diff --git a/packages/sdk/src/index.e2e.test.ts b/packages/sdk/src/index.e2e.test.ts
index 99592e1..6e863a1 100644
--- a/packages/sdk/src/index.e2e.test.ts
+++ b/packages/sdk/src/index.e2e.test.ts
@@ -267,3 +267,29 @@ describe('suggestPrSummary', () => {
     }
   }, 60000); // 60 seconds timeout for AI operations
 });
+
+describe('regenerateDiagram', () => {
+  it('should regenerate a diagram from updated source files', async () => {
+    const code = `flowchart TD\n  A[Start] --> B[Process]\n  B --> C[End]`;
+    const sourceFiles = [
+      'function processOrder(order) {\n  validateOrder(order);\n  shipOrder(order);\n}',
+    ];
+
+    try {
+      const result = await client.regenerateDiagram({
+        code,
+        sourceFiles,
+      });
+
+      // Verify response structure
+      expect(result).toHaveProperty('result');
+      expect(result).toHaveProperty('code');
+      expect(['ok', 'fail']).toContain(result.result);
+    } catch (error) {
+      if (error instanceof AICreditsLimitExceededError) {
+        return; // Credits exceeded is acceptable for E2E test
+      }
+      throw error;
+    }
+  }, 60000); // 60 seconds timeout for AI operations
+});
diff --git a/packages/sdk/src/index.test.ts b/packages/sdk/src/index.test.ts
index a3d9b3b..e744549 100644
--- a/packages/sdk/src/index.test.ts
+++ b/packages/sdk/src/index.test.ts
@@ -220,4 +220,75 @@ describe('MermaidChart', () => {
       ).rejects.toThrow(AICreditsLimitExceededError);
     });
   });
+
+  describe('#regenerateDiagram', () => {
+    beforeEach(async () => {
+      await client.setAccessToken('test-access-token');
+    });
+
+    it('should POST to the regenerate endpoint with the request body and return response.data', async () => {
+      const jsonResponse = {
+        result: 'ok' as const,
+        code: '```mermaid\nflowchart TD\n  A --> B --> C\n```',
+        solved: true,
+      };
+
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const postSpy = vi.spyOn((client as any).axios, 'post').mockResolvedValue({
+        data: jsonResponse,
+      });
+
+      const requestBody = {
+        code: 'flowchart TD\n  A --> B',
+        sourceFiles: ['const x = 1;', 'function foo() {}'],
+      };
+
+      const result = await client.regenerateDiagram(requestBody);
+
+      expect(postSpy).toHaveBeenCalledWith(URLS.rest.openai.regenerate, requestBody);
+      expect(result).toEqual(jsonResponse);
+    });
+
+    it('should include creditUsage in response when present', async () => {
+      const jsonResponse = {
+        result: 'ok' as const,
+        code: '```mermaid\nflowchart TD\n  A --> B\n```',
+        solved: true,
+        creditUsage: {
+          creditsToDeduct: 1,
+          baseCost: 1,
+          reason: 'regeneration',
+        },
+      };
+
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      vi.spyOn((client as any).axios, 'post').mockResolvedValue({
+        data: jsonResponse,
+      });
+
+      const result = await client.regenerateDiagram({
+        code: 'flowchart TD\n  A --> B',
+        sourceFiles: ['const x = 1;'],
+      });
+
+      expect(result.creditUsage).toEqual(jsonResponse.creditUsage);
+    });
+
+    it('should throw AICreditsLimitExceededError on 402', async () => {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      vi.spyOn((client as any).axios, 'post').mockRejectedValue({
+        response: {
+          status: 402,
+          data: 'AI credits limit exceeded',
+        },
+      });
+
+      await expect(
+        client.regenerateDiagram({
+          code: 'flowchart TD\n  A --> B',
+          sourceFiles: [],
+        }),
+      ).rejects.toThrow(AICreditsLimitExceededError);
+    });
+  });
 });
diff --git a/packages/sdk/src/index.ts b/packages/sdk/src/index.ts
index 4ffe783..9200077 100644
--- a/packages/sdk/src/index.ts
+++ b/packages/sdk/src/index.ts
@@ -21,6 +21,8 @@ import type {
   RepairDiagramResponse,
   PrSummaryRequest,
   PrSummaryResponse,
+  RegenerateDiagramRequest,
+  RegenerateDiagramResponse,
   AICreditsUsage,
 } from './types.js';
 import { URLS } from './urls.js';
@@ -351,6 +353,26 @@ export class MermaidChart {
     }
   }
 
+  /**
+   * Regenerates a Mermaid diagram based on updated source files using AI.
+   *
+   * @param request - `code` (current diagram source) and `sourceFiles` (full contents of related source files)
+   * @throws {@link AICreditsLimitExceededError} if credits limit exceeded (HTTP 402)
+   */
+  public async regenerateDiagram(
+    request: RegenerateDiagramRequest,
+  ): Promise<RegenerateDiagramResponse> {
+    try {
+      const response = await this.axios.post<RegenerateDiagramResponse>(
+        URLS.rest.openai.regenerate,
+        request,
+      );
+      return response.data;
+    } catch (error: unknown) {
+      throwIfAICreditsExceeded(error);
+    }
+  }
+
   /**
    * Chat with Mermaid AI about a diagram.
    *
diff --git a/packages/sdk/src/types.ts b/packages/sdk/src/types.ts
index 029733b..08e4578 100644
--- a/packages/sdk/src/types.ts
+++ b/packages/sdk/src/types.ts
@@ -114,6 +114,42 @@ export interface PrSummaryResponse {
   commitMessage: string;
 }
 
+/**
+ * Request parameters for regenerating a Mermaid diagram from updated source files.
+ */
+export interface RegenerateDiagramRequest {
+  /** The current Mermaid diagram source to be regenerated. */
+  code: string;
+  /** Ordered full contents of the source files that the diagram is based on. */
+  sourceFiles: string[];
+}
+
+/**
+ * Response from regenerating a Mermaid diagram.
+ */
+export interface RegenerateDiagramResponse {
+  /**
+   * The status of the regeneration: 'ok' if a valid mermaid code block was generated, 'fail' otherwise.
+   */
+  result: 'ok' | 'fail';
+  /**
+   * Markdown message that may contain a valid mermaid code block.
+   */
+  code: string;
+  /**
+   * Whether the diagram regeneration was successful.
+   */
+  solved?: boolean;
+  /**
+   * Credit usage for client-side deduction (only present when solved).
+   */
+  creditUsage?: {
+    creditsToDeduct: number;
+    baseCost: number;
+    reason: string;
+  };
+}
+
 /**
  * Request parameters for chatting with the Mermaid AI about a diagram.
  */
diff --git a/packages/sdk/src/urls.ts b/packages/sdk/src/urls.ts
index 54d53f3..d525eac 100644
--- a/packages/sdk/src/urls.ts
+++ b/packages/sdk/src/urls.ts
@@ -42,6 +42,7 @@ export const URLS = {
     openai: {
       repair: `/rest-api/openai/repair`,
       prSummary: `/rest-api/openai/pr-summary`,
+      regenerate: `/rest-api/openai/regenerate`,
       chat: `/rest-api/openai/chat`,
     },
   },