fix: return success response from void operations (AI-164) (#168)

* fix: return success response from void operations (AI-164)

- Add SuccessResponse type for operations that don't return data
- Update all void operations to return { success: true }
- Affected operations: pauseProject, restoreProject, deleteBranch,
  mergeBranch, resetBranch, rebaseBranch, applyMigration, updateStorageConfig
- Prevents LLMs from thinking operations failed and attempting retries

Fixes AI-164

* refactor: return SUCCESS_RESPONSE in tool layer instead of platform layer

- Keep Promise<void> return types in platform abstraction
- Return SUCCESS_RESPONSE in tool execute functions
- Affects: pauseProject, restoreProject, deleteBranch, mergeBranch, resetBranch, rebaseBranch, applyMigration, updateStorageConfig
- Avoids need to update hosted/self-hosted remote MCP implementations

Implements feedback from Matt's review on PR #168

Author: Rodriguespn

packages/mcp-server-supabase/src/platform/api-platform.ts

@@ -29,6 +29,7 @@ import {
   type DebuggingOperations,
   type DeployEdgeFunctionOptions,
   type DevelopmentOperations,
+  type SuccessResponse,
   type EdgeFunction,
   type EdgeFunctionsOperations,
   type EdgeFunctionWithBody,
@@ -42,6 +43,8 @@ import {
 
 const { version } = packageJson;
 
+const SUCCESS_RESPONSE: SuccessResponse = { success: true };
+
 export type SupabaseApiPlatformOptions = {
   /**
    * The access token for the Supabase Management API.
@@ -724,8 +727,6 @@ export function createSupabaseApiPlatform(
       );
 
       assertSuccess(response, 'Failed to update storage config');
-
-      return response.data;
     },
   };
 

packages/mcp-server-supabase/src/platform/types.ts

@@ -2,6 +2,10 @@ import type { InitData } from '@supabase/mcp-utils';
 import { z } from 'zod';
 import { AWS_REGION_CODES } from '../regions.js';
 
+export type SuccessResponse = {
+  success: true;
+};
+
 export const storageBucketSchema = z.object({
   id: z.string(),
   name: z.string(),
@@ -218,7 +222,10 @@ export type DevelopmentOperations = {
 
 export type StorageOperations = {
   getStorageConfig(projectId: string): Promise<StorageConfig>;
-  updateStorageConfig(projectId: string, config: StorageConfig): Promise<void>;
+  updateStorageConfig(
+    projectId: string,
+    config: StorageConfig
+  ): Promise<void>;
   listAllBuckets(projectId: string): Promise<StorageBucket[]>;
 };
 
@@ -230,7 +237,10 @@ export type BranchingOperations = {
   ): Promise<Branch>;
   deleteBranch(branchId: string): Promise<void>;
   mergeBranch(branchId: string): Promise<void>;
-  resetBranch(branchId: string, options: ResetBranchOptions): Promise<void>;
+  resetBranch(
+    branchId: string,
+    options: ResetBranchOptions
+  ): Promise<void>;
   rebaseBranch(branchId: string): Promise<void>;
 };
 

packages/mcp-server-supabase/src/tools/account-tools.ts

@@ -5,6 +5,8 @@ import { type Cost, getBranchCost, getNextProjectCost } from '../pricing.js';
 import { AWS_REGION_CODES } from '../regions.js';
 import { hashObject } from '../util.js';
 
+const SUCCESS_RESPONSE = { success: true };
+
 export type AccountToolsOptions = {
   account: AccountOperations;
   readOnly?: boolean;
@@ -187,7 +189,8 @@ export function getAccountTools({ account, readOnly }: AccountToolsOptions) {
           throw new Error('Cannot pause a project in read-only mode.');
         }
 
-        return await account.pauseProject(project_id);
+        await account.pauseProject(project_id);
+        return SUCCESS_RESPONSE;
       },
     }),
     restore_project: tool({
@@ -207,7 +210,8 @@ export function getAccountTools({ account, readOnly }: AccountToolsOptions) {
           throw new Error('Cannot restore a project in read-only mode.');
         }
 
-        return await account.restoreProject(project_id);
+        await account.restoreProject(project_id);
+        return SUCCESS_RESPONSE;
       },
     }),
   };

packages/mcp-server-supabase/src/tools/branching-tools.ts

@@ -5,6 +5,8 @@ import { getBranchCost } from '../pricing.js';
 import { hashObject } from '../util.js';
 import { injectableTool } from './util.js';
 
+const SUCCESS_RESPONSE = { success: true };
+
 export type BranchingToolsOptions = {
   branching: BranchingOperations;
   projectId?: string;
@@ -93,7 +95,8 @@ export function getBranchingTools({
           throw new Error('Cannot delete a branch in read-only mode.');
         }
 
-        return await branching.deleteBranch(branch_id);
+        await branching.deleteBranch(branch_id);
+        return SUCCESS_RESPONSE;
       },
     }),
     merge_branch: tool({
@@ -114,7 +117,8 @@ export function getBranchingTools({
           throw new Error('Cannot merge a branch in read-only mode.');
         }
 
-        return await branching.mergeBranch(branch_id);
+        await branching.mergeBranch(branch_id);
+        return SUCCESS_RESPONSE;
       },
     }),
     reset_branch: tool({
@@ -141,9 +145,10 @@ export function getBranchingTools({
           throw new Error('Cannot reset a branch in read-only mode.');
         }
 
-        return await branching.resetBranch(branch_id, {
+        await branching.resetBranch(branch_id, {
           migration_version,
         });
+        return SUCCESS_RESPONSE;
       },
     }),
     rebase_branch: tool({
@@ -164,7 +169,8 @@ export function getBranchingTools({
           throw new Error('Cannot rebase a branch in read-only mode.');
         }
 
-        return await branching.rebaseBranch(branch_id);
+        await branching.rebaseBranch(branch_id);
+        return SUCCESS_RESPONSE;
       },
     }),
   };

packages/mcp-server-supabase/src/tools/database-operation-tools.ts

@@ -8,6 +8,8 @@ import {
 import type { DatabaseOperations } from '../platform/types.js';
 import { injectableTool } from './util.js';
 
+const SUCCESS_RESPONSE = { success: true };
+
 export type DatabaseOperationToolsOptions = {
   database: DatabaseOperations;
   projectId?: string;
@@ -218,7 +220,7 @@ export function getDatabaseTools({
           query,
         });
 
-        return { success: true };
+        return SUCCESS_RESPONSE;
       },
     }),
     execute_sql: injectableTool({

packages/mcp-server-supabase/src/tools/storage-tools.ts

@@ -2,6 +2,8 @@ import { z } from 'zod';
 import type { StorageOperations } from '../platform/types.js';
 import { injectableTool } from './util.js';
 
+const SUCCESS_RESPONSE = { success: true };
+
 export type StorageToolsOptions = {
   storage: StorageOperations;
   projectId?: string;
@@ -76,7 +78,7 @@ export function getStorageTools({
         }
 
         await storage.updateStorageConfig(project_id, config);
-        return { success: true };
+        return SUCCESS_RESPONSE;
       },
     }),
   };