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 # AGENTS.md
 
+## Change Scope
+
+- Default to the smallest change that satisfies the request. Most work in this repo is presentation-layer work in `apps/web` and `apps/mobile` — refine what already exists rather than adding behavior.
+- Do not add features, settings, config flags, or abstractions that were not asked for. "While I was in there" cleanups belong in a separate change, or nowhere.
+- Do not change existing behavior as a side effect of a visual change. Restyling a component must not alter what it does.
+- Changes reaching `apps/server`, `packages/contracts`, or persistence/migrations are full-stack work requiring explicit intent. A new schema field, WebSocket message, or migration is never an incidental part of a frontend task. If a UI request appears to need one, say so and confirm before writing it.
+- Prefer fixing over rewriting, and deleting over adding. If both a targeted fix and a refactor would work, ship the fix.
+- Do not mix unrelated fixes into one change. `CONTRIBUTING.md` describes the PR expectations; they apply to agent-authored changes too.
+
 ## Task Completion Requirements
 
 - Keep local verification focused on the files and packages changed. Run the smallest relevant test set; do not run the full workspace test suite as a routine completion step.