Add Atelier Arith Julia Development Skills (#139)

Author: terasakisatoshi

.agents/plugins/marketplace.json

@@ -78,6 +78,21 @@
       "description": "Gives coding agents the architecture, rules, and prior decisions of the repo via skills, hooks, and MCP — so new changes land where the project says they belong across Claude Code, Cursor, and Codex CLI.",
       "icon": "./plugins/archcore-ai/plugin/assets/icon.png"
     },
+    {
+      "name": "aa-jl",
+      "displayName": "Atelier Arith Julia Development Skills",
+      "source": {
+        "source": "local",
+        "path": "./plugins/AtelierArith/atelier-arith-julia-development-skills"
+      },
+      "policy": {
+        "installation": "AVAILABLE",
+        "authentication": "ON_INSTALL"
+      },
+      "category": "Development & Workflow",
+      "description": "Codex skills for Julia installation, package creation, app creation, and test workflows.",
+      "icon": "./plugins/AtelierArith/atelier-arith-julia-development-skills/assets/icon.svg"
+    },
     {
       "name": "bringyour-migration-auditor",
       "displayName": "Bring Your AI Migration Auditor",

README.md

@@ -125,6 +125,7 @@ Third-party plugins built by the community. [PRs welcome](#contributing)!
 - [AgentOps](https://github.com/boshu2/agentops) - DevOps layer for coding agents with flow, feedback, and memory that compounds between sessions.
 - [Antigravity Workspace Template](https://github.com/study8677/antigravity-workspace-template) - Multi-agent codebase knowledge graph generator with context-aware planning and automatic scope management — turns codebases into coherent agent workspaces.
 - [Archcore](https://github.com/archcore-ai/plugin) - Gives coding agents the architecture, rules, and prior decisions of the repo via skills, hooks, and MCP — so new changes land where the project says they belong across Claude Code, Cursor, and Codex CLI.
+- [Atelier Arith Julia Development Skills](https://github.com/AtelierArith/atelier-arith-julia-development-skills) - Codex skills for Julia installation, package creation, app creation, and test workflows.
 - [Bring Your AI Migration Auditor](https://github.com/unitedideas/bringyour-mcp) - Read-only Codex plugin for auditing Claude Code to Codex migrations before Codex edits code. Checks AGENTS.md/CLAUDE.md scope, hooks, MCP config, skills, secret references, and validation notes.
 - [Brooks Lint](https://github.com/hyhmrright/brooks-lint) - AI code reviews grounded in six classic engineering books — decay risk diagnostics with book citations, severity labels, and four analysis modes (PR review, architecture audit, tech debt, test quality).
 - [Changelog Forge](./plugins/mturac/changelog-forge) - Conventional commits → CHANGELOG section + semver bump.

plugins.json

@@ -2,8 +2,8 @@
   "$schema": "https://json-schema.org/draft/2020-12/schema",
   "name": "awesome-codex-plugins",
   "version": "1.0.0",
-  "last_updated": "2026-05-18",
-  "total": 80,
+  "last_updated": "2026-05-20",
+  "total": 81,
   "categories": [
     "Development & Workflow",
     "Tools & Integrations"
@@ -59,6 +59,16 @@
       "source": "awesome-codex-plugins",
       "install_url": "https://raw.githubusercontent.com/archcore-ai/plugin/HEAD/.codex-plugin/plugin.json"
     },
+    {
+      "name": "Atelier Arith Julia Development Skills",
+      "url": "https://github.com/AtelierArith/atelier-arith-julia-development-skills",
+      "owner": "AtelierArith",
+      "repo": "atelier-arith-julia-development-skills",
+      "description": "Codex skills for Julia installation, package creation, app creation, and test workflows.",
+      "category": "Development & Workflow",
+      "source": "awesome-codex-plugins",
+      "install_url": "https://raw.githubusercontent.com/AtelierArith/atelier-arith-julia-development-skills/HEAD/.codex-plugin/plugin.json"
+    },
     {
       "name": "Bring Your AI Migration Auditor",
       "url": "https://github.com/unitedideas/bringyour-mcp",

plugins/AtelierArith/atelier-arith-julia-development-skills/.codex-plugin/plugin.json

@@ -0,0 +1,30 @@
+{
+  "name": "aa-jl",
+  "version": "0.2.0",
+  "description": "Codex skills for Julia installation, package creation, app creation, and test workflows.",
+  "author": {
+    "name": "Atelier Arith",
+    "url": "https://github.com/AtelierArith"
+  },
+  "homepage": "https://github.com/AtelierArith/atelier-arith-julia-development-skills",
+  "repository": "https://github.com/AtelierArith/atelier-arith-julia-development-skills",
+  "license": "MIT",
+  "keywords": ["julia", "codex", "skills", "testing", "package-development"],
+  "skills": "./skills/",
+  "interface": {
+    "displayName": "Atelier Arith Julia Development Skills",
+    "shortDescription": "Julia development workflows for Codex.",
+    "longDescription": "A collection of Codex skills for installing Julia, generating Julia packages, creating Julia apps, creating test environments, and running Julia tests.",
+    "developerName": "Atelier Arith",
+    "category": "Developer Tools",
+    "capabilities": ["Write"],
+    "websiteURL": "https://github.com/AtelierArith/atelier-arith-julia-development-skills",
+    "composerIcon": "./assets/icon.svg",
+    "defaultPrompt": [
+      "Create a Julia package in this directory.",
+      "Add a Julia test environment.",
+      "Run the Julia test workflow."
+    ],
+    "brandColor": "#9558B2"
+  }
+}

plugins/AtelierArith/atelier-arith-julia-development-skills/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 AtelierArith
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

plugins/AtelierArith/atelier-arith-julia-development-skills/README.md

@@ -0,0 +1,112 @@
+# atelier-arith-julia-development-skills
+
+Plugin containing Julia development skills for both **Claude Code** and **Codex**.
+
+## Included Skills
+
+- `installing-julia` — install the Julia runtime
+- `generating-julia-package` — create Julia project environments and package layouts
+- `creating-julia-app` — create Julia command-line apps with `@main` and `[apps]`
+- `creating-julia-test-env` — add a Julia package test environment
+- `running-julia-test` — run standard and faster local Julia test workflows
+
+## Installation
+
+### Claude Code
+
+```sh
+/plugin marketplace add atelierarith/atelier-arith-julia-development-skills
+/plugin install aa-jl@atelier-arith-julia-development-skills
+```
+
+Session-only (no permanent install):
+
+```sh
+claude --plugin-dir /path/to/atelier-arith-julia-development-skills
+# or
+claude --plugin-url https://github.com/atelierarith/atelier-arith-julia-development-skills/archive/main.zip
+```
+
+### Codex
+
+If your Codex client supports plugins, add this repository URL in the Codex
+plugin settings. The manifest is at `.codex-plugin/plugin.json`.
+
+For local development, add this repository as a local Codex plugin marketplace
+entry. The Codex plugin name is `aa-jl`; it is intentionally short so namespaced
+skill IDs such as `aa-jl:finding-latest-julia-version` stay under Codex's
+64-character skill name limit.
+
+```sh
+git clone https://github.com/AtelierArith/atelier-arith-julia-development-skills.git ~/.codex/aa-jl
+mkdir -p ~/.agents/plugins
+python3 - <<'PY'
+import json
+from pathlib import Path
+
+marketplace = Path.home() / ".agents" / "plugins" / "marketplace.json"
+plugin_path = Path.home() / ".codex" / "aa-jl"
+entry = {
+    "name": "aa-jl",
+    "source": {"source": "local", "path": str(plugin_path)},
+    "policy": {"installation": "AVAILABLE", "authentication": "ON_INSTALL"},
+    "category": "Developer Tools",
+}
+
+if marketplace.exists():
+    data = json.loads(marketplace.read_text())
+else:
+    data = {
+        "name": "local-codex-plugins",
+        "interface": {"displayName": "Local Codex Plugins"},
+        "plugins": [],
+    }
+
+data["plugins"] = [p for p in data.get("plugins", []) if p.get("name") != "aa-jl"]
+data["plugins"].append(entry)
+marketplace.write_text(json.dumps(data, indent=2) + "\n")
+PY
+```
+
+Then install `aa-jl` from the local Codex plugin marketplace and restart Codex
+so it reloads the skill list.
+
+## Repository Structure
+
+```
+.
+├── .claude-plugin/
+│   ├── plugin.json       # Claude Code plugin manifest
+│   └── marketplace.json  # Claude Code marketplace manifest (references this repo)
+├── .codex-plugin/
+│   └── plugin.json       # Codex plugin manifest
+├── AGENTS.md
+├── CLAUDE.md
+├── LICENSE
+├── README.md
+├── plans/
+└── skills/
+    ├── creating-julia-app/
+    │   └── SKILL.md
+    ├── creating-julia-test-env/
+    │   └── SKILL.md
+    ├── generating-julia-package/
+    │   └── SKILL.md
+    ├── installing-julia/
+    │   └── SKILL.md
+    └── running-julia-test/
+        └── SKILL.md
+```
+
+## Adding a New Skill
+
+1. Create `skills/<skill-name>/SKILL.md` with YAML frontmatter:
+
+   ```markdown
+   ---
+   name: <skill-name>
+   description: Use when ...
+   ---
+   ```
+
+2. Bump `version` in `.claude-plugin/plugin.json`, `.claude-plugin/marketplace.json`, and `.codex-plugin/plugin.json`.

plugins/AtelierArith/atelier-arith-julia-development-skills/assets/icon.svg

@@ -0,0 +1,50 @@
+---
+name: creating-julia-app
+description: Use when you create a CLI written in Julia packages or MCP servers
+---
+
+# Creating a Julia app
+
+Apps are Julia packages that are intended to be run as "standalone programs" (by e.g. typing the name of the app in the terminal possibly together with some arguments or flags/options). This is in contrast to most Julia packages that are used as "libraries" and are loaded by other files or in the Julia REPL.
+
+A Julia app is structured similar to a standard Julia library with the following additions:
+
+A `@main` entry point in the package module (see the Julia help on `@main` for details)
+An `[apps]` section in the `Project.toml` file listing the executable names that the package provides.
+A very simple example of an app that prints the reversed input arguments would be:
+
+```julia
+# src/MyReverseApp.jl
+module MyReverseApp
+
+function (@main)(ARGS)
+    for arg in ARGS
+        print(stdout, reverse(arg), " ")
+    end
+    return
+end
+
+end # module
+```
+
+```toml
+# Project.toml
+
+# standard fields here
+
+[apps]
+reverse = {}
+```
+
+The empty table `{}` is to allow for giving metadata about the app.
+
+After installing this app one could run:
+
+```
+$ ~/.julia/bin/reverse some input string
+ emos tupni gnirts
+```
+
+directly in the terminal. See the following link to learn more:
+
+- [Multiple Apps per Package](https://pkgdocs.julialang.org/v1/apps/#Multiple-Apps-per-Package)

plugins/AtelierArith/atelier-arith-julia-development-skills/skills/creating-julia-app/SKILL.md

@@ -0,0 +1,88 @@
+---
+name: creating-julia-test-env
+description: Use when you add tests for Julia packages
+---
+
+# creating-julia-test-env
+
+A minimal Julia package layout looks like this:
+
+```sh
+$ tree
+.
+├── Project.toml
+└── src
+    └── MyPkg.jl # Assume the package is named MyPkg for this example.
+
+```
+
+To add software tests for this package, follow the steps below.
+
+Step 1: Create the `test` directory, `runtests.jl`, and a `Project.toml` for the test environment.
+
+```sh
+mkdir test
+touch test/runtests.jl
+touch test/Project.toml
+```
+
+Step 2: Add a `[workspace]` section to `./Project.toml` (not `test/Project.toml`):
+
+```toml
+name = "MyPkg"
+
+...
+...<omitted>
+...
+
+# Add this section
+[workspace]
+projects = ["test"]
+```
+
+---
+
+**Note:** If you are on Julia 1.11 or older, do **not** use `[workspace]`. Instead, add `[extras]` and `[targets]`:
+
+```toml
+[extras]
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[targets]
+test = ["Test"]
+```
+
+Step 3: Set up `./test/Project.toml` as follows:
+
+```sh
+$ cd test
+$ ls
+runtests.jl Project.toml
+$ julia --project -e 'using Pkg; Pkg.add("Test")'
+$ julia --project -e 'using Pkg; Pkg.develop(path="../")'
+$ cat Project.toml
+[deps]
+MyPkg = <UUID for MyPkg goes here>
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[sources]
+MyPkg = {path = ".."}
+```
+
+Step 4: Put a simple sample test in `test/runtests.jl` (replace `MyPkg` with your actual package name).
+
+```julia
+using Test
+
+using MyPkg
+
+@testset "sample" begin
+    @test 1 + 1 == 2
+end
+```
+
+Step 5: Run the following to verify:
+
+```sh
+$ julia --project -e 'using Pkg; Pkg.test()'
+```