TMDL Authoring Agent Skill

Name: TMDL Authoring
Author: data-goblin

Direct TMDL file authoring and BIM-to-TMDL conversion for semantic models in PBIP projects.

Install this skill Read the source first Free Written by data-goblin

Context cost: 14.3k tokensestimated from the bundle, loaded when it triggers
Bundle: 6 of 17 fileshanded out here; the rest is at its source
Licence: GPL-3.0the author’s own terms
Last change: —no release on file
Servers it uses: Noneruns standalone

What it does

Direct TMDL file authoring and BIM-to-TMDL conversion for semantic models in PBIP projects. Automatically invoke when the user asks to "edit TMDL", "add a measure in TMDL", "TMDL syntax", "fix formatString", "fix summarizeBy", "TMDL indentation", "convert BIM to TMDL", "add a column description", "create a calculated column in TMDL", or mentions .tmdl file editing or BIM-to-TMDL migration.

What this skill changes about the agent has not been set out here as a list. Its SKILL.md, shown below, says it in the author’s own words.

database

Filed under

Databases

The skill itself

A skill is instructions the model reads, so you can see what you are getting: below is the start of its SKILL.md. The front matter loads with every session, the body loads when the skill triggers, and the whole file comes with the install.

SKILL.md21.7 kB · preview

--- name: tmdl ---

6# TMDL Authoring

8Expert guidance for authoring and editing TMDL (Tabular Model Definition Language) files directly in PBIP projects.

10> **This skill is a last resort.** Direct TMDL file editing lacks the validation, atomicity, and DAX query capabilities of the Tabular Editor CLI, Power BI MCP server, or the connect-pbid skill (TOM via PowerShell). Use those tools when available. TMDL editing is appropriate when:

11>

12> - Working with PBIP files in a Git repo without Power BI Desktop open

13> - No Tabular Editor CLI or MCP server is installed

14> - Making quick text-level fixes (descriptions, format strings, display folders) where a full tool chain is overkill

15>

16> Direct TMDL editing does not validate DAX syntax, check referential integrity, or verify that property values are valid. Errors will only surface when the model is next loaded in Power BI Desktop or deployed via XMLA. Use the **pbip-validator** agent to check TMDL files for syntax issues, indentation errors, and referential integrity before opening in PBI Desktop.

18## When to Use This Skill

20Activate only when the Tabular Editor CLI, Power BI MCP server, or connect-pbid skill are not available, and tasks involve:

22- Editing .tmdl files directly (measures, columns, tables, relationships)

23- Adding or modifying measure definitions in TMDL

24- Adding descriptions to columns, measures, or tables

This is a preview of SKILL.md. Download or install the skill to get the whole thing.

In the file

SKILL.md2,978 words

Files6

LicenceGPL-3.0

Why you can read it

Nothing in a skill executes. The client loads the text and the model follows it, so a skill can be audited the way a runbook is — by reading it.

What it costs in context

Skills are not billed by the call. They are paid for in context: every token the instructions occupy is a token your code, your diff and your conversation cannot use. Here is what this one takes and when it takes it.

≈110

always loaded

The name and description, so the model knows the skill exists and when to reach for it.

14,140

on trigger

The instruction body and 5 supporting files, read only when the skill fires.

7.1%

of a 200k window

Ten skills this size would take about 71% of the window before you open a file.

050k100k150k200k context window

14.3k tokens, estimated from the bundle at four bytes to the token, held for the rest of the session once it triggers. Heavy. Teams tend to install this one per project rather than globally, and load it only when the job comes up.

Servers bill, skills cost

A server charges by the month. A skill charges once per session, in context, and then keeps charging it for as long as the session lives.

Before and after

The same question, put to the same model twice: once as it comes, and once with these instructions loaded.

No worked example has been published for this skill yet.

The procedure it runs

The procedure has not been set out here step by step. It is in the body of its SKILL.md: the start of it is shown above, and the whole file comes with the install.

Prose, not code

These steps are written for a model to follow, not executed by a runtime. It can still be told to skip one, and it will say so when it does.

Servers it uses

None. This skill calls no MCP servers at all.

Everything it needs is in the instructions, so it works in a project with nothing connected — the model reads the file and changes how it works with what it can already reach.

Its SKILL.md does not declare which tools it asks the agent for, so what it touches is whatever the instructions themselves ask for — read them before you install it.

What it asks for

Writes filesnot declared

Network accessnot declared

This SKILL.md carries no allowed-tools line, so neither is declared. A skill grants no permissions of its own — it can only ask for tools your client already has.

What it will not do

Every skill is narrow, and the useful ones say where they stop. These are the jobs this one is the wrong tool for.

What this skill is not for has not been published here. Nothing is implied by that: it is a section the author has not filled in.

If this is not it

2114 other skills in Databases

What is in the bundle

The download carries 6 of the 17 files in its source folder; the list here names 6 files, 57.0 kB on disk. A bundle is text throughout: the instructions the model reads, plus the templates it fills in. The other 11 are not in the download, nor are 39 files of types a skill download does not carry — listed after these, with why.

SKILL.md21.7 kB
references/bim-to-tmdl.md1.4 kB
references/column-properties.md9.1 kB
references/naming-conventions.md4.5 kB
references/object-properties.md16.2 kB
references/tmdl-file-examples.md4.1 kB

Not in the download

Not carried is a type a skill download does not hold. Marked read: its SKILL.md or scripts name the file, so without it the skill works only in part. Take them from its source.

examples/SpaceParts.SemanticModel/definition/database.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/expressions.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/functions.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/model.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/perspectives/Measure Selection.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/relationships.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/roles/Account Managers.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/tables/__Measures.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/tables/Date.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/tables/Invoices.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/tables/Z04CG1 - Time Intelligence.tmdlread · not carried
examples/SpaceParts.SemanticModel/definition/cultures/en-US.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/perspectives/No Measure Selection.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/Brand VPs.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/Business Line Leaders.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/Key Account Managers.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/Station Sales Managers.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/System Regional Managers.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/System Sales Directors.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/roles/Territory Managers.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/__Demo UDFs.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/__SVGs.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/1) Selected Metric.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/2) Selected Unit.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/3) Selected Target.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/4) Selected Period.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Brands.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Budget Rate.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Budget.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Customers.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Employees.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Exchange Rate.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Forecast.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/FP - MTD.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Invoice Document Type.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Last Refresh.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/On-Time Delivery.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Order Document Type.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Order Status.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Orders.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Products.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Regions.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z01CG1 - Quantity.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z01CG2 - Value (Budget Rate).tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z01CG4 - Lines.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z02CG1 - Unit.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z03CG1 - Sales Target.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z03CG2 - Orders Target.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/Z04CG1 - Time Intelligence - UDFs.tmdlnot carried
examples/SpaceParts.SemanticModel/definition/tables/zz_ReportObjects.tmdlnot carried

What is not in it

No dependencies and nothing executable: a skill is text the agent reads, so the download is 6 files — not the whole of its source: 50 files are left out, and the skill reads 11 of them. They are listed under the files, with why. The GPL-3.0 licence covers the templates and examples as well as the instructions.

Install

Installing copies the bundle into your project. Nothing runs at install time — the files sit on disk until the model reads them.

# TMDL Authoring · 14.3k tokens when loaded · macOS, Linux
mkdir -p .claude/skills && t=$(mktemp -d) &&
  curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/tmdl-authoring/bundle.tar.gz &&
  tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/tmdl-authoring" ] &&
  { [ ! -e .claude/skills/tmdl-authoring ] || { mv .claude/skills/tmdl-authoring "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } &&
  mv "$t/tmdl-authoring" .claude/skills/ && echo "Installed .claude/skills/tmdl-authoring"

On Windows, or any OS with Node 20+

npx mcprush@latest skill add data-goblin/tmdl-authoring

Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither. Writes to .claude/skills/tmdl-authoring/ in the current project. For every project instead, run mkdir -p ~/.claude/skills && t=$(mktemp -d) && curl -fsSL -o "$t/bundle.tar.gz" https://mcprush.com/api/skills/tmdl-authoring/bundle.tar.gz && tar -xzf "$t/bundle.tar.gz" -C "$t" && [ -d "$t/tmdl-authoring" ] && { [ ! -e ~/.claude/skills/tmdl-authoring ] || { mv ~/.claude/skills/tmdl-authoring "$t/.previous" && echo "Previous copy moved to $t/.previous"; }; } && mv "$t/tmdl-authoring" ~/.claude/skills/ && echo "Installed ~/.claude/skills/tmdl-authoring" (macOS, Linux) — or add --global to the npx line. The curl line replaces .claude/skills/tmdl-authoring/ only after the download succeeds, so files left there by another skill of the same name, or by an older release, do not mix in. A copy already there is moved aside, not deleted, and the line prints where. It appears as tmdl in Gemini CLI, Codex, Copilot and Grok (its own name); Claude Code lists it by the folder name, tmdl-authoring. Not in this download: 50 files of its source, 11 of them read by its SKILL.md or scripts (the full list, and why). Take them from its source.

Which clients pick it up on their own

A skill is a folder of text. Most of these read a skills folder and pick it up without being told; the rest take the same folder another way — an upload in the app, a parameter on an API call — and then choose it by its description just the same.

Claude Code.claude/skills/

Claude DesktopCustomize › Skills

ChatGPTSkills › Create › Upload

Cursor.cursor/skills/

VS Code.github/skills/

Codex CLI.agents/skills/

Gemini CLI.gemini/skills/

Grok Build.grok/skills/

Microsoft CopilotSkills › Upload a skill

PerplexityComputer › Skills › Upload a skill

DeepSeek Harness.dsh/skills/

Zed.agents/skills/

Devin Desktop.devin/skills/

Windsurf (legacy).windsurf/skills/

OpenAI Agents SDKInstructions or sandbox Skills

HTTP / APIa request parameter

This release

Versionnot versioned

Publishedno release date on file

PriceFree

Referencedata-goblin/tmdl-authoring

Versions

Its author publishes no version number, so there is nothing here to pin to: what you install is the folder as it stands today. Instructions change more often than APIs do — a skill can be rewritten entirely without anything it depends on moving.

Pinning

Nothing to pin to: this skill carries no version number of its own. What you install is what the folder holds on the day you install it.

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Who wrote it

data-goblin

Publishes on mcprush.

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