1 files changed, 111 insertions, 0 deletions
diff --git a/pkg/aflow/func_tool_test.go b/pkg/aflow/func_tool_test.go
new file mode 100644
index 000000000..429566dbe
--- /dev/null
+++ b/pkg/aflow/func_tool_test.go
@@ -0,0 +1,111 @@
+// Copyright 2026 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package aflow
+
+import (
+	"context"
+	"errors"
+	"path/filepath"
+	"testing"
+
+	"github.com/google/syzkaller/pkg/aflow/trajectory"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/genai"
+)
+
+func TestToolErrors(t *testing.T) {
+	type flowOutputs struct {
+		Reply string
+	}
+	type toolArgs struct {
+		CallError bool `jsonschema:"call error"`
+	}
+	flows := make(map[string]*Flow)
+	err := register[struct{}, flowOutputs]("test", "description", flows, []*Flow{
+		{
+			Root: &LLMAgent{
+				Name:        "smarty",
+				Model:       "model",
+				Reply:       "Reply",
+				Temperature: 0,
+				Instruction: "Do something!",
+				Prompt:      "Prompt",
+				Tools: []Tool{
+					NewFuncTool("faulty", func(ctx *Context, state struct{}, args toolArgs) (struct{}, error) {
+						if args.CallError {
+							return struct{}{}, BadCallError("you are wrong")
+						}
+						return struct{}{}, errors.New("hard error")
+					}, "tool 1 description"),
+				},
+			},
+		},
+	})
+	require.NoError(t, err)
+	replySeq := 0
+	stub := &stubContext{
+		// nolint:dupl
+		generateContent: func(model string, cfg *genai.GenerateContentConfig, req []*genai.Content) (
+			*genai.GenerateContentResponse, error) {
+			replySeq++
+			switch replySeq {
+			case 1:
+				return &genai.GenerateContentResponse{
+					Candidates: []*genai.Candidate{{
+						Content: &genai.Content{
+							Role: string(genai.RoleModel),
+							Parts: []*genai.Part{
+								{
+									FunctionCall: &genai.FunctionCall{
+										ID:   "id0",
+										Name: "faulty",
+										Args: map[string]any{
+											"CallError": true,
+										},
+									},
+								},
+							}}}}}, nil
+			case 2:
+				assert.Equal(t, req[2], &genai.Content{
+					Role: string(genai.RoleUser),
+					Parts: []*genai.Part{
+						{
+							FunctionResponse: &genai.FunctionResponse{
+								ID:   "id0",
+								Name: "faulty",
+								Response: map[string]any{
+									"error": "you are wrong",
+								},
+							},
+						}}})
+				return &genai.GenerateContentResponse{
+					Candidates: []*genai.Candidate{{
+						Content: &genai.Content{
+							Role: string(genai.RoleModel),
+							Parts: []*genai.Part{
+								{
+									FunctionCall: &genai.FunctionCall{
+										ID:   "id0",
+										Name: "faulty",
+										Args: map[string]any{
+											"CallError": false,
+										},
+									},
+								},
+							}}}}}, nil
+			default:
+				t.Fatal("unexpected LLM calls")
+				return nil, nil
+			}
+		},
+	}
+	ctx := context.WithValue(context.Background(), stubContextKey, stub)
+	workdir := t.TempDir()
+	cache, err := newTestCache(t, filepath.Join(workdir, "cache"), 0, stub.timeNow)
+	require.NoError(t, err)
+	onEvent := func(span *trajectory.Span) error { return nil }
+	_, err = flows["test"].Execute(ctx, "", workdir, nil, cache, onEvent)
+	require.Equal(t, err.Error(), "tool faulty failed: error: hard error\nargs: map[CallError:false]")
+}