simple-english

Files (3)

• SKILL.md
• checklist.md · references/
• use-cases.md · references/

SKILL.md (first lines)

# Simple English: Write Like an Aerospace Manual

Write technical text with the rules of ASD-STE100 Simplified Technical English. STE is the controlled language that aerospace and defense manufacturers use for maintenance documentation. The rules exist so that a tired reader who is not a native English speaker cannot misread an instruction. They remove the usual signs of AI-generated text as a side effect: long sentences, synonym rotation, hedges, filler, and decorative clauses.

Write for that tired reader. Each sentence must survive one read.

## Your Task

When asked to write or rewrite technical text:

1. **Select the mode** (pragmatic or strict, below).
2. **Classify each passage** as procedural or descriptive. Every other rule depends on this.
3. **Fix your vocabulary before drafting.** Pick ONE verb for the check/verify/confirm/validate concept and ONE noun for config/settings. Use no other word for these concepts in the whole document.
4. **Apply the rules** from the catalog below.
5. **Run the self-check** before you deliver. This step is not optional.
6. **Never touch code**, identifiers, commands, or quoted errors (see Untouchables).

When asked to CHECK text instead of writing it, report each violation as: rule number, the offending text, a compliant rewrite. Cite only rule numbers that exist in this file. Do not cite rule numbers from memory: the numbering is unintuitive and models invent it (tested — an agent without this file cited "Rule 3.1: short sentences"; the real Rule 3.1 is about verb forms).

## Two Modes

| Mode | When | What you apply |
|---|---|---|
| **Pragmatic** (default) | Docs, READMEs, error messages — the user wants clear text | All structural rules. Domain words stay ("idempotent", "webhook"). |
| **Strict** | The user names STE, ASD-STE100, or compliance | Structural rules + full vocabulary discipline, and tell the user that full compliance needs the official dictionary (free at asd-ste100.org). |

## Step 1: Classify the Text

| | Procedural (instructions) | Descriptive (explanations) |
|---|---|---|
| Purpose | Tell the reader what to do | Explain what a thing is or does |
| Verb form | Imperative: "Install the pump." | Simple present/past/future |
| Sentence limit | **20 words** (Rule 5.1) | **25 words** (Rule 6.3) |
| Unit rule | One instruction per sentence (5.2) | One topic per paragraph (6.5), max six sentences per paragraph (6.6) |

Do not mix the two in one passage. A "Getting started" section is procedural. An "Architecture" section is descriptive. A note inside a procedure is descriptive (25-word limit, no imperative).

## THE RULE CATALOG

53 rules in 9 sections, paraphrased from ASD-STE100 Issue 9 with software examples. The official wording is in the free standard at asd-ste100.org.

### Section 1 — Words (Rules 1.1-1.14)

| Rule | Instruction |
|---|---|
| 1.1 | Use only approved words, technical nouns, or technical verbs. |
| 1.2 | Use an approved word only as its listed part of speech. |
| 1.3 | Use an approved word only with its approved meaning. |
| 1.4 | Use only the approved forms of verbs and adjectives. |
| 1.5 | You can use domain words as technical nouns ("webhook", "commit", "endpoint"). |
| 1.6 | Use an unapproved word only when it is a technical noun or part of one. |
| 1.7 | Do not use technical nouns as verbs. |
| 1.8 | Use the technical nouns of your project or industry. |
| 1.9 | When you pick a technical noun, pick a short and clear one. |
| 1.10 | No regional, slang, or jargon words as technical nouns. |
| 1.11 | One item, one name. Do not call it "config" here and "settings" there. |
| 1.12 | You can use domain verbs as technical verbs ("deploy", "compile", "merge"). |
| 1.13 | Do not use technical verbs as nouns. |
| 1.14 | Use American English spelling. |

In pragmatic mode, rules 1.5, 1.8, and 1.12 do the heavy lifting: your domain vocabulary is legal. The ones agents break are 1.7, 1.11, and 1.13.

**Before:** You can webhook the event, then do a deploy.
**After:** Send the event to the webhook. Then deploy the service.

### Section 2 — Multi-word nouns (Rules 2.1-2.2)

| Rule | Instruction |
|---|---|
| 2.1 | Write multi-word nouns of three words or fewer. |
| 2.2 | When a technical noun needs more than three words, write it in full once, then give a short form or hyphenate the units. |

Break long noun chains with prepositions (of, on, in, for):

**Before:** the connection pool timeout configuration value
**After:** the timeout value for the connection pool

### Section 3 — Verbs (Rules 3.1-3.7)

| Rule | Instruction |
|---|---|
| 3.1 | Use only the verb forms that the dictionary gives. |
| 3.2 | Use only: infinitive, imperative, simple present, simple past, simple future, past participle as adjective. |
| 3.3 | Use the past participle only as an adjective ("the cached response"). |
| 3.4 | No auxiliary verbs for complex constructions. No present perfect, no "is to be installed". |
| 3.5 | Use an "-ing" form only as a technical noun or inside one ("logging", "the mounting bracket") — never as a verb. |
| 3.6 | Active voice. In descriptive text, passive is legal only when the agent is unknown. |
| 3.7 | Describe an action with a verb, not a noun ("compress the file", not "perform compression of the file"). |

**Approved modals: can, will, must. Banned: should, would, may, might, could.**
The standard rejects "could" even for possibility: write "an explosion can occur", never "could occur". For "should": a requirement becomes "must"; a suggestion is stated as fact or deleted. This matters double for agent instructions — models read "should" as optional.

**Before:** The migration has completed and the table is being rebuilt.
**After:** The migration is complete. The database rebuilds the table.

**Before:** The flag can be set in the config file, making restarts unnecessary.
**After:** You can set the flag in the config file. Then a restart is not necessary.

**Before:** The temperature must be adjusted.
**After:** Adjust the temperature.

### Section 4 — Sentences (Rules 4.1-4.5)

| Rule | Instruction |
|---|---|
| 4.1 | Write short and clear sentences. |
| 4.2 | Do not omit words or use contractions to shorten sentences. Keep articles, keep "that". |
| 4.3 | Use a vertical list for complex text. |
| 4.4 | Use connecting words between sentences on related topics ("Then", "As a result"). |
| 4.5 | Put an article (the, a, an) or a demonstrative adjective (this, these) before nouns where applicable. |

Rule 4.2 is the anti-terseness rule. STE is short sentences with complete grammar, not telegraph style:

**Wrong shortening:** Ensure file exists before running.
**STE:** Make sure that the file exists before you run the command.

### Section 5 — Procedural writing (Rules 5.1-5.5)

| Rule | Instruction |

From WaylonWalker/skills, MIT.

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