gateway: Kiro is sent the images a tool gave back, and tool names longer than 64 characters (#369)

A tool result's images (Claude Code's Read of a screenshot or a render) were dropped on the way to Kiro, whose tool results carry text alone, so the model saw "(no output)"; they now go with the message that answers the call, as a user's own images do. And a tool name Kiro doesn't take (longer than 64 characters, as an MCP server's prefixed names can be: Vercel's plugin has several) was sent as it was, which Kiro turns the whole request down for once the history holds a call ("Invalid tool use format", REQUEST_BODY_INVALID); it is cut and told apart by a hash, the same each time, and a call Kiro makes by that name comes back by the caller's. Co-authored-by: Claude <noreply@anthropic.com>
2026-10-01 05:37:11 +08:00
1 parent f1906bca6a
commit e3b6397abe
@@ -88,7 +88,7 @@ func (s *Server) askKiro(p provider.Provider, model string) round {
 		events := make(chan Event, 16)
 		go func() {
 			defer res.Body.Close()
-			decodeKiro(ctx, res.Body, events, model, window, thinking)
+			decodeKiro(ctx, res.Body, events, model, window, thinking, kiroNames(req))
 		}()
 		return events, 0, ""
 	}
@@ -245,6 +245,47 @@ func kiroToolID(id string) string {
 	return "t_" + base64.RawURLEncoding.EncodeToString(sum[:])[:32]
 }

+var (
+	kiroToolNameRe  = regexp.MustCompile(`^[a-zA-Z0-9_-]{1,64}$`)
+	kiroToolNameBad = regexp.MustCompile(`[^a-zA-Z0-9_-]`)
+)
+
+// kiroToolName is a tool's name as Kiro takes one: a longer one (an MCP
+// server's, prefixed) is rejected once the history holds a call, so it is
+// cut and told apart by a hash, the same each time; kiroNames maps it back.
+func kiroToolName(name string) string {
+	if kiroToolNameRe.MatchString(name) {
+		return name
+	}
+	sum := sha256.Sum256([]byte(name))
+	short := kiroToolNameBad.ReplaceAllString(name, "_")
+	if len(short) > 55 {
+		short = short[:55]
+	}
+	return short + "_" + fmt.Sprintf("%x", sum[:4])
+}
+
+// kiroNames is the caller's name for each name kiroToolName changed.
+func kiroNames(r *Request) map[string]string {
+	names := map[string]string{}
+	add := func(n string) {
+		if k := kiroToolName(n); k != n {
+			names[k] = n
+		}
+	}
+	for _, t := range r.Tools {
+		add(t.Name)
+	}
+	for _, m := range r.Messages {
+		for _, p := range m.Parts {
+			if p.Kind == ToolCall {
+				add(p.Name)
+			}
+		}
+	}
+	return names
+}
+
 // buildKiro is the body of a generateAssistantResponse call.
 func buildKiro(r *Request, model, profile string, thinking bool) []byte {
 	var entries []kiroEntry
@@ -264,7 +305,7 @@ func buildKiro(r *Request, model, profile string, thinking bool) []byte {
 					if !bytes.HasPrefix(bytes.TrimSpace(args), []byte("{")) {
 						args = json.RawMessage("{}")
 					}
-					a.ToolUses = append(a.ToolUses, kiroToolUse{Name: p.Name, ToolUseID: kiroToolID(p.ID), Input: args})
+					a.ToolUses = append(a.ToolUses, kiroToolUse{Name: kiroToolName(p.Name), ToolUseID: kiroToolID(p.ID), Input: args})
 				}
 			}
 			a.Content = strings.Join(texts, "\n\n")
@@ -309,6 +350,15 @@ func buildKiro(r *Request, model, profile string, thinking bool) []byte {
 					status = "error"
 				}
 				results = append(results, kiroToolResult{ToolUseID: kiroToolID(p.CallID), Status: status, Content: []kiroText{{Text: out}}})
+				// a tool's images (a screenshot, a file read) go with the
+				// message, as Kiro's tool results carry text alone
+				for _, im := range p.Images {
+					if im.Data != "" {
+						img := kiroImage{Format: kiroImageFormat(im.MediaType)}
+						img.Source.Bytes = im.Data
+						u.Images = append(u.Images, img)
+					}
+				}
 			}
 		}
 		u.Content = strings.Join(texts, "\n\n")
@@ -414,7 +464,7 @@ func buildKiro(r *Request, model, profile string, thinking bool) []byte {
 	offered := map[string]bool{}
 	for _, t := range r.Tools {
 		kt := kiroTool{}
-		kt.Spec.Name, kt.Spec.Description = t.Name, t.Description
+		kt.Spec.Name, kt.Spec.Description = kiroToolName(t.Name), t.Description
 		if kt.Spec.Description == "" {
 			kt.Spec.Description = t.Name
 		}
@@ -422,7 +472,7 @@ func buildKiro(r *Request, model, profile string, thinking bool) []byte {
 		if len(bytes.TrimSpace(t.Schema)) == 0 || string(bytes.TrimSpace(t.Schema)) == "null" {
 			kt.Spec.InputSchema.JSON = json.RawMessage(`{"type":"object","properties":{}}`)
 		}
-		offered[t.Name] = true
+		offered[kt.Spec.Name] = true
 		tools = append(tools, kt)
 	}
 	for _, e := range entries {
@@ -576,7 +626,7 @@ func readKiroFrame(r *bufio.Reader) (kiroFrame, error) {
 }

 // decodeKiro turns Kiro's reply into events.
-func decodeKiro(ctx context.Context, body io.Reader, out chan<- Event, model string, window int, thinking bool) {
+func decodeKiro(ctx context.Context, body io.Reader, out chan<- Event, model string, window int, thinking bool, names map[string]string) {
 	defer close(out)
 	send := func(ev Event) bool {
 		select {
@@ -589,7 +639,7 @@ func decodeKiro(ctx context.Context, body io.Reader, out chan<- Event, model str
 	if !send(Event{Kind: KStart, MsgID: "msg_" + randomToken()[:24], Model: model}) {
 		return
 	}
-	d := kiroDecoder{thinking: thinking}
+	d := kiroDecoder{thinking: thinking, names: names}
 	br := bufio.NewReaderSize(body, 64<<10)
 	var failed string
 	for {
@@ -647,6 +697,7 @@ func decodeKiro(ctx context.Context, body io.Reader, out chan<- Event, model str
 type kiroDecoder struct {
 	thinking bool
 	think    kiroThinkParser
+	names    map[string]string // the caller's name for a tool kiroToolName cut

 	tool       string // the id of the call being streamed
 	tools      int
@@ -694,6 +745,9 @@ func (d *kiroDecoder) frame(f kiroFrame) (evs []Event, failed string) {
 		}
 	case "toolUseEvent":
 		id, name := str("toolUseId"), str("name")
+		if n, ok := d.names[name]; ok {
+			name = n
+		}
 		if id != "" && id != d.tool {
 			// the text before a call is all said
 			evs = append(evs, d.think.end()...)
@@ -43,7 +43,7 @@ func kiroEvent(kind, payload string) []byte {
 func kiroEvents(t *testing.T, thinking bool, frames ...[]byte) []Event {
 	t.Helper()
 	out := make(chan Event, 256)
-	decodeKiro(context.Background(), bytes.NewReader(bytes.Join(frames, nil)), out, "claude-sonnet-4.5", 200000, thinking)
+	decodeKiro(context.Background(), bytes.NewReader(bytes.Join(frames, nil)), out, "claude-sonnet-4.5", 200000, thinking, nil)
 	var evs []Event
 	for ev := range out {
 		evs = append(evs, ev)
@@ -262,6 +262,45 @@ func TestBuildKiro(t *testing.T) {
 	}
 }

+func TestBuildKiroToolImagesAndLongNames(t *testing.T) {
+	long := "mcp__plugin_vercel_vercel__create_sandboxes_sessions_by_session_id_snapshot_v2"
+	r := &Request{
+		Tools: []Tool{{Name: long, Description: "Snapshot", Schema: json.RawMessage(`{"type":"object"}`)}, {Name: "Read", Schema: json.RawMessage(`{"type":"object"}`)}},
+		Messages: []Message{
+			{Role: "user", Parts: []Part{{Kind: Text, Text: "look"}}},
+			{Role: "assistant", Parts: []Part{{Kind: ToolCall, ID: "c1", Name: "Read", Args: json.RawMessage(`{}`)}, {Kind: ToolCall, ID: "c2", Name: long, Args: json.RawMessage(`{}`)}}},
+			{Role: "user", Parts: []Part{
+				{Kind: ToolResult, CallID: "c1", Images: []Part{{Kind: Image, MediaType: "image/png", Data: "PNG"}}},
+				{Kind: ToolResult, CallID: "c2", Text: "ok"},
+			}},
+		},
+	}
+	b := buildKiroBody(t, r, false)
+	cur := b.ConversationState.CurrentMessage.UserInputMessage
+	// the image a tool read goes with the message answering it
+	if len(cur.Images) != 1 || cur.Images[0].Format != "png" || cur.Images[0].Source.Bytes != "PNG" {
+		t.Fatalf("images = %+v", cur.Images)
+	}
+	short := kiroToolName(long)
+	if len(short) > 64 || !kiroToolNameRe.MatchString(short) || short != kiroToolName(long) {
+		t.Fatalf("short = %q", short)
+	}
+	if calls := b.ConversationState.History[1].Asst.ToolUses; calls[0].Name != "Read" || calls[1].Name != short {
+		t.Fatalf("calls = %+v", calls)
+	}
+	if tools := cur.Context.Tools; len(tools) != 2 || tools[0].Spec.Name != short || tools[1].Spec.Name != "Read" {
+		t.Fatalf("tools = %+v", tools)
+	}
+	// and a call Kiro makes by the short name comes back by the caller's
+	out := make(chan Event, 16)
+	decodeKiro(context.Background(), bytes.NewReader(kiroEvent("toolUseEvent", `{"toolUseId":"t1","name":"`+short+`","input":"{}"}`)), out, "claude-sonnet-4.5", 200000, false, kiroNames(r))
+	for ev := range out {
+		if ev.Kind == KToolStart && ev.Name != long {
+			t.Fatalf("name = %q", ev.Name)
+		}
+	}
+}
+
 func TestBuildKiroThinkingAndOneMessage(t *testing.T) {
 	r := &Request{Effort: "high", Messages: []Message{{Role: "user", Parts: []Part{{Kind: Text, Text: "why?"}}}}}
 	b := buildKiroBody(t, r, true)