Negative Constraints That Hold Under Pressure

Negative constraints — instructions about what not to do — are where most CLAUDE.md files fail. It is easy to write "never force-push" and assume it holds. It does not always hold. When the agent is mid-task, has encountered a merge conflict, and has been instructed to "fix this and get it working," the pressure to find a path forward can override a vague constraint. The constraint must be strong enough to survive the task context.

1. Make the consequence explicit "Never use git reset --hard" is weaker than "Never use git reset --hard — this permanently discards uncommitted changes and cannot be undone." The consequence anchors the constraint. The agent understands why the constraint exists, not just that it does.
2. Specify the alternative "Do not delete files" leaves the agent with no path forward when deletion seems like the solution. "Do not delete files — use git mv to rename or ask before removing anything" gives the agent an alternative action. Constraints that block without redirecting create stuck agents.
3. Make scope explicit "Do not modify the database schema" is ambiguous if the project has a test database and a production database. "Do not modify the production database schema — test database modifications are pre-authorized" eliminates the ambiguity. Scope ambiguity is where constraints get rationalized away.
4. Put the hardest constraints first The instructions that must survive the most pressure — the ones protecting irreversible actions — belong at the top of their section, not buried in a list. Constraint priority should be visible in document structure.