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/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<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="Reviewed on agentmods" width="80" 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 | $0.02367 |
| Opus 5.5 | $0.00036 | $0.00947 |
| Sonnet 5.5 | $0.00018 | $0.00473 |
| Haiku 4.5 | $0.00009 | $0.00237 |
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 2d 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 — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MPS Language Aspects — Overview
Loading companion skills
Companion names in this skill are lazy dependencies: load only those relevant to the current task. If this skill came from an MCP server, use the host's skill loader to resolve the companion's unique discovered entry URI on the same host-assigned originating server. If the host has no server-backed skill loader, stop and report that limitation; do not silently fall back to a filesystem copy. If this skill came from a filesystem catalog, load the named sibling from that same catalog at <skills-root>/<skill-name>/SKILL.md, even if remote skill loaders are also available. Do not invent a tool name or server endpoint.
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 names a dedicated companion 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 (smodel), mps-collections-and-closures (collections, closures) |
| Inline node literals | — | any aspect using quotations | jetbrains.mps.lang.quotation |
mps-quotations |
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago Changed 27e78de582fc
- 8d ago Changed c314ff4d39c1
- 29d ago Changed f4815eefb415
- 1mo ago Changed 124dd1bdc7aa
- 1mo ago Changed · +4 lines 84bd42375e85
- 2mo 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 (1,666 stars, last pushed yesterday), licensed Apache-2.0. It adds 90 tokens to every session and 2,367 once invoked, about $0.0004 per session on Opus 5.5. 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.
mps-language-aspects-overview compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| mps-language-aspects-overviewJetBrains/MPS | Skill | 1.7k | yesterday | Apache-2.0 | A | 90 | Claude Code, Codex |
| langiumeclipse-langium/langium-ai | Skill | 31 | 4d ago | MIT | A | 33 | Claude Code |
| lai-gen-evalseclipse-langium/langium-ai | Skill | 31 | 4d ago | MIT | A | 42 | Claude Code |
| laieclipse-langium/langium-ai | Skill | 31 | 4d ago | MIT | A | 52 | Claude Code |
| lai-gen-descriptoreclipse-langium/langium-ai | Skill | 31 | 4d ago | MIT | A | 49 | Claude Code |
| lai-gen-mcpeclipse-langium/langium-ai | Skill | 31 | 4d ago | MIT | A | 43 | Claude Code |
| lai-gen-language-skilleclipse-langium/langium-ai | Skill | 31 | 4d ago | MIT | A | 33 | Claude Code |