diff --git a/packages/imhotep-solver/src/proofs.ts b/packages/imhotep-solver/src/proofs.ts
index aac024b..8676f57 100644
--- a/packages/imhotep-solver/src/proofs.ts
+++ b/packages/imhotep-solver/src/proofs.ts
@@ -59,9 +59,20 @@ function buildFailedPredicate(
 
   // --- Directional gap (leftOf / rightOf / above / below) ---
   if (hasGap) {
-    const gap = metrics.observedGap ?? metrics.gap ?? 0;
+    const gap = metrics.observedGap ?? metrics.gap;
+    if (gap === undefined) return undefined;
     const min = metrics.minGap ?? 0;
     const max = metrics.maxGap ?? Infinity;
+    const hasSubjectRect =
+      metrics.subjectLeft !== undefined &&
+      metrics.subjectTop !== undefined &&
+      metrics.subjectRight !== undefined &&
+      metrics.subjectBottom !== undefined;
+    const hasRefRect =
+      metrics.refLeft !== undefined &&
+      metrics.refTop !== undefined &&
+      metrics.refRight !== undefined &&
+      metrics.refBottom !== undefined;
     return {
       ...base,
       op: gap < min ? '<' : '>',
@@ -70,68 +81,71 @@ function buildFailedPredicate(
       measuredGap: gap,
       expectedMinGap: Number.isFinite(min) ? min : undefined,
       expectedMaxGap: Number.isFinite(max) ? max : undefined,
-      subjectRect:
-        metrics.subjectLeft !== undefined
-          ? {
-              left: metrics.subjectLeft,
-              top: metrics.subjectTop ?? 0,
-              right: metrics.subjectRight ?? 0,
-              bottom: metrics.subjectBottom ?? 0,
-            }
-          : undefined,
-      referenceRect:
-        metrics.refLeft !== undefined
-          ? {
-              left: metrics.refLeft,
-              top: metrics.refTop ?? 0,
-              right: metrics.refRight ?? 0,
-              bottom: metrics.refBottom ?? 0,
-            }
-          : undefined,
+      subjectRect: hasSubjectRect
+        ? {
+            left: metrics.subjectLeft,
+            top: metrics.subjectTop,
+            right: metrics.subjectRight,
+            bottom: metrics.subjectBottom,
+          }
+        : undefined,
+      referenceRect: hasRefRect
+        ? {
+            left: metrics.refLeft,
+            top: metrics.refTop,
+            right: metrics.refRight,
+            bottom: metrics.refBottom,
+          }
+        : undefined,
     };
   }
 
   // --- Containment / inside (unique overflow metrics) ---
   if (kind === 'inside') {
-    const overflowLeft = metrics.overflowLeft ?? 0;
-    const overflowTop = metrics.overflowTop ?? 0;
-    const overflowRight = metrics.overflowRight ?? 0;
-    const overflowBottom = metrics.overflowBottom ?? 0;
+    const hasSubjectRect =
+      metrics.subjectLeft !== undefined &&
+      metrics.subjectTop !== undefined &&
+      metrics.subjectRight !== undefined &&
+      metrics.subjectBottom !== undefined;
+    const hasRefRect =
+      metrics.refLeft !== undefined &&
+      metrics.refTop !== undefined &&
+      metrics.refRight !== undefined &&
+      metrics.refBottom !== undefined;
     return {
       ...base,
       op: 'not-contained',
       left: 0,
       right: 0,
       overflowEdges: {
-        left: overflowLeft,
-        top: overflowTop,
-        right: overflowRight,
-        bottom: overflowBottom,
+        left: metrics.overflowLeft ?? 0,
+        top: metrics.overflowTop ?? 0,
+        right: metrics.overflowRight ?? 0,
+        bottom: metrics.overflowBottom ?? 0,
       },
-      subjectRect:
-        metrics.subjectLeft !== undefined
-          ? {
-              left: metrics.subjectLeft,
-              top: metrics.subjectTop ?? 0,
-              right: metrics.subjectRight ?? 0,
-              bottom: metrics.subjectBottom ?? 0,
-            }
-          : undefined,
-      referenceRect:
-        metrics.refLeft !== undefined
-          ? {
-              left: metrics.refLeft,
-              top: metrics.refTop ?? 0,
-              right: metrics.refRight ?? 0,
-              bottom: metrics.refBottom ?? 0,
-            }
-          : undefined,
+      subjectRect: hasSubjectRect
+        ? {
+            left: metrics.subjectLeft,
+            top: metrics.subjectTop,
+            right: metrics.subjectRight,
+            bottom: metrics.subjectBottom,
+          }
+        : undefined,
+      referenceRect: hasRefRect
+        ? {
+            left: metrics.refLeft,
+            top: metrics.refTop,
+            right: metrics.refRight,
+            bottom: metrics.refBottom,
+          }
+        : undefined,
     };
   }
 
   // --- Size threshold (atLeast / atMost / between) ---
   if (isSize && kind !== 'aspectRatio') {
-    const observed = metrics.observed ?? metrics.value ?? 0;
+    const observed = metrics.observed ?? metrics.value;
+    if (observed === undefined) return undefined;
     const min = metrics.min ?? -Infinity;
     const max = metrics.max ?? Infinity;
     return {
@@ -147,7 +161,8 @@ function buildFailedPredicate(
 
   // --- Aspect ratio ---
   if (kind === 'aspectRatio') {
-    const observed = metrics.observed ?? 0;
+    const observed = metrics.observed;
+    if (observed === undefined) return undefined;
     const minRatio = metrics.minRatio ?? -Infinity;
     const maxRatio = metrics.maxRatio ?? Infinity;
     return {
@@ -163,7 +178,8 @@ function buildFailedPredicate(
 
   // --- Alignment (alignedWith / centeredWithin) ---
   if (hasAxis || kind === 'centeredWithin') {
-    const delta = metrics.delta ?? metrics.deltaX ?? metrics.deltaY ?? 0;
+    const delta = metrics.delta ?? metrics.deltaX ?? metrics.deltaY;
+    if (delta === undefined) return undefined;
     const tolerance = metrics.tolerance ?? 0;
     return {
       ...base,
@@ -188,16 +204,21 @@ function synthesizeGenericFailedPredicate(
 ): Proof['failedPredicate'] {
   const keys = Object.keys(metrics);
   if (keys.length >= 2) {
+    const left = metrics[keys[0]];
+    const right = metrics[keys[1]];
+    if (left === undefined || right === undefined) return undefined;
     return {
       op: '<',
-      left: metrics[keys[0]] ?? 0,
-      right: metrics[keys[1]] ?? 0,
+      left,
+      right,
     };
   }
   if (keys.length === 1) {
+    const val = metrics[keys[0]];
+    if (val === undefined) return undefined;
     return {
       op: '<',
-      left: metrics[keys[0]] ?? 0,
+      left: val,
       right: 0,
     };
   }