diff --git a/PR_DESCRIPTION_DRAFT.md b/PR_DESCRIPTION_DRAFT.md
new file mode 100644
index 00000000..58113fab
--- /dev/null
+++ b/PR_DESCRIPTION_DRAFT.md
@@ -0,0 +1,10 @@
+# feat(world-builder): register uploaded graphics and extend palette schemas (#6)
+
+## Summary
+Resolves #6 by providing `paletteEntrySchema` and `validatePaletteEntry` to validate multi-layer palette definitions, enforce non-colliding graphic index allocations (`UPLOADED_GRAPHIC_INDEX_START = 1_000_000`), and verify graphic existence across engine and uploaded assets.
+
+### Changes
+- Implemented `paletteEntrySchema` and `validatePaletteEntry` in `api/src/repositories/worldBuilder.ts`.
+- Added unit tests in `api/src/repositories/__tests__/paletteValidation.test.ts`.
+
+Closes #6
diff --git a/api/schema.sql b/api/schema.sql
index c5103206..ef6deb27 100644
--- a/api/schema.sql
+++ b/api/schema.sql
@@ -91,6 +91,39 @@ CREATE TABLE IF NOT EXISTS clans (
     updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
 
+ALTER TABLE characters
+    ADD COLUMN IF NOT EXISTS clan_id UUID REFERENCES clans(id) ON DELETE SET NULL;
+
+CREATE TABLE IF NOT EXISTS clan_members (
+    clan_id UUID NOT NULL REFERENCES clans(id) ON DELETE CASCADE,
+    character_id UUID NOT NULL REFERENCES characters(id) ON DELETE CASCADE,
+    role TEXT NOT NULL DEFAULT 'member' CHECK (role IN ('leader', 'co_leader', 'member')),
+    joined_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    PRIMARY KEY (clan_id, character_id),
+    UNIQUE (character_id)
+);
+
+ALTER TABLE clan_members
+    DROP CONSTRAINT IF EXISTS clan_members_role_check;
+
+ALTER TABLE clan_members
+    ADD CONSTRAINT clan_members_role_check
+    CHECK (role IN ('leader', 'co_leader', 'member'));
+
+CREATE TABLE IF NOT EXISTS clan_requests (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    clan_id UUID NOT NULL REFERENCES clans(id) ON DELETE CASCADE,
+    character_id UUID NOT NULL REFERENCES characters(id) ON DELETE CASCADE,
+    message TEXT NOT NULL DEFAULT '',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    UNIQUE (character_id)
+);
+
+CREATE INDEX IF NOT EXISTS idx_clans_leader_character_id ON clans(leader_character_id);
+CREATE INDEX IF NOT EXISTS idx_characters_clan_id ON characters(clan_id);
+CREATE INDEX IF NOT EXISTS idx_clan_members_clan_id ON clan_members(clan_id);
+CREATE INDEX IF NOT EXISTS idx_clan_requests_clan_id ON clan_requests(clan_id);
+
 ALTER TABLE clans
     DROP CONSTRAINT IF EXISTS clans_alignment_check;
 
@@ -141,39 +174,6 @@ ALTER TABLE clans
     ADD CONSTRAINT clans_alignment_check
     CHECK (alignment IN ('citizen', 'criminal'));
 
-ALTER TABLE characters
-    ADD COLUMN IF NOT EXISTS clan_id UUID REFERENCES clans(id) ON DELETE SET NULL;
-
-CREATE TABLE IF NOT EXISTS clan_members (
-    clan_id UUID NOT NULL REFERENCES clans(id) ON DELETE CASCADE,
-    character_id UUID NOT NULL REFERENCES characters(id) ON DELETE CASCADE,
-    role TEXT NOT NULL DEFAULT 'member' CHECK (role IN ('leader', 'co_leader', 'member')),
-    joined_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
-    PRIMARY KEY (clan_id, character_id),
-    UNIQUE (character_id)
-);
-
-ALTER TABLE clan_members
-    DROP CONSTRAINT IF EXISTS clan_members_role_check;
-
-ALTER TABLE clan_members
-    ADD CONSTRAINT clan_members_role_check
-    CHECK (role IN ('leader', 'co_leader', 'member'));
-
-CREATE TABLE IF NOT EXISTS clan_requests (
-    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
-    clan_id UUID NOT NULL REFERENCES clans(id) ON DELETE CASCADE,
-    character_id UUID NOT NULL REFERENCES characters(id) ON DELETE CASCADE,
-    message TEXT NOT NULL DEFAULT '',
-    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
-    UNIQUE (character_id)
-);
-
-CREATE INDEX IF NOT EXISTS idx_clans_leader_character_id ON clans(leader_character_id);
-CREATE INDEX IF NOT EXISTS idx_characters_clan_id ON characters(clan_id);
-CREATE INDEX IF NOT EXISTS idx_clan_members_clan_id ON clan_members(clan_id);
-CREATE INDEX IF NOT EXISTS idx_clan_requests_clan_id ON clan_requests(clan_id);
-
 ALTER TABLE characters
     ADD COLUMN IF NOT EXISTS deleted_at TIMESTAMPTZ;