🦥 refactor: Event-Driven Lazy Tool Loading (#11588)

* refactor: json schema tools with lazy loading

- Added LocalToolExecutor class for lazy loading and caching of tools during execution.
- Introduced ToolExecutionContext and ToolExecutor interfaces for better type management.
- Created utility functions to generate tool proxies with JSON schema support.
- Added ExtendedJsonSchema type for enhanced schema definitions.
- Updated existing toolkits to utilize the new schema and executor functionalities.
- Introduced a comprehensive tool definitions registry for managing various tool schemas.

chore: update @librechat/agents to version 3.1.2

refactor: enhance tool loading optimization and classification

- Improved the loadAgentToolsOptimized function to utilize a proxy pattern for all tools, enabling deferred execution and reducing overhead.
- Introduced caching for tool instances and refined tool classification logic to streamline tool management.
- Updated the handling of MCP tools to improve logging and error reporting for missing tools in the cache.
- Enhanced the structure of tool definitions to support better classification and integration with existing tools.

refactor: modularize tool loading and enhance optimization

- Moved the loadAgentToolsOptimized function to a new service file for better organization and maintainability.
- Updated the ToolService to utilize the new service for optimized tool loading, improving code clarity.
- Removed legacy tool loading methods and streamlined the tool loading process to enhance performance and reduce complexity.
- Introduced feature flag handling for optimized tool loading, allowing for easier toggling of this functionality.

refactor: replace loadAgentToolsWithFlag with loadAgentTools in tool loader

refactor: enhance MCP tool loading with proxy creation and classification

refactor: optimize MCP tool loading by grouping tools by server

- Introduced a Map to group cached tools by server name, improving the organization of tool data.
- Updated the createMCPProxyTool function to accept server name directly, enhancing clarity.
- Refactored the logic for handling MCP tools, streamlining the process of creating proxy tools for classification.

refactor: enhance MCP tool loading and proxy creation

- Added functionality to retrieve MCP server tools and reinitialize servers if necessary, improving tool availability.
- Updated the tool loading logic to utilize a Map for organizing tools by server, enhancing clarity and performance.
- Refactored the createToolProxy function to ensure a default response format, streamlining tool creation.

refactor: update createToolProxy to ensure consistent response format

- Modified the createToolProxy function to await the executor's execution and validate the result format.
- Ensured that the function returns a default response structure when the result is not an array of two elements, enhancing reliability in tool proxy creation.

refactor: ToolExecutionContext with toolCall property

- Added toolCall property to ToolExecutionContext interface for improved context handling during tool execution.
- Updated LocalToolExecutor to include toolCall in the runnable configuration, allowing for more flexible tool invocation.
- Modified createToolProxy to pass toolCall from the configuration, ensuring consistent context across tool executions.

refactor: enhance event-driven tool execution and logging

- Introduced ToolExecuteOptions for improved handling of event-driven tool execution, allowing for parallel execution of tool calls.
- Updated getDefaultHandlers to include support for ON_TOOL_EXECUTE events, enhancing the flexibility of tool invocation.
- Added detailed logging in LocalToolExecutor to track tool loading and execution metrics, improving observability and debugging capabilities.
- Refactored initializeClient to integrate event-driven tool loading, ensuring compatibility with the new execution model.

chore: update @librechat/agents to version 3.1.21

refactor: remove legacy tool loading and executor components

- Eliminated the loadAgentToolsWithFlag function, simplifying the tool loading process by directly using loadAgentTools.
- Removed the LocalToolExecutor and related executor components to streamline the tool execution architecture.
- Updated ToolService and related files to reflect the removal of deprecated features, enhancing code clarity and maintainability.

refactor: enhance tool classification and definitions handling

- Updated the loadAgentTools function to return toolDefinitions alongside toolRegistry, improving the structure of tool data returned to clients.
- Removed the convertRegistryToDefinitions function from the initialize.js file, simplifying the initialization process.
- Adjusted the buildToolClassification function to ensure toolDefinitions are built and returned simultaneously with the toolRegistry, enhancing efficiency in tool management.
- Updated type definitions in initialize.ts to include toolDefinitions, ensuring consistency across the codebase.

refactor: implement event-driven tool execution handler

- Introduced createToolExecuteHandler function to streamline the handling of ON_TOOL_EXECUTE events, allowing for parallel execution of tool calls.
- Updated getDefaultHandlers to utilize the new handler, simplifying the event-driven architecture.
- Added handlers.ts file to encapsulate tool execution logic, improving code organization and maintainability.
- Enhanced OpenAI handlers to integrate the new tool execution capabilities, ensuring consistent event handling across the application.

refactor: integrate event-driven tool execution options

- Added toolExecuteOptions to support event-driven tool execution in OpenAI and responses controllers, enhancing flexibility in tool handling.
- Updated handlers to utilize createToolExecuteHandler, allowing for streamlined execution of tools during agent interactions.
- Refactored service dependencies to include toolExecuteOptions, ensuring consistent integration across the application.

refactor: enhance tool loading with definitionsOnly parameter

- Updated createToolLoader and loadAgentTools functions to include a definitionsOnly parameter, allowing for the retrieval of only serializable tool definitions in event-driven mode.
- Adjusted related interfaces and documentation to reflect the new parameter, improving clarity and flexibility in tool management.
- Ensured compatibility across various components by integrating the definitionsOnly option in the initialization process.

refactor: improve agent tool presence check in initialization

- Added a check for tool presence using a new hasAgentTools variable, which evaluates both structuredTools and toolDefinitions.
- Updated the conditional logic in the agent initialization process to utilize the hasAgentTools variable, enhancing clarity and maintainability in tool management.

refactor: enhance agent tool extraction to support tool definitions

- Updated the extractMCPServers function to handle both tool instances and serializable tool definitions, improving flexibility in agent tool management.
- Added a new property toolDefinitions to the AgentWithTools type for better integration of event-driven mode.
- Enhanced documentation to clarify the function's capabilities in extracting unique MCP server names from both tools and tool definitions.

refactor: enhance tool classification and registry building

- Added serverName property to ToolDefinition for improved tool identification.
- Introduced buildToolRegistry function to streamline the creation of tool registries based on MCP tool definitions and agent options.
- Updated buildToolClassification to utilize the new registry building logic, ensuring basic definitions are returned even when advanced classification features are not allowed.
- Enhanced documentation and logging for clarity in tool classification processes.

refactor: update @librechat/agents dependency to version 3.1.22

fix: expose loadTools function in ToolService

- Added loadTools function to the exported module in ToolService.js, enhancing the accessibility of tool loading functionality.

chore: remove configurable options from tool execute options in OpenAI controller

refactor: enhance tool loading mechanism to utilize agent-specific context

chore: update @librechat/agents dependency to version 3.1.23

fix: simplify result handling in createToolExecuteHandler

* refactor: loadToolDefinitions for efficient tool loading in event-driven mode

* refactor: replace legacy tool loading with loadToolsForExecution in OpenAI and responses controllers

- Updated OpenAIChatCompletionController and createResponse functions to utilize loadToolsForExecution for improved tool loading.
- Removed deprecated loadToolsLegacy references, streamlining the tool execution process.
- Enhanced tool loading options to include agent-specific context and configurations.

* refactor: enhance tool loading and execution handling

- Introduced loadActionToolsForExecution function to streamline loading of action tools, improving organization and maintainability.
- Updated loadToolsForExecution to handle both regular and action tools, optimizing the tool loading process.
- Added detailed logging for missing tools in createToolExecuteHandler, enhancing error visibility.
- Refactored tool definitions to normalize action tool names, improving consistency in tool management.

* refactor: enhance built-in tool definitions loading

- Updated loadToolDefinitions to include descriptions and parameters from the tool registry for built-in tools, improving the clarity and usability of tool definitions.
- Integrated getToolDefinition to streamline the retrieval of tool metadata, enhancing the overall tool management process.

* feat: add action tool definitions loading to tool service

- Introduced getActionToolDefinitions function to load action tool definitions based on agent ID and tool names, enhancing the tool loading process.
- Updated loadToolDefinitions to integrate action tool definitions, allowing for better management and retrieval of action-specific tools.
- Added comprehensive tests for action tool definitions to ensure correct loading and parameter handling, improving overall reliability and functionality.

* chore: update @librechat/agents dependency to version 3.1.26

* refactor: add toolEndCallback to handle tool execution results

* fix: tool definitions and execution handling

- Introduced native tools (execute_code, file_search, web_search) to the tool service, allowing for better integration and management of these tools.
- Updated isBuiltInTool function to include native tools in the built-in check, improving tool recognition.
- Added comprehensive tests for loading parameters of native tools, ensuring correct functionality and parameter handling.
- Enhanced tool definitions registry to include new agent tool definitions, streamlining tool retrieval and management.

* refactor: enhance tool loading and execution context

- Added toolRegistry to the context for OpenAIChatCompletionController and createResponse functions, improving tool management.
- Updated loadToolsForExecution to utilize toolRegistry for better integration of programmatic tools and tool search functionalities.
- Enhanced the initialization process to include toolRegistry in agent context, streamlining tool access and configuration.
- Refactored tool classification logic to support event-driven execution, ensuring compatibility with new tool definitions.

* chore: add request duration logging to OpenAI and Responses controllers

- Introduced logging for request start and completion times in OpenAIChatCompletionController and createResponse functions.
- Calculated and logged the duration of each request, enhancing observability and performance tracking.
- Improved debugging capabilities by providing detailed logs for both streaming and non-streaming responses.

* chore: update @librechat/agents dependency to version 3.1.27

* refactor: implement buildToolSet function for tool management

- Introduced buildToolSet function to streamline the creation of tool sets from agent configurations, enhancing tool management across various controllers.
- Updated AgentClient, OpenAIChatCompletionController, and createResponse functions to utilize buildToolSet, improving consistency in tool handling.
- Added comprehensive tests for buildToolSet to ensure correct functionality and edge case handling, enhancing overall reliability.

* refactor: update import paths for ToolExecuteOptions and createToolExecuteHandler

* fix: update GoogleSearch.js description for maximum search results

- Changed the default maximum number of search results from 10 to 5 in the Google Search JSON schema description, ensuring accurate documentation of the expected behavior.

* chore: remove deprecated Browser tool and associated assets

- Deleted the Browser tool definition from manifest.json, which included its name, plugin key, description, and authentication configuration.
- Removed the web-browser.svg asset as it is no longer needed following the removal of the Browser tool.

* fix: ensure tool definitions are valid before processing

- Added a check to verify the existence of tool definitions in the registry before accessing their properties, preventing potential runtime errors.
- Updated the loading logic for built-in tool definitions to ensure that only valid definitions are pushed to the built-in tool definitions array.

* fix: extend ExtendedJsonSchema to support 'null' type and nullable enums

- Updated the ExtendedJsonSchema type to include 'null' as a valid type option.
- Modified the enum property to accept an array of values that can include strings, numbers, booleans, and null, enhancing schema flexibility.

* test: add comprehensive tests for tool definitions loading and registry behavior

- Implemented tests to verify the handling of built-in tools without registry definitions, ensuring they are skipped correctly.
- Added tests to confirm that built-in tools include descriptions and parameters in the registry.
- Enhanced tests for action tools, checking for proper inclusion of metadata and handling of tools without parameters in the registry.

* test: add tests for mixed-type and number enum schema handling

- Introduced tests to validate the parsing of mixed-type enum values, including strings, numbers, booleans, and null.
- Added tests for number enum schema values to ensure correct parsing of numeric inputs, enhancing schema validation coverage.

* fix: update mock implementation for @librechat/agents

- Changed the mock for @librechat/agents to spread the actual module's properties, ensuring that all necessary functionalities are preserved in tests.
- This adjustment enhances the accuracy of the tests by reflecting the real structure of the module.

* fix: change max_results type in GoogleSearch schema from number to integer

- Updated the type of max_results in the Google Search JSON schema to 'integer' for better type accuracy and validation consistency.

* fix: update max_results description and type in GoogleSearch schema

- Changed the type of max_results from 'number' to 'integer' for improved type accuracy.
- Updated the description to reflect the new default maximum number of search results, changing it from 10 to 5.

* refactor: remove unused code and improve tool registry handling

- Eliminated outdated comments and conditional logic related to event-driven mode in the ToolService.
- Enhanced the handling of the tool registry by ensuring it is configurable for better integration during tool execution.

* feat: add definitionsOnly option to buildToolClassification for event-driven mode

- Introduced a new parameter, definitionsOnly, to the BuildToolClassificationParams interface to enable a mode that skips tool instance creation.
- Updated the buildToolClassification function to conditionally add tool definitions without instantiating tools when definitionsOnly is true.
- Modified the loadToolDefinitions function to pass definitionsOnly as true, ensuring compatibility with the new feature.

* test: add unit tests for buildToolClassification with definitionsOnly option

- Implemented tests to verify the behavior of buildToolClassification when definitionsOnly is set to true or false.
- Ensured that tool instances are not created when definitionsOnly is true, while still adding necessary tool definitions.
- Confirmed that loadAuthValues is called appropriately based on the definitionsOnly parameter, enhancing test coverage for this new feature.

api/server/controllers/agents/openai.js

@@ -11,6 +11,7 @@ const {
   writeSSE,
   createRun,
   createChunk,
+  buildToolSet,
   sendFinalChunk,
   createSafeUser,
   validateRequest,
@@ -19,11 +20,12 @@ const {
   buildNonStreamingResponse,
   createOpenAIStreamTracker,
   createOpenAIContentAggregator,
+  createToolExecuteHandler,
   isChatCompletionValidationFailure,
 } = require('@librechat/api');
+const { loadAgentTools, loadToolsForExecution } = require('~/server/services/ToolService');
 const { createToolEndCallback } = require('~/server/controllers/agents/callbacks');
 const { findAccessibleResources } = require('~/server/services/PermissionService');
-const { loadAgentTools } = require('~/server/services/ToolService');
 const { getConvoFiles } = require('~/models/Conversation');
 const { getAgent, getAgents } = require('~/models/Agent');
 const db = require('~/models');
@@ -31,8 +33,10 @@ const db = require('~/models');
 /**
  * Creates a tool loader function for the agent.
  * @param {AbortSignal} signal - The abort signal
+ * @param {boolean} [definitionsOnly=true] - When true, returns only serializable
+ *   tool definitions without creating full tool instances (for event-driven mode)
  */
-function createToolLoader(signal) {
+function createToolLoader(signal, definitionsOnly = true) {
   return async function loadTools({
     req,
     res,
@@ -51,6 +55,7 @@ function createToolLoader(signal) {
         agent,
         signal,
         tool_resources,
+        definitionsOnly,
         streamId: null, // No resumable stream for OpenAI compat
       });
     } catch (error) {
@@ -123,6 +128,7 @@ function sendErrorResponse(res, statusCode, message, type = 'invalid_request_err
  */
 const OpenAIChatCompletionController = async (req, res) => {
   const appConfig = req.config;
+  const requestStartTime = Date.now();
 
   // Validate request
   const validation = validateRequest(req.body);
@@ -157,6 +163,10 @@ const OpenAIChatCompletionController = async (req, res) => {
     model: agentId,
   };
 
+  logger.debug(
+    `[OpenAI API] Request ${requestId} started for agent ${agentId}, stream: ${request.stream}`,
+  );
+
   // Set up abort controller
   const abortController = new AbortController();
 
@@ -239,19 +249,31 @@ const OpenAIChatCompletionController = async (req, res) => {
         }
       : null;
 
-    // We need custom handlers that stream in OpenAI format
     const collectedUsage = [];
     /** @type {Promise<import('librechat-data-provider').TAttachment | null>[]} */
     const artifactPromises = [];
 
-    // Create tool end callback for processing artifacts (images, file citations, code output)
     const toolEndCallback = createToolEndCallback({ req, res, artifactPromises, streamId: null });
 
-    // Convert messages to internal format
+    const toolExecuteOptions = {
+      loadTools: async (toolNames) => {
+        return loadToolsForExecution({
+          req,
+          res,
+          agent,
+          toolNames,
+          signal: abortController.signal,
+          toolRegistry: primaryConfig.toolRegistry,
+          userMCPAuthMap: primaryConfig.userMCPAuthMap,
+          tool_resources: primaryConfig.tool_resources,
+        });
+      },
+      toolEndCallback,
+    };
+
     const openaiMessages = convertMessages(request.messages);
 
-    // Format for agent
-    const toolSet = new Set((primaryConfig.tools ?? []).map((tool) => tool && tool.name));
+    const toolSet = buildToolSet(primaryConfig);
     const { messages: formattedMessages, indexTokenCountMap } = formatAgentMessages(
       openaiMessages,
       {},
@@ -425,6 +447,8 @@ const OpenAIChatCompletionController = async (req, res) => {
       on_chain_end: createHandler(),
       on_agent_update: createHandler(),
       on_custom_event: createHandler(),
+      // Event-driven tool execution handler
+      on_tool_execute: createToolExecuteHandler(toolExecuteOptions),
     };
 
     // Create and run the agent
@@ -474,9 +498,11 @@ const OpenAIChatCompletionController = async (req, res) => {
     });
 
     // Finalize response
+    const duration = Date.now() - requestStartTime;
     if (isStreaming) {
       sendFinalChunk(handlerConfig);
       res.end();
+      logger.debug(`[OpenAI API] Request ${requestId} completed in ${duration}ms (streaming)`);
 
       // Wait for artifact processing after response ends (non-blocking)
       if (artifactPromises.length > 0) {
@@ -515,6 +541,7 @@ const OpenAIChatCompletionController = async (req, res) => {
         usage,
       );
       res.json(response);
+      logger.debug(`[OpenAI API] Request ${requestId} completed in ${duration}ms (non-streaming)`);
     }
   } catch (error) {
     const errorMessage = error instanceof Error ? error.message : 'An error occurred';