diff --git a/write-discoverable-code/SKILL.md b/write-discoverable-code/SKILL.md
index a5255e8..966c720 100644
--- a/write-discoverable-code/SKILL.md
+++ b/write-discoverable-code/SKILL.md
@@ -34,7 +34,8 @@ rules make code resolvable in one search instead of five.
   disambiguates `users/diff.ts` from `orders/diff.ts` sits at the top of the file; the
   search hit is at line 300. Put the context in the symbol (`formatDurationMs`), not the
   folder. Exception: rigid, absolute conventions where the path carries the meaning
-  (e.g. every contract file exporting `Input`/`Output`).
+  (e.g. every contract file exporting `Input`/`Output`). Folders still group related
+  files (section 2); they just don't carry the name's context.
 - **One concept, one spelling.** Pick `organizationId` or `orgId` and use it everywhere;
   every synonym splits every future search in half. Reuse existing vocabulary in the
   codebase you are editing rather than introducing near-synonyms.
@@ -47,7 +48,16 @@ rules make code resolvable in one search instead of five.
   `billing-plan-config.ts`, not `config.ts`. (`index.ts` is acceptable only as a
   thin re-export entry point.)
 
-## 2. Types are the documentation agents can't skip
+## 2. Folders are the map
+
+A directory listing is the first search in an unfamiliar codebase, and it should read
+as a map of the system. Group related files into folders — by feature, domain, or
+layer, whichever organizing principle the codebase already follows — so each listing
+shows a handful of named areas rather than every file at once. Folders carry the
+grouping; context still lives in the symbol (section 1), so a name should make sense
+even when quoted without its path.
+
+## 3. Types are the documentation agents can't skip
 
 - **Brand your primitive IDs.** `z.string().brand<'UserId'>()` (TS) or newtypes (Rust).
   A `transferOwnership(userId: string, orgId: string)` signature makes argument
@@ -61,7 +71,7 @@ rules make code resolvable in one search instead of five.
   uses to self-correct. `OrgScopedDb` explains itself; `Ctx2` does not. Avoid `any`: every
   `any` is a spot where the compiler goes silent and the agent is back to guessing.
 
-## 3. Say it where the search lands
+## 4. Say it where the search lands
 
 - **One-line doc comment on every export**, stating the sharpest constraint the code
   itself can't show (units, timezone, "source time, not insert time", ownership).
@@ -105,3 +115,5 @@ rules make code resolvable in one search instead of five.
 4. Do all log/error strings exist verbatim in the source?
 5. Did anything change behavior without changing its name?
 6. When code moved, is it gone from where it came from?
+7. Does each new file sit in a folder alongside related code, and does the listing
+   still read as a map of the system?