1# Strict ASD-STE100 mode
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3Use this reference only when the user explicitly asks for STE or ASD-STE100.
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5This is a working approximation. The official specification and dictionary belong to ASD ([asd-ste100.org](https://www.asd-ste100.org)). Certified aerospace or defense deliverables need the official specification and human sign-off.
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7Before drafting, classify each section as procedural or descriptive. Read `word-substitutions.md`. Read `ste-examples.md` when rewriting existing text or when a rule is unclear.
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9## Sentences
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11- Limit procedural sentences to 20 words.
12- Limit descriptive sentences to 25 words.
13- Limit a paragraph to six sentences and one topic.
14- Put a condition before its command.
15- Give one instruction in each sentence. Combine actions only when they occur at the same time.
16- Keep articles, subjects, and verbs.
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18## Verbs
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20- Use the infinitive, imperative, simple present, simple past, simple future, or a past participle used as an adjective.
21- Do not use perfect or continuous verb forms.
22- Use active voice. Use passive voice in descriptive text only when the agent is unknown or unimportant.
23- Use the imperative for instructions.
24- Express an action with a verb, not a noun.
25- Use `can` for possibility, `will` for the future, and `must` for a requirement.
26- Do not use phrasal verbs when a simple verb has the same meaning.
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28## Words
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30- Give one word one meaning and one part of speech.
31- Use the same word for the same object or action.
32- Keep domain-specific terms and code identifiers unchanged.
33- Limit noun clusters to three words. Decompose longer clusters with prepositions or clear hyphenation.
34- Use American English spelling.
35- Replace Latin abbreviations with full words.
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37## Punctuation
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39- Do not use semicolons.
40- Use parentheses only for references, abbreviations, and item numbers.
41- Use hyphens for words that act as one unit.
42- Do not use contractions.
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44## Safety labels
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46- Use `WARNING` for risk of injury or death.
47- Use `CAUTION` for risk of damage.
48- Use `NOTE` for information only. Do not put an instruction in a note.
49- Put the command or condition before the risk.
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51## Self-check
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53Check sentence length, verb forms, modals, articles, synonym rotation, unapproved words, and the order of safety text.
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