diff --git a/src/index.ts b/src/index.ts
index c1c6246..5442c9d 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -146,6 +146,22 @@ export {
   handleSonarQubeUpdateHotspotStatus,
 } from './handlers/index.js';
 
+// Helper function to parse JSON string arrays in parameters
+function parseArrayParameters(params: Record<string, unknown>, paramNames: string[]): void {
+  for (const key of paramNames) {
+    if (typeof params[key] === 'string') {
+      try {
+        const parsed = JSON.parse(params[key] as string);
+        if (Array.isArray(parsed)) {
+          params[key] = parsed;
+        }
+      } catch {
+        // Not valid JSON, keep as string for backward compatibility
+      }
+    }
+  }
+}
+
 // Lambda functions for the MCP tools
 /**
  * Lambda function for projects tool
@@ -166,6 +182,16 @@ export const metricsHandler = async (params: { page: number | null; page_size: n
  * Lambda function for issues tool
  */
 export const issuesHandler = async (params: Record<string, unknown>) => {
+  // Parse JSON strings to arrays for array parameters
+  parseArrayParameters(params, [
+    'projects', 'component_keys', 'components', 'directories', 'files', 
+    'scopes', 'issues', 'severities', 'statuses', 'resolutions', 'types',
+    'clean_code_attribute_categories', 'impact_severities', 'impact_software_qualities',
+    'issue_statuses', 'rules', 'tags', 'assignees', 'authors', 'cwe',
+    'owasp_top10', 'owasp_top10_v2021', 'sans_top25', 'sonarsource_security',
+    'sonarsource_security_category', 'languages', 'facets', 'additional_fields'
+  ]);
+  
   return handleSonarQubeGetIssues(mapToSonarQubeParams(params));
 };
 
diff --git a/src/schemas/common.ts b/src/schemas/common.ts
index 86ae5e2..e109390 100644
--- a/src/schemas/common.ts
+++ b/src/schemas/common.ts
@@ -13,102 +13,40 @@ export const severitySchema = z
 
 export const severitiesSchema = z
   .union([z.array(z.enum(['INFO', 'MINOR', 'MAJOR', 'CRITICAL', 'BLOCKER'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid severities
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) => ['INFO', 'MINOR', 'MAJOR', 'CRITICAL', 'BLOCKER'].includes(v));
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
 // Status schemas
 export const statusSchema = z
   .union([z.array(z.enum(['OPEN', 'CONFIRMED', 'REOPENED', 'RESOLVED', 'CLOSED'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid statuses
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) =>
-        ['OPEN', 'CONFIRMED', 'REOPENED', 'RESOLVED', 'CLOSED'].includes(v)
-      );
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
 // Resolution schemas
 export const resolutionSchema = z
   .union([z.array(z.enum(['FALSE-POSITIVE', 'WONTFIX', 'FIXED', 'REMOVED'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid resolutions
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) => ['FALSE-POSITIVE', 'WONTFIX', 'FIXED', 'REMOVED'].includes(v));
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
 // Type schemas
 export const typeSchema = z
   .union([z.array(z.enum(['CODE_SMELL', 'BUG', 'VULNERABILITY', 'SECURITY_HOTSPOT'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid types
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) =>
-        ['CODE_SMELL', 'BUG', 'VULNERABILITY', 'SECURITY_HOTSPOT'].includes(v)
-      );
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
 // Clean Code taxonomy schemas
 export const cleanCodeAttributeCategoriesSchema = z
   .union([z.array(z.enum(['ADAPTABLE', 'CONSISTENT', 'INTENTIONAL', 'RESPONSIBLE'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid categories
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) =>
-        ['ADAPTABLE', 'CONSISTENT', 'INTENTIONAL', 'RESPONSIBLE'].includes(v)
-      );
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
 export const impactSeveritiesSchema = z
   .union([z.array(z.enum(['HIGH', 'MEDIUM', 'LOW'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid impact severities
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) => ['HIGH', 'MEDIUM', 'LOW'].includes(v));
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
 export const impactSoftwareQualitiesSchema = z
   .union([z.array(z.enum(['MAINTAINABILITY', 'RELIABILITY', 'SECURITY'])), z.string()])
-  .transform((val) => {
-    const parsed = parseJsonStringArray(val);
-    // Validate that all values are valid software qualities
-    if (parsed && Array.isArray(parsed)) {
-      return parsed.filter((v) => ['MAINTAINABILITY', 'RELIABILITY', 'SECURITY'].includes(v));
-    }
-    return parsed;
-  })
   .nullable()
   .optional();
 
diff --git a/src/schemas/issues.ts b/src/schemas/issues.ts
index b32e05a..1990b0b 100644
--- a/src/schemas/issues.ts
+++ b/src/schemas/issues.ts
@@ -130,13 +130,11 @@ export const issuesToolSchema = {
   project_key: z.string().optional().describe('Single project key for backward compatibility'), // Made optional to support projects array
   projects: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe('Filter by project keys'),
   component_keys: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe(
@@ -144,7 +142,6 @@ export const issuesToolSchema = {
     ),
   components: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe('Alias for component_keys - filter by file paths, directories, or modules'),
@@ -155,26 +152,16 @@ export const issuesToolSchema = {
     .describe('Return only issues on the specified components, not on their sub-components'),
   directories: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe('Filter by directory paths'),
   files: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe('Filter by specific file paths'),
   scopes: z
     .union([z.array(z.enum(['MAIN', 'TEST', 'OVERALL'])), z.string()])
-    .transform((val) => {
-      const parsed = parseJsonStringArray(val);
-      // Validate that all values are valid scopes
-      if (parsed && Array.isArray(parsed)) {
-        return parsed.filter((v) => ['MAIN', 'TEST', 'OVERALL'].includes(v));
-      }
-      return parsed;
-    })
     .nullable()
     .optional()
     .describe('Filter by issue scopes (MAIN, TEST, OVERALL)'),
@@ -186,7 +173,6 @@ export const issuesToolSchema = {
   // Issue filters
   issues: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
   severity: severitySchema, // Deprecated single value
@@ -208,13 +194,11 @@ export const issuesToolSchema = {
   // Rules and tags
   rules: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe('Filter by rule keys'),
   tags: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe(
@@ -235,7 +219,6 @@ export const issuesToolSchema = {
     .describe('Filter to only assigned (true) or unassigned (false) issues'),
   assignees: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe(
@@ -244,7 +227,6 @@ export const issuesToolSchema = {
   author: z.string().nullable().optional().describe('Filter by single issue author'), // Single author
   authors: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe('Filter by multiple issue authors'), // Multiple authors
@@ -252,46 +234,38 @@ export const issuesToolSchema = {
   // Security standards
   cwe: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
   owasp_top10: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
   owasp_top10_v2021: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(), // New 2021 version
   sans_top25: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
   sonarsource_security: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
   sonarsource_security_category: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
 
   // Languages
   languages: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),
 
   // Facets
   facets: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional()
     .describe(
@@ -325,7 +299,6 @@ export const issuesToolSchema = {
   // Response optimization
   additional_fields: z
     .union([z.array(z.string()), z.string()])
-    .transform(parseJsonStringArray)
     .nullable()
     .optional(),