🫱🏼‍🫲🏽 refactor: Improve Agent Handoffs (#11172)

* fix: Tool Resources Dropped between Agent Handoffs

* fix: agent deletion process to remove handoff edges

- Added logic to the `deleteAgent` function to remove references to the deleted agent from other agents' handoff edges.
- Implemented error handling to log any issues encountered during the edge removal process.
- Introduced a new test case to verify that handoff edges are correctly removed when an agent is deleted, ensuring data integrity across agent relationships.

* fix: Improve agent loading process by handling orphaned references

- Added logic to track and log agents that fail to load during initialization, preventing errors from interrupting the process.
- Introduced a Set to store skipped agent IDs and updated edge filtering to exclude these orphaned references, enhancing data integrity in agent relationships.

* chore: Update @librechat/agents to version 3.0.62

* feat: Enhance agent initialization with edge collection and filtering

- Introduced new functions for edge collection and filtering orphaned edges, improving the agent loading process.
- Refactored the `initializeClient` function to utilize breadth-first search (BFS) for discovering connected agents, enabling transitive handoffs.
- Added a new module for edge-related utilities, including deduplication and participant extraction, to streamline edge management.
- Updated the agent configuration handling to ensure proper edge processing and integrity during initialization.

* refactor: primary agent ID selection for multi-agent conversations

- Added a new function `findPrimaryAgentId` to determine the primary agent ID from a set of agent IDs based on suffix rules.
- Updated `createMultiAgentMapper` to filter messages by primary agent for parallel agents and handle handoffs appropriately.
- Enhanced message processing logic to ensure correct inclusion of agent content based on group and agent ID presence.
- Improved documentation to clarify the distinctions between parallel execution and handoff scenarios.

* feat: Implement primary agent ID selection for multi-agent content filtering

* chore: Update @librechat/agents to version 3.0.63 in package.json and package-lock.json

* chore: Update @librechat/agents to version 3.0.64 in package.json and package-lock.json

* chore: Update @librechat/agents to version 3.0.65 in package.json and package-lock.json

* feat: Add optional agent name to run creation for improved identification

* chore: Update @librechat/agents to version 3.0.66 in package.json and package-lock.json

* test: Add unit tests for edge utilities including key generation, participant extraction, and orphaned edge filtering

- Implemented tests for `getEdgeKey`, `getEdgeParticipants`, `filterOrphanedEdges`, and `createEdgeCollector` functions.
- Ensured comprehensive coverage for various edge cases, including handling of arrays and default values.
- Verified correct behavior of edge filtering based on skipped agents and deduplication of edges.

packages/api/package.json

@@ -87,7 +87,7 @@
     "@azure/storage-blob": "^12.27.0",
     "@keyv/redis": "^4.3.3",
     "@langchain/core": "^0.3.80",
-    "@librechat/agents": "^3.0.61",
+    "@librechat/agents": "^3.0.66",
     "@librechat/data-schemas": "*",
     "@modelcontextprotocol/sdk": "^1.25.1",
     "@smithy/node-http-handler": "^4.4.5",

packages/api/src/agents/edges.spec.ts

@@ -0,0 +1,257 @@
+import type { GraphEdge } from 'librechat-data-provider';
+import { getEdgeKey, getEdgeParticipants, filterOrphanedEdges, createEdgeCollector } from './edges';
+
+describe('edges utilities', () => {
+  describe('getEdgeKey', () => {
+    it('should create key from simple string from/to', () => {
+      const edge: GraphEdge = { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' };
+      expect(getEdgeKey(edge)).toBe('agent_a=>agent_b::handoff');
+    });
+
+    it('should default edgeType to handoff when not provided', () => {
+      const edge = { from: 'agent_a', to: 'agent_b' } as GraphEdge;
+      expect(getEdgeKey(edge)).toBe('agent_a=>agent_b::handoff');
+    });
+
+    it('should handle array from values by sorting', () => {
+      const edge: GraphEdge = { from: ['agent_b', 'agent_a'], to: 'agent_c', edgeType: 'handoff' };
+      expect(getEdgeKey(edge)).toBe('agent_a|agent_b=>agent_c::handoff');
+    });
+
+    it('should handle array to values by sorting', () => {
+      const edge: GraphEdge = { from: 'agent_a', to: ['agent_c', 'agent_b'], edgeType: 'handoff' };
+      expect(getEdgeKey(edge)).toBe('agent_a=>agent_b|agent_c::handoff');
+    });
+
+    it('should handle both from and to as arrays', () => {
+      const edge: GraphEdge = {
+        from: ['agent_b', 'agent_a'],
+        to: ['agent_d', 'agent_c'],
+        edgeType: 'direct',
+      };
+      expect(getEdgeKey(edge)).toBe('agent_a|agent_b=>agent_c|agent_d::direct');
+    });
+
+    it('should produce same key regardless of array order', () => {
+      const edge1: GraphEdge = { from: ['a', 'b', 'c'], to: 'd', edgeType: 'handoff' };
+      const edge2: GraphEdge = { from: ['c', 'a', 'b'], to: 'd', edgeType: 'handoff' };
+      expect(getEdgeKey(edge1)).toBe(getEdgeKey(edge2));
+    });
+  });
+
+  describe('getEdgeParticipants', () => {
+    it('should return both from and to as participants', () => {
+      const edge: GraphEdge = { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' };
+      expect(getEdgeParticipants(edge)).toEqual(['agent_a', 'agent_b']);
+    });
+
+    it('should handle array from values', () => {
+      const edge: GraphEdge = { from: ['agent_a', 'agent_b'], to: 'agent_c', edgeType: 'handoff' };
+      expect(getEdgeParticipants(edge)).toEqual(['agent_a', 'agent_b', 'agent_c']);
+    });
+
+    it('should handle array to values', () => {
+      const edge: GraphEdge = { from: 'agent_a', to: ['agent_b', 'agent_c'], edgeType: 'handoff' };
+      expect(getEdgeParticipants(edge)).toEqual(['agent_a', 'agent_b', 'agent_c']);
+    });
+
+    it('should handle both from and to as arrays', () => {
+      const edge: GraphEdge = {
+        from: ['agent_a', 'agent_b'],
+        to: ['agent_c', 'agent_d'],
+        edgeType: 'handoff',
+      };
+      expect(getEdgeParticipants(edge)).toEqual(['agent_a', 'agent_b', 'agent_c', 'agent_d']);
+    });
+
+    it('should return empty array for edge with no valid ids', () => {
+      const edge = { from: undefined, to: undefined } as unknown as GraphEdge;
+      expect(getEdgeParticipants(edge)).toEqual([]);
+    });
+  });
+
+  describe('filterOrphanedEdges', () => {
+    const edges: GraphEdge[] = [
+      { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' },
+      { from: 'agent_a', to: 'agent_c', edgeType: 'handoff' },
+      { from: 'agent_b', to: 'agent_d', edgeType: 'handoff' },
+    ];
+
+    it('should return all edges when no agents are skipped', () => {
+      const skipped = new Set<string>();
+      expect(filterOrphanedEdges(edges, skipped)).toEqual(edges);
+    });
+
+    it('should filter out edges with orphaned to targets', () => {
+      const skipped = new Set(['agent_b']);
+      const result = filterOrphanedEdges(edges, skipped);
+      // Only filters edges where `to` is in skipped set
+      // agent_a -> agent_b (filtered - to=agent_b is skipped)
+      // agent_a -> agent_c (kept - to=agent_c not skipped)
+      // agent_b -> agent_d (kept - to=agent_d not skipped, from is not checked)
+      expect(result).toHaveLength(2);
+      expect(result.map((e) => e.to)).toEqual(['agent_c', 'agent_d']);
+    });
+
+    it('should filter out multiple orphaned edges', () => {
+      const skipped = new Set(['agent_b', 'agent_c']);
+      const result = filterOrphanedEdges(edges, skipped);
+      // agent_a -> agent_b (filtered)
+      // agent_a -> agent_c (filtered)
+      // agent_b -> agent_d (kept - to=agent_d not skipped)
+      expect(result).toHaveLength(1);
+      expect(result[0].to).toBe('agent_d');
+    });
+
+    it('should handle array to values', () => {
+      const edgesWithArray: GraphEdge[] = [
+        { from: 'agent_a', to: ['agent_b', 'agent_c'], edgeType: 'handoff' },
+        { from: 'agent_a', to: ['agent_d'], edgeType: 'handoff' },
+      ];
+      const skipped = new Set(['agent_b']);
+      const result = filterOrphanedEdges(edgesWithArray, skipped);
+      expect(result).toHaveLength(1);
+      expect(result[0].to).toEqual(['agent_d']);
+    });
+
+    it('should return original edges array when edges is null/undefined', () => {
+      const skipped = new Set(['agent_b']);
+      expect(filterOrphanedEdges(null as unknown as GraphEdge[], skipped)).toBeNull();
+      expect(filterOrphanedEdges(undefined as unknown as GraphEdge[], skipped)).toBeUndefined();
+    });
+
+    it('should return original edges when skippedAgentIds is empty', () => {
+      const skipped = new Set<string>();
+      expect(filterOrphanedEdges(edges, skipped)).toBe(edges);
+    });
+  });
+
+  describe('createEdgeCollector', () => {
+    it('should collect edges and track new agents to process', () => {
+      const initializedAgents = new Set(['primary']);
+      const checkAgentInit = (id: string) => initializedAgents.has(id);
+      const skippedAgentIds = new Set<string>();
+
+      const { edgeMap, agentsToProcess, collectEdges } = createEdgeCollector(
+        checkAgentInit,
+        skippedAgentIds,
+      );
+
+      const edges: GraphEdge[] = [
+        { from: 'primary', to: 'agent_a', edgeType: 'handoff' },
+        { from: 'primary', to: 'agent_b', edgeType: 'handoff' },
+      ];
+
+      collectEdges(edges);
+
+      expect(edgeMap.size).toBe(2);
+      expect(agentsToProcess.has('agent_a')).toBe(true);
+      expect(agentsToProcess.has('agent_b')).toBe(true);
+      expect(agentsToProcess.has('primary')).toBe(false);
+    });
+
+    it('should deduplicate edges by key', () => {
+      const checkAgentInit = () => false;
+      const skippedAgentIds = new Set<string>();
+
+      const { edgeMap, collectEdges } = createEdgeCollector(checkAgentInit, skippedAgentIds);
+
+      const edges: GraphEdge[] = [
+        { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' },
+        { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' },
+      ];
+
+      collectEdges(edges);
+
+      expect(edgeMap.size).toBe(1);
+    });
+
+    it('should not add skipped agents to process queue', () => {
+      const checkAgentInit = () => false;
+      const skippedAgentIds = new Set(['agent_b']);
+
+      const { agentsToProcess, collectEdges } = createEdgeCollector(
+        checkAgentInit,
+        skippedAgentIds,
+      );
+
+      const edges: GraphEdge[] = [
+        { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' },
+        { from: 'agent_a', to: 'agent_c', edgeType: 'handoff' },
+      ];
+
+      collectEdges(edges);
+
+      expect(agentsToProcess.has('agent_a')).toBe(true);
+      expect(agentsToProcess.has('agent_b')).toBe(false);
+      expect(agentsToProcess.has('agent_c')).toBe(true);
+    });
+
+    it('should not add already initialized agents to process queue', () => {
+      const initializedAgents = new Set(['agent_a', 'agent_b']);
+      const checkAgentInit = (id: string) => initializedAgents.has(id);
+      const skippedAgentIds = new Set<string>();
+
+      const { agentsToProcess, collectEdges } = createEdgeCollector(
+        checkAgentInit,
+        skippedAgentIds,
+      );
+
+      const edges: GraphEdge[] = [
+        { from: 'agent_a', to: 'agent_b', edgeType: 'handoff' },
+        { from: 'agent_a', to: 'agent_c', edgeType: 'handoff' },
+      ];
+
+      collectEdges(edges);
+
+      expect(agentsToProcess.has('agent_a')).toBe(false);
+      expect(agentsToProcess.has('agent_b')).toBe(false);
+      expect(agentsToProcess.has('agent_c')).toBe(true);
+    });
+
+    it('should handle undefined/empty edge list', () => {
+      const checkAgentInit = () => false;
+      const skippedAgentIds = new Set<string>();
+
+      const { edgeMap, agentsToProcess, collectEdges } = createEdgeCollector(
+        checkAgentInit,
+        skippedAgentIds,
+      );
+
+      collectEdges(undefined);
+      expect(edgeMap.size).toBe(0);
+      expect(agentsToProcess.size).toBe(0);
+
+      collectEdges([]);
+      expect(edgeMap.size).toBe(0);
+      expect(agentsToProcess.size).toBe(0);
+    });
+
+    it('should support multiple collectEdges calls (BFS pattern)', () => {
+      const initializedAgents = new Set(['primary']);
+      const checkAgentInit = (id: string) => initializedAgents.has(id);
+      const skippedAgentIds = new Set<string>();
+
+      const { edgeMap, agentsToProcess, collectEdges } = createEdgeCollector(
+        checkAgentInit,
+        skippedAgentIds,
+      );
+
+      // First call - primary's edges
+      collectEdges([{ from: 'primary', to: 'agent_a', edgeType: 'handoff' }]);
+
+      expect(edgeMap.size).toBe(1);
+      expect(agentsToProcess.has('agent_a')).toBe(true);
+
+      // Simulate processing agent_a
+      initializedAgents.add('agent_a');
+      agentsToProcess.delete('agent_a');
+
+      // Second call - agent_a's edges (transitive handoff)
+      collectEdges([{ from: 'agent_a', to: 'agent_b', edgeType: 'handoff' }]);
+
+      expect(edgeMap.size).toBe(2);
+      expect(agentsToProcess.has('agent_b')).toBe(true);
+    });
+  });
+});

packages/api/src/agents/edges.ts

@@ -0,0 +1,90 @@
+import type { GraphEdge } from 'librechat-data-provider';
+
+/**
+ * Creates a stable key for edge deduplication.
+ * Handles both single and array-based from/to values.
+ */
+export function getEdgeKey(edge: GraphEdge): string {
+  const from = Array.isArray(edge.from) ? [...edge.from].sort().join('|') : edge.from;
+  const to = Array.isArray(edge.to) ? [...edge.to].sort().join('|') : edge.to;
+  const type = edge.edgeType ?? 'handoff';
+  return `${from}=>${to}::${type}`;
+}
+
+/**
+ * Extracts all agent IDs referenced in an edge (both from and to).
+ */
+export function getEdgeParticipants(edge: GraphEdge): string[] {
+  const participants: string[] = [];
+  if (Array.isArray(edge.from)) {
+    participants.push(...edge.from);
+  } else if (typeof edge.from === 'string') {
+    participants.push(edge.from);
+  }
+  if (Array.isArray(edge.to)) {
+    participants.push(...edge.to);
+  } else if (typeof edge.to === 'string') {
+    participants.push(edge.to);
+  }
+  return participants;
+}
+
+/**
+ * Filters out edges that reference non-existent (orphaned) agents.
+ * Only filters based on the 'to' field since those are the handoff targets.
+ */
+export function filterOrphanedEdges(edges: GraphEdge[], skippedAgentIds: Set<string>): GraphEdge[] {
+  if (!edges || skippedAgentIds.size === 0) {
+    return edges;
+  }
+  return edges.filter((edge) => {
+    const toIds = Array.isArray(edge.to) ? edge.to : [edge.to];
+    return !toIds.some((id) => typeof id === 'string' && skippedAgentIds.has(id));
+  });
+}
+
+/**
+ * Result of discovering and aggregating edges from connected agents.
+ */
+export interface EdgeDiscoveryResult {
+  /** Deduplicated edges from all discovered agents */
+  edges: GraphEdge[];
+  /** Agent IDs that were not found (orphaned references) */
+  skippedAgentIds: Set<string>;
+}
+
+/**
+ * Collects and deduplicates edges, tracking new agents to process.
+ * Used for BFS discovery of connected agents.
+ */
+export function createEdgeCollector(
+  checkAgentInit: (agentId: string) => boolean,
+  skippedAgentIds: Set<string>,
+): {
+  edgeMap: Map<string, GraphEdge>;
+  agentsToProcess: Set<string>;
+  collectEdges: (edgeList: GraphEdge[] | undefined) => void;
+} {
+  const edgeMap = new Map<string, GraphEdge>();
+  const agentsToProcess = new Set<string>();
+
+  const collectEdges = (edgeList: GraphEdge[] | undefined): void => {
+    if (!edgeList || edgeList.length === 0) {
+      return;
+    }
+    for (const edge of edgeList) {
+      const key = getEdgeKey(edge);
+      if (!edgeMap.has(key)) {
+        edgeMap.set(key, edge);
+      }
+      const participants = getEdgeParticipants(edge);
+      for (const id of participants) {
+        if (!checkAgentInit(id) && !skippedAgentIds.has(id)) {
+          agentsToProcess.add(id);
+        }
+      }
+    }
+  };
+
+  return { edgeMap, agentsToProcess, collectEdges };
+}

packages/api/src/agents/index.ts

@@ -1,4 +1,5 @@
 export * from './chain';
+export * from './edges';
 export * from './initialize';
 export * from './legacy';
 export * from './memory';

packages/api/src/agents/initialize.ts

@@ -150,7 +150,13 @@ export async function initializeAgent(
   const provider = agent.provider;
   agent.endpoint = provider;
 
-  if (isInitialAgent && conversationId != null && resendFiles) {
+  /**
+   * Load conversation files for ALL agents, not just the initial agent.
+   * This enables handoff agents to access files that were uploaded earlier
+   * in the conversation. Without this, file_search and execute_code tools
+   * on handoff agents would fail to find previously attached files.
+   */
+  if (conversationId != null && resendFiles) {
     const fileIds = (await db.getConvoFiles(conversationId)) ?? [];
     const toolResourceSet = new Set<EToolResources>();
     for (const tool of agent.tools ?? []) {
@@ -162,7 +168,7 @@ export async function initializeAgent(
     if (requestFiles.length || toolFiles.length) {
       currentFiles = (await db.updateFilesUsage(requestFiles.concat(toolFiles))) as IMongoFile[];
     }
-  } else if (isInitialAgent && requestFiles.length) {
+  } else if (requestFiles.length) {
     currentFiles = (await db.updateFilesUsage(requestFiles)) as IMongoFile[];
   }
 

packages/api/src/agents/run.ts

@@ -140,6 +140,7 @@ export async function createRun({
       provider,
       reasoningKey,
       agentId: agent.id,
+      name: agent.name ?? undefined,
       tools: agent.tools,
       clientOptions: llmConfig,
       instructions: systemContent,