tools: avoid matching braces that are part of tool content (#12039)

tools/tools.go

@@ -224,22 +224,45 @@ func findArguments(buffer []byte) (map[string]any, int) {
 		return nil, 0
 	}
 
+	start := -1
 	var braces int
-	var start int = -1
+	var inString, escaped bool
+
+	for i := range buffer {
+		c := buffer[i]
+
+		if escaped {
+			escaped = false
+			continue
+		}
+
+		if c == '\\' {
+			escaped = true
+			continue
+		}
+
+		if c == '"' {
+			inString = !inString
+			continue
+		}
+
+		if inString {
+			continue
+		}
 
-	for i, c := range buffer {
 		if c == '{' {
 			if braces == 0 {
 				start = i
 			}
 			braces++
-		} else if c == '}' && braces > 0 {
+		} else if c == '}' {
 			braces--
 			if braces == 0 && start != -1 {
 				object := buffer[start : i+1]
 
 				var data map[string]any
 				if err := json.Unmarshal(object, &data); err != nil {
+					// not a valid object, keep looking
 					start = -1
 					continue
 				}
@@ -282,6 +305,10 @@ func findArguments(buffer []byte) (map[string]any, int) {
 
 				return data, i
 			}
+
+			if braces < 0 {
+				braces = 0
+			}
 		}
 	}