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-aspect-intentions/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-aspect-intentions)<a href="https://agentmods.dev/skills/jetbrains/mps/mps-aspect-intentions"><img src="https://agentmods.dev/badge/skills/jetbrains/mps/mps-aspect-intentions.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00089 | $0.01727 |
| Opus 5 | $0.00044 | $0.00864 |
| Sonnet 5 | $0.00018 | $0.00345 |
| Haiku 4.5 | $0.00009 | $0.00173 |
Grade A, and why
mps-aspect-intentions 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 — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MPS Intentions Aspect
Intentions are user-invoked transformations shown in the Alt+Enter popup on a node. They are the canonical way to offer optional refactorings (wrap, convert, introduce, preview) alongside quick-fixes. Authoring lives in <lang>/languageModels/intentions.mps, language jetbrains.mps.lang.intentions.
Critical Directives
- Edit intention roots through MPS MCP tools (
mps_mcp_insert_root_node_from_json,mps_mcp_update_node,mps_mcp_parse_java_and_insert). Do not hand-edit serialized.mpsfiles. - The intentions model must list every language used in any block body as a used language. In particular, the
add new initialized(...)surface syntax requiresjetbrains.mps.lang.actions— add it withmps_mcp_model_used_language(kind="language"). Plain (non-NF_*) variants likeparent.role.add new(C)do not need this import. - Use
n as C(MPSSNodeTypeCastExpressionwithasCast=true) — never a Java(C) ncast. - Use
:eq:(NPEEqualsExpression) instead of==whenever either operand might benull. - The execute body runs on the EDT inside an MPS write action automatically — do not spawn threads or open dialogs that block.
descriptionFunctionruns every time the Alt+Enter popup opens — keep it cheap.- After editing, validate with
mps_mcp_check_root_node_problemson the intention root and rebuild the language before testing.
Common-Path Workflow
- Ensure an
intentionsmodel exists in the language (create withmps_mcp_create_modelandmodelName: "<lang>.intentions"— aspect IDintentions, case-sensitive, no@suffix; see aspect-model-stereotypes.md). Used languages:jetbrains.mps.lang.intentions; addjetbrains.mps.lang.actionsif you will use factory-initialized splicing. - Insert an
IntentionDeclarationroot withmps_mcp_insert_root_node_from_json(see blueprint inreferences/json-blueprints.md). Setname,forConcept, andisAvailableInChildNodesif the popup should bubble from descendants. - Fill
descriptionFunction(returns a short label String),executeFunction(the transformation), and optionallyisApplicableFunction(gate predicate) andchildFilterFunction(per-descendant filter whenisAvailableInChildNodes=true). - For multiple menu entries per blueprint use
ParameterizedIntentionDeclarationwithparamType+queryFunction; useIntentionParameterwherever you want "the current value" inside other blocks. - For wrap-the-selection transforms use
SurroundWithIntentionDeclarationand readeditorContext.getSelectedNodes(). - Validate (
mps_mcp_check_root_node_problems), rebuild the language, exercise via Alt+Enter on a sandbox instance. Headlessly: after MAKE, callmps_mcp_list_node_intentionson a sandbox node to confirm the intention is registered and shows the expected description, thenmps_mcp_apply_intention(nodeReference = <the entry's targetNode>, intentionId = <the entry's id>)to smoke-testexecuteFunction(for parameterized declarations also pass the rowdescription). Surround-with intentions are not covered by these tools.
What ships with it
7 files 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.
- 8d ago First seen · 59 lines · 89 tokens per session scan A 249f25ff731a
mps-aspect-intentions is a skill published in the GitHub repository JetBrains/MPS (1,656 stars, last pushed yesterday), licensed Apache-2.0. It adds 89 tokens to every session and 1,727 once invoked, about $0.0004 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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