diff --git a/.pr_agent_accepted_suggestions.md b/.pr_agent_accepted_suggestions.md
index 1cccb42..e88e1b1 100644
--- a/.pr_agent_accepted_suggestions.md
+++ b/.pr_agent_accepted_suggestions.md
@@ -1,3 +1,145 @@
+<!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='https://github.com/gnh1201/welsonjs/pull/320#issuecomment-3204803405'>PR 320</a></b> (2025-08-20)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
+
+</td></tr></table>
+
+
+
+<!-- suggestion --><details><summary>[possible issue]  Handle empty/invalid inputs safely</summary>
+
+___
+
+✅ Handle empty/invalid inputs safely
+
+**Guard against empty coords after validation; current code will use Math.min/max on empty arrays, yielding Infinity/-Infinity and NaN density. Return false if no valid cells remain. Also coerce minDensity to a number and clamp between 0 and 1 to avoid unexpected truthy strings.**
+
+[lib/extramath.js [73-106]](https://github.com/gnh1201/welsonjs/pull/320/files#diff-d76f6c7464ea00689b45d5f11872891148869f73e11c497d62d14602ea486bbdR73-R106)
+
+```diff
+ function clusteredCellsDensity(numbers, size, minDensity) {
+-    if (!numbers || !numbers.length) return false;
+-    if (typeof size !== 'number' || size <= 0) size = 4; // default grid size = 4
+-    if (typeof minDensity === 'undefined') minDensity = 0.6;
++    if (!Array.isArray(numbers) || numbers.length === 0) return false;
++    if (typeof size !== 'number' || size <= 0) size = 4;
++    if (typeof minDensity !== 'number' || isNaN(minDensity)) minDensity = 0.6;
++    if (minDensity < 0) minDensity = 0;
++    if (minDensity > 1) minDensity = 1;
+ 
+-    var maxIndex = size * size; // because it's 1-based (1..size*size)
++    var maxIndex = size * size;
+ 
+-    // 1. Convert cell number → (x,y) coordinates with 1-based check
+     var coords = [];
+     for (var i = 0; i < numbers.length; i++) {
+-    var n = numbers[i];
+-    // must be within 1..maxIndex
+-    if (typeof n !== 'number' || n < 1 || n > maxIndex) {
+-      return false; // invalid index -> immediately return false
+-    }
+-    var idx = n - 1; // shift to 0-based
++        var n = numbers[i];
++        if (typeof n !== 'number' || !isFinite(n) || n % 1 !== 0 || n < 1 || n > maxIndex) {
++            return false;
++        }
++        var idx = n - 1;
+         coords.push({ x: idx % size, y: Math.floor(idx / size) });
+     }
++
++    if (coords.length === 0) return false;
+ 
+     var xs = coords.map(function (c) { return c.x; });
+     var ys = coords.map(function (c) { return c.y; });
+ 
+-    // 2. Compute bounding box of selected cells
+     var minX = Math.min.apply(Math, xs), maxX = Math.max.apply(Math, xs);
+     var minY = Math.min.apply(Math, ys), maxY = Math.max.apply(Math, ys);
+ 
+-    // 3. Compute area and density
+-    var w = maxX - minX + 1;
+-    var h = maxY - minY + 1;
++    var w = (maxX - minX + 1);
++    var h = (maxY - minY + 1);
+     var boxArea = w * h;
++    if (!isFinite(boxArea) || boxArea <= 0) return false;
+ 
+     var density = coords.length / boxArea;
+     return density >= minDensity;
+ }
+```
+
+
+
+
+
+Suggestion importance[1-10]: 8
+
+__
+
+Why: The suggestion correctly points out that if all numbers in the input array are invalid, `coords` will be empty, causing `Math.min`/`max` to return `Infinity`, leading to a `NaN` density.
+
+___
+
+</details>
+
+
+
+<!-- suggestion --><details><summary>[general]  Validate tile position inputs</summary>
+
+___
+
+✅ Validate tile position inputs
+
+**Add input validation to prevent NaN/Infinity when tiles is zero/negative or index is out of range. Clamp col/row to non-negative and return null for invalid arguments to avoid propagating bad coordinates.**
+
+[lib/extramath.js [108-119]](https://github.com/gnh1201/welsonjs/pull/320/files#diff-d76f6c7464ea00689b45d5f11872891148869f73e11c497d62d14602ea486bbdR108-R119)
+
+```diff
+-function estimateTileStartPosition(index, tiles, spreadSize, gap) {  
++function estimateTileStartPosition(index, tiles, spreadSize, gap) {
++    if (typeof tiles !== 'number' || tiles <= 0) return null;
++    if (typeof spreadSize !== 'number' || !isFinite(spreadSize)) return null;
++    if (typeof gap !== 'number' || !isFinite(gap) || gap < 0) gap = 0;
++    if (typeof index !== 'number' || !isFinite(index) || index % 1 !== 0 || index < 1) return null;
++
++    var totalSlots = tiles * tiles;
++    if (index > totalSlots) return null;
++
+     var tileSize = (spreadSize - gap * (tiles - 1)) / tiles;
++    if (!isFinite(tileSize)) return null;
+ 
+     var i = index - 1;
+     var col = i % tiles;
+     var row = Math.floor(i / tiles);
+-  
+-    return {  
+-        x: col * (tileSize + gap),
+-        y: row * (tileSize + gap)
++
++    return {
++        x: Math.max(0, col) * (tileSize + gap),
++        y: Math.max(0, row) * (tileSize + gap)
+     };
+ }
+```
+
+
+
+
+
+Suggestion importance[1-10]: 8
+
+__
+
+Why: The suggestion correctly identifies that if `tiles` is zero, a division by zero will occur, resulting in `NaN`/`Infinity` values, and proposes adding necessary input validation.
+
+___
+
+</details>
+
+___
+
+
+
 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='https://github.com/gnh1201/welsonjs/pull/318#issuecomment-3194328108'>PR 318</a></b> (2025-08-17)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 </td></tr></table>
@@ -165,6 +307,8 @@ ___
 
 
 
+
+
 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='https://github.com/gnh1201/welsonjs/pull/309#issuecomment-3172799544'>PR 309</a></b> (2025-08-10)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 </td></tr></table>
@@ -209,6 +353,8 @@ ___
 
 
 
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='https://github.com/gnh1201/welsonjs/pull/307#issuecomment-3154116053'>PR 307</a></b> (2025-08-05)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 </td></tr></table>
@@ -302,6 +448,8 @@ ___
 
 
 
+
+
 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='3055522397'>PR 284</a></b> (2025-07-10)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 </td></tr></table>
@@ -374,6 +522,8 @@ ___
 
 
 
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='3006712754'>PR 279</a></b> (2025-06-26)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
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@@ -428,6 +578,8 @@ ___
 
 
 
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='2982794401'>PR 276</a></b> (2025-06-18)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 </td></tr></table>
@@ -479,6 +631,8 @@ ___
 
 
 
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='2953770469'>PR 272</a></b> (2025-06-08)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
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@@ -540,6 +694,8 @@ ___
 
 
 
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='2868572186'>PR 249</a></b> (2025-05-10)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
 </td></tr></table>
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='2868568893'>PR 248</a></b> (2025-05-10)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
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 <!-- PR --><table><tr><td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <b><a href='2850302530'>PR 245</a></b> (2025-05-05)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 
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