pbir` is unavailable): the `pbir-format` skill in the pbip plugin.

Full loop on an open PBIP: change the model with TOM here, change visuals with `pbir-cli`, then reload and screenshot with the Desktop Bridge here to verify, and iterate.


## Critical

- Power BI Desktop must be open with a model loaded before connecting; if there are errors it is likely due to a "thin report" connected to a remote model, or a Direct Lake model (which uses a remote proxy that blocks external connections)
- The local Analysis Services instance only accepts connections from `localhost`
- Multiple PBI Desktop files open means multiple `msmdsrv.exe` processes on different ports. Connect to each port, read `$server.Databases[0].Name`, and ask the user which model to work with if more than one is found. When the `pbir` CLI is installed, prefer `pbir desktop list` to map each Desktop PID to the exact file it has open (see Section 2a)
- A workspace engine reporting `Databases: 0` belongs to a thin report (live connection to a remote model); there is no local model to connect to. Query thin reports through their remote model instead (`pbir model -q` routes there automatically)
- Always use a timeout of 60000ms or higher for PowerShell commands via Bash
- **Shell escaping**: Bash eats PowerShell `$` variables (`$env:TEMP`, `$server`, etc.) silently. Two options: (1) single-quote the `-Command` arg so Bash passes `$` literally to PowerShell; (2) write a `.ps1` file with a heredoc (single-quoted delimiter preserves `$`) and use `-File`. On macOS via Parallels, the `prlctl` -> `cmd.exe` -> `powershell.exe` chain adds extra escaping layers; `.ps1` files are more reliable for complex scripts but inline `-Command` with single quotes works for short commands.
- **Always use `-ExecutionPolicy Bypass`** when running PowerShell commands or scripts. Windows blocks unsigned scripts by default.
- **Script file location** -- persistent scripts should go in the agent harness's scripts directory for the project (`.claude/scripts/`, `.github/scripts/`, `.cursor/scripts/`, `.gemini/scripts/`, etc. depending on the harness). Ephemeral or throwaway scripts should go in a project `tmp/` directory (which should be `.gitignored`). Do not write scripts to `./` root or `/tmp/`.
- Do not modify model metadata without explicit user direction
- Always call `$model.SaveChanges()` to persist modifications; without it, changes are discarded
- For macOS users running PBI Desktop in Parallels, see [parallels-macos.md](./references/parallels-macos.md)
- **Validation hooks** are active for this plugin; they validate DAX references, enforce measure metadata, check referential integrity, and report compatibility level upgrade opportunities. Toggle checks in `hooks/config.yaml`.


## 1. Prerequisites

| Requirement | Description |
|-------------|-------------|
| **Power BI Desktop** | Open with a model loaded (`.pbix` or `.pbip`) |
| **PowerShell** | Available on the machine running PBI Desktop |
| **NuGet CLI** | For package installation (`winget install Microsoft.NuGet`) |
| **TOM NuGet Package** | `Microsoft.AnalysisServices.retail.amd64` -- model metadata |
| **ADOMD.NET Package** | `Microsoft.AnalysisServices.AdomdClient.retail.amd64` -- DAX queries |

Install both packages only if