diff --git a/packages/core/src/core/prompts.test.ts b/packages/core/src/core/prompts.test.ts
index bb7b0b52..028f044f 100644
--- a/packages/core/src/core/prompts.test.ts
+++ b/packages/core/src/core/prompts.test.ts
@@ -106,3 +106,96 @@ describe('Core System Prompt (prompts.ts)', () => {
     expect(prompt).toMatchSnapshot();
   });
 });
+
+describe('URL matching with trailing slash compatibility', () => {
+  it('should match URLs with and without trailing slash', () => {
+    const config = {
+      systemPromptMappings: [
+        {
+          baseUrls: ['https://api.example.com'],
+          modelNames: ['gpt-4'],
+          template: 'Custom template for example.com',
+        },
+        {
+          baseUrls: ['https://api.openai.com/'],
+          modelNames: ['gpt-3.5-turbo'],
+          template: 'Custom template for openai.com',
+        },
+      ],
+    };
+
+    // Simulate environment variables
+    const originalEnv = process.env;
+
+    // Test case 1: No trailing slash in config, actual URL has trailing slash
+    process.env = {
+      ...originalEnv,
+      OPENAI_BASE_URL: 'https://api.example.com/',
+      OPENAI_MODEL: 'gpt-4',
+    };
+
+    const result1 = getCoreSystemPrompt(undefined, config);
+    expect(result1).toContain('Custom template for example.com');
+
+    // Test case 2: Config has trailing slash, actual URL has no trailing slash
+    process.env = {
+      ...originalEnv,
+      OPENAI_BASE_URL: 'https://api.openai.com',
+      OPENAI_MODEL: 'gpt-3.5-turbo',
+    };
+
+    const result2 = getCoreSystemPrompt(undefined, config);
+    expect(result2).toContain('Custom template for openai.com');
+
+    // Test case 3: No trailing slash in config, actual URL has no trailing slash
+    process.env = {
+      ...originalEnv,
+      OPENAI_BASE_URL: 'https://api.example.com',
+      OPENAI_MODEL: 'gpt-4',
+    };
+
+    const result3 = getCoreSystemPrompt(undefined, config);
+    expect(result3).toContain('Custom template for example.com');
+
+    // Test case 4: Config has trailing slash, actual URL has trailing slash
+    process.env = {
+      ...originalEnv,
+      OPENAI_BASE_URL: 'https://api.openai.com/',
+      OPENAI_MODEL: 'gpt-3.5-turbo',
+    };
+
+    const result4 = getCoreSystemPrompt(undefined, config);
+    expect(result4).toContain('Custom template for openai.com');
+
+    // Restore original environment variables
+    process.env = originalEnv;
+  });
+
+  it('should not match when URLs are different', () => {
+    const config = {
+      systemPromptMappings: [
+        {
+          baseUrls: ['https://api.example.com'],
+          modelNames: ['gpt-4'],
+          template: 'Custom template for example.com',
+        },
+      ],
+    };
+
+    const originalEnv = process.env;
+
+    // Test case: URLs do not match
+    process.env = {
+      ...originalEnv,
+      OPENAI_BASE_URL: 'https://api.different.com',
+      OPENAI_MODEL: 'gpt-4',
+    };
+
+    const result = getCoreSystemPrompt(undefined, config);
+    // Should return default template, not contain custom template
+    expect(result).not.toContain('Custom template for example.com');
+
+    // Restore original environment variables
+    process.env = originalEnv;
+  });
+});
diff --git a/packages/core/src/core/prompts.ts b/packages/core/src/core/prompts.ts
index 09b1d60e..664501d9 100644
--- a/packages/core/src/core/prompts.ts
+++ b/packages/core/src/core/prompts.ts
@@ -28,6 +28,21 @@ export interface SystemPromptConfig {
   systemPromptMappings?: ModelTemplateMapping[];
 }
 
+/**
+ * Normalizes a URL by removing trailing slash for consistent comparison
+ */
+function normalizeUrl(url: string): string {
+  return url.endsWith('/') ? url.slice(0, -1) : url;
+}
+
+/**
+ * Checks if a URL matches any URL in the array, ignoring trailing slashes
+ */
+function urlMatches(urlArray: string[], targetUrl: string): boolean {
+  const normalizedTarget = normalizeUrl(targetUrl);
+  return urlArray.some((url) => normalizeUrl(url) === normalizedTarget);
+}
+
 export function getCoreSystemPrompt(
   userMemory?: string,
   config?: SystemPromptConfig,
@@ -59,13 +74,13 @@ export function getCoreSystemPrompt(
       if (
         baseUrls &&
         modelNames &&
-        baseUrls.includes(currentBaseUrl) &&
+        urlMatches(baseUrls, currentBaseUrl) &&
         modelNames.includes(currentModel)
       ) {
         return true;
       }
 
-      if (baseUrls && baseUrls.includes(currentBaseUrl) && !modelNames) {
+      if (baseUrls && urlMatches(baseUrls, currentBaseUrl) && !modelNames) {
         return true;
       }
       if (modelNames && modelNames.includes(currentModel) && !baseUrls) {