agentmods.dev

MPS: Skill for Claude Code

.agents/skills/mps-lang-core-xml/SKILL.md

mps-lang-core-xml is a skill for Claude Code, Codex from JetBrains/MPS. It costs 80 tokens per session (1,097 once invoked), scanned A, original, Apache-2.0.

An MPS language for writing XML documents and XML-generating templates inside JetBrains MPS. XML is a text format commonly used for structured data and configuration.

In plain words
What is it for?
Use it to author XML files in MPS or build generator templates containing XML elements, attributes, CDATA, entity references, processing instructions, and template substitutions.
Why use it?
It provides the model structure needed to represent XML documents correctly, including declarations, elements, attributes, comments, and generated-code macros.

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 +4 changed 1mo ago A scan SkillSpector: pass 80 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 · 1,666 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-lang-core-xml/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-lang-core-xml

README.md
[![agentmods](https://agentmods.dev/badge/skills/jetbrains/mps/mps-lang-core-xml/github.svg)](https://agentmods.dev/skills/jetbrains/mps/mps-lang-core-xml)
Your own site
<a href="https://agentmods.dev/skills/jetbrains/mps/mps-lang-core-xml"><img src="https://agentmods.dev/badge/skills/jetbrains/mps/mps-lang-core-xml/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.

agentmods 80×15 button for mps-lang-core-xml

Your own site · 80×15
<a href="https://agentmods.dev/skills/jetbrains/mps/mps-lang-core-xml"><img src="https://agentmods.dev/badge/skills/jetbrains/mps/mps-lang-core-xml.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,097 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 $0.00080 $0.01097
Opus 5.5 $0.00032 $0.00439
Sonnet 5.5 $0.00016 $0.00219
Haiku 4.5 $0.00008 $0.00110

Measured 1mo ago against content hash f0d805f9aa37, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mps-lang-core-xml 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 1mo 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-lang-core-xml/SKILL.md · 48 lines

How it starts

The opening of the file, as written. The whole thing — 48 lines — stays where its author put it; the contents beside it link to each section on GitHub.

jetbrains.mps.core.xml Language

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.

jetbrains.mps.core.xml is an MPS language for authoring and generating XML documents inside MPS models. It is used either for direct XML authoring (an XmlFile root holds a complete document) or for generator templates (an XmlFile carries RootTemplateAnnotation and macros via smodelAttribute child roles).

Language reference: l:479c7a8c-02f9-43b5-9139-d910cb22f298:jetbrains.mps.core.xml

Critical Directives

  • Wrap everything in XmlFile → XmlDocument. XmlFile is the only rootable concept. XmlDocument.rootElement has cardinality 1 — put the root there, not in content.
  • XmlProlog is optional (0..1). Omit it entirely when no prolog is needed.
  • Attribute values are lists of XmlValuePart. A plain string is a single XmlTextValue. An attribute with no value children renders as a valueless (boolean) attribute.
  • Property name asymmetry: XmlText / XmlSingleLineText use the property value. XmlTextValue (attribute value part) uses the property text. Do not swap them.
  • In generators, macros go in the smodelAttribute child role of the node they annotate — not as siblings in content or attributes.
  • Subclass the base types. Extend XmlBaseAttribute (not XmlAttribute) and XmlBaseElement (not XmlElement) when defining custom concepts for derived languages.
  • Do not hand-edit serialized .mps files. Use MPS MCP node tools for all changes.

Read the full file on GitHub · 48 lines

Files

What ships with it

4 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. 1mo ago Changed · +4 lines f0d805f9aa37
  2. 2mo ago First seen · 44 lines · 80 tokens per session scan A b76d4c2ace3b

Subscribe to this mod's changes

mps-lang-core-xml is a skill published in the GitHub repository JetBrains/MPS (1,666 stars, last pushed yesterday), licensed Apache-2.0. It adds 80 tokens to every session and 1,097 once invoked, about $0.0003 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.

Languagesdomain-specific-languagedsl
Related

mps-lang-core-xml compared with skills from other repositories

mps-lang-core-xml next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
mps-lang-core-xmlJetBrains/MPSSkill1.7kyesterdayApache-2.0A80Claude Code, Codex
langiumeclipse-langium/langium-aiSkill314d agoMITA33Claude Code
lai-gen-descriptoreclipse-langium/langium-aiSkill314d agoMITA49Claude Code
lai-gen-mcpeclipse-langium/langium-aiSkill314d agoMITA43Claude Code
lai-gen-language-skilleclipse-langium/langium-aiSkill314d agoMITA33Claude Code
triton-syntaxmindspore-ai/akgSkill2652d agoApache-2.0A21Claude Code, Codex
triton-ascendmindspore-ai/akgSkill2652d agoApache-2.0A28Claude Code, Codex