GitHub - JarrodAI/asd-ste100-plugin: Your AI agent writes to you in ASD-STE100 Simplified Technical English. Plugin for Claude Code, Codex, OpenCode, Copilot, Antigravity, Kiro, VS Code.

 █████╗ ███████╗██████╗       ███████╗████████╗███████╗ ██╗ ██████╗  ██████╗
██╔══██╗██╔════╝██╔══██╗      ██╔════╝╚══██╔══╝██╔════╝███║██╔═████╗██╔═████╗
███████║███████╗██║  ██║█████╗███████╗   ██║   █████╗  ╚██║██║██╔██║██║██╔██║
██╔══██║╚════██║██║  ██║╚════╝╚════██║   ██║   ██╔══╝   ██║████╔╝██║████╔╝██║
██║  ██║███████║██████╔╝      ███████║   ██║   ███████╗ ██║╚██████╔╝╚██████╔╝
╚═╝  ╚═╝╚══════╝╚═════╝       ╚══════╝   ╚═╝   ╚══════╝ ╚═╝ ╚═════╝  ╚═════╝

██████╗ ██╗     ██╗   ██╗ ██████╗ ██╗███╗   ██╗
██╔══██╗██║     ██║   ██║██╔════╝ ██║████╗  ██║
██████╔╝██║     ██║   ██║██║  ███╗██║██╔██╗ ██║
██╔═══╝ ██║     ██║   ██║██║   ██║██║██║╚██╗██║
██║     ███████╗╚██████╔╝╚██████╔╝██║██║ ╚████║
╚═╝     ╚══════╝ ╚═════╝  ╚═════╝ ╚═╝╚═╝  ╚═══╝

Your AI agent writes to you like an aircraft maintenance manual.

Short sentences. One action per step. One term per object. The key result first.

Claude Code · Codex · Copilot CLI · OpenCode · Antigravity · Kiro · VS Code · AGENTS.md

Turn it on or off at any time. Type asd off or asd on.

Article · Install · On and off · The rules · Limits

What it does

ASD-STE100 is an international standard for controlled natural language. It was created to make aerospace and defense maintenance documentation clear and unambiguous.

This plugin loads a rules file at the start of every agent session. The agent then writes all prose to you in that style.

It is built for a supervisor. You do not have time to read long text. You must find the key result fast, find every question fast, and know how serious each problem is.

Andrej Karpathy suggested this idea on 2 October 2026. He asked language models to write in ASD-STE100, and said the output is "a lot more readable". Read the Article for the full story.

Before and after

Before

I noticed that there might potentially be a problem with how the config is being loaded, which could possibly cause some issues down the line, so it may be worth taking a look when you get a chance.

After

Result: The config file does not load.

Severity: medium.

Cause: The path conf/app.json does not exist.

Action: Create the file, or change the path.

This example is illustrative. It is not a recorded log.

Turn it on and off

You can switch the mode at any time. Type one of these in the chat:

You type	Result
`asd off`	The agent writes normally.
`asd on`	The agent writes in ASD-STE100 again.

stop asd-ste100, start asd-ste100, and normal mode also work.

The agent confirms with one line: ASD-STE100 mode: off. or ASD-STE100 mode: on.

Does the switch stay after you close the session?

Tool	Chat switch	Stays after restart
Claude Code, Codex, Copilot CLI	`asd off` / `asd on`	Yes. A hook saves the switch.
OpenCode	`asd off` / `asd on`	Use the terminal switch below.
Kiro, VS Code, Antigravity, `AGENTS.md`	`asd off` / `asd on` (current session)	No. To remove it, run the `--remove` command below.

Terminal switch. It works for the plugin installs (Claude Code, Codex, Copilot CLI, OpenCode). It takes effect in new sessions.

npx @threegroup/asd-ste100-plugin off
npx @threegroup/asd-ste100-plugin on
npx @threegroup/asd-ste100-plugin status

Remove the rule file (Kiro, VS Code, Antigravity, AGENTS.md). Run it in your project:

npx @threegroup/asd-ste100-plugin kiro --remove
npx @threegroup/asd-ste100-plugin vscode --remove
npx @threegroup/asd-ste100-plugin antigravity --remove
npx @threegroup/asd-ste100-plugin agents --remove

--remove deletes the file the installer made. For a shared file such as AGENTS.md, it removes only the block that the installer added.

Disable in the tool. Claude Code also has /plugin disable asd-ste100-plugin@asd-ste100-plugin and /plugin enable asd-ste100-plugin@asd-ste100-plugin.

The saved switch is one empty file: ~/.asd-ste100/off. If the file exists, the mode is off.

Install

node must be on your PATH. The Claude Code, Codex, and Copilot hooks need it. The skill still loads without node, but the always-on activation stays quiet.

Tool	Method	Always-on
Claude Code	Plugin	Yes, session-start hook
Codex	Plugin	Yes, session-start hook
GitHub Copilot CLI	Plugin	Yes, session-start hook
OpenCode	Plugin	Yes, system-prompt transform
Antigravity CLI	Extension	Yes, context file
Antigravity IDE	Rule file	Yes
Kiro IDE and CLI	Steering file	Yes, `inclusion: always`
VS Code	Instructions file	Yes
Other tools	`AGENTS.md`	Yes

Install with npm

The npm package is @threegroup/asd-ste100-plugin. Node.js 18 or later is required.

What npm can install

Tool	npm method
OpenCode	Yes. Add the package name to `opencode.json`.
Kiro IDE and CLI	Yes. Run the installer: `npx @threegroup/asd-ste100-plugin kiro`
Antigravity IDE	Yes. Run the installer: `npx @threegroup/asd-ste100-plugin antigravity`
VS Code	Yes. Run the installer: `npx @threegroup/asd-ste100-plugin vscode`
Any `AGENTS.md` tool	Yes. Run the installer: `npx @threegroup/asd-ste100-plugin agents`
Claude Code	No. Use the plugin install below.
Codex	No. Use the plugin install below.
Copilot CLI	No. Use the plugin install below.

Claude Code, Codex, and Copilot CLI install plugins from a GitHub marketplace. The npm package does not install into them.

Run once with npx (no install):

cd your-project
npx @threegroup/asd-ste100-plugin kiro

Install globally (then run from any folder):

npm install -g @threegroup/asd-ste100-plugin
cd your-project
asd-ste100-plugin vscode

Installer targets

Target	File written	Tools
`kiro`	`.kiro/steering/asd-ste100.md`	Kiro IDE, Kiro CLI
`antigravity`	`.agents/rules/asd-ste100.md`	Antigravity IDE
`vscode`	`.github/copilot-instructions.md`	VS Code, GitHub Copilot
`opencode` or `agents`	`AGENTS.md`	OpenCode, and any tool that reads `AGENTS.md`

Add --global to the kiro target to write to ~/.kiro/steering/ for all projects.

OpenCode with npm. Add the package to opencode.json. OpenCode installs it at startup:

{ "plugin": ["@threegroup/asd-ste100-plugin"] }

Update. Run npm install -g @threegroup/asd-ste100-plugin@latest, then run the installer target again. A repeat run does not duplicate a block in a shared file.

Claude Code

Send these two commands as two separate prompts:

/plugin marketplace add JarrodAI/asd-ste100-plugin

/plugin install asd-ste100-plugin@asd-ste100-plugin

The same steps work in the Claude Code desktop app.

Codex

codex plugin marketplace add JarrodAI/asd-ste100-plugin
codex plugin add asd-ste100-plugin@asd-ste100-plugin

Run codex.
Open /hooks.
Trust the session-start hook.
Start a new thread.

GitHub Copilot CLI

copilot plugin marketplace add JarrodAI/asd-ste100-plugin
copilot plugin install asd-ste100-plugin@asd-ste100-plugin

OpenCode

Clone the repository:

git clone https://github.com/JarrodAI/asd-ste100-plugin

Add the plugin file to opencode.json. Use the absolute path:

{ "plugin": ["/absolute/path/to/asd-ste100-plugin/.opencode/plugins/asd-ste100.mjs"] }

To skip the clone, use the npm package. See Install with npm.

The plugin adds the rules to the system prompt on every turn. It also registers the skill.

Antigravity CLI

agy plugin install https://github.com/JarrodAI/asd-ste100-plugin

This uses gemini-extension.json, which loads AGENTS.md as always-on context.

Antigravity IDE

Run this in your project. It writes .agents/rules/asd-ste100.md.

npx @threegroup/asd-ste100-plugin antigravity

Kiro IDE and Kiro CLI

Run this in your project. It writes .kiro/steering/asd-ste100.md with inclusion: always.

npx @threegroup/asd-ste100-plugin kiro

For all projects, add --global. It writes to ~/.kiro/steering/.

A Kiro CLI custom agent does not load steering files by default. Add this line to the resources field of the agent:

"file://.kiro/steering/asd-ste100.md"

VS Code

Run this in your project. It writes .github/copilot-instructions.md, or adds a marked block if the file exists.

npx @threegroup/asd-ste100-plugin vscode

Other tools

Any tool that reads AGENTS.md:

npx @threegroup/asd-ste100-plugin agents

The installer never overwrites a shared file. It adds a block that starts with . It adds the block once only.

The rules

All rules are in skills/asd-ste100/SKILL.md.

#	Rule
1	Write short, direct sentences. One idea in each sentence.
2	Procedure sentences: 20 words or fewer. Other sentences: 25 words or fewer.
3	Use the active voice. Use the imperative for instructions.
4	Put the key result in the first line.
5	Write one action in each procedure step. Number the steps.
6	Put a warning before the step it applies to.
7	Use one term for one object. Never change the term. Never use a synonym.
8	Use a word in one meaning and one part of speech only.
9	Use simple words and articles. Do not use contractions.
10	One topic and six sentences or fewer in each paragraph.
11	No polite filler, apology, or recap.

Questions. Every question starts with Question:. You find every request for your input in one glance.

Observations. Every observation has three parts: what the agent saw, a severity, and a recommended action.

Severity	Meaning
High	Work stops, data is lost, or security is at risk.
Medium	The result is wrong or incomplete, but work continues.
Low	The result is correct, but there is a possible improvement.

The agent does not use "high" for a risk that is only possible. It states what must be true for the risk to occur.

Scope. The rules apply to prose written to you. They do not apply to code, commands, file content, or quoted output.

How it works

              skills/asd-ste100/SKILL.md      <- the only file you edit
                         |
        +----------------+-------------------+
        |                                    |
   runtime read                         scripts/sync.js
        |                                    |
  +-----+------+                  +----------+-----------+-----------+
  |            |                  |          |           |           |
hooks/     .opencode/        AGENTS.md  .agents/rules/  .kiro/     .github/
activate.js  plugins/                                  steering/  copilot-
  |          asd-ste100.mjs                                       instructions.md
  |            |
SessionStart   system-prompt
(Claude Code,  transform
 Codex,        (OpenCode)
 Copilot)

Prompt hook. hooks/toggle.js watches for asd on and asd off. It saves the switch in ~/.asd-ste100/off and tells the agent the new mode.
Session-start hook. hooks/activate.js reads the rules and prints them as hidden context. Claude Code and Codex get hookSpecificOutput.additionalContext. Copilot gets additionalContext. The hook runs on startup, resume, clear, and compact, so the rules survive a context reset.
OpenCode plugin. .opencode/plugins/asd-ste100.mjs adds the rules to the system prompt on every turn. It also adds the skills/ folder to the skill search path.
Static rule files. Tools with no hook system load a rule file. scripts/sync.js generates these files from the skill file. A test fails if a copy is out of date.

Stop, change, or remove it

Turn it off or on. See Turn it on and off.

Change the rules.

Edit skills/asd-ste100/SKILL.md.
Run npm run sync.
Run npm test.

Remove it.

Tool	Command
Claude Code	`/plugin uninstall asd-ste100-plugin@asd-ste100-plugin`
Codex	`codex plugin remove asd-ste100-plugin`
Copilot CLI	`copilot plugin uninstall asd-ste100-plugin`
OpenCode	Remove the entry from `opencode.json`.
`npx` installs	Delete the file that the installer printed. For a shared file, delete the block that starts at `<!-- asd-ste100-plugin -->`.

Limits

This is a style instruction. It is not a certified STE checker. The plugin does not include the full ASD-STE100 approved dictionary. It does not check output against the standard. The ASD-STE100 maintainers state that no tool can replace a trained writer.
Readable is not correct. A short sentence can be wrong. Verify the claims of the agent.
A model can look like STE without following STE. Expect drift in long sessions. The session-start hook reloads the rules on resume and compact.
Not every install is tested. See the table below.

Tool	Status
Claude Code	Manifest validated. Plugin tested in a live session.
Codex	Plugin install tested in a temporary Codex home.
OpenCode	Plugin unit-tested. Not tested in a live session.
Copilot CLI	Not tested.
Antigravity CLI and IDE	Not tested.
Kiro IDE and CLI	Not tested. Steering format follows the Kiro documentation.
VS Code	Not tested. Format follows the Copilot instructions convention.

FAQ

Why not paste the instruction into the chat? It works for a short time. The model drifts as the context grows, and you must paste it again in each new session. The plugin loads it for you.

Does it change my code? No. The rules apply to prose only.

Does it make the agent slower or more costly? The rules add a short block of text to each session. Short replies use fewer output tokens.

Is this the same as the full 900-word ASD-STE100 vocabulary? No. See Limits. Andrej Karpathy suggested asking for "80% of the way to ASD-STE100". This plugin is in that range.

Can I use a stricter or softer version? Yes. Edit the skill file and run npm run sync.

Does it work in languages other than English? No. ASD-STE100 is a standard for English.

Repository layout

asd-ste100-plugin/
├── skills/asd-ste100/SKILL.md      the rules (single source)
├── hooks/
│   ├── rules.js                    reads the rules from SKILL.md
│   ├── state.js                    the on/off switch (~/.asd-ste100/off)
│   ├── activate.js                 session-start hook
│   ├── toggle.js                   prompt hook: "asd on" / "asd off"
│   ├── claude-codex-hooks.json     hook config: Claude Code, Codex
│   └── copilot-hooks.json          hook config: Copilot
├── .claude-plugin/                 Claude Code plugin + marketplace
├── .codex-plugin/                  Codex plugin
├── .agents/
│   ├── plugins/marketplace.json    Codex marketplace
│   └── rules/asd-ste100.md         Antigravity rule (generated)
├── .github/
│   ├── plugin/                     Copilot plugin + marketplace
│   └── copilot-instructions.md     VS Code instructions (generated)
├── .kiro/steering/asd-ste100.md    Kiro steering (generated)
├── .opencode/plugins/              OpenCode plugin
├── gemini-extension.json           Antigravity CLI extension
├── AGENTS.md                       generic context file (generated)
├── bin/install.js                  npx installer
├── scripts/sync.js                 generates the copies
├── tests/rules.test.js             tests
└── Article.md                      the story behind this plugin

Development

npm run sync   # regenerate AGENTS.md, .agents/rules, .kiro/steering, .github/copilot-instructions.md
npm test       # 7 tests: copies in sync, hooks, on/off switch, installer, OpenCode plugin

The tests need Node.js 18 or later.

Credits

ASD-STE100 Simplified Technical English, maintained by ASD.
Andrej Karpathy, for the suggestion to ask models for output in ASD-STE100.
Ponytail, for the multi-tool plugin layout that this project follows.

This is an independent project. It is not affiliated with or endorsed by ASD, the ASD-STE100 maintainers, or Andrej Karpathy.

License

MIT. See LICENSE.

Navigation Menu

Repository navigation

About

Repository files navigation

Contents

What it does

Before and after

Turn it on and off

Install

Install with npm

Claude Code

Codex

GitHub Copilot CLI

OpenCode

Antigravity CLI

Antigravity IDE

Kiro IDE and Kiro CLI

VS Code

Other tools

The rules

How it works

Stop, change, or remove it

Limits

FAQ

Repository layout

Development

Credits

License

About

Releases

Packages

Contributors

Languages

Name		Name	Last commit message	Last commit date
.agents		.agents
.claude-plugin		.claude-plugin
.codex-plugin		.codex-plugin
.github		.github
.kiro/steering		.kiro/steering
.opencode/plugins		.opencode/plugins
bin		bin
hooks		hooks
scripts		scripts
skills/asd-ste100		skills/asd-ste100
tests		tests
.gitattributes		.gitattributes
.gitignore		.gitignore
AGENTS.md		AGENTS.md
Article.md		Article.md
LICENSE		LICENSE
README.md		README.md
gemini-extension.json		gemini-extension.json
opencode.json		opencode.json
package.json		package.json

Latest commit

History

Folders and files

Repository files navigation

Contents

What it does

Before and after

Turn it on and off

Install

Install with npm

Claude Code

Codex

GitHub Copilot CLI

OpenCode

Antigravity CLI

Antigravity IDE

Kiro IDE and Kiro CLI

VS Code

Other tools

The rules

How it works

Stop, change, or remove it

Limits

FAQ

Repository layout

Development

Credits

License

About

Topics

Resources

Stars

Watchers

Forks

Releases

Packages

Contributors

Languages