🤖 feat: Agent Handoffs (Routing) (#10176)

* feat: Add support for agent handoffs with edges in agent forms and schemas

chore: Mark `agent_ids` field as deprecated in favor of edges across various schemas and types

chore: Update dependencies for @langchain/core and @librechat/agents to latest versions

chore: Update peer dependency for @librechat/agents to version 3.0.0-rc2 in package.json

chore: Update @librechat/agents dependency to version 3.0.0-rc3 in package.json and package-lock.json

feat: first pass, multi-agent handoffs

fix: update output type to ToolMessage in memory handling functions

fix: improve type checking for graphConfig in createRun function

refactor: remove unused content filtering logic in AgentClient

chore: update @librechat/agents dependency to version 3.0.0-rc4 in package.json and package-lock.json

fix: update @langchain/core peer dependency version to ^0.3.72 in package.json and package-lock.json

fix: update @librechat/agents dependency to version 3.0.0-rc6 in package.json and package-lock.json; refactor stream rate handling in various endpoints

feat: Agent handoff UI

chore: update @librechat/agents dependency to version 3.0.0-rc8 in package.json and package-lock.json

fix: improve hasInfo condition and adjust UI element classes in AgentHandoff component

refactor: remove current fixed agent display from AgentHandoffs component due to redundancy

feat: enhance AgentHandoffs UI with localized beta label and improved layout

chore: update @librechat/agents dependency to version 3.0.0-rc10 in package.json and package-lock.json

feat: add `createSequentialChainEdges` function to add back agent chaining via multi-agents

feat: update `createSequentialChainEdges` call to only provide conversation context between agents

feat: deprecate Agent Chain functionality and update related methods for improved clarity

* chore: update @librechat/agents dependency to version 3.0.0-rc11 in package.json and package-lock.json

* refactor: remove unused addCacheControl function and related imports and import from @librechat/agents

* chore: remove unused i18n keys

* refactor: remove unused format export from index.ts

* chore: update @librechat/agents to v3.0.0-rc13

* chore: remove BEDROCK_LEGACY provider from Providers enum

* chore: update @librechat/agents to version 3.0.2 in package.json

client/src/components/Chat/Messages/Content/AgentHandoff.tsx

@@ -0,0 +1,92 @@
+import React, { useMemo, useState } from 'react';
+import { EModelEndpoint, Constants } from 'librechat-data-provider';
+import { ChevronDown } from 'lucide-react';
+import type { TMessage } from 'librechat-data-provider';
+import MessageIcon from '~/components/Share/MessageIcon';
+import { useAgentsMapContext } from '~/Providers';
+import { useLocalize } from '~/hooks';
+import { cn } from '~/utils';
+
+interface AgentHandoffProps {
+  name: string;
+  args: string | Record<string, unknown>;
+  output?: string | null;
+}
+
+const AgentHandoff: React.FC<AgentHandoffProps> = ({ name, args: _args = '' }) => {
+  const localize = useLocalize();
+  const agentsMap = useAgentsMapContext();
+  const [showInfo, setShowInfo] = useState(false);
+
+  /** Extracted agent ID from tool name (e.g., "lc_transfer_to_agent_gUV0wMb7zHt3y3Xjz-8_4" -> "agent_gUV0wMb7zHt3y3Xjz-8_4") */
+  const targetAgentId = useMemo(() => {
+    if (typeof name !== 'string' || !name.startsWith(Constants.LC_TRANSFER_TO_)) {
+      return null;
+    }
+    return name.replace(Constants.LC_TRANSFER_TO_, '');
+  }, [name]);
+
+  const targetAgent = useMemo(() => {
+    if (!targetAgentId || !agentsMap) {
+      return null;
+    }
+    return agentsMap[targetAgentId];
+  }, [agentsMap, targetAgentId]);
+
+  const args = useMemo(() => {
+    if (typeof _args === 'string') {
+      return _args;
+    }
+    try {
+      return JSON.stringify(_args, null, 2);
+    } catch {
+      return '';
+    }
+  }, [_args]) as string;
+
+  /** Requires more than 2 characters as can be an empty object: `{}` */
+  const hasInfo = useMemo(() => (args?.trim()?.length ?? 0) > 2, [args]);
+
+  return (
+    <div className="my-3">
+      <div
+        className={cn(
+          'flex items-center gap-2.5 text-sm text-text-secondary',
+          hasInfo && 'cursor-pointer transition-colors hover:text-text-primary',
+        )}
+        onClick={() => hasInfo && setShowInfo(!showInfo)}
+      >
+        <div className="flex h-6 w-6 items-center justify-center overflow-hidden rounded-full">
+          <MessageIcon
+            message={
+              {
+                endpoint: EModelEndpoint.agents,
+                isCreatedByUser: false,
+              } as TMessage
+            }
+            agent={targetAgent || undefined}
+          />
+        </div>
+        <span className="select-none">{localize('com_ui_transferred_to')}</span>
+        <span className="select-none font-medium text-text-primary">
+          {targetAgent?.name || localize('com_ui_agent')}
+        </span>
+        {hasInfo && (
+          <ChevronDown
+            className={cn('ml-1 h-3 w-3 transition-transform', showInfo && 'rotate-180')}
+          />
+        )}
+      </div>
+      {hasInfo && showInfo && (
+        <div className="ml-8 mt-2 rounded-md bg-surface-secondary p-3 text-xs">
+          <div className="mb-1 font-medium text-text-secondary">
+            {localize('com_ui_handoff_instructions')}:
+          </div>
+          <pre className="overflow-x-auto whitespace-pre-wrap text-text-primary">{args}</pre>
+        </div>
+      )}
+    </div>
+  );
+};
+
+export default AgentHandoff;