diff --git a/packages/imhotep-core/src/geometry-cache.ts b/packages/imhotep-core/src/geometry-cache.ts
index 59f1e9d..74bc1e9 100644
--- a/packages/imhotep-core/src/geometry-cache.ts
+++ b/packages/imhotep-core/src/geometry-cache.ts
@@ -250,7 +250,8 @@ function evictOldestEntries(cacheDir: string, maxEntries: number): void {
       const fullPath = join(cacheDir, f)
       try {
         return { name: f, path: fullPath, mtime: statSync(fullPath).mtimeMs }
-      } catch {
+      } catch (err) {
+        console.warn(`[imhotep-core] cache eviction: stat failed for ${f}: ${err instanceof Error ? err.message : err}`)
         return null
       }
     })
@@ -262,8 +263,8 @@ function evictOldestEntries(cacheDir: string, maxEntries: number): void {
     for (let i = 0; i < toRemove; i++) {
       try {
         rmSync(files[i].path)
-      } catch {
-        // ignore deletion errors
+      } catch (err) {
+        console.warn(`[imhotep-core] cache eviction: failed to remove ${files[i].path}: ${err instanceof Error ? err.message : err}`)
       }
     }
   }
@@ -277,7 +278,8 @@ export async function readCachedWorld(cacheDir: string, cacheKey: string): Promi
   try {
     const json = await readFile(path, 'utf-8')
     return deserializeGeometryWorld(json)
-  } catch {
+  } catch (err) {
+    console.warn(`[imhotep-core] readCachedWorld failed for ${cacheKey}: ${err instanceof Error ? err.message : err}. Cache miss.`)
     return null
   }
 }
@@ -303,8 +305,8 @@ export function clearGeometryCache(cacheDir: string = DEFAULT_CACHE_DIR): void {
     if (file.endsWith('.json')) {
       try {
         rmSync(join(cacheDir, file))
-      } catch {
-        // ignore deletion errors
+      } catch (err) {
+        console.warn(`[imhotep-core] cache clear: failed to remove ${file}: ${err instanceof Error ? err.message : err}`)
       }
     }
   }
@@ -390,7 +392,8 @@ export async function readCachedExtractionResult(
   try {
     const json = await readFile(path, 'utf-8')
     return deserializeExtractionResult(json)
-  } catch {
+  } catch (err) {
+    console.warn(`[imhotep-core] readCachedExtractionResult failed for cacheKey=${cacheKey}: ${err instanceof Error ? err.message : err}. Cache miss.`)
     return null
   }
 }
diff --git a/packages/imhotep-playwright/src/extraction.ts b/packages/imhotep-playwright/src/extraction.ts
index b8a5c23..f662b11 100644
--- a/packages/imhotep-playwright/src/extraction.ts
+++ b/packages/imhotep-playwright/src/extraction.ts
@@ -726,7 +726,9 @@ export async function extractWorldFastGeometry(
       for (const el of nodes) {
         el.removeAttribute('data-imhotep-runtime-id')
       }
-    }).catch(() => {})
+    }).catch((err) => {
+      console.debug('[imhotep-playwright] fast-geometry cleanup evaluate failed:', err instanceof Error ? err.message : err)
+    })
   }
 }
 
@@ -910,7 +912,9 @@ export async function extractWorldCdp(
       for (const el of nodes) {
         el.removeAttribute('data-imhotep-runtime-id')
       }
-    }).catch(() => {})
+    }).catch((err) => {
+      console.debug('[imhotep-playwright] CDP cleanup evaluate failed:', err instanceof Error ? err.message : err)
+    })
     await sessionManager.detach()
   }
 }
@@ -940,7 +944,8 @@ export async function extractWorld(
         width: Number.isFinite(measured?.width) ? Number(measured.width) : 0,
         height: Number.isFinite(measured?.height) ? Number(measured.height) : 0,
       }
-    } catch {
+    } catch (err) {
+      console.warn(`[imhotep-playwright] resolveViewport: page.evaluate failed (${err instanceof Error ? err.message : err}), falling back to 0x0 viewport`)
       return { width: 0, height: 0 }
     }
   }
diff --git a/packages/imhotep-solver/src/predicates.ts b/packages/imhotep-solver/src/predicates.ts
index 9ca96c2..d816f6c 100644
--- a/packages/imhotep-solver/src/predicates.ts
+++ b/packages/imhotep-solver/src/predicates.ts
@@ -166,17 +166,17 @@ export function getRequiredFactsForPredicate(name: string): string[] {
 // Built-in Predicate Evaluators
 // ---------------------------------------------------------------------------
 
+const boxIndexCache = new WeakMap<GeometryWorld, Map<number, number>>()
+
 function getBorderRect(world: GeometryWorld, subjectId: number) {
   const { boxes } = world;
-  // Build a subjectId -> boxIndex map on first use for O(1) lookups.
-  // This avoids O(n) linear scans on every predicate evaluation.
-  let index = (world as any).__boxIndex as Map<number, number> | undefined;
+  let index = boxIndexCache.get(world);
   if (!index) {
     index = new Map<number, number>();
     for (let i = 0; i < boxes.subjectId.length; i++) {
       index.set(boxes.subjectId[i], i);
     }
-    (world as any).__boxIndex = index;
+    boxIndexCache.set(world, index);
   }
   const i = index.get(subjectId);
   if (i === undefined) {