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MPS: Skill for Claude Code

.agents/skills/mps-quotations/SKILL.md

mps-quotations is a skill for Claude Code, Codex from JetBrains/MPS. It costs 127 tokens per session (2,061 once invoked), scanned A, original, Apache-2.0.

A guide to quotations and anti-quotations in JetBrains MPS, where code-like notation creates or inserts tree-shaped language-model objects. It covers using literal model structures and placing calculated values inside them.

In plain words
What is it for?
Use it when writing or debugging MPS behavior, type-system, intention, or generator code that builds model nodes with quotations and anti-quotations.
Why use it?
It explains rules that prevent common mistakes, such as confusing a model node with a constructor call or inserting a value in the wrong place. These details matter when generating or manipulating MPS models.

Skill for Claude CodeCodex ✓ vendor

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is JetBrains/MPS's own configuration. It tells Claude Code and Codex how to work on MPS itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything MPS configures →

not rated 1.7krepo +2 today A scan SkillSpector: pass 127 tokens original Apache-2.0
View source ↗ JetBrains/MPS jetbrains.com
About the project

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.

JetBrains/MPS · 1,657 stars · on GitHub · jetbrains.com

Reuse

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.

Copy the file
curl -O https://raw.githubusercontent.com/JetBrains/MPS/master/.agents/skills/mps-quotations/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/JetBrains/MPS

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for mps-quotations

README.md
[![agentmods](https://agentmods.dev/badge/skills/jetbrains/mps/mps-quotations.svg)](https://agentmods.dev/skills/jetbrains/mps/mps-quotations)
Your own site
<a href="https://agentmods.dev/skills/jetbrains/mps/mps-quotations"><img src="https://agentmods.dev/badge/skills/jetbrains/mps/mps-quotations.svg" alt="Measured on agentmods" height="20"></a>
Per session 127 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,061 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00127 $0.02061
Opus 5 $0.00063 $0.01030
Sonnet 5 $0.00025 $0.00412
Haiku 4.5 $0.00013 $0.00206

Measured 8d ago against content hash a7cb75520650, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

mps-quotations 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.

.agents/skills/mps-quotations/SKILL.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MPS Quotations and Anti-quotations

A quotation is a node literal — a concise expression that evaluates to an SNode (or tree of SNodes) at runtime. Instead of building nodes manually via the smodel API, you write the desired structure in the target language syntax and let MPS wrap it. Anti-quotations ("antiquotations") are escape holes inside a quotation where a runtime expression is spliced in.

Required used language: jetbrains.mps.lang.quotation (UUID 3a13115c-633c-4c5c-bbcc-75c4219e9555)

Critical Directives

  • Quotations do not call behavior constructors. Using <Car()> produces an SNode of concept Car without running its constructor. Use new node<Car>() (smodel API) when you need the constructor to run.
  • Use the concept identifier inside a quotation, not an alias. Write <IntegerType>, not <int>.
  • All four anti-quotation kinds attach via the inherited smodelAttribute role on any BaseConcept. The anti-quotation node is a sibling attribute of the host node, not a replacement child. The runtime substitution happens during materialisation. See references/antiquotations.md.
  • ListAntiquotation constraint: the list role must contain at least one placeholder child before you can activate a list antiquotation. The placeholder is replaced at runtime with zero-or-more nodes.
  • PropertyAntiquotation.propertyId and ReferenceAntiquotation.linkId are filled in automatically by MPS when you type $ / ^ in a property/reference cell. Do not construct these encoded ids manually unless you have already verified the exact language-uuid/concept-id/property-or-link-id form against the running MPS. See references/property-and-reference-ids.md.
  • Prefer heavy quotation (<...>) for readability; switch to light quotation (NodeBuilder) only for bootstrapping (the target language can't be a used language), for generators-of-generators, or when nesting depth makes embedded syntax unreadable. See references/heavy-vs-light.md.
  • The deprecated NodeBuilderInitLink.expression (cardinality 0..1) was removed in 2019.2. Use initValue with a NodeBuilderExpression instead.
  • Edit quotation-bearing models through MPS MCP tools (mps_mcp_insert_root_node_from_json, mps_mcp_update_node). Do not hand-edit .mps files.
  • Validate with mps_mcp_check_root_node_problems; quotations frequently expose missing used-languages on the host model (the quoted concept's language must be a used language, not just a dependency).

Read the full file on GitHub · 72 lines

Files

What ships with it

11 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.

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. 8d ago First seen · 72 lines · 127 tokens per session scan A a7cb75520650

Subscribe to this mod's changes

mps-quotations is a skill published in the GitHub repository JetBrains/MPS (1,657 stars, last pushed today), licensed Apache-2.0. It adds 127 tokens to every session and 2,061 once invoked, about $0.0006 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.

domain-specific-languagedsl
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