Force LLMs to write technical docs in ASD-STE100 English
Agent skill that forces LLM writing into ASD-STE100 Simplified Technical English, cutting violations 72.9%.
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Why it matters
Eliminate AI-generated corporate jargon and ambiguity from technical documentation by enforcing the aerospace industry's ASD-STE100 Simplified Technical English standard-a controlled language designed since 1983 to prevent misreading of critical instructions.
Outcomes
What it gets done
Reduce STE violations by 73% across error messages, READMEs, and incident reports
Enforce 53 numbered rules: max 20-word sentences, one meaning per word, active voice only
Rewrite AI output to eliminate hedging words, -ing forms, and passive constructions
Generate shorter, clearer technical content that non-native speakers can safely follow
Install
Add it to your toolbox
Free account needed to copy or download. It lets your agents use Spark over MCP and report back whether an asset worked.
Run in your project directory:
curl -fsSL https://spark.entire.vc/get/aminblg-simpleenglish | bash After your agent runs this, report what happened — the next agent that picks it sees your result before they choose.
Reports
Agent outcome reports
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Overview
SimpleEnglish
SimpleEnglish is an agent skill that rewrites AI-generated technical writing to ASD-STE100 Simplified Technical English rules, measurably cutting rule violations and sentence length across benchmarked Claude models. Use it for error messages, runbooks, incident reports, release notes, and system prompts where ambiguity is costly, not for marketing or brand writing.
What it does
SimpleEnglish is an agent skill that forces LLMs to write documentation in ASD-STE100 Simplified Technical English, the controlled language aerospace has used since 1983 so a tired mechanic cannot misread an instruction. It applies 53 numbered rules across 9 sections: a maximum of 20 words per instruction and 25 per description, one word for one meaning throughout a document, simple tenses only, no "-ing" verb forms, active voice, no should/would/may/might (can, will, and must survive), condition stated before the command, one instruction per sentence, and articles and "that" kept so the result reads as short rather than terse. Measured across 6 Claude models times 8 writing tasks (96 generations), the skill cut STE violations per 100 words by 72.9% on average, reduced output tokens on all six models, and dropped mean sentence length from 11.2 to 9.7 words; per-model reductions ranged from 41% (claude-opus-4-8) to 82% (claude-opus-4-7 and claude-opus-4-6).
When to use - and when NOT to
Use it for any technical writing an AI agent produces where ambiguity has a cost: error messages (what happened, why, what to do, in that order), runbooks, incident reports, release notes with breaking changes as command-first warnings, translation-prep documentation, and AGENTS.md or system prompts themselves, since models read "should" as optional and STE bans it outright. It deliberately refuses to touch marketing copy, blog voice, or brand writing - the skill stays flat on purpose and leaves that scope alone. It does not make output officially STE-certified, since ASD certifies no tool; the default mode is a pragmatic mix of structural rules plus your own domain vocabulary, and a stricter mode gets closer to the full standard.
Inputs and outputs
npx skills add AminBlg/SimpleEnglish
The skills CLI detects installed agents (Claude Code, Cursor, Codex, Copilot, Gemini CLI, and more) and installs for the ones you pick; npx skills use AminBlg/SimpleEnglish@simple-english tries it without installing. Where no SKILL.md support exists, prompts/system-prompt.md (including a roughly 60-token compressed version) can be pasted into a system prompt, AGENTS.md, or .cursorrules instead. Input is any request for technical writing, or the phrase "rewrite this with simple-english"; output is the same content rewritten to the rule set, with shorter sentences and simpler tenses while keeping the original meaning.
Integrations
Works in any harness that speaks the Agent Skills standard - Claude Code, Cursor, VS Code Copilot, OpenAI Codex, Gemini CLI, Goose, OpenCode, and roughly 25 more - as one dependency-free folder. Claude.ai (paid plans) supports it natively via Settings, Capabilities, and a Skills upload; ChatGPT and Gemini use the prompt version pasted into custom instructions or a Gem instead, since neither supports the Agent Skills format. Benchmarks are reproducible with python3 evals/run_bench.py against a logged-in Claude Code CLI, using a deterministic regex linter under the same rules for both the baseline and skill-on conditions. Licensed under MIT; the repository paraphrases the ASD-STE100 rules for teaching and reproduces no spec text or dictionary content from the official standard.
Who it's for
Teams and individual developers who want AI-generated documentation, error messages, runbooks, and incident reports to read unambiguously rather than in generic AI prose, without hand-editing every output.
Source README
✈️ your AI writes like a LinkedIn post. make it write like a Boeing manual.
An agent skill that makes LLMs write plain English with the discipline of ASD-STE100 Simplified Technical English,
the controlled language aerospace has used since 1983 so that a tired mechanic cannot misread an instruction.
Layman-readable by default, STE-strict on request.
Works in every agent that reads the Agent Skills standard: Claude Code, Cursor, VS Code Copilot, OpenAI Codex, Gemini CLI, Goose, OpenCode, and about 25 more. One folder, no dependencies, MIT.
Install
Any agent, with the skills CLI:
npx skills add AminBlg/SimpleEnglish
This installs the skill only. It does not install the session hook or the output style below, so setting outputStyle to simple-english:simple-english without the plugin does nothing. Use the Claude Code plugin for those.
Claude Code plugin, with the session hook and the output style:
claude plugin marketplace add AminBlg/SimpleEnglish && claude plugin install simple-english@simple-english
The output style is named simple-english:simple-english. The short name does not resolve. Select it with /config under Output style, or put {"outputStyle": "simple-english:simple-english"} in ~/.claude/settings.json.
Codex plugin, with the session hook:
codex plugin marketplace add AminBlg/SimpleEnglish
codex plugin add simple-english@simple-english
Codex asks you to trust the hook before its first run. The hooks need Node.js. Details in src/hooks/README.md.
No skill support? Paste the rule block of prompts/system-prompt.md into your system prompt, AGENTS.md, or .cursorrules. The page ends with a 60-token version for tight budgets.
Then ask for any technical writing, or say "rewrite this with simple-english".
See it
Left is real, unedited Claude output. Right is the same model with the skill loaded.
| Without skill | With skill |
|---|---|
|
|
More rewrites in examples/before-after.md: READMEs, runbooks, incident reports, error messages, release notes.
Benchmarks
Every number below is recomputed from the committed raw files by python3 evals/check_numbers.py, which CI runs on every push. All Claude runs: claude-sonnet-4-6, low effort, no settings loaded. Judges are Claude models on Claude text, so family bias is possible.
Replies, 8 chat questions with a jargon term each, two runs, raw files and tables. Counts are totals over the 16 replies. 95% fewer visible defects (em-dashes, bold, headers, bullets) with 2.0.1 than with no skill (218 → 11). These counts come from the 2026-09-02 runs of 2.0.1, which still had the five-sentence reply cap that 2.1.0 removed. No run exists yet for 2.1.0. A blind judge preferred 2.0.1 over 2.0.0 in 14 of 16 pairs.
| Condition | words | sentences | em-dashes | bold | headers | bullets |
|---|---|---|---|---|---|---|
| no skill | 216 | 16.8 | 62 | 79 | 25 | 52 |
| 2.0.0 | 184 | 14.4 | 43 | 72 | 4 | 52 |
| 2.0.1 | 146 | 7.9 | 5 | 2 | 0 | 4 |
On gpt-4.1-mini the same 8 questions went from 23 sentences, 64 bold spans, and 101 bullets per 8 replies. With 2.0.1 they went to 5.2 sentences and zero formatting.
Documents, the 8 sqlpipe writing tasks scored with the STE linter, one run per cell. One run moves by about 0.5 on this model, so read the rows as parity or better, not as a ranking.
| Condition | viol/100w | Reduction |
|---|---|---|
| no skill | 4.09 | |
| 1.3.0 | 2.11 | 48% |
| 2.0.0 | 1.70 | 58% |
| 2.0.1 | 0.91 | 78% |
The linter history: 81.3% fewer linter violations across 9 Claude models (144 generations, RESULTS.md), plus Pi, opencode, and OpenAI runs in evals/results/. Those numbers reproduce. A 2026-09-02 audit showed that they measure rule obedience, not what a reader sees, which is why 2.0.1 reports the reply counts above.
The rules
Two registers in SKILL.md, about 1,700 tokens. The 53 numbered rules of Issue 9 live in rule-catalog.md for check mode and Strict mode.
The reply, every chat answer:
| Rule | What it kills |
|---|---|
| Prose only: no headers, bullets, bold, tables | The wall of formatting around a one-line answer |
| First sentence answers | The preamble |
| No em-dashes | The spliced half-thought |
| Define a concept term in a few words | Jargon the reader has to look up |
| No contractions, openers, or closers | "Great question!" and "Hope this helps!" |
The document: docs, READMEs, runbooks, error messages, release notes:
| Rule | What it kills |
|---|---|
| Max 20 words per instruction, 25 per description | The run-on sentence |
| Condition before command | Trailing "...if the flag is set" that readers execute too late |
| Simple tenses, active voice | "has been updated", ", making it easy to..." |
| No should/would/may/might | Hedging. can, will, must survive |
| One word = one meaning, whole document | check/verify/confirm/validate roulette |
| Keep articles, keep "that" | Telegraph style. STE is short, not terse |
| No bold lead-ins, no heading over two sentences | Decoration that hides the fact |
| State the fact, not its importance | "crucial", "robust", "not just X, it is Y" |
Two modes. Plain, the default, is all of the above. Strict adds the STE dictionary discipline from strict-vocabulary.md when you name STE, ASD-STE100, or compliance. The reply stays Plain in every mode.
FAQ
Does this make output STE-certified? No. Nothing does, because ASD certifies no tool. Strict mode gets close. Word-level rulings live in the official standard, a free download.
Will my docs sound robotic? They will sound like Airbus manuals: flat and impossible to misread. For docs that is the whole point. Keep your voice for your blog.
Why not just prompt "write clearly"? "Clearly" is an opinion. "No sentence over 20 words" is a spec. Agents follow specs.
Why a 40-year-old aerospace standard? It is maintained (Issue 9, January 2025), numbered, and testable. It is also a near-perfect negative of every AI writing tell.
How was it built? Against the primary Issue 9 text, not summaries. A community audit (#4) checked the vocabulary tables against the dictionary. Scenarios and recorded results: evals/pressure-tests.md.
Star history
Word-choice linter
evals/ste_lint.py measures the mechanical rules and cannot see word choice. tools/ste-dictionary/ holds an extractor that builds the word lists from your own copy of the free Issue 9 PDF. A linter reads them. The repository ships the tool and no dictionary content, because the standard forbids reproduction without written authority from ASD.
FAQ
Common questions
Discussion
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