From ce1812b7c23ef8bcdf7c67920859e1cc6cf85655 Mon Sep 17 00:00:00 2001
From: Danny Avila <danny@librechat.ai>
Date: Tue, 18 Nov 2025 18:28:57 -0500
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20fix:=20Error=20Handling=20in=20M?=
 =?UTF-8?q?CP=20Tool=20List=20Controller=20(#10570)?=
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* 🔧 fix: Handle errors when fetching server tools and log missing tools in MCP tools controller, to prevent all MCP tools from not getting listed

* 🔧 fix: Remove trailing colons from error messages in MCPConnection class

* chore: Update test command patterns in package.json for cache integration tests
---
 api/server/controllers/mcp.js      | 8 +++++++-
 api/server/services/Config/mcp.js  | 5 +++++
 packages/api/package.json          | 6 +++---
 packages/api/src/mcp/connection.ts | 8 ++++----
 4 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/api/server/controllers/mcp.js b/api/server/controllers/mcp.js
index e113b01f17..5bc6f8f23c 100644
--- a/api/server/controllers/mcp.js
+++ b/api/server/controllers/mcp.js
@@ -44,7 +44,13 @@ const getMCPTools = async (req, res) => {
         continue;
       }
 
-      const serverTools = await mcpManager.getServerToolFunctions(userId, serverName);
+      let serverTools;
+      try {
+        serverTools = await mcpManager.getServerToolFunctions(userId, serverName);
+      } catch (error) {
+        logger.error(`[getMCPTools] Error fetching tools for server ${serverName}:`, error);
+        continue;
+      }
       if (!serverTools) {
         logger.debug(`[getMCPTools] No tools found for server ${serverName}`);
         continue;
diff --git a/api/server/services/Config/mcp.js b/api/server/services/Config/mcp.js
index 7f4210f8c9..15ea62a028 100644
--- a/api/server/services/Config/mcp.js
+++ b/api/server/services/Config/mcp.js
@@ -16,6 +16,11 @@ async function updateMCPServerTools({ userId, serverName, tools }) {
     const serverTools = {};
     const mcpDelimiter = Constants.mcp_delimiter;
 
+    if (tools == null || tools.length === 0) {
+      logger.debug(`[MCP Cache] No tools to update for server ${serverName} (user: ${userId})`);
+      return serverTools;
+    }
+
     for (const tool of tools) {
       const name = `${tool.name}${mcpDelimiter}${serverName}`;
       serverTools[name] = {
diff --git a/packages/api/package.json b/packages/api/package.json
index f079cccb87..600f88b088 100644
--- a/packages/api/package.json
+++ b/packages/api/package.json
@@ -20,9 +20,9 @@
     "build:watch:prod": "rollup -c -w --bundleConfigAsCjs",
     "test": "jest --coverage --watch --testPathIgnorePatterns=\"\\.*integration\\.|\\.*helper\\.\"",
     "test:ci": "jest --coverage --ci --testPathIgnorePatterns=\"\\.*integration\\.|\\.*helper\\.\"",
-    "test:cache-integration:core": "jest --testPathPattern=\"src/cache/.*\\.cache_integration\\.spec\\.ts$\" --coverage=false",
-    "test:cache-integration:cluster": "jest --testPathPattern=\"src/cluster/.*\\.cache_integration\\.spec\\.ts$\" --coverage=false --runInBand",
-    "test:cache-integration:mcp": "jest --testPathPattern=\"src/mcp/.*\\.cache_integration\\.spec\\.ts$\" --coverage=false",
+    "test:cache-integration:core": "jest --testPathPatterns=\"src/cache/.*\\.cache_integration\\.spec\\.ts$\" --coverage=false",
+    "test:cache-integration:cluster": "jest --testPathPatterns=\"src/cluster/.*\\.cache_integration\\.spec\\.ts$\" --coverage=false --runInBand",
+    "test:cache-integration:mcp": "jest --testPathPatterns=\"src/mcp/.*\\.cache_integration\\.spec\\.ts$\" --coverage=false",
     "test:cache-integration": "npm run test:cache-integration:core && npm run test:cache-integration:cluster && npm run test:cache-integration:mcp",
     "verify": "npm run test:ci",
     "b:clean": "bun run rimraf dist",
diff --git a/packages/api/src/mcp/connection.ts b/packages/api/src/mcp/connection.ts
index 7e75acf751..c130b3a467 100644
--- a/packages/api/src/mcp/connection.ts
+++ b/packages/api/src/mcp/connection.ts
@@ -336,7 +336,7 @@ export class MCPConnection extends EventEmitter {
         }
       }
     } catch (error) {
-      this.emitError(error, 'Failed to construct transport:');
+      this.emitError(error, 'Failed to construct transport');
       throw error;
     }
   }
@@ -631,7 +631,7 @@ export class MCPConnection extends EventEmitter {
       const { resources } = await this.client.listResources();
       return resources;
     } catch (error) {
-      this.emitError(error, 'Failed to fetch resources:');
+      this.emitError(error, 'Failed to fetch resources');
       return [];
     }
   }
@@ -641,7 +641,7 @@ export class MCPConnection extends EventEmitter {
       const { tools } = await this.client.listTools();
       return tools;
     } catch (error) {
-      this.emitError(error, 'Failed to fetch tools:');
+      this.emitError(error, 'Failed to fetch tools');
       return [];
     }
   }
@@ -651,7 +651,7 @@ export class MCPConnection extends EventEmitter {
       const { prompts } = await this.client.listPrompts();
       return prompts;
     } catch (error) {
-      this.emitError(error, 'Failed to fetch prompts:');
+      this.emitError(error, 'Failed to fetch prompts');
       return [];
     }
   }