Project rules: teach it your standards once

By the fourth session you will have typed “British spelling, no bullet lists in the summary, always state the counter-argument” four times. A project rules file is where that goes so it applies by default.

What belongs in it

Standing constraints. Things that are true of every document you produce in this workspace, regardless of what the document is.

• Voice. “Short sentences. No adjectives in the summary. Never open with ‘In today’s fast-moving…’.”
• Evidence rules. “Every claim about users cites a file in research/. If there is no source, write ‘unevidenced’ rather than softening the claim.”
• Vocabulary. “We say workspace, not project. We say activation, and it means completing a first task within seven days — not signing up.”
• Shape. “PRDs use the template in context/prd-template.md. Updates are under 300 words.”
• Prohibitions. “Never invent a statistic. Never attribute a quote that is not in a research file. Never write a competitor’s pricing from memory.”

What does not belong in it

Task instructions. “Write the Q3 roadmap” is not a rule. Anything specific to one document belongs in the request, and putting it in the rules file means every future document is quietly contaminated by it.

Why most rules files stop working

They grow. A file with forty rules is a file where the agent picks a subset, and you cannot predict which. Three tests:

1. Under a page. If it does not fit, you are describing tasks, not standards.
2. Each rule is checkable. “Write clearly” is not a rule. “No sentence over 25 words in the summary” is.
3. You would enforce it on a colleague. If you would not send a document back for breaking the rule, delete the rule.

Exercise

Write context/rules.md with no more than eight rules. Then test it adversarially:

Following @context/rules.md, write a 200-word update on activation for the leadership team. Then, separately, list every rule in that file you broke and why.

The second half is the test. A rule that gets broken and not noticed is a rule that is too vague to be worth having — rewrite it, or drop it.