JetBrains MPS is a development environment for creating domain-specific languages, which are programming languages designed for a particular field or task. It provides editors with features such as completion, semantic checks, and type checking, and can generate code in languages including Java and XML.
Borrowing it
Nothing to install: this file belongs to JetBrains/MPS. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/JetBrains/MPS/master/.agents/skills/mps-language-aspects-overview/SKILL.mdgit clone --depth 1 https://github.com/JetBrains/MPSWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/jetbrains/mps/mps-language-aspects-overview)<a href="https://agentmods.dev/skills/jetbrains/mps/mps-language-aspects-overview"><img src="https://agentmods.dev/badge/skills/jetbrains/mps/mps-language-aspects-overview.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Prompt Injection · line 13 Subtle instructions detected that may alter agent decision-making or introduce hidden biases.Fix: Review content for implicit steering or bias. Ensure instructions are explicit and align with the skill's stated purpose.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00090 | $0.02260 |
| Opus 5 | $0.00045 | $0.01130 |
| Sonnet 5 | $0.00018 | $0.00452 |
| Haiku 4.5 | $0.00009 | $0.00226 |
Grade A, and why
mps-language-aspects-overview 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 8d ago.
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.
How it starts
The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MPS Language Aspects — Overview
An MPS language is a collection of aspects, each a separate model inside the language module. Together they define syntax, semantics, UI, and output. Edit each aspect through its own language (its DSL). This skill is the router; each aspect links to a dedicated skill.
Critical Directives
- Always prefer MPS MCP tools over hand-editing
.mpsXML. Hand edits can silently corrupt model files. - Keep aspect rules thin and declarative — push logic into behavior methods, then call them from any aspect.
- When something in a consumer is wrong, re-check the root cause on the language side (structure / generator / typesystem) before patching generated Java.
- Choose a modularity strategy before authoring when this language must relate to others — reference, extend, embed, or adapt them. The kind you pick (referencing / extension / reuse / embedding) changes how you use structure, constraints, typesystem, and generator. See
mps-language-modularity.
Aspects and Where to Find Detailed Guidance
| Aspect | Aspect ID / Stereotype | Model file | Language DSL | Detailed skill |
|---|---|---|---|---|
| Structure | structure |
models/structure.mps |
jetbrains.mps.lang.structure |
mps-aspect-structure-concepts |
| Editor | editor |
models/editor.mps |
jetbrains.mps.lang.editor |
mps-aspect-editor, mps-aspect-editor-menus-and-keymaps |
| Constraints | constraints |
models/constraints.mps |
jetbrains.mps.lang.constraints |
mps-aspect-constraints |
| Behavior | behavior |
models/behavior.mps |
jetbrains.mps.lang.behavior |
mps-aspect-behavior |
| Typesystem & Checking | typesystem |
models/typesystem.mps |
jetbrains.mps.lang.typesystem |
mps-aspect-typesystem |
| Intentions | intentions |
models/intentions.mps |
jetbrains.mps.lang.intentions |
mps-aspect-intentions |
| Actions | actions |
models/actions.mps |
jetbrains.mps.lang.actions |
mps-aspect-actions |
| Generator | @generator (stereotype) |
generator/template/[email protected] |
jetbrains.mps.lang.generator |
mps-aspect-generator |
| TextGen | textGen |
models/textGen.mps |
jetbrains.mps.lang.textGen |
mps-aspect-textgen |
| Dataflow | dataFlow (camelCase) |
models/dataFlow.mps |
jetbrains.mps.lang.dataFlow |
mps-aspect-dataflow |
| Migrations | migration |
models/migration.mps |
jetbrains.mps.lang.migration |
mps-aspect-migrations |
| Enhancement scripts | scripts |
models/scripts.mps |
jetbrains.mps.lang.script |
mps-aspect-migrations |
| Find Usages | findUsages (camelCase) |
models/findUsages.mps |
jetbrains.mps.lang.findUsages |
— |
| Refactorings | refactorings |
models/refactorings.mps |
jetbrains.mps.lang.refactoring |
— |
| IDE plugin | plugin |
models/plugin.mps |
jetbrains.mps.lang.plugin |
mps-ide-plugin |
| Feedback | feedback |
models/feedback.mps |
jetbrains.mps.lang.feedback |
— |
| Accessories / Dependencies | — (no model created) | .mpl and per-model |
— | mps-aspect-accessories |
| Code inside bodies | — | any aspect that holds BL | baseLanguage, smodel, collections, closures |
mps-model-manipulation |
| Inline node literals | — | any aspect using quotations | jetbrains.mps.lang.quotation |
mps-quotations |
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.
- 8d ago First seen · 97 lines · 90 tokens per session scan A b1518805edd7
mps-language-aspects-overview is a skill published in the GitHub repository JetBrains/MPS (1,657 stars, last pushed today), licensed Apache-2.0. It adds 90 tokens to every session and 2,260 once invoked, about $0.0005 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.
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