From 0c3893ee8b007a6cec76a38131bcf225fe075800 Mon Sep 17 00:00:00 2001
From: Bryan Frimin <bryan@getprobo.com>
Date: Fri, 13 Mar 2026 19:31:09 +0100
Subject: [PATCH] Skip nil handoffs to prevent panic during run

Signed-off-by: Bryan Frimin <bryan@getprobo.com>
---
 pkg/agent/agent.go      |  10 +++-
 pkg/agent/agent_test.go | 110 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 118 insertions(+), 2 deletions(-)

diff --git a/pkg/agent/agent.go b/pkg/agent/agent.go
index 569ea0050..dad6c8804 100644
--- a/pkg/agent/agent.go
+++ b/pkg/agent/agent.go
@@ -178,14 +178,20 @@ func WithTools(tools ...Tool) Option {
 func WithHandoffs(agents ...*Agent) Option {
 	return func(a *Agent) {
 		for _, ag := range agents {
-			a.handoffs = append(a.handoffs, &Handoff{Agent: ag})
+			if ag != nil {
+				a.handoffs = append(a.handoffs, &Handoff{Agent: ag})
+			}
 		}
 	}
 }
 
 func WithHandoffConfigs(handoffs ...*Handoff) Option {
 	return func(a *Agent) {
-		a.handoffs = append(a.handoffs, handoffs...)
+		for _, h := range handoffs {
+			if h != nil && h.Agent != nil {
+				a.handoffs = append(a.handoffs, h)
+			}
+		}
 	}
 }
 
diff --git a/pkg/agent/agent_test.go b/pkg/agent/agent_test.go
index 2842595b8..00b1e7db3 100644
--- a/pkg/agent/agent_test.go
+++ b/pkg/agent/agent_test.go
@@ -3103,3 +3103,113 @@ func TestResume_HandoffWithInputFilter(t *testing.T) {
 	assert.Equal(t, "Filtered specialist here.", result.FinalMessage().Text())
 	assert.Equal(t, "specialist", result.LastAgent.Name())
 }
+
+func TestRun_NilHandoffsAreSkipped(t *testing.T) {
+	t.Parallel()
+
+	t.Run(
+		"nil agent in WithHandoffs",
+		func(t *testing.T) {
+			t.Parallel()
+
+			provider := &mockProvider{
+				responses: []*llm.ChatCompletionResponse{
+					stopResponse("Hello."),
+				},
+			}
+
+			client := newTestClient(provider)
+
+			billing := agent.New(
+				"billing",
+				client,
+				agent.WithModel("test-model"),
+			)
+
+			a := agent.New(
+				"triage",
+				client,
+				agent.WithModel("test-model"),
+				agent.WithHandoffs(nil, billing, nil),
+			)
+
+			result, err := a.Run(
+				context.Background(),
+				[]llm.Message{userMessage("hi")},
+			)
+
+			require.NoError(t, err)
+			assert.Equal(t, "Hello.", result.FinalMessage().Text())
+		},
+	)
+
+	t.Run(
+		"nil handoff in WithHandoffConfigs",
+		func(t *testing.T) {
+			t.Parallel()
+
+			provider := &mockProvider{
+				responses: []*llm.ChatCompletionResponse{
+					stopResponse("Hello."),
+				},
+			}
+
+			client := newTestClient(provider)
+
+			billing := agent.New(
+				"billing",
+				client,
+				agent.WithModel("test-model"),
+			)
+
+			a := agent.New(
+				"triage",
+				client,
+				agent.WithModel("test-model"),
+				agent.WithHandoffConfigs(
+					nil,
+					agent.HandoffTo(billing),
+					nil,
+				),
+			)
+
+			result, err := a.Run(
+				context.Background(),
+				[]llm.Message{userMessage("hi")},
+			)
+
+			require.NoError(t, err)
+			assert.Equal(t, "Hello.", result.FinalMessage().Text())
+		},
+	)
+
+	t.Run(
+		"HandoffTo with nil agent in WithHandoffConfigs",
+		func(t *testing.T) {
+			t.Parallel()
+
+			provider := &mockProvider{
+				responses: []*llm.ChatCompletionResponse{
+					stopResponse("Hello."),
+				},
+			}
+
+			client := newTestClient(provider)
+
+			a := agent.New(
+				"triage",
+				client,
+				agent.WithModel("test-model"),
+				agent.WithHandoffConfigs(agent.HandoffTo(nil)),
+			)
+
+			result, err := a.Run(
+				context.Background(),
+				[]llm.Message{userMessage("hi")},
+			)
+
+			require.NoError(t, err)
+			assert.Equal(t, "Hello.", result.FinalMessage().Text())
+		},
+	)
+}