MPS: Skill for Claude Code

.agents/skills/actions/SKILL.md

actions is a skill for Claude Code, Codex from JetBrains/MPS. It costs 31 tokens per session (298 once invoked), scanned A, original, Apache-2.0.

Guidelines for writing IntelliJ actions, which are commands users trigger from menus, toolbars, or keyboard shortcuts in IntelliJ-based IDEs. They cover how actions should be declared, named, translated, and connected to icons.

In plain words
What is it for?
Use it when creating or changing an IntelliJ action, including its Kotlin class, plugin.xml registration, icon, identifier, and message-bundle text.
Why use it?
Following these conventions helps actions appear correctly in the IDE and keeps their labels and descriptions maintainable. It also avoids common construction and configuration mistakes.

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 →

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/actions/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 actions

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/jetbrains/mps/actions"><img src="https://agentmods.dev/badge/skills/jetbrains/mps/actions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 298 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 $0.00031 $0.00298
Opus 5.5 $0.00012 $0.00119
Sonnet 5.5 $0.00006 $0.00060
Haiku 4.5 $0.00003 $0.00030

Measured 2mo ago against content hash 6c2c742437cb, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

actions 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 2mo 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/actions/SKILL.md · 44 lines

What it actually says

Actions

Guidelines for implementing IntelliJ actions (AnAction).

Documentation

Best Practices

  • NEVER instantiate Presentation in action constructors - Use no-argument constructors
  • Define text, description, and icon in plugin.xml - Not in constructor parameters
  • Follow the convention:
    1. Set the id attribute for the action in plugin.xml
    2. Optionally set the icon attribute if an icon is needed
    3. Set text and description in the message bundle (e.g., GitBundle.properties):
    • action.<action-id>.text=Translated Action Text
    • action.<action-id>.description=Translated Action Description

Good example:

Kotlin:

class MyAction : AnAction()

plugin.xml:

<action id="My.Action.Id"
        class="my.package.MyAction"
        icon="my.package.MyIcons.ICON"/>

Bundle.properties:

action.My.Action.Id.text=My Action
action.My.Action.Id.description=Description of my action
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. 2mo ago First seen · 44 lines · 31 tokens per session scan A 6c2c742437cb

Subscribe to this mod's changes

actions is a skill published in the GitHub repository JetBrains/MPS (1,666 stars, last pushed yesterday), licensed Apache-2.0. It adds 31 tokens to every session and 298 once invoked, about $0.0001 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.

Related

actions compared with skills from other repositories

actions next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
actionsJetBrains/MPSSkill1.7kyesterdayApache-2.0A31Claude Code, Codex
langiumeclipse-langium/langium-aiSkill314d agoMITA33Claude Code
lai-gen-evalseclipse-langium/langium-aiSkill314d agoMITA42Claude Code
laieclipse-langium/langium-aiSkill314d agoMITA52Claude 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