diff --git a/api/server/controllers/agents/request.js b/api/server/controllers/agents/request.js
index 01effa0049..0e09f14294 100644
--- a/api/server/controllers/agents/request.js
+++ b/api/server/controllers/agents/request.js
@@ -8,7 +8,6 @@ const {
   isEphemeralAgentId,
 } = require('librechat-data-provider');
 const {
-  sendEvent,
   toPendingSteer,
   getViolationInfo,
   buildMessageFiles,
@@ -27,12 +26,11 @@ const {
   buildRecoveredSteerPayload,
   deleteAgentCheckpoint,
 } = require('@librechat/api');
-const { disposeClient, clientRegistry, requestDataMap } = require('~/server/cleanup');
+const { disposeClient } = require('~/server/cleanup');
 const {
   getMCPRequestContext,
   cleanupMCPRequestContextForReq,
 } = require('~/server/services/MCPRequestContext');
-const { handleAbortError } = require('~/server/middleware');
 const { logViolation } = require('~/cache');
 const { saveMessage, getMessages, getConvo } = require('~/models');
 const {
@@ -63,24 +61,6 @@ function getResourceRecoveryFailure(error) {
   };
 }
 
-function createCloseHandler(abortController) {
-  return function (manual) {
-    if (!manual) {
-      logger.debug('[AgentController] Request closed');
-    }
-    if (!abortController) {
-      return;
-    } else if (abortController.signal.aborted) {
-      return;
-    } else if (abortController.requestCompleted) {
-      return;
-    }
-
-    abortController.abort();
-    logger.debug('[AgentController] Request aborted on close');
-  };
-}
-
 function resolveConversationCreatedAt({ userId, conversationId, isNewConvo }) {
   return resolveConversationAnchor({
     isNewConversation: isNewConvo,
@@ -1953,359 +1933,4 @@ const ResumableAgentController = async (req, res, next, initializeClient, addTit
   }
 };
 
-/**
- * Agent Controller - Routes to ResumableAgentController for all requests.
- * The legacy non-resumable path is kept below but no longer used by default.
- */
-const AgentController = async (req, res, next, initializeClient, addTitle) => {
-  return ResumableAgentController(req, res, next, initializeClient, addTitle);
-};
-
-/**
- * Legacy Non-resumable Agent Controller - Uses GenerationJobManager for abort handling.
- * Response is streamed directly to client via res, but abort state is managed centrally.
- * @deprecated Use ResumableAgentController instead
- */
-const _LegacyAgentController = async (req, res, next, initializeClient, addTitle) => {
-  const {
-    text,
-    isRegenerate,
-    endpointOption,
-    conversationId: reqConversationId,
-    isContinued = false,
-    editedContent = null,
-    parentMessageId = null,
-    overrideParentMessageId = null,
-    responseMessageId: editedResponseMessageId = null,
-  } = req.body;
-
-  // Generate conversationId upfront if not provided - streamId === conversationId always
-  // Treat "new" as a placeholder that needs a real UUID (frontend may send "new" for new convos)
-  const isNewConvo = !reqConversationId || reqConversationId === 'new';
-  const conversationId = isNewConvo ? crypto.randomUUID() : reqConversationId;
-  const streamId = conversationId;
-
-  let userMessage;
-  let userMessageId;
-  let responseMessageId;
-  let client = null;
-  let jobCreatedAt;
-  let cleanupHandlers = [];
-
-  // Match the same logic used for conversationId generation above
-  const userId = req.user.id;
-
-  if (
-    await isUnpersistedPreliminaryParent({
-      userId,
-      conversationId: reqConversationId,
-      parentMessageId,
-      getMessages,
-    })
-  ) {
-    return rejectPreliminaryParentMessageId(res);
-  }
-
-  await attachConversationCreatedAt(req, { userId, conversationId, isNewConvo });
-
-  // Create handler to avoid capturing the entire parent scope
-  let getReqData = (data = {}) => {
-    for (let key in data) {
-      if (key === 'userMessage') {
-        userMessage = data[key];
-        userMessageId = data[key].messageId;
-      } else if (key === 'responseMessageId') {
-        responseMessageId = data[key];
-      } else if (key === 'promptTokens') {
-        // Update job metadata with prompt tokens for abort handling
-        GenerationJobManager.updateMetadata(streamId, { promptTokens: data[key] }, jobCreatedAt);
-      } else if (key === 'sender') {
-        GenerationJobManager.updateMetadata(streamId, { sender: data[key] }, jobCreatedAt);
-      }
-      // conversationId is pre-generated, no need to update from callback
-    }
-  };
-
-  // Create a function to handle final cleanup
-  const performCleanup = async () => {
-    logger.debug('[AgentController] Performing cleanup');
-    if (Array.isArray(cleanupHandlers)) {
-      for (const handler of cleanupHandlers) {
-        try {
-          if (typeof handler === 'function') {
-            handler();
-          }
-        } catch (e) {
-          logger.error('[AgentController] Error in cleanup handler', e);
-        }
-      }
-    }
-
-    // Complete the job in GenerationJobManager
-    if (jobCreatedAt != null) {
-      logger.debug('[AgentController] Completing job in GenerationJobManager');
-      await GenerationJobManager.completeJob(streamId, undefined, jobCreatedAt);
-    }
-
-    // Dispose client properly
-    if (client) {
-      disposeClient(client);
-    }
-
-    // Clear all references
-    client = null;
-    getReqData = null;
-    userMessage = null;
-    cleanupHandlers = null;
-
-    // Clear request data map
-    if (requestDataMap.has(req)) {
-      requestDataMap.delete(req);
-    }
-    logger.debug('[AgentController] Cleanup completed');
-  };
-
-  try {
-    let prelimAbortController = new AbortController();
-    const prelimCloseHandler = createCloseHandler(prelimAbortController);
-    res.on('close', prelimCloseHandler);
-    const removePrelimHandler = (manual) => {
-      try {
-        prelimCloseHandler(manual);
-        res.removeListener('close', prelimCloseHandler);
-      } catch (e) {
-        logger.error('[AgentController] Error removing close listener', e);
-      }
-    };
-    cleanupHandlers.push(removePrelimHandler);
-
-    /** @type {{ client: TAgentClient; userMCPAuthMap?: Record<string, Record<string, string>> }} */
-    const result = await initializeClient({
-      req,
-      res,
-      endpointOption,
-      signal: prelimAbortController.signal,
-    });
-
-    if (prelimAbortController.signal?.aborted) {
-      prelimAbortController = null;
-      throw new Error('Request was aborted before initialization could complete');
-    } else {
-      prelimAbortController = null;
-      removePrelimHandler(true);
-      cleanupHandlers.pop();
-    }
-    client = result.client;
-
-    // Register client with finalization registry if available
-    if (clientRegistry) {
-      clientRegistry.register(client, { userId }, client);
-    }
-
-    // Store request data in WeakMap keyed by req object
-    requestDataMap.set(req, { client });
-
-    // Create job in GenerationJobManager for abort handling
-    // streamId === conversationId (pre-generated above)
-    const job = await GenerationJobManager.createJob(streamId, userId, conversationId);
-    jobCreatedAt = job.createdAt;
-    client.jobCreatedAt = jobCreatedAt;
-    client.checkpointNamespace = job.metadata?.checkpointNamespace ?? '';
-
-    // Store endpoint metadata for abort handling
-    GenerationJobManager.updateMetadata(
-      streamId,
-      {
-        endpoint: endpointOption.endpoint,
-        iconURL: getEndpointIconURL(req, endpointOption),
-        model: getAgentResponseModel(req, endpointOption),
-        sender: client?.sender,
-      },
-      jobCreatedAt,
-    );
-
-    // Store content parts reference for abort
-    if (client?.contentParts) {
-      GenerationJobManager.setContentParts(streamId, client.contentParts, jobCreatedAt);
-    }
-
-    const closeHandler = createCloseHandler(job.abortController);
-    res.on('close', closeHandler);
-    cleanupHandlers.push(() => {
-      try {
-        res.removeListener('close', closeHandler);
-      } catch (e) {
-        logger.error('[AgentController] Error removing close listener', e);
-      }
-    });
-
-    /**
-     * onStart callback - stores user message and response ID for abort handling
-     */
-    const onStart = (userMsg, respMsgId, _isNewConvo) => {
-      sendEvent(res, { message: userMsg, created: true });
-      userMessage = userMsg;
-      userMessageId = userMsg.messageId;
-      responseMessageId = respMsgId;
-
-      // Store metadata for abort handling (conversationId is pre-generated)
-      GenerationJobManager.updateMetadata(
-        streamId,
-        {
-          responseMessageId: respMsgId,
-          userMessage: {
-            messageId: userMsg.messageId,
-            parentMessageId: userMsg.parentMessageId,
-            conversationId,
-            text: userMsg.text,
-            quotes: userMsg.quotes,
-          },
-        },
-        jobCreatedAt,
-      );
-    };
-
-    const messageOptions = {
-      user: userId,
-      onStart,
-      getReqData,
-      isContinued,
-      isRegenerate,
-      editedContent,
-      conversationId,
-      parentMessageId,
-      abortController: job.abortController,
-      overrideParentMessageId,
-      isEdited: !!editedContent,
-      userMCPAuthMap: result.userMCPAuthMap,
-      responseMessageId: editedResponseMessageId,
-      progressOptions: {
-        res,
-      },
-    };
-
-    let response = await client.sendMessage(text, messageOptions);
-
-    // Extract what we need and immediately break reference
-    const messageId = response.messageId;
-    const endpoint = endpointOption.endpoint;
-    response.endpoint = endpoint;
-
-    // Store database promise locally
-    const databasePromise = response.databasePromise;
-    delete response.databasePromise;
-
-    // Resolve database-related data
-    const { conversation: convoData = {} } = await databasePromise;
-    const conversation = { ...convoData };
-    conversation.title =
-      conversation && !conversation.title ? null : conversation?.title || 'New Chat';
-
-    if (req.body.files && Array.isArray(client.options.attachments)) {
-      const files = buildMessageFiles(req.body.files, client.options.attachments);
-      if (files.length > 0) {
-        userMessage.files = files;
-      }
-      delete userMessage.image_urls;
-    }
-
-    // Only send if not aborted
-    if (!job.abortController.signal.aborted) {
-      // Create a new response object with minimal copies
-      const finalResponse = { ...response };
-
-      sendEvent(res, {
-        final: true,
-        conversation,
-        title: conversation.title,
-        requestMessage: sanitizeMessageForTransmit(userMessage),
-        responseMessage: finalResponse,
-      });
-      res.end();
-
-      // Save the message if needed
-      if (client.savedMessageIds && !client.savedMessageIds.has(messageId)) {
-        await saveMessage(
-          {
-            userId: req?.user?.id,
-            isTemporary: req?.body?.isTemporary,
-            interfaceConfig: req?.config?.interfaceConfig,
-          },
-          { ...finalResponse, user: userId },
-          { context: 'api/server/controllers/agents/request.js - response end' },
-        );
-      }
-    }
-    // Edge case: sendMessage completed but abort happened during sendCompletion
-    // We need to ensure a final event is sent
-    else if (!res.headersSent && !res.finished) {
-      logger.debug(
-        '[AgentController] Handling edge case: `sendMessage` completed but aborted during `sendCompletion`',
-      );
-
-      const finalResponse = { ...response };
-      finalResponse.error = true;
-
-      sendEvent(res, {
-        final: true,
-        conversation,
-        title: conversation.title,
-        requestMessage: sanitizeMessageForTransmit(userMessage),
-        responseMessage: finalResponse,
-        error: { message: 'Request was aborted during completion' },
-      });
-      res.end();
-    }
-
-    // Save user message if needed
-    if (!client.skipSaveUserMessage) {
-      await saveMessage(
-        {
-          userId: req?.user?.id,
-          isTemporary: req?.body?.isTemporary,
-          interfaceConfig: req?.config?.interfaceConfig,
-        },
-        userMessage,
-        { context: "api/server/controllers/agents/request.js - don't skip saving user message" },
-      );
-    }
-
-    // Add title if needed - extract minimal data
-    if (addTitle && parentMessageId === Constants.NO_PARENT && isNewConvo) {
-      addTitle(req, {
-        text,
-        response: { ...response },
-        client,
-      })
-        .then(() => {
-          logger.debug('[AgentController] Title generation started');
-        })
-        .catch((err) => {
-          logger.error('[AgentController] Error in title generation', err);
-        })
-        .finally(() => {
-          logger.debug('[AgentController] Title generation completed');
-          performCleanup();
-        });
-    } else {
-      performCleanup();
-    }
-  } catch (error) {
-    // Handle error without capturing much scope
-    handleAbortError(res, req, error, {
-      conversationId,
-      sender: client?.sender,
-      messageId: responseMessageId,
-      parentMessageId: overrideParentMessageId ?? userMessageId ?? parentMessageId,
-      userMessageId,
-    })
-      .catch((err) => {
-        logger.error('[api/server/controllers/agents/request] Error in `handleAbortError`', err);
-      })
-      .finally(() => {
-        performCleanup();
-      });
-  }
-};
-
-module.exports = AgentController;
+module.exports = ResumableAgentController;
diff --git a/packages/api/src/agents/activityPhases/runtime.ts b/packages/api/src/agents/activityPhases/runtime.ts
index 37f2708da5..c542d7c258 100644
--- a/packages/api/src/agents/activityPhases/runtime.ts
+++ b/packages/api/src/agents/activityPhases/runtime.ts
@@ -611,104 +611,6 @@ function mergeAnchors(earlier: TrackedActivity, later: TrackedActivity): Tracked
   return fields;
 }
 
-/**
- * Every field of a bounded anchor, stated explicitly. Anchors are built by
- * demoting an activity and by folding two together, and both used to spread
- * one side and hand-pick the rest — so any field nobody named was dropped
- * silently, and nothing failed until a boundary happened to land badly.
- * Mapping over `keyof Required<TrackedActivity>` makes every field mandatory
- * at the construction site: adding one to `TrackedActivity` is a type error
- * until its anchor semantics are decided here.
- */
-type AnchorFields = { [K in keyof Required<TrackedActivity>]: TrackedActivity[K] };
-
-function laterDefinedIndex(earlier?: number, later?: number): number | undefined {
-  if (earlier == null) {
-    return later;
-  }
-  return later == null ? earlier : Math.max(earlier, later);
-}
-
-function foldedAgentIds(earlier: TrackedActivity, later: TrackedActivity): string[] | undefined {
-  const folded = [
-    ...new Set(
-      [
-        ...(earlier.mergedAgentIds ?? []),
-        ...(earlier.agentId != null ? [earlier.agentId] : []),
-        ...(later.mergedAgentIds ?? []),
-        ...(later.agentId != null ? [later.agentId] : []),
-      ].filter((id) => id !== earlier.agentId),
-    ),
-  ];
-  return folded.length > 0 ? folded : undefined;
-}
-
-/** Strips prompt evidence while keeping everything a boundary reasons about. */
-function boundedAnchor(activity: TrackedActivity): TrackedActivity {
-  const fields: AnchorFields = {
-    startIndex: activity.startIndex,
-    bounded: true,
-    status: activity.status,
-    partitionStartIndex: activity.partitionStartIndex,
-    unresolvedToolStartIndex: activity.unresolvedToolStartIndex,
-    toolCallIds: activity.toolCallIds?.slice(-MAX_RETAINED_TOOL_ENTRIES),
-    thinkingExcerpts: activity.thinkingExcerpts
-      ?.slice(-MAX_RETAINED_TOOL_ENTRIES)
-      .map((text) => text.slice(-REASONING_ANCHOR_CHARS)),
-    agentId: activity.agentId,
-    mergedCount: activity.mergedCount,
-    mergedFailedCount: activity.mergedFailedCount,
-    mergedPartialCount: activity.mergedPartialCount,
-    mergedAgentIds: activity.mergedAgentIds,
-    /** An anchor is never summarized directly, so prompt evidence and the
-     *  child-label slot are deliberately not carried. */
-    label: undefined,
-    entries: undefined,
-    childLabelIndex: undefined,
-  };
-  return fields;
-}
-
-/** Folds `later` into `earlier`, which keeps its position. */
-function mergeAnchors(earlier: TrackedActivity, later: TrackedActivity): TrackedActivity {
-  const mergedFailedCount = countFailedActivities([earlier, later]);
-  const mergedPartialCount = countPartialActivities([earlier, later]);
-  const excerpts =
-    earlier.thinkingExcerpts != null || later.thinkingExcerpts != null
-      ? [...(earlier.thinkingExcerpts ?? []), ...(later.thinkingExcerpts ?? [])].slice(
-          -MAX_RETAINED_TOOL_ENTRIES,
-        )
-      : undefined;
-  const fields: AnchorFields = {
-    /** The pair starts where its first activity did; the later side's floor
-     *  describes a position being absorbed and must not move the survivor. */
-    startIndex: earlier.startIndex,
-    partitionStartIndex: earlier.partitionStartIndex,
-    bounded: true,
-    status: earlier.status,
-    /** The later side may still be waiting on a tool call. Dropping its
-     *  fallback lets a boundary close the whole merged count on the earlier
-     *  side; resolution clears it once every retained id materializes. */
-    unresolvedToolStartIndex: laterDefinedIndex(
-      earlier.unresolvedToolStartIndex,
-      later.unresolvedToolStartIndex,
-    ),
-    toolCallIds: [...(earlier.toolCallIds ?? []), ...(later.toolCallIds ?? [])].slice(
-      -MAX_RETAINED_TOOL_ENTRIES,
-    ),
-    thinkingExcerpts: excerpts,
-    agentId: earlier.agentId,
-    mergedCount: (earlier.mergedCount ?? 1) + (later.mergedCount ?? 1),
-    mergedFailedCount: mergedFailedCount > 0 ? mergedFailedCount : undefined,
-    mergedPartialCount: mergedPartialCount > 0 ? mergedPartialCount : undefined,
-    mergedAgentIds: foldedAgentIds(earlier, later),
-    label: undefined,
-    entries: undefined,
-    childLabelIndex: undefined,
-  };
-  return fields;
-}
-
 /** Every activity is represented by exactly one positioned item, so run totals
  *  are a sum over that list rather than a separately maintained scalar. */
 function countActivities(activities: ReadonlyArray<TrackedActivity>): number {