diff --git a/src/Netclaw.Actors.Tests/Tools/MetaFieldResolutionTests.cs b/src/Netclaw.Actors.Tests/Tools/MetaFieldResolutionTests.cs
index cb4f8e107..137d446c1 100644
--- a/src/Netclaw.Actors.Tests/Tools/MetaFieldResolutionTests.cs
+++ b/src/Netclaw.Actors.Tests/Tools/MetaFieldResolutionTests.cs
@@ -25,7 +25,9 @@ public class MetaFieldResolutionTests
     [Theory]
     [InlineData("_rationale", "_rationale")]
     [InlineData("Rationale", "_rationale")]
+    [InlineData("r_rationale", "_rationale")]
     [InlineData("rationale", "_rationale")]
+    [InlineData("rationalle", "_rationale")]
     [InlineData("_timeout_seconds", "_timeout_seconds")]
     [InlineData("TimeoutSeconds", "_timeout_seconds")]
     [InlineData("timeout_seconds", "_timeout_seconds")]
diff --git a/src/Netclaw.Tools.Abstractions/FuzzyMatcher.cs b/src/Netclaw.Tools.Abstractions/FuzzyMatcher.cs
new file mode 100644
index 000000000..414014152
--- /dev/null
+++ b/src/Netclaw.Tools.Abstractions/FuzzyMatcher.cs
@@ -0,0 +1,64 @@
+
+// -----------------------------------------------------------------------
+// <copyright file="FuzzyMatcher.cs" company="Petabridge, LLC">
+//      Copyright (C) 2026 - 2026 Petabridge, LLC <https://petabridge.com>
+// </copyright>
+// -----------------------------------------------------------------------
+using System.Linq;
+
+namespace Netclaw.Tools
+{
+    public static class FuzzyMatcher
+    {
+        public static string? FindBestMatch(string input, System.Collections.Generic.IEnumerable<string> candidates, double threshold = 0.75)
+        {
+            if (string.IsNullOrWhiteSpace(input)) return null;
+            var normalisedInput = Normalise(input);
+            if (normalisedInput.Length == 0) return null;
+
+            string? bestMatch = null;
+            double bestScore = 0;
+
+            foreach (var candidate in candidates)
+            {
+                var normalisedCandidate = Normalise(candidate);
+                if (normalisedCandidate.Length == 0) continue;
+                double score = Similarity(normalisedInput, normalisedCandidate);
+                if (normalisedCandidate.Contains(normalisedInput, StringComparison.Ordinal)) score = System.Math.Max(score, 0.85);
+                if (score > bestScore)
+                {
+                    bestScore = score;
+                    bestMatch = candidate;
+                }
+            }
+
+            return bestScore >= threshold ? bestMatch : null;
+        }
+
+        private static string Normalise(string value) =>
+            new string(value.Where(char.IsLetterOrDigit).Select(char.ToLowerInvariant).ToArray());
+
+        private static double Similarity(string a, string b)
+        {
+            int distance = LevenshteinDistance(a, b);
+            return 1.0 - (double)distance / System.Math.Max(a.Length, b.Length);
+        }
+
+        private static int LevenshteinDistance(string a, string b)
+        {
+            var previous = System.Linq.Enumerable.Range(0, b.Length + 1).ToArray();
+            var current = new int[b.Length + 1];
+            for (int i = 1; i <= a.Length; i++)
+            {
+                current[0] = i;
+                for (int j = 1; j <= b.Length; j++)
+                {
+                    int cost = a[i - 1] == b[j - 1] ? 0 : 1;
+                    current[j] = System.Math.Min(System.Math.Min(current[j - 1] + 1, previous[j] + 1), previous[j - 1] + cost);
+                }
+                (previous, current) = (current, previous);
+            }
+            return previous[b.Length];
+        }
+    }
+}
diff --git a/src/Netclaw.Tools.Abstractions/ToolArgumentHelper.cs b/src/Netclaw.Tools.Abstractions/ToolArgumentHelper.cs
index 4595fa999..f488855c1 100644
--- a/src/Netclaw.Tools.Abstractions/ToolArgumentHelper.cs
+++ b/src/Netclaw.Tools.Abstractions/ToolArgumentHelper.cs
@@ -112,11 +112,7 @@ private static Dictionary<string, string> BuildNormalizedMetaFields()
     {
         var map = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
         foreach (var canonical in ToolCallMeta.MetaFieldNames)
-            map[NormalizeKey(canonical)] = canonical;
-
-        map["timeout"] = "_timeout_seconds";
-        map["rational"] = "_rationale";
-        map["rationalle"] = "_rationale";
+            map[NormalizeKey(canonical)] = canonical;            
         return map;
     }
 
@@ -132,7 +128,15 @@ private static Dictionary<string, string> BuildNormalizedMetaFields()
     public static string? ResolveMetaField(string? key)
         => string.IsNullOrWhiteSpace(key)
             ? null
-            : NormalizedMetaFields.TryGetValue(NormalizeKey(key), out var canonical) ? canonical : null;
+            : NormalizedMetaFields.TryGetValue(NormalizeKey(key), out var canonical)
+                ? canonical
+                : FuzzyMatchUnmatched(key);
+
+    private static string? FuzzyMatchUnmatched(string key)
+    {
+        const double threshold = 0.75;
+        return FuzzyMatcher.FindBestMatch(key, ToolCallMeta.MetaFieldNames, threshold);
+    }
 
     public static string? GetString(IDictionary<string, object?>? arguments, string key)
     {