fix: add proxy_ prefix handling for tool_reference content blocks (#1)

applyClaudeToolPrefix, stripClaudeToolPrefixFromResponse, and
stripClaudeToolPrefixFromStreamLine now handle "tool_reference" blocks
(field "tool_name") in addition to "tool_use" blocks (field "name").

Without this fix, tool_reference blocks in conversation history retain
their original unprefixed names while tool definitions carry the proxy_
prefix, causing Anthropic API 400 errors: "Tool reference 'X' not found
in available tools."

Co-authored-by: Kirill Turanskiy <kt@novamedia.ru>

internal/runtime/executor/claude_executor.go

@@ -784,15 +784,22 @@ func applyClaudeToolPrefix(body []byte, prefix string) []byte {
 				return true
 			}
 			content.ForEach(func(contentIndex, part gjson.Result) bool {
-				if part.Get("type").String() != "tool_use" {
+				partType := part.Get("type").String()
-					return true
+				if partType == "tool_use" {
-				}
 					name := part.Get("name").String()
 					if name == "" || strings.HasPrefix(name, prefix) {
 						return true
 					}
 					path := fmt.Sprintf("messages.%d.content.%d.name", msgIndex.Int(), contentIndex.Int())
 					body, _ = sjson.SetBytes(body, path, prefix+name)
+				} else if partType == "tool_reference" {
+					toolName := part.Get("tool_name").String()
+					if toolName == "" || strings.HasPrefix(toolName, prefix) {
+						return true
+					}
+					path := fmt.Sprintf("messages.%d.content.%d.tool_name", msgIndex.Int(), contentIndex.Int())
+					body, _ = sjson.SetBytes(body, path, prefix+toolName)
+				}
 				return true
 			})
 			return true
@@ -811,15 +818,22 @@ func stripClaudeToolPrefixFromResponse(body []byte, prefix string) []byte {
 		return body
 	}
 	content.ForEach(func(index, part gjson.Result) bool {
-		if part.Get("type").String() != "tool_use" {
+		partType := part.Get("type").String()
-			return true
+		if partType == "tool_use" {
-		}
 			name := part.Get("name").String()
 			if !strings.HasPrefix(name, prefix) {
 				return true
 			}
 			path := fmt.Sprintf("content.%d.name", index.Int())
 			body, _ = sjson.SetBytes(body, path, strings.TrimPrefix(name, prefix))
+		} else if partType == "tool_reference" {
+			toolName := part.Get("tool_name").String()
+			if !strings.HasPrefix(toolName, prefix) {
+				return true
+			}
+			path := fmt.Sprintf("content.%d.tool_name", index.Int())
+			body, _ = sjson.SetBytes(body, path, strings.TrimPrefix(toolName, prefix))
+		}
 		return true
 	})
 	return body
@@ -834,17 +848,35 @@ func stripClaudeToolPrefixFromStreamLine(line []byte, prefix string) []byte {
 		return line
 	}
 	contentBlock := gjson.GetBytes(payload, "content_block")
-	if !contentBlock.Exists() || contentBlock.Get("type").String() != "tool_use" {
+	if !contentBlock.Exists() {
 		return line
 	}
+
+	blockType := contentBlock.Get("type").String()
+	var updated []byte
+	var err error
+
+	if blockType == "tool_use" {
 		name := contentBlock.Get("name").String()
 		if !strings.HasPrefix(name, prefix) {
 			return line
 		}
-	updated, err := sjson.SetBytes(payload, "content_block.name", strings.TrimPrefix(name, prefix))
+		updated, err = sjson.SetBytes(payload, "content_block.name", strings.TrimPrefix(name, prefix))
 		if err != nil {
 			return line
 		}
+	} else if blockType == "tool_reference" {
+		toolName := contentBlock.Get("tool_name").String()
+		if !strings.HasPrefix(toolName, prefix) {
+			return line
+		}
+		updated, err = sjson.SetBytes(payload, "content_block.tool_name", strings.TrimPrefix(toolName, prefix))
+		if err != nil {
+			return line
+		}
+	} else {
+		return line
+	}
 
 	trimmed := bytes.TrimSpace(line)
 	if bytes.HasPrefix(trimmed, []byte("data:")) {

internal/runtime/executor/claude_executor_test.go

@@ -25,6 +25,18 @@ func TestApplyClaudeToolPrefix(t *testing.T) {
 	}
 }
 
+func TestApplyClaudeToolPrefix_WithToolReference(t *testing.T) {
+	input := []byte(`{"tools":[{"name":"alpha"}],"messages":[{"role":"user","content":[{"type":"tool_reference","tool_name":"beta"},{"type":"tool_reference","tool_name":"proxy_gamma"}]}]}`)
+	out := applyClaudeToolPrefix(input, "proxy_")
+
+	if got := gjson.GetBytes(out, "messages.0.content.0.tool_name").String(); got != "proxy_beta" {
+		t.Fatalf("messages.0.content.0.tool_name = %q, want %q", got, "proxy_beta")
+	}
+	if got := gjson.GetBytes(out, "messages.0.content.1.tool_name").String(); got != "proxy_gamma" {
+		t.Fatalf("messages.0.content.1.tool_name = %q, want %q", got, "proxy_gamma")
+	}
+}
+
 func TestApplyClaudeToolPrefix_SkipsBuiltinTools(t *testing.T) {
 	input := []byte(`{"tools":[{"type":"web_search_20250305","name":"web_search"},{"name":"my_custom_tool","input_schema":{"type":"object"}}]}`)
 	out := applyClaudeToolPrefix(input, "proxy_")
@@ -49,6 +61,18 @@ func TestStripClaudeToolPrefixFromResponse(t *testing.T) {
 	}
 }
 
+func TestStripClaudeToolPrefixFromResponse_WithToolReference(t *testing.T) {
+	input := []byte(`{"content":[{"type":"tool_reference","tool_name":"proxy_alpha"},{"type":"tool_reference","tool_name":"bravo"}]}`)
+	out := stripClaudeToolPrefixFromResponse(input, "proxy_")
+
+	if got := gjson.GetBytes(out, "content.0.tool_name").String(); got != "alpha" {
+		t.Fatalf("content.0.tool_name = %q, want %q", got, "alpha")
+	}
+	if got := gjson.GetBytes(out, "content.1.tool_name").String(); got != "bravo" {
+		t.Fatalf("content.1.tool_name = %q, want %q", got, "bravo")
+	}
+}
+
 func TestStripClaudeToolPrefixFromStreamLine(t *testing.T) {
 	line := []byte(`data: {"type":"content_block_start","content_block":{"type":"tool_use","name":"proxy_alpha","id":"t1"},"index":0}`)
 	out := stripClaudeToolPrefixFromStreamLine(line, "proxy_")
@@ -61,3 +85,16 @@ func TestStripClaudeToolPrefixFromStreamLine(t *testing.T) {
 		t.Fatalf("content_block.name = %q, want %q", got, "alpha")
 	}
 }
+
+func TestStripClaudeToolPrefixFromStreamLine_WithToolReference(t *testing.T) {
+	line := []byte(`data: {"type":"content_block_start","content_block":{"type":"tool_reference","tool_name":"proxy_beta"},"index":0}`)
+	out := stripClaudeToolPrefixFromStreamLine(line, "proxy_")
+
+	payload := bytes.TrimSpace(out)
+	if bytes.HasPrefix(payload, []byte("data:")) {
+		payload = bytes.TrimSpace(payload[len("data:"):])
+	}
+	if got := gjson.GetBytes(payload, "content_block.tool_name").String(); got != "beta" {
+		t.Fatalf("content_block.tool_name = %q, want %q", got, "beta")
+	}
+}