Speculative fix on preferences weirdness.

AGENTS.md

@@ -14,6 +14,16 @@ This repository is a screen reader. Prioritize accessibility, correctness, and s
   - `meson compile -C _build`
   - `meson install -C _build`
 
+## Runtime target and testing rules
+- Make source changes in this repo, not in `~/.local/lib/python*/site-packages/cthulhu/`, unless the user explicitly asks for an installed-package hotfix.
+- If you confirm the active import comes from `~/.local/...`, that does **not** mean you should edit there. It means you should update the repo and then run `./build-local.sh` to replace the installed copy for testing.
+- Default test/apply workflow for local Cthulhu fixes:
+  - edit repo files
+  - run `./build-local.sh`
+  - reproduce/test against the refreshed `~/.local` install
+- If repo and installed behavior differ, prefer rebuilding with `./build-local.sh` over patching the installed package directly.
+- Treat direct edits under `~/.local/.../cthulhu/` as an exception path that requires explicit user approval.
+
 ## Coding guidelines
 - **When modifying existing code:** follow the surrounding code’s conventions.
 - **When writing new code from scratch:** prefer
@@ -55,3 +65,8 @@ This repository is a screen reader. Prioritize accessibility, correctness, and s
 ## Meson install reminder (important)
 - If you add new Python modules under `src/cthulhu/`, update `src/cthulhu/meson.build` so they get installed (otherwise imports can fail after install).
 - If you add a new plugin directory, update `src/cthulhu/plugins/meson.build` and add a `meson.build` in the plugin directory.
+
+## Common Cthulhu agent mistakes
+- Checking the import origin, seeing `~/.local/...`, and then editing the installed package instead of the repo.
+- Forgetting that `./build-local.sh` is the normal way to apply repo changes into the installed copy for testing.
+- Making repo fixes and then diagnosing the old installed copy without rebuilding.