Decision 0005
Writing our own house-style skill
In plain English
A skill is a short instruction sheet an AI agent picks up when a job calls for it. We wrote one that teaches agents to write the way Method7 writes: British English, plain words, no em-dashes. We wrote it ourselves because our rules are specific, and the job is small enough that writing it was quicker than finding and checking someone else’s.
Context
Roofus publishes its journal on method7.co.uk, so its copy has to match the
site’s house style. The rules already existed in the Method7 site’s CLAUDE.md,
but that file only reaches agents working in that repo, and it mixes copy rules
with code rules.
A skill has a name, a description and instructions. The agent reads every skill’s description up front and loads the instructions only when the description matches the task. The description decides everything.
Options
- Download a general “UK English” skill. Saves writing it, but none will know Method7’s specific rules, and anything downloaded has to be read in full before it is trusted.
- Put the rules in
CLAUDE.mdonly. Always loaded, so it costs attention on every task, including ones that have nothing to do with copy. - Write our own skill.
Decision
Option 3. Simon set the trigger: “when writing copy for people to read, not code or comments, but any copy that is published.” That became the skill’s description.
We also drew a line that will apply to every rule from now on: skills for judgement, automated checks for anything a machine can verify. Spelling, tone and plain English need judgement, so they live in the skill. The em-dash ban is mechanical and applies everywhere, code comments included, so it is enforced by CI (issue #5). The skill mentions it only so copy is right first time.
Consequences
- The skill lives in
.claude/skills/uk-house-style/and any agent working in Roofus can use it. - It may move into a shared Method7 rules pack, depending on the house-rules audit (issue #7 and decision 0004).
- One lesson on day one: the skill’s own “before” example first contained a real em-dash, which would have failed the check it describes. The rules files name the character instead of printing it.
- Tested before merge by asking a small, fast model to write journal copy using only the skill. It got spelling, dates and punctuation right, but wrote “between 5 and 10 pounds” because the brief did. The money rule was tightened to say the house style wins over the brief’s wording.
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