Strict ASD-STE100 mode

Use this reference only when the user explicitly asks for STE or ASD-STE100.

This is a working approximation. The official specification and dictionary belong to ASD (asd-ste100.org). Certified aerospace or defense deliverables need the official specification and human sign-off.

Before 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.

Sentences

• Limit procedural sentences to 20 words.
• Limit descriptive sentences to 25 words.
• Limit a paragraph to six sentences and one topic.
• Put a condition before its command.
• Give one instruction in each sentence. Combine actions only when they occur at the same time.
• Keep articles, subjects, and verbs.

Verbs

• Use the infinitive, imperative, simple present, simple past, simple future, or a past participle used as an adjective.
• Do not use perfect or continuous verb forms.
• Use active voice. Use passive voice in descriptive text only when the agent is unknown or unimportant.
• Use the imperative for instructions.
• Express an action with a verb, not a noun.
• Use can for possibility, will for the future, and must for a requirement.
• Do not use phrasal verbs when a simple verb has the same meaning.

Words

• Give one word one meaning and one part of speech.
• Use the same word for the same object or action.
• Keep domain-specific terms and code identifiers unchanged.
• Limit noun clusters to three words. Decompose longer clusters with prepositions or clear hyphenation.
• Use American English spelling.
• Replace Latin abbreviations with full words.

Punctuation

• Do not use semicolons.
• Use parentheses only for references, abbreviations, and item numbers.
• Use hyphens for words that act as one unit.
• Do not use contractions.

Safety labels

• Use WARNING for risk of injury or death.
• Use CAUTION for risk of damage.
• Use NOTE for information only. Do not put an instruction in a note.
• Put the command or condition before the risk.

Self-check

Check sentence length, verb forms, modals, articles, synonym rotation, unapproved words, and the order of safety text.