fix: normalize missing agent handoff edges

packages/api/src/agents/__tests__/run-summarization.test.ts

@@ -465,6 +465,24 @@ describe('summarizationConfig field passthrough', () => {
 // Suite 5: Multi-agent + per-agent overrides
 // ---------------------------------------------------------------------------
 describe('multi-agent + per-agent overrides', () => {
+  it('normalizes missing persisted edges before creating the SDK graph', async () => {
+    await createRun({
+      agents: [makeAgent({ id: 'agent_1' }), makeAgent({ id: 'agent_2' })] as never,
+      signal: new AbortController().signal,
+      streaming: true,
+      streamUsage: true,
+    });
+
+    const createMock = Run.create as jest.Mock;
+    const runConfig = createMock.mock.calls[0][0] as {
+      graphConfig: { type: string; edges: unknown[] };
+    };
+    expect(runConfig.graphConfig).toMatchObject({
+      type: 'multi-agent',
+      edges: [],
+    });
+  });
+
   it('different agents get different effectiveMaxContextTokens', async () => {
     const agents = await callAndCapture({
       agents: [

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

@@ -73,6 +73,20 @@ const createSdkProcess = (): jest.MockedFunction<ProcessHandoffReception> =>
   });
 
 describe('applyCustomHandoffPromptKeyCompatibility', () => {
+  it('leaves multi-agent graphs without edges unpatched', () => {
+    const sdkProcess = createSdkProcess();
+    const { run, graph } = createRun(sdkProcess);
+    const originalProcess = graph.processHandoffReception;
+    // Persisted agents can predate `edges`, even though the current SDK type requires it.
+    const graphConfig = {
+      type: 'multi-agent',
+      agents: [],
+    } as unknown as RunConfig['graphConfig'];
+
+    expect(() => applyCustomHandoffPromptKeyCompatibility(run, graphConfig)).not.toThrow();
+    expect(graph.processHandoffReception).toBe(originalProcess);
+  });
+
   it('recovers a custom prompt key for scalar and array handoff endpoints', () => {
     const sdkProcess = createSdkProcess();
     const { run, graph } = createRun(sdkProcess);

packages/api/src/agents/handoffPromptKeyCompatibility.ts

@@ -121,7 +121,8 @@ export function applyCustomHandoffPromptKeyCompatibility(
     return;
   }
 
-  const hasCustomPromptKey = graphConfig.edges.some((edge) => {
+  const edges = graphConfig.edges ?? [];
+  const hasCustomPromptKey = edges.some((edge) => {
     const promptKey = edge.promptKey;
     return (
       edge.edgeType !== 'direct' &&
@@ -152,7 +153,7 @@ export function applyCustomHandoffPromptKeyCompatibility(
       return result;
     }
 
-    const labels = getCustomPromptLabels(graphConfig.edges, agentId);
+    const labels = getCustomPromptLabels(edges, agentId);
     if (labels.length === 0) {
       return result;
     }

packages/api/src/agents/run.ts

@@ -1362,7 +1362,7 @@ export async function createRun({
   const graphConfig: RunConfig['graphConfig'] = {
     signal,
     agents: agentInputs,
-    edges: agents[0].edges,
+    edges: agents[0].edges ?? [],
   };
 
   if (agentInputs.length > 1 || ((graphConfig as MultiAgentGraphConfig).edges?.length ?? 0) > 0) {