ASD-STE100 or Markdown? The same answer, written in Simplified Technical English
By Soumen Sarkar · October 2026
Short answer: Markdown controls the layout of a page. STE controls the words and the sentences. Use the two together. Write the file in Markdown. Write the procedures, rules and warnings in STE.
Two versions of this page
You read the STE version of this page. [The ordinary English version](/answers/ste100-vs-markdown) gives the same information in usual English, with longer sentences. This version follows these rules:
- Each sentence has 20 words or less.
- Each instruction is in a different sentence.
- Each instruction starts with a verb.
- If there is a condition, the condition comes before the instruction.
- All verbs are in the active voice and in a simple tense.
- Each paragraph has one topic and six sentences or less.
Compare one sentence from each version:
- Ordinary English: "In STE a word means one thing, and every instruction says who does what."
- STE: "In STE, each approved word has one meaning. Each instruction tells the reader the action to do."
We did not use a formal STE checker. Thus, some words can be outside the STE dictionary.
Markdown
Markdown is a syntax for the layout of text. It gives headings, lists, links and code blocks. It does not control the words or the sentences. Thus, a Markdown file can contain clear text or text that is not clear.
ASD-STE100
ASD-STE100 is a standard for technical English. Its name is Simplified Technical English (STE). The European aerospace industry started it in the 1980s. It makes maintenance manuals clear to all technicians.
The standard has two parts:
- Rules for grammar and style.
- A dictionary of approved words.
The current issue is Issue 9. ASD released it on 15 January 2025. Issue 9 has 53 rules. ASD changed the text of 31 rules and 555 dictionary entries. You can get the standard free of charge from asd-ste100.org.
Some STE rules
- Do not write more than 20 words in an instruction.
- Do not write more than 25 words in a description.
- Write one instruction in each sentence.
- Start each instruction with a verb. For example, write "Remove the cover."
- Use the active voice.
- Use each word only with its approved meaning.
- Do not use more than three nouns together.
Why you can use STE
- Each sentence has one meaning. In usual English, many words have many meanings. In STE, each approved word has one meaning. Each instruction tells the reader the action to do.
- Readers understand complex documents better. In 1995, four researchers did a test with airplane procedures. The Simplified English procedures were easier to understand. Readers also found information more quickly. The time to read the procedures did not change.
- More people can read the document. In aviation maintenance, approximately four of five technicians do not have English as their first language. Short sentences and a small vocabulary help these readers.
- Translation is easier. STE uses the same words for the same thing. Thus, translation tools can use more of the old translations.
- You can examine the text with a tool. A tool can find long sentences, the passive voice and words that are not approved.
- AI agents get clear instructions. An agent reads all the instructions in its file at each start. The agent does each instruction as you wrote it. STE makes each instruction clear. Thus, you can test if the agent follows each instruction.
STE and AI agents in 2026
Many developers now give STE rules to AI agents. The rules go into a "skill", a file that tells the agent how to write. One of these skills is SimpleEnglish on GitHub. In 2026, approximately 4,000 people starred it.
The author of SimpleEnglish did tests on Claude models. With the skill, the STE errors decreased from 4.09 to 0.91 in each 100 words. Claude models also gave the scores. Thus, the results possibly are not correct. Some developers think that one line in a prompt gives the same result.
Problems with STE
- Writers must learn the rules and the dictionary. A checker tool can help them.
- STE text is not natural. Use STE for procedures, descriptions and warnings only.
- Too few words can cause problems. A 2025 study of maintenance manuals shows this risk. If you remove the connection words, the reader can understand less.
- You must make a list of your technical names and technical verbs. Use the same name for the same thing each time.
Which one to use
Use Markdown and STE together. Do these steps:
- Write the file in Markdown.
- Write the procedures, rules and warnings in STE.
- Write the explanations in clear, usual English.
The principle behind this: Let the work speak: Our work explains itself, so nobody ever has to come and ask us.
Move as one at agent speed. Nobody waits. Add Campfyrr to Claude: it briefs every agent before it touches the code, keeps assumptions and handoffs where the team can see them, and never takes your code (what it keeps).