fix(translator): prevent silent model downgrade with boundary-aware matching

- Add missing claude-sonnet-4-7/4.7 and claude-haiku-4-7/4.7 mappings;
  previously claude-sonnet-4.7 was substring-matched by the bare
  "claude-sonnet-4" key and silently downgraded to claude-sonnet-4.
- Introduce modelMapping.boundary flag and modelKeyMatches() helper.
  Bare digit-ending keys (like claude-sonnet-4) now require the next
  character to NOT be a digit, dot, or dash-digit, so future versions
  (4.8, 5.x) also pass through without silent downgrade.
- Add 8 regression tests in TestParseModelAndThinkingNoSilentDowngrade
  covering the 4.7 family, hypothetical 4.8, Bedrock-style names, and
  thinking-suffix variants.

proxy/translator.go

@@ -12,33 +12,66 @@ import (
 
 // 模型映射（有序，长 key 优先匹配，避免 "claude-sonnet-4" 误匹配 "claude-sonnet-4.5"）
 type modelMapping struct {
-	key   string
-	value string
+	key      string
+	value    string
+	boundary bool // 仅在 key 末位为单纯版本号时启用：要求 key 后面不能再跟 .X / -X / 数字
 }
 
 var modelMapOrdered = []modelMapping{
-	{"claude-sonnet-4-20250514", "claude-sonnet-4"},
-	{"claude-sonnet-4-5", "claude-sonnet-4.5"},
-	{"claude-sonnet-4.5", "claude-sonnet-4.5"},
-	{"claude-sonnet-4-6", "claude-sonnet-4.6"},
-	{"claude-sonnet-4.6", "claude-sonnet-4.6"},
-	{"claude-opus-4-7", "claude-opus-4.7"},
-	{"claude-opus-4.7", "claude-opus-4.7"},
-	{"claude-haiku-4-5", "claude-haiku-4.5"},
-	{"claude-haiku-4.5", "claude-haiku-4.5"},
-	{"claude-opus-4-5", "claude-opus-4.5"},
-	{"claude-opus-4.5", "claude-opus-4.5"},
-	{"claude-opus-4-6", "claude-opus-4.6"},
-	{"claude-opus-4.6", "claude-opus-4.6"},
-	{"claude-sonnet-4", "claude-sonnet-4"},
-	{"claude-3-5-sonnet", "claude-sonnet-4.5"},
-	{"claude-3-opus", "claude-sonnet-4.5"},
-	{"claude-3-sonnet", "claude-sonnet-4"},
-	{"claude-3-haiku", "claude-haiku-4.5"},
-	{"gpt-4-turbo", "claude-sonnet-4.5"},
-	{"gpt-4o", "claude-sonnet-4.5"},
-	{"gpt-4", "claude-sonnet-4.5"},
-	{"gpt-3.5-turbo", "claude-sonnet-4.5"},
+	{key: "claude-sonnet-4-20250514", value: "claude-sonnet-4"},
+	{key: "claude-sonnet-4-5", value: "claude-sonnet-4.5"},
+	{key: "claude-sonnet-4.5", value: "claude-sonnet-4.5"},
+	{key: "claude-sonnet-4-6", value: "claude-sonnet-4.6"},
+	{key: "claude-sonnet-4.6", value: "claude-sonnet-4.6"},
+	{key: "claude-sonnet-4-7", value: "claude-sonnet-4.7"},
+	{key: "claude-sonnet-4.7", value: "claude-sonnet-4.7"},
+	{key: "claude-opus-4-7", value: "claude-opus-4.7"},
+	{key: "claude-opus-4.7", value: "claude-opus-4.7"},
+	{key: "claude-haiku-4-5", value: "claude-haiku-4.5"},
+	{key: "claude-haiku-4.5", value: "claude-haiku-4.5"},
+	{key: "claude-haiku-4-7", value: "claude-haiku-4.7"},
+	{key: "claude-haiku-4.7", value: "claude-haiku-4.7"},
+	{key: "claude-opus-4-5", value: "claude-opus-4.5"},
+	{key: "claude-opus-4.5", value: "claude-opus-4.5"},
+	{key: "claude-opus-4-6", value: "claude-opus-4.6"},
+	{key: "claude-opus-4.6", value: "claude-opus-4.6"},
+	{key: "claude-sonnet-4", value: "claude-sonnet-4", boundary: true},
+	{key: "claude-3-5-sonnet", value: "claude-sonnet-4.5"},
+	{key: "claude-3-opus", value: "claude-sonnet-4.5"},
+	{key: "claude-3-sonnet", value: "claude-sonnet-4"},
+	{key: "claude-3-haiku", value: "claude-haiku-4.5"},
+	{key: "gpt-4-turbo", value: "claude-sonnet-4.5"},
+	{key: "gpt-4o", value: "claude-sonnet-4.5"},
+	{key: "gpt-4", value: "claude-sonnet-4.5"},
+	{key: "gpt-3.5-turbo", value: "claude-sonnet-4.5"},
+}
+
+// modelKeyMatches 判断 input 是否匹配 mapping 的 key。
+// 当 mapping.boundary=true 时，要求 key 后紧跟的字符不属于版本号延续
+// （数字、点、或 "-数字"），防止 "claude-sonnet-4" 误吃 "claude-sonnet-4.7"。
+func modelKeyMatches(input string, m modelMapping) bool {
+	idx := strings.Index(input, m.key)
+	if idx < 0 {
+		return false
+	}
+	if !m.boundary {
+		return true
+	}
+	end := idx + len(m.key)
+	if end >= len(input) {
+		return true
+	}
+	next := input[end]
+	if (next >= '0' && next <= '9') || next == '.' {
+		return false
+	}
+	if next == '-' && end+1 < len(input) {
+		n2 := input[end+1]
+		if n2 >= '0' && n2 <= '9' {
+			return false
+		}
+	}
+	return true
 }
 
 // Thinking 模式提示
@@ -61,9 +94,9 @@ func ParseModelAndThinking(model string, thinkingSuffix string) (string, bool) {
 		lower = strings.ToLower(model)
 	}
 
-	// 映射模型（有序匹配，长 key 优先）
+	// 映射模型（有序匹配，长 key 优先；带 boundary 标记的 key 要求版本号边界）
 	for _, m := range modelMapOrdered {
-		if strings.Contains(lower, m.key) {
+		if modelKeyMatches(lower, m) {
 			return m.value, thinking
 		}
 	}

proxy/translator_test.go

@@ -260,3 +260,40 @@ func TestToolResultsContinuationIncludesInstructionPrefix(t *testing.T) {
 		t.Fatalf("expected tool result text in continuation content, got %q", content)
 	}
 }
+
+func TestParseModelAndThinkingNoSilentDowngrade(t *testing.T) {
+	cases := []struct {
+		input    string
+		want     string
+		thinking bool
+	}{
+		// 4.7 family must not silently fall back to 4
+		{"claude-sonnet-4.7", "claude-sonnet-4.7", false},
+		{"claude-sonnet-4-7", "claude-sonnet-4.7", false},
+		{"claude-sonnet-4.7-thinking", "claude-sonnet-4.7", true},
+		{"claude-opus-4.7", "claude-opus-4.7", false},
+		{"claude-opus-4-7", "claude-opus-4.7", false},
+		{"claude-opus-4.7-thinking", "claude-opus-4.7", true},
+		{"claude-haiku-4.7", "claude-haiku-4.7", false},
+		{"claude-haiku-4-7", "claude-haiku-4.7", false},
+
+		// Existing canonical names still work
+		{"claude-sonnet-4", "claude-sonnet-4", false},
+		{"claude-sonnet-4.5", "claude-sonnet-4.5", false},
+		{"claude-sonnet-4.5-thinking", "claude-sonnet-4.5", true},
+		{"claude-sonnet-4-20250514", "claude-sonnet-4", false},
+
+		// Bedrock-style still maps via Contains on dated keys
+		{"anthropic.claude-sonnet-4-5-20250929-v1:0", "claude-sonnet-4.5", false},
+
+		// Hypothetical future 4.8 must not silently downgrade to 4
+		{"claude-sonnet-4.8", "claude-sonnet-4.8", false},
+	}
+	for _, tc := range cases {
+		got, gotThinking := ParseModelAndThinking(tc.input, "-thinking")
+		if got != tc.want || gotThinking != tc.thinking {
+			t.Errorf("ParseModelAndThinking(%q) = (%q, %v); want (%q, %v)",
+				tc.input, got, gotThinking, tc.want, tc.thinking)
+		}
+	}
+}