mdl-entities

A complete syntax reference for Mendix Domain Language, the language used to define data entities, their fields, and relationships. It covers stored, temporary, and calculated data models.

In plain words
What is it for?
Use it when creating or changing Mendix domain models, including business data, temporary data, calculated views, attributes, and associations.
Why use it?
It reduces errors when exact entity types, field formats, names, or relationship syntax are required.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/mendixlabs/mxcli/mdl-entities
Any agent
npx skills add mendixlabs/mxcli --skill mdl-entities
Clone the repo
git clone --depth 1 https://github.com/mendixlabs/mxcli

Made for: Claude Code, Codex.

Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,267 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00039 $0.02267
Opus 5 $0.00019 $0.01133
Sonnet 5 $0.00008 $0.00453
Haiku 4.5 $0.00004 $0.00227

Measured yesterday against content hash 1a640a0aa99f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mdl-entities scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/mendix/mdl-entities/SKILL.md · 378 lines

How it starts

The opening of the file, as written. The whole thing — 378 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MDL Entity Syntax Reference

Complete syntax reference for creating entities, attributes, and associations.

Entity Types

Type Keyword Stored in DB Use Case
Persistent create persistent entity Yes Business data
Non-Persistent create non-persistent entity No Temporary/view data
View create view entity No (OQL query) Aggregated/computed data

Persistent Entity

/**
 * Customer entity for storing customer data
 */
create persistent entity Module.Customer (
  -- String attributes
  Name: string(100) not null,
  Email: string(200),
  Code: string(20) unique,

  -- Numeric attributes
  Age: integer,
  CreditLimit: decimal,

  -- Boolean
  IsActive: boolean default true,

  -- Date/Time
  BirthDate: date,
  -- Use autocreateddate (not datetime) to record when the object was created.
  -- 'CreatedDate' as a plain datetime triggers lint error MDL020.
  CreatedDate: autocreateddate,

  -- Enumeration
  status: Module.CustomerStatus default Active,

  -- Auto-number (REQUIRES a seed via `default N` — without it the build fails
  -- CE7247 "Value cannot be empty")
  CustomerNumber: autonumber default 1
);
/

Non-Persistent Entity

Used for temporary data, form parameters, or calculated values.

/**
 * Search parameters for customer search form
 */
create non-persistent entity Module.CustomerSearchParams (
  SearchName: string(100),
  SearchEmail: string(200),
  MinCreditLimit: decimal,
  IncludeInactive: boolean default false
);
/

Attribute Types

Type Syntax Example
String Name: string(length) Name: string(100)
Integer Name: integer count: integer
Long Name: long BigNumber: long
Decimal Name: decimal Amount: decimal
Boolean Name: boolean IsActive: boolean
DateTime Name: datetime CreatedAt: datetime
Date Name: date BirthDate: date
Enumeration Name: Module.EnumName status: Module.Status
AutoNumber Name: autonumber default 1 Code: autonumber default 1 (seed required)
Binary Name: binary FileData: binary
Hashed String Name: hashedstring password: hashedstring

Read the full file on GitHub · 378 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 378 lines · 39 tokens per session scan A 1a640a0aa99f

Subscribe to this mod's changes

mdl-entities is a skill published in the GitHub repository mendixlabs/mxcli (115 stars, last pushed 2d ago), licensed Apache-2.0. It adds 39 tokens to every session and 2,267 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.