asd-ste100

Simplified Technical English (ASD-STE100)

ASD-STE100 is a controlled-language standard built by the aerospace and defense industry (ASD, the AeroSpace and Defense Industries Association of Europe) to stop maintenance technicians from misreading English instructions. The standard removes the two biggest sources of misreading: words with more than one meaning, and sentences with more than one possible structure.

This skill borrows that same discipline for a different reader: an AI agent or a downstream system that has to parse an English string — an error message, a tool description, an inter-agent instruction, a status report — without a human in the loop to resolve ambiguity. If a maintenance technician can misread "close the valve" as an adjective ("the valve that is near") instead of a command, so can a language model.

When to Use This Skill

• An agent's output (explanation, instruction, log message, tool description) reads as dense, jargon-heavy, or ambiguous.
• Text will be consumed by another agent, a translation pipeline, or a non-native English reader, and misparsing has a real cost.
• You are writing a prompt, system message, or tool description and want to remove ambiguity before a model ever sees it.
• You want a before/after comparison showing exactly which rule was violated and how the rewrite fixes it. Ask for it — the default output is the rewritten text alone (see Output Format).

This skill is not for creative or marketing copy — STE is deliberately flat and literal. Do not apply it to text where voice, nuance, or persuasion is the point.

Two Modes

Pick a mode before rewriting. If the user does not say which, infer from the text type and state the choice in one line.

Strict — procedures, error messages, tool and function descriptions, inter-agent instructions, safety text. Anywhere a wrong reading has a cost. Apply every rule below, including the hard length caps and one-word-one-meaning discipline.

STE-flavored — READMEs, PR descriptions, changelogs, explanatory prose. Apply the structural rules in full and treat the lexical rules as advisory (see Core Rewrite Rules for that split). In practice that means keeping the sentence length caps, active voice, simple tenses, no phrasal verbs, no semicolons, no nominalization and no marketing adjectives, while dropping the one-word-one-meaning lockdown: prose needs some range, and a strict rewrite of prose reads as a personality transplant rather than a clarification.