fix(translator): preserve typed Anthropic server tools through full conversion

Addresses the follow-up Codex review on PR #3804. The normalizer already
left typed Anthropic server tools (e.g. web_search_20250305) untouched, but
the downstream tool mapper in ConvertOpenAIRequestToClaude only emitted
type=="function" tools, silently dropping typed server tools from the final
Claude request when sent alongside a bare custom tool.

Pass typed server tools (type present, not "function") through verbatim into
the Claude tools array. Add TestConvertOpenAIRequestToClaude_TypedServerToolPreserved
to assert end-to-end survival through the full conversion, not just the
normalizer.

Author: HatriGt

internal/translator/claude/openai/chat-completions/claude_openai_normalize_test.go

@@ -186,6 +186,48 @@ func TestNormalizeAnthropicRequestBlocks_TypedToolNotWrapped(t *testing.T) {
 	}
 }
 
+func TestConvertOpenAIRequestToClaude_TypedServerToolPreserved(t *testing.T) {
+	// End-to-end guard: a typed Anthropic server tool sent alongside a bare
+	// custom tool must survive the FULL conversion, not just the normalizer.
+	// The downstream tool mapper previously emitted only type=="function"
+	// tools, silently dropping typed server tools like web_search_20250305.
+	inputJSON := `{
+		"model": "claude-sonnet-4-5",
+		"messages": [{"role": "user", "content": "search the web"}],
+		"tools": [
+			{"type": "web_search_20250305", "name": "web_search", "max_uses": 5},
+			{"name": "read_file", "description": "Read a file", "input_schema": {"type": "object"}}
+		]
+	}`
+
+	out := ConvertOpenAIRequestToClaude("claude-sonnet-4-5", []byte(inputJSON), false)
+	outJSON := gjson.ParseBytes(out)
+	tools := outJSON.Get("tools").Array()
+
+	if len(tools) != 2 {
+		t.Fatalf("Expected 2 tools after full conversion, got %d: %s", len(tools), outJSON.Get("tools").Raw)
+	}
+
+	typed := outJSON.Get(`tools.#(name=="web_search")`)
+	if !typed.Exists() {
+		t.Fatalf("Expected typed server tool web_search to survive conversion, got: %s", outJSON.Get("tools").Raw)
+	}
+	if got := typed.Get("type").String(); got != "web_search_20250305" {
+		t.Fatalf("Expected typed tool type preserved as web_search_20250305, got %q (%s)", got, typed.Raw)
+	}
+	if got := typed.Get("max_uses").Int(); got != 5 {
+		t.Fatalf("Expected typed tool fields preserved (max_uses=5), got %d", got)
+	}
+
+	bare := outJSON.Get(`tools.#(name=="read_file")`)
+	if !bare.Exists() {
+		t.Fatalf("Expected bare custom tool read_file mapped to Claude tool, got: %s", outJSON.Get("tools").Raw)
+	}
+	if !bare.Get("input_schema").Exists() {
+		t.Fatalf("Expected read_file mapped with input_schema, got: %s", bare.Raw)
+	}
+}
+
 func TestConvertOpenAIRequestToClaude_StandardOpenAIUnchanged(t *testing.T) {
 	// A normal OpenAI payload must pass through normalization untouched.
 	inputJSON := `{

internal/translator/claude/openai/chat-completions/claude_openai_request.go

@@ -298,6 +298,12 @@ func ConvertOpenAIRequestToClaude(modelName string, inputRawJSON []byte, stream
 
 				out, _ = sjson.SetRawBytes(out, "tools.-1", anthropicTool)
 				hasAnthropicTools = true
+			} else if t := tool.Get("type").String(); t != "" {
+				// Typed Anthropic server tools (e.g. {"type":"web_search_20250305",...})
+				// are already in Claude's native shape. Pass them through unchanged
+				// instead of dropping them, so they survive the full conversion.
+				out, _ = sjson.SetRawBytes(out, "tools.-1", []byte(tool.Raw))
+				hasAnthropicTools = true
 			}
 			return true
 		})