diff --git a/backend/cmd/server/VERSION b/backend/cmd/server/VERSION
index a0e8ec1d4e..22a9c16f5e 100644
--- a/backend/cmd/server/VERSION
+++ b/backend/cmd/server/VERSION
@@ -1 +1 @@
-0.1.145
+0.1.146
diff --git a/backend/internal/handler/gateway_handler.go b/backend/internal/handler/gateway_handler.go
index b20d9ef652..0caa7f718b 100644
--- a/backend/internal/handler/gateway_handler.go
+++ b/backend/internal/handler/gateway_handler.go
@@ -158,6 +158,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	bodyRef := service.NewRequestBodyRef(body)
 	parsedReq, err := service.ParseGatewayRequest(bodyRef, domain.PlatformAnthropic)
 	if err != nil {
+		logRequestBodyParseFailure(reqLog, body, err)
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
@@ -1796,6 +1797,7 @@ func (h *GatewayHandler) CountTokens(c *gin.Context) {
 	bodyRef := service.NewRequestBodyRef(body)
 	parsedReq, err := service.ParseGatewayRequest(bodyRef, domain.PlatformAnthropic)
 	if err != nil {
+		logRequestBodyParseFailure(reqLog, body, err)
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/gateway_handler_chat_completions.go b/backend/internal/handler/gateway_handler_chat_completions.go
index d0ecc01e6a..03ceb0d952 100644
--- a/backend/internal/handler/gateway_handler_chat_completions.go
+++ b/backend/internal/handler/gateway_handler_chat_completions.go
@@ -64,6 +64,7 @@ func (h *GatewayHandler) ChatCompletions(c *gin.Context) {
 
 	// Validate JSON
 	if !gjson.ValidBytes(body) {
+		logRequestBodyParseFailure(reqLog, body, nil)
 		h.chatCompletionsErrorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/gateway_handler_responses.go b/backend/internal/handler/gateway_handler_responses.go
index 4a8d752193..f5ee18b722 100644
--- a/backend/internal/handler/gateway_handler_responses.go
+++ b/backend/internal/handler/gateway_handler_responses.go
@@ -64,6 +64,7 @@ func (h *GatewayHandler) Responses(c *gin.Context) {
 
 	// Validate JSON
 	if !gjson.ValidBytes(body) {
+		logRequestBodyParseFailure(reqLog, body, nil)
 		h.responsesErrorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/openai_chat_completions.go b/backend/internal/handler/openai_chat_completions.go
index baff1dcbd6..847d386cde 100644
--- a/backend/internal/handler/openai_chat_completions.go
+++ b/backend/internal/handler/openai_chat_completions.go
@@ -64,6 +64,7 @@ func (h *OpenAIGatewayHandler) ChatCompletions(c *gin.Context) {
 	}
 
 	if !gjson.ValidBytes(body) {
+		logRequestBodyParseFailure(reqLog, body, nil)
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/openai_embeddings.go b/backend/internal/handler/openai_embeddings.go
index 8be533c723..56d775eb7c 100644
--- a/backend/internal/handler/openai_embeddings.go
+++ b/backend/internal/handler/openai_embeddings.go
@@ -60,6 +60,7 @@ func (h *OpenAIGatewayHandler) Embeddings(c *gin.Context) {
 		return
 	}
 	if !gjson.ValidBytes(body) {
+		logRequestBodyParseFailure(reqLog, body, nil)
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/openai_gateway_count_tokens.go b/backend/internal/handler/openai_gateway_count_tokens.go
index fc9c4d5df7..9a6709cc4f 100644
--- a/backend/internal/handler/openai_gateway_count_tokens.go
+++ b/backend/internal/handler/openai_gateway_count_tokens.go
@@ -64,6 +64,7 @@ func (h *OpenAIGatewayHandler) CountTokens(c *gin.Context) {
 	bodyRef := service.NewRequestBodyRef(body)
 	parsedReq, err := service.ParseGatewayRequest(bodyRef, domain.PlatformAnthropic)
 	if err != nil {
+		logRequestBodyParseFailure(reqLog, body, err)
 		h.anthropicErrorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/openai_gateway_handler.go b/backend/internal/handler/openai_gateway_handler.go
index 7f097afa4b..551de2dd61 100644
--- a/backend/internal/handler/openai_gateway_handler.go
+++ b/backend/internal/handler/openai_gateway_handler.go
@@ -218,6 +218,7 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 
 	// 校验请求体 JSON 合法性
 	if !gjson.ValidBytes(body) {
+		logRequestBodyParseFailure(reqLog, body, nil)
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
@@ -697,6 +698,7 @@ func (h *OpenAIGatewayHandler) Messages(c *gin.Context) {
 	}
 
 	if !gjson.ValidBytes(body) {
+		logRequestBodyParseFailure(reqLog, body, nil)
 		h.anthropicErrorResponse(c, http.StatusBadRequest, "invalid_request_error", "Failed to parse request body")
 		return
 	}
diff --git a/backend/internal/handler/request_body_parse_log.go b/backend/internal/handler/request_body_parse_log.go
new file mode 100644
index 0000000000..c38a7f9bd5
--- /dev/null
+++ b/backend/internal/handler/request_body_parse_log.go
@@ -0,0 +1,54 @@
+package handler
+
+import (
+	"strconv"
+
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"go.uber.org/zap"
+)
+
+// parseFailureSnippetLen bounds the head/tail snippets logged on body parse
+// failure. 256 bytes is enough to see the structural context (model field,
+// first content block / trailing brace) without dumping user payloads.
+const parseFailureSnippetLen = 256
+
+// logRequestBodyParseFailure records the real reason a request body failed
+// JSON parsing/validation. The client keeps receiving the generic
+// "Failed to parse request body"; the sanitized diagnostics (underlying
+// error with byte offset, body length, escaped head/tail snippets) land in
+// the server log only, so operators can distinguish genuinely invalid JSON
+// from a truncated or partially consumed body.
+//
+// err may be nil for call sites that validate with gjson.ValidBytes directly;
+// the diagnostic error is derived from the body in that case.
+func logRequestBodyParseFailure(reqLog *zap.Logger, body []byte, err error) {
+	if reqLog == nil {
+		return
+	}
+	if err == nil {
+		err = service.DescribeInvalidJSON(body)
+	}
+
+	head := body
+	var tail []byte
+	if len(body) > parseFailureSnippetLen {
+		head = body[:parseFailureSnippetLen]
+		tail = body[len(body)-parseFailureSnippetLen:]
+	}
+
+	fields := []zap.Field{
+		zap.Error(err),
+		zap.Int("body_len", len(body)),
+		zap.String("body_head", sanitizeBodySnippet(head)),
+	}
+	if len(tail) > 0 {
+		fields = append(fields, zap.String("body_tail", sanitizeBodySnippet(tail)))
+	}
+	reqLog.Warn("parse request body failed", fields...)
+}
+
+// sanitizeBodySnippet escapes control characters and invalid UTF-8 so the
+// snippet is always a single printable log line.
+func sanitizeBodySnippet(b []byte) string {
+	return strconv.Quote(string(b))
+}
diff --git a/backend/internal/handler/request_body_parse_log_test.go b/backend/internal/handler/request_body_parse_log_test.go
new file mode 100644
index 0000000000..c1477eb4d7
--- /dev/null
+++ b/backend/internal/handler/request_body_parse_log_test.go
@@ -0,0 +1,100 @@
+//go:build unit
+
+package handler
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zaptest/observer"
+)
+
+func newObservedLogger(t *testing.T) (*zap.Logger, *observer.ObservedLogs) {
+	t.Helper()
+	core, logs := observer.New(zap.WarnLevel)
+	return zap.New(core), logs
+}
+
+func loggedFields(t *testing.T, logs *observer.ObservedLogs) map[string]any {
+	t.Helper()
+	entries := logs.All()
+	require.Len(t, entries, 1)
+	fields := map[string]any{}
+	for _, f := range entries[0].Context {
+		switch f.Key {
+		case "body_len":
+			fields[f.Key] = int(f.Integer)
+		case "error":
+			fields[f.Key] = f.Interface.(error).Error()
+		default:
+			fields[f.Key] = f.String
+		}
+	}
+	return fields
+}
+
+func TestLogRequestBodyParseFailure_DerivesErrorWhenNil(t *testing.T) {
+	log, logs := newObservedLogger(t)
+	body := []byte(`{"model": bad}`)
+
+	logRequestBodyParseFailure(log, body, nil)
+
+	fields := loggedFields(t, logs)
+	require.Equal(t, len(body), fields["body_len"])
+	require.Contains(t, fields["error"], "invalid json")
+	require.Contains(t, fields["error"], "offset=11")
+}
+
+func TestLogRequestBodyParseFailure_ShortBodyHasNoTail(t *testing.T) {
+	log, logs := newObservedLogger(t)
+	body := []byte(`{"broken":`)
+
+	logRequestBodyParseFailure(log, body, nil)
+
+	fields := loggedFields(t, logs)
+	require.Contains(t, fields, "body_head")
+	require.NotContains(t, fields, "body_tail")
+	require.Contains(t, fields["body_head"].(string), `{\"broken\":`)
+}
+
+func TestLogRequestBodyParseFailure_LargeBodyBoundedSnippets(t *testing.T) {
+	log, logs := newObservedLogger(t)
+	// ~1MB body: head must show the structural prefix, tail the trailing bytes,
+	// and neither snippet may exceed the configured bound (plus quoting overhead).
+	body := []byte(`{"model":"claude-sonnet-4-6","big":"` + strings.Repeat("A", 1<<20) + `"`)
+
+	logRequestBodyParseFailure(log, body, nil)
+
+	fields := loggedFields(t, logs)
+	require.Equal(t, len(body), fields["body_len"])
+	head := fields["body_head"].(string)
+	tail := fields["body_tail"].(string)
+	require.Contains(t, head, "claude-sonnet-4-6")
+	require.Contains(t, tail, "AAA")
+	require.NotContains(t, tail, "claude-sonnet-4-6")
+	// strconv.Quote adds surrounding quotes and escapes; 4x is a generous cap.
+	require.LessOrEqual(t, len(head), parseFailureSnippetLen*4)
+	require.LessOrEqual(t, len(tail), parseFailureSnippetLen*4)
+}
+
+func TestLogRequestBodyParseFailure_EscapesControlCharacters(t *testing.T) {
+	log, logs := newObservedLogger(t)
+	body := []byte("{\"model\":\x01\n\"x\"}")
+
+	logRequestBodyParseFailure(log, body, nil)
+
+	fields := loggedFields(t, logs)
+	head := fields["body_head"].(string)
+	require.NotContains(t, head, "\n")
+	require.NotContains(t, head, "\x01")
+	require.Contains(t, head, `\n`)
+	require.Contains(t, head, `\x01`)
+}
+
+func TestLogRequestBodyParseFailure_NilLoggerNoPanic(t *testing.T) {
+	require.NotPanics(t, func() {
+		logRequestBodyParseFailure(nil, []byte(`{`), nil)
+	})
+}
diff --git a/backend/internal/pkg/xai/models.go b/backend/internal/pkg/xai/models.go
index 4902fcb94f..a5b800cf2c 100644
--- a/backend/internal/pkg/xai/models.go
+++ b/backend/internal/pkg/xai/models.go
@@ -12,6 +12,7 @@ type Model struct {
 var defaultModels = []Model{
 	{ID: "grok-4.3", Object: "model", OwnedBy: "xai", DisplayName: "Grok 4.3"},
 	{ID: "grok-build-0.1", Object: "model", OwnedBy: "xai", DisplayName: "Grok Build 0.1"},
+	{ID: "grok-composer-2.5-fast", Object: "model", OwnedBy: "xai", DisplayName: "Grok Composer 2.5 Fast"},
 	{ID: "grok-4.20-0309-reasoning", Object: "model", OwnedBy: "xai", DisplayName: "Grok 4.20 Reasoning"},
 	{ID: "grok-4.20-0309-non-reasoning", Object: "model", OwnedBy: "xai", DisplayName: "Grok 4.20 Non Reasoning"},
 	{ID: "grok-4.20-multi-agent-0309", Object: "model", OwnedBy: "xai", DisplayName: "Grok 4.20 Multi Agent"},
@@ -46,6 +47,7 @@ func DefaultModelMapping() map[string]string {
 	mapping["grok"] = "grok-4.3"
 	mapping["grok-latest"] = "grok-4.3"
 	mapping["grok-build"] = "grok-build-0.1"
+	mapping["grok-composer"] = "grok-composer-2.5-fast"
 	mapping["grok-4.20-reasoning"] = "grok-4.20-0309-reasoning"
 	mapping["grok-4.20-non-reasoning"] = "grok-4.20-0309-non-reasoning"
 	return mapping
diff --git a/backend/internal/pkg/xai/oauth_test.go b/backend/internal/pkg/xai/oauth_test.go
index 68a4fea240..28609a08fa 100644
--- a/backend/internal/pkg/xai/oauth_test.go
+++ b/backend/internal/pkg/xai/oauth_test.go
@@ -210,6 +210,7 @@ func TestDefaultModelMappingIncludesGrokAliases(t *testing.T) {
 	require.Equal(t, "grok-4.3", mapping["grok"])
 	require.Equal(t, "grok-4.3", mapping["grok-latest"])
 	require.Equal(t, "grok-build-0.1", mapping["grok-build"])
+	require.Equal(t, "grok-composer-2.5-fast", mapping["grok-composer"])
 	require.Equal(t, "grok-4.20-0309-reasoning", mapping["grok-4.20-reasoning"])
 	require.Equal(t, "grok-4.20-0309-non-reasoning", mapping["grok-4.20-non-reasoning"])
 	require.Equal(t, "grok-4.20-multi-agent-0309", mapping["grok-4.20-multi-agent-0309"])
diff --git a/backend/internal/service/antigravity_gateway_service.go b/backend/internal/service/antigravity_gateway_service.go
index aa4cab22d7..585170438e 100644
--- a/backend/internal/service/antigravity_gateway_service.go
+++ b/backend/internal/service/antigravity_gateway_service.go
@@ -153,14 +153,24 @@ type antigravityRetryLoopResult struct {
 }
 
 // resolveAntigravityForwardBaseURL 解析转发用 base URL。
-// 默认使用 daily（ForwardBaseURLs 的首个地址）；当环境变量为 prod 时使用第二个地址。
+//
+// 默认使用生产端点 cloudcode-pa.googleapis.com（antigravity.BaseURLs 的首个地址，
+// 与账号 OAuth 登录/测试连接所用的 antigravity.BaseURL 一致）。
+//
+// 历史上这里改用 ForwardBaseURLs()（把 daily/sandbox 排到首位）并默认取首个地址，
+// 导致网关把带生产 OAuth token 的请求发到 daily-cloudcode-pa.sandbox.googleapis.com，
+// 上游拒绝 → 账号被 401「Invalid bearer token」/502 打入临时不可调度且无法恢复
+// （见 #3611 / #2962）。后台「测试连接」用的是生产端点，所以「测试成功但网关 401」。
+//
+// daily/sandbox 端点仅供内部联调，需显式设置
+// GATEWAY_ANTIGRAVITY_FORWARD_BASE_URL=daily（或 sandbox）才启用。
 func resolveAntigravityForwardBaseURL() string {
-	baseURLs := antigravity.ForwardBaseURLs()
+	baseURLs := antigravity.BaseURLs
 	if len(baseURLs) == 0 {
 		return ""
 	}
 	mode := strings.ToLower(strings.TrimSpace(os.Getenv(antigravityForwardBaseURLEnv)))
-	if mode == "prod" && len(baseURLs) > 1 {
+	if (mode == "daily" || mode == "sandbox") && len(baseURLs) > 1 {
 		return baseURLs[1]
 	}
 	return baseURLs[0]
diff --git a/backend/internal/service/gateway_request.go b/backend/internal/service/gateway_request.go
index a90714ca1d..1665b1fe47 100644
--- a/backend/internal/service/gateway_request.go
+++ b/backend/internal/service/gateway_request.go
@@ -3,6 +3,7 @@ package service
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"math"
 	"regexp"
@@ -168,7 +169,7 @@ func parseGatewayRequestCurrentBody(parsed *ParsedRequest, protocol string) erro
 
 	bodyBytes := parsed.Body.Bytes()
 	if !gjson.ValidBytes(bodyBytes) {
-		return fmt.Errorf("invalid json")
+		return DescribeInvalidJSON(bodyBytes)
 	}
 
 	// 只在当前函数内零拷贝读取 JSON 字段；ReplaceBody 后必须重新进入本函数刷新派生状态。
@@ -216,6 +217,26 @@ func refreshGatewayRequestRanges(parsed *ParsedRequest, protocol string) error {
 	return parseGatewayRequestCurrentBody(parsed, protocol)
 }
 
+// DescribeInvalidJSON returns a diagnostic error for a request body that
+// failed JSON validation. It re-parses with encoding/json (failure path only)
+// to pinpoint the first offending byte, so operators can distinguish genuinely
+// invalid JSON from a truncated / partially consumed body. The error carries
+// only length/offset/character information — never body content — so callers
+// may safely wrap or log it.
+func DescribeInvalidJSON(body []byte) error {
+	var raw json.RawMessage
+	if err := json.Unmarshal(body, &raw); err != nil {
+		var syntaxErr *json.SyntaxError
+		if errors.As(err, &syntaxErr) {
+			return fmt.Errorf("invalid json (len=%d, offset=%d): %s", len(body), syntaxErr.Offset, syntaxErr.Error())
+		}
+		return fmt.Errorf("invalid json (len=%d): %w", len(body), err)
+	}
+	// gjson rejected the body but encoding/json accepted it (divergent edge
+	// cases, e.g. certain malformed UTF-8 sequences); report the basics.
+	return fmt.Errorf("invalid json (len=%d)", len(body))
+}
+
 // ParsedRequest 保存网关请求的预解析结果
 //
 // 性能优化说明：
diff --git a/backend/internal/service/gateway_request_invalid_json_test.go b/backend/internal/service/gateway_request_invalid_json_test.go
new file mode 100644
index 0000000000..cc69a41e72
--- /dev/null
+++ b/backend/internal/service/gateway_request_invalid_json_test.go
@@ -0,0 +1,52 @@
+//go:build unit
+
+package service
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/domain"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDescribeInvalidJSON_TruncatedBody(t *testing.T) {
+	// Simulates a body cut off mid-stream (e.g. partially consumed by middleware).
+	body := []byte(`{"model":"claude-sonnet-4-6","messages":[{"role":"user","content":"hi`)
+
+	err := DescribeInvalidJSON(body)
+
+	require.Error(t, err)
+	require.Contains(t, err.Error(), fmt.Sprintf("len=%d", len(body)))
+	require.Contains(t, err.Error(), "unexpected end of JSON input")
+}
+
+func TestDescribeInvalidJSON_InvalidCharacterWithOffset(t *testing.T) {
+	body := []byte(`{"model": bad}`)
+
+	err := DescribeInvalidJSON(body)
+
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "offset=11")
+	require.Contains(t, err.Error(), "invalid character")
+}
+
+func TestDescribeInvalidJSON_DoesNotLeakBodyContent(t *testing.T) {
+	secret := "sk-super-secret-value"
+	body := []byte(`{"api_key":"` + secret + `","broken":`)
+
+	err := DescribeInvalidJSON(body)
+
+	require.Error(t, err)
+	require.NotContains(t, err.Error(), secret)
+}
+
+func TestParseGatewayRequest_InvalidJSONErrorIsDiagnostic(t *testing.T) {
+	body := []byte(`{"model":"claude-sonnet-4-6","messages":[`)
+
+	_, err := ParseGatewayRequest(NewRequestBodyRef(body), domain.PlatformAnthropic)
+
+	require.Error(t, err)
+	require.True(t, strings.HasPrefix(err.Error(), "invalid json (len="), "error should carry diagnostics, got: %s", err.Error())
+}
diff --git a/backend/internal/service/gateway_service.go b/backend/internal/service/gateway_service.go
index dcaf3a645c..2ca554edb3 100644
--- a/backend/internal/service/gateway_service.go
+++ b/backend/internal/service/gateway_service.go
@@ -5105,6 +5105,13 @@ func (s *GatewayService) Forward(ctx context.Context, c *gin.Context, account *A
 	if err := replaceBody(StripEmptyTextBlocks(body)); err != nil {
 		return nil, err
 	}
+	// Pre-filter: strip web-search history blocks the upstream cannot accept
+	// (emulation-synthesized server_tool_use / web_search_tool_result always;
+	// genuine ones additionally for passback-required upstreams). See
+	// FilterWebSearchHistoryBlocks. reqModel 此时已是映射后的模型 ID。
+	if err := replaceBody(FilterWebSearchHistoryBlocks(body, reqModel)); err != nil {
+		return nil, err
+	}
 	// Pre-filter: remove thinking blocks with missing/invalid signatures before forwarding.
 	// Clients (e.g. Claude Code) sometimes send multi-turn conversations where a historical
 	// assistant message contains a thinking block that is missing the required "signature" field,
@@ -5688,6 +5695,11 @@ func (s *GatewayService) forwardAnthropicAPIKeyPassthroughWithInput(
 	}
 	// Pre-filter: strip empty text blocks (including nested in tool_result) to prevent upstream 400.
 	input.Body = StripEmptyTextBlocks(input.Body)
+	// Pre-filter: strip web-search history blocks the upstream cannot accept
+	// (emulation-synthesized ones always; genuine ones additionally for
+	// passback-required third-party upstreams such as GLM/Kimi/DeepSeek,
+	// which reject server_tool_use with 400). input.RequestModel 已是映射后的模型 ID。
+	input.Body = FilterWebSearchHistoryBlocks(input.Body, input.RequestModel)
 	if input.Parsed != nil {
 		// 透传分支也会改写实际 wire body，成功 usage hash 依赖这里同步当前 body。
 		if err := input.Parsed.ReplaceBody(input.Body); err != nil {
diff --git a/backend/internal/service/gateway_websearch_block_filter.go b/backend/internal/service/gateway_websearch_block_filter.go
new file mode 100644
index 0000000000..a0706c5c2d
--- /dev/null
+++ b/backend/internal/service/gateway_websearch_block_filter.go
@@ -0,0 +1,138 @@
+package service
+
+import (
+	"bytes"
+	"encoding/json"
+	"strings"
+	"unsafe"
+
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+const (
+	blockTypeServerToolUse       = "server_tool_use"
+	blockTypeWebSearchToolResult = "web_search_tool_result"
+)
+
+// Fast-path byte patterns: both block types only ever appear as quoted JSON
+// string values, so a raw substring check is a safe pre-filter regardless of
+// key/value spacing.
+var (
+	patternServerToolUse       = []byte(`"server_tool_use"`)
+	patternWebSearchToolResult = []byte(`"web_search_tool_result"`)
+)
+
+// FilterWebSearchHistoryBlocks removes web-search content blocks from
+// historical messages when the upstream cannot accept them:
+//
+//  1. Emulation-synthesized blocks — server_tool_use / web_search_tool_result
+//     whose tool-use ID carries webSearchToolUseIDPrefix — are fabricated
+//     locally by the web-search emulation (gateway_websearch_emulation.go).
+//     No upstream ever issued them, so clients replaying the conversation
+//     (e.g. Claude Code) poison every follow-up request. They are stripped
+//     for all upstreams.
+//  2. For passback-required upstreams (DeepSeek/Kimi/GLM …, see
+//     ResolveThinkingProtocol) all server_tool_use / web_search_tool_result
+//     blocks are stripped: these upstreams only accept
+//     text/thinking/image/tool_use/tool_result and reject anything else with
+//     400 "invalid value: `server_tool_use`". anthropic-strict and unknown
+//     upstreams keep genuine blocks untouched.
+//
+// The emulated assistant turn always carries a trailing text summary, so the
+// search context survives the strip. A message whose content would become
+// empty gets a placeholder text block (mirroring FilterThinkingBlocksForRetry).
+// Returns the original body unchanged when nothing needs stripping.
+func FilterWebSearchHistoryBlocks(body []byte, mappedModel string) []byte {
+	if !bytes.Contains(body, patternServerToolUse) && !bytes.Contains(body, patternWebSearchToolResult) {
+		return body
+	}
+
+	stripAll := ResolveThinkingProtocol(mappedModel) == ThinkingProtocolPassbackRequired
+
+	jsonStr := *(*string)(unsafe.Pointer(&body))
+	msgsRes := gjson.Get(jsonStr, "messages")
+	if !msgsRes.Exists() || !msgsRes.IsArray() {
+		return body
+	}
+
+	var messages []any
+	if err := json.Unmarshal(sliceRawFromBody(body, msgsRes), &messages); err != nil {
+		return body
+	}
+
+	modified := false
+	for _, msg := range messages {
+		msgMap, ok := msg.(map[string]any)
+		if !ok {
+			continue
+		}
+		content, ok := msgMap["content"].([]any)
+		if !ok {
+			continue
+		}
+
+		// 延迟分配：只有命中需剥离的块才构建新 slice。
+		var newContent []any
+		for i, block := range content {
+			blockMap, isMap := block.(map[string]any)
+			if isMap && shouldStripWebSearchBlock(blockMap, stripAll) {
+				if newContent == nil {
+					newContent = make([]any, 0, len(content))
+					newContent = append(newContent, content[:i]...)
+				}
+				continue
+			}
+			if newContent != nil {
+				newContent = append(newContent, block)
+			}
+		}
+		if newContent == nil {
+			continue
+		}
+		modified = true
+		if len(newContent) == 0 {
+			role, _ := msgMap["role"].(string)
+			placeholder := "(content removed)"
+			if role == "assistant" {
+				placeholder = "(assistant content removed)"
+			}
+			newContent = []any{map[string]any{"type": "text", "text": placeholder}}
+		}
+		msgMap["content"] = newContent
+	}
+
+	if !modified {
+		return body
+	}
+
+	msgsBytes, err := json.Marshal(messages)
+	if err != nil {
+		return body
+	}
+	out, err := sjson.SetRawBytes(body, "messages", msgsBytes)
+	if err != nil {
+		return body
+	}
+	return out
+}
+
+func shouldStripWebSearchBlock(block map[string]any, stripAll bool) bool {
+	blockType, _ := block["type"].(string)
+	switch blockType {
+	case blockTypeServerToolUse:
+		if stripAll {
+			return true
+		}
+		id, _ := block["id"].(string)
+		return strings.HasPrefix(id, webSearchToolUseIDPrefix)
+	case blockTypeWebSearchToolResult:
+		if stripAll {
+			return true
+		}
+		id, _ := block["tool_use_id"].(string)
+		return strings.HasPrefix(id, webSearchToolUseIDPrefix)
+	default:
+		return false
+	}
+}
diff --git a/backend/internal/service/gateway_websearch_block_filter_test.go b/backend/internal/service/gateway_websearch_block_filter_test.go
new file mode 100644
index 0000000000..cebda4d37b
--- /dev/null
+++ b/backend/internal/service/gateway_websearch_block_filter_test.go
@@ -0,0 +1,140 @@
+//go:build unit
+
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/tidwall/gjson"
+)
+
+// emulatedWebSearchBody is a follow-up /v1/messages request whose history
+// contains an assistant turn synthesized by the web-search emulation
+// (server_tool_use + web_search_tool_result with the local srvtoolu_ws_ ID
+// prefix, followed by the text summary).
+const emulatedWebSearchBody = `{"model":"claude-sonnet-4-6","max_tokens":1024,"messages":[` +
+	`{"role":"user","content":[{"type":"text","text":"search the weather"}]},` +
+	`{"role":"assistant","content":[` +
+	`{"type":"server_tool_use","id":"srvtoolu_ws_0123456789abcdef","name":"web_search","input":{"query":"weather"}},` +
+	`{"type":"web_search_tool_result","tool_use_id":"srvtoolu_ws_0123456789abcdef","content":[{"type":"web_search_result","url":"https://example.com","title":"Weather"}]},` +
+	`{"type":"text","text":"Here are the search results for \"weather\":"}]},` +
+	`{"role":"user","content":[{"type":"text","text":"thanks, continue"}]}]}`
+
+// genuineWebSearchBody carries real Anthropic web-search blocks (upstream IDs
+// do NOT have the local srvtoolu_ws_ prefix).
+const genuineWebSearchBody = `{"model":"claude-sonnet-4-6","max_tokens":1024,"messages":[` +
+	`{"role":"user","content":[{"type":"text","text":"search"}]},` +
+	`{"role":"assistant","content":[` +
+	`{"type":"server_tool_use","id":"srvtoolu_01ABCDEF","name":"web_search","input":{"query":"weather"}},` +
+	`{"type":"web_search_tool_result","tool_use_id":"srvtoolu_01ABCDEF","content":[{"type":"web_search_result","url":"https://example.com","title":"Weather"}]},` +
+	`{"type":"text","text":"summary with citations"}]}]}`
+
+func collectContentTypes(t *testing.T, body []byte) []string {
+	t.Helper()
+	var types []string
+	for _, msg := range gjson.GetBytes(body, "messages").Array() {
+		for _, block := range msg.Get("content").Array() {
+			types = append(types, block.Get("type").String())
+		}
+	}
+	return types
+}
+
+func TestFilterWebSearchHistoryBlocks_StripsEmulatedBlocksForAnthropicStrict(t *testing.T) {
+	out := FilterWebSearchHistoryBlocks([]byte(emulatedWebSearchBody), "claude-sonnet-4-6")
+
+	require.Equal(t, []string{"text", "text", "text"}, collectContentTypes(t, out))
+	// The emulated text summary must survive so the search context is preserved.
+	require.Contains(t, string(out), "Here are the search results")
+	require.NotContains(t, string(out), "srvtoolu_ws_")
+	require.True(t, gjson.ValidBytes(out))
+}
+
+func TestFilterWebSearchHistoryBlocks_KeepsGenuineBlocksForAnthropicStrict(t *testing.T) {
+	body := []byte(genuineWebSearchBody)
+	out := FilterWebSearchHistoryBlocks(body, "claude-sonnet-4-6")
+
+	require.Equal(t, string(body), string(out))
+}
+
+func TestFilterWebSearchHistoryBlocks_StripsAllBlocksForPassbackRequired(t *testing.T) {
+	// GLM only accepts text/thinking/image/tool_use/tool_result and rejects
+	// server_tool_use with 400, so genuine blocks must be stripped as well.
+	out := FilterWebSearchHistoryBlocks([]byte(genuineWebSearchBody), "glm-4.7")
+
+	require.Equal(t, []string{"text", "text"}, collectContentTypes(t, out))
+	require.NotContains(t, string(out), "server_tool_use")
+	require.NotContains(t, string(out), "web_search_tool_result")
+	require.Contains(t, string(out), "summary with citations")
+}
+
+func TestFilterWebSearchHistoryBlocks_StripsEmulatedBlocksForUnknownModel(t *testing.T) {
+	out := FilterWebSearchHistoryBlocks([]byte(emulatedWebSearchBody), "totally-unknown-model")
+
+	require.Equal(t, []string{"text", "text", "text"}, collectContentTypes(t, out))
+	require.NotContains(t, string(out), "srvtoolu_ws_")
+}
+
+func TestFilterWebSearchHistoryBlocks_KeepsGenuineBlocksForUnknownModel(t *testing.T) {
+	body := []byte(genuineWebSearchBody)
+	out := FilterWebSearchHistoryBlocks(body, "totally-unknown-model")
+
+	require.Equal(t, string(body), string(out))
+}
+
+func TestFilterWebSearchHistoryBlocks_NoWebSearchBlocksFastPath(t *testing.T) {
+	body := []byte(`{"model":"claude-sonnet-4-6","messages":[{"role":"user","content":[{"type":"text","text":"hi"}]}]}`)
+	out := FilterWebSearchHistoryBlocks(body, "claude-sonnet-4-6")
+
+	require.Equal(t, string(body), string(out))
+}
+
+func TestFilterWebSearchHistoryBlocks_EmptiedMessageGetsPlaceholder(t *testing.T) {
+	body := []byte(`{"model":"glm-4.7","messages":[` +
+		`{"role":"user","content":[{"type":"text","text":"search"}]},` +
+		`{"role":"assistant","content":[` +
+		`{"type":"server_tool_use","id":"srvtoolu_01X","name":"web_search","input":{"query":"q"}},` +
+		`{"type":"web_search_tool_result","tool_use_id":"srvtoolu_01X","content":[]}]}]}`)
+
+	out := FilterWebSearchHistoryBlocks(body, "glm-4.7")
+
+	msgs := gjson.GetBytes(out, "messages").Array()
+	require.Len(t, msgs, 2)
+	assistant := msgs[1]
+	require.Equal(t, "assistant", assistant.Get("role").String())
+	content := assistant.Get("content").Array()
+	require.Len(t, content, 1)
+	require.Equal(t, "text", content[0].Get("type").String())
+	require.Equal(t, "(assistant content removed)", content[0].Get("text").String())
+}
+
+func TestFilterWebSearchHistoryBlocks_StringContentUntouched(t *testing.T) {
+	// A string mentioning the pattern inside a text value must not trigger a rewrite.
+	body := []byte(`{"model":"claude-sonnet-4-6","messages":[` +
+		`{"role":"user","content":"please explain \"server_tool_use\" blocks"}]}`)
+
+	out := FilterWebSearchHistoryBlocks(body, "claude-sonnet-4-6")
+
+	require.Equal(t, string(body), string(out))
+}
+
+func TestFilterWebSearchHistoryBlocks_InvalidMessagesUnchanged(t *testing.T) {
+	body := []byte(`{"model":"claude-sonnet-4-6","messages":"server_tool_use"}`)
+	out := FilterWebSearchHistoryBlocks(body, "claude-sonnet-4-6")
+
+	require.Equal(t, string(body), string(out))
+}
+
+func TestFilterWebSearchHistoryBlocks_PreservesOtherToolBlocks(t *testing.T) {
+	body := []byte(`{"model":"glm-4.7","messages":[` +
+		`{"role":"assistant","content":[` +
+		`{"type":"tool_use","id":"toolu_01A","name":"get_weather","input":{}},` +
+		`{"type":"server_tool_use","id":"srvtoolu_ws_abc","name":"web_search","input":{"query":"q"}},` +
+		`{"type":"text","text":"result"}]},` +
+		`{"role":"user","content":[{"type":"tool_result","tool_use_id":"toolu_01A","content":"sunny"}]}]}`)
+
+	out := FilterWebSearchHistoryBlocks(body, "glm-4.7")
+
+	require.Equal(t, []string{"tool_use", "text", "tool_result"}, collectContentTypes(t, out))
+}
diff --git a/backend/internal/service/openai_gateway_chat_completions_raw.go b/backend/internal/service/openai_gateway_chat_completions_raw.go
index 348213a992..023440f94f 100644
--- a/backend/internal/service/openai_gateway_chat_completions_raw.go
+++ b/backend/internal/service/openai_gateway_chat_completions_raw.go
@@ -105,6 +105,33 @@ func (s *OpenAIGatewayService) forwardAsRawChatCompletions(
 		return nil, policyErr
 	}
 	upstreamBody = updatedBody
+
+	// Grok Composer does not accept image_url parts directly, but Grok Build
+	// can describe the images first. Bridge only this exact failure mode.
+	token, tokenKind, err := s.GetAccessToken(ctx, account)
+	if err != nil {
+		return nil, err
+	}
+	if strings.TrimSpace(token) == "" {
+		return nil, fmt.Errorf("account %d missing %s credential", account.ID, tokenKind)
+	}
+
+	var bridgeUsage OpenAIUsage
+	if account.Platform == PlatformGrok {
+		bridgedBody, usage, bridged, bridgeErr := s.bridgeGrokComposerImageInputs(ctx, c, account, upstreamBody, token)
+		if bridgeErr != nil {
+			var failoverErr *UpstreamFailoverError
+			if !errors.As(bridgeErr, &failoverErr) && c != nil && c.Writer != nil && !c.Writer.Written() {
+				writeChatCompletionsError(c, http.StatusBadGateway, "upstream_error", bridgeErr.Error())
+			}
+			return nil, bridgeErr
+		}
+		if bridged {
+			upstreamBody = bridgedBody
+			addOpenAIUsage(&bridgeUsage, usage)
+		}
+	}
+
 	if clientStream {
 		var usageErr error
 		upstreamBody, usageErr = ensureOpenAIChatStreamUsage(upstreamBody)
@@ -122,14 +149,6 @@ func (s *OpenAIGatewayService) forwardAsRawChatCompletions(
 	)
 
 	// 5. Build upstream request
-	token, tokenKind, err := s.GetAccessToken(ctx, account)
-	if err != nil {
-		return nil, err
-	}
-	if strings.TrimSpace(token) == "" {
-		return nil, fmt.Errorf("account %d missing %s credential", account.ID, tokenKind)
-	}
-
 	targetURL, err := s.rawChatCompletionsURL(account)
 	if err != nil {
 		return nil, err
@@ -245,10 +264,17 @@ func (s *OpenAIGatewayService) forwardAsRawChatCompletions(
 	}
 
 	// 8. Forward response
+	var result *OpenAIForwardResult
+	var forwardErr error
 	if clientStream {
-		return s.streamRawChatCompletions(c, resp, account, originalModel, billingModel, upstreamModel, reasoningEffort, serviceTier, startTime, len(body))
+		result, forwardErr = s.streamRawChatCompletions(c, resp, account, originalModel, billingModel, upstreamModel, reasoningEffort, serviceTier, startTime, len(body))
+	} else {
+		result, forwardErr = s.bufferRawChatCompletions(c, resp, originalModel, billingModel, upstreamModel, reasoningEffort, serviceTier, startTime)
 	}
-	return s.bufferRawChatCompletions(c, resp, originalModel, billingModel, upstreamModel, reasoningEffort, serviceTier, startTime)
+	if result != nil {
+		addOpenAIUsage(&result.Usage, bridgeUsage)
+	}
+	return result, forwardErr
 }
 
 func (s *OpenAIGatewayService) rawChatCompletionsURL(account *Account) (string, error) {
diff --git a/backend/internal/service/openai_gateway_grok.go b/backend/internal/service/openai_gateway_grok.go
index 4961b9c589..4a0ad06d46 100644
--- a/backend/internal/service/openai_gateway_grok.go
+++ b/backend/internal/service/openai_gateway_grok.go
@@ -10,12 +10,18 @@ import (
 	"strings"
 	"time"
 
+	"github.com/Wei-Shaw/sub2api/internal/pkg/apicompat"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/xai"
 	"github.com/gin-gonic/gin"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
 )
 
+const (
+	grokComposerImageBridgeVisionModel     = "grok-build-0.1"
+	grokComposerImageBridgeMaxOutputTokens = 512
+)
+
 func (s *OpenAIGatewayService) forwardGrokResponses(
 	ctx context.Context,
 	c *gin.Context,
@@ -309,6 +315,303 @@ func shouldDropGrokToolChoice(toolChoice gjson.Result, tools []json.RawMessage)
 	return false
 }
 
+func (s *OpenAIGatewayService) bridgeGrokComposerImageInputs(
+	ctx context.Context,
+	c *gin.Context,
+	account *Account,
+	body []byte,
+	token string,
+) ([]byte, OpenAIUsage, bool, error) {
+	if !shouldBridgeGrokComposerImageInputs(body) {
+		return body, OpenAIUsage{}, false, nil
+	}
+
+	var reqBody map[string]any
+	if err := json.Unmarshal(body, &reqBody); err != nil {
+		return body, OpenAIUsage{}, false, fmt.Errorf("parse grok composer image bridge request: %w", err)
+	}
+
+	imageURLs := collectGrokComposerImageURLs(reqBody)
+	if len(imageURLs) == 0 {
+		return body, OpenAIUsage{}, false, nil
+	}
+
+	descriptions := make([]string, 0, len(imageURLs))
+	var bridgeUsage OpenAIUsage
+	for index, imageURL := range imageURLs {
+		description, usage, err := s.describeGrokComposerImage(ctx, c, account, token, imageURL, index+1)
+		if err != nil {
+			return body, bridgeUsage, false, err
+		}
+		descriptions = append(descriptions, description)
+		addOpenAIUsage(&bridgeUsage, usage)
+	}
+
+	if !rewriteGrokComposerImagesAsText(reqBody, descriptions) {
+		return body, bridgeUsage, false, nil
+	}
+	bridgedBody, err := marshalOpenAIUpstreamJSON(reqBody)
+	if err != nil {
+		return body, bridgeUsage, false, fmt.Errorf("serialize grok composer image bridge request: %w", err)
+	}
+	return bridgedBody, bridgeUsage, true, nil
+}
+
+func shouldBridgeGrokComposerImageInputs(body []byte) bool {
+	if len(body) == 0 || !isGrokComposerModel(gjson.GetBytes(body, "model").String()) {
+		return false
+	}
+	messages := gjson.GetBytes(body, "messages")
+	if !messages.Exists() {
+		return false
+	}
+	return openAIJSONValueMayContainImageInput(messages)
+}
+
+func isGrokComposerModel(model string) bool {
+	model = strings.TrimSpace(strings.ToLower(model))
+	if model == "" {
+		return false
+	}
+	if strings.Contains(model, "/") {
+		parts := strings.Split(model, "/")
+		model = strings.TrimSpace(parts[len(parts)-1])
+	}
+	return strings.Contains(model, "composer")
+}
+
+func collectGrokComposerImageURLs(reqBody map[string]any) []string {
+	messages, ok := reqBody["messages"].([]any)
+	if !ok {
+		return nil
+	}
+
+	var imageURLs []string
+	for _, msg := range messages {
+		msgMap, ok := msg.(map[string]any)
+		if !ok {
+			continue
+		}
+		parts, ok := msgMap["content"].([]any)
+		if !ok {
+			continue
+		}
+		for _, part := range parts {
+			if imageURL := grokComposerImageURLFromPart(part); imageURL != "" {
+				imageURLs = append(imageURLs, imageURL)
+			}
+		}
+	}
+	return imageURLs
+}
+
+func grokComposerImageURLFromPart(part any) string {
+	partMap, ok := part.(map[string]any)
+	if !ok {
+		return ""
+	}
+	if strings.TrimSpace(strings.ToLower(fmt.Sprint(partMap["type"]))) != "image_url" {
+		return ""
+	}
+	switch imageURL := partMap["image_url"].(type) {
+	case string:
+		return normalizeGrokComposerImageURL(imageURL)
+	case map[string]any:
+		raw, _ := imageURL["url"].(string)
+		return normalizeGrokComposerImageURL(raw)
+	default:
+		return ""
+	}
+}
+
+func normalizeGrokComposerImageURL(raw string) string {
+	trimmed := strings.TrimSpace(raw)
+	if trimmed == "" || isEmptyBase64DataURI(trimmed) {
+		return ""
+	}
+	return trimmed
+}
+
+func (s *OpenAIGatewayService) describeGrokComposerImage(
+	ctx context.Context,
+	c *gin.Context,
+	account *Account,
+	token string,
+	imageURL string,
+	index int,
+) (string, OpenAIUsage, error) {
+	body, err := buildGrokComposerImageDescriptionBody(imageURL, index)
+	if err != nil {
+		return "", OpenAIUsage{}, err
+	}
+
+	upstreamCtx, releaseUpstreamCtx := detachUpstreamContext(ctx)
+	upstreamReq, err := buildGrokResponsesRequest(upstreamCtx, c, account, body, token)
+	releaseUpstreamCtx()
+	if err != nil {
+		return "", OpenAIUsage{}, fmt.Errorf("build grok composer image bridge request: %w", err)
+	}
+
+	proxyURL := ""
+	if account.ProxyID != nil && account.Proxy != nil {
+		proxyURL = account.Proxy.URL()
+	}
+
+	resp, err := s.httpUpstream.Do(upstreamReq, proxyURL, account.ID, account.Concurrency)
+	if err != nil {
+		return "", OpenAIUsage{}, s.handleOpenAIUpstreamTransportError(ctx, c, account, err, false)
+	}
+	defer func() { _ = resp.Body.Close() }()
+
+	if resp.StatusCode >= 400 {
+		respBody := s.readUpstreamErrorBody(resp)
+		s.updateGrokUsageSnapshot(ctx, account.ID, xai.ParseQuotaHeaders(resp.Header, resp.StatusCode))
+		upstreamMsg := sanitizeUpstreamErrorMessage(extractUpstreamErrorMessage(respBody))
+		if upstreamMsg == "" {
+			upstreamMsg = fmt.Sprintf("xAI image bridge upstream returned status %d", resp.StatusCode)
+		}
+		appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+			Platform:           account.Platform,
+			AccountID:          account.ID,
+			AccountName:        account.Name,
+			UpstreamStatusCode: resp.StatusCode,
+			UpstreamRequestID:  firstNonEmpty(resp.Header.Get("x-request-id"), resp.Header.Get("xai-request-id")),
+			Kind:               "failover",
+			Message:            upstreamMsg,
+		})
+		s.handleGrokAccountUpstreamError(ctx, account, resp.StatusCode, resp.Header, respBody)
+		if s.shouldFailoverUpstreamError(resp.StatusCode) {
+			return "", OpenAIUsage{}, &UpstreamFailoverError{
+				StatusCode:             resp.StatusCode,
+				ResponseBody:           respBody,
+				RetryableOnSameAccount: account.IsPoolMode() && account.IsPoolModeRetryableStatus(resp.StatusCode),
+			}
+		}
+		return "", OpenAIUsage{}, fmt.Errorf("grok composer image bridge upstream error: %s", upstreamMsg)
+	}
+
+	s.updateGrokUsageSnapshot(ctx, account.ID, xai.ParseQuotaHeaders(resp.Header, resp.StatusCode))
+	respBody, err := ReadUpstreamResponseBody(resp.Body, s.cfg, c, nil)
+	if err != nil {
+		return "", OpenAIUsage{}, fmt.Errorf("read grok composer image bridge response: %w", err)
+	}
+
+	var parsed apicompat.ResponsesResponse
+	if err := json.Unmarshal(respBody, &parsed); err != nil {
+		return "", OpenAIUsage{}, fmt.Errorf("parse grok composer image bridge response: %w", err)
+	}
+	description := strings.TrimSpace(grokResponsesOutputText(&parsed))
+	if description == "" {
+		return "", copyOpenAIUsageFromResponsesUsage(parsed.Usage), fmt.Errorf("grok composer image bridge returned empty description")
+	}
+	return description, copyOpenAIUsageFromResponsesUsage(parsed.Usage), nil
+}
+
+func buildGrokComposerImageDescriptionBody(imageURL string, index int) ([]byte, error) {
+	prompt := fmt.Sprintf("Describe image %d in concise, factual text for a downstream coding/composer model. Include visible text, UI elements, diagrams, errors, and spatial relationships. Do not mention that you are an image analysis bridge.", index)
+	req := map[string]any{
+		"model":             grokComposerImageBridgeVisionModel,
+		"stream":            false,
+		"store":             false,
+		"max_output_tokens": grokComposerImageBridgeMaxOutputTokens,
+		"input": []any{
+			map[string]any{
+				"type": "message",
+				"role": "user",
+				"content": []any{
+					map[string]any{"type": "input_text", "text": prompt},
+					map[string]any{"type": "input_image", "image_url": imageURL},
+				},
+			},
+		},
+	}
+	return marshalOpenAIUpstreamJSON(req)
+}
+
+func grokResponsesOutputText(resp *apicompat.ResponsesResponse) string {
+	if resp == nil {
+		return ""
+	}
+	var parts []string
+	for _, output := range resp.Output {
+		for _, content := range output.Content {
+			if content.Type == "output_text" || content.Type == "text" || content.Type == "input_text" {
+				if text := strings.TrimSpace(content.Text); text != "" {
+					parts = append(parts, text)
+				}
+			}
+		}
+	}
+	return strings.Join(parts, "\n\n")
+}
+
+func rewriteGrokComposerImagesAsText(reqBody map[string]any, descriptions []string) bool {
+	messages, ok := reqBody["messages"].([]any)
+	if !ok {
+		return false
+	}
+
+	imageIndex := 0
+	changed := false
+	for _, msg := range messages {
+		msgMap, ok := msg.(map[string]any)
+		if !ok {
+			continue
+		}
+		parts, ok := msgMap["content"].([]any)
+		if !ok {
+			continue
+		}
+		var textParts []string
+		messageChanged := false
+		for _, part := range parts {
+			if imageURL := grokComposerImageURLFromPart(part); imageURL != "" {
+				if imageIndex < len(descriptions) {
+					textParts = append(textParts, fmt.Sprintf("Image %d description: %s", imageIndex+1, strings.TrimSpace(descriptions[imageIndex])))
+				}
+				imageIndex++
+				messageChanged = true
+				continue
+			}
+			if text := grokComposerTextFromPart(part); text != "" {
+				textParts = append(textParts, text)
+			}
+		}
+		if messageChanged {
+			msgMap["content"] = strings.Join(textParts, "\n\n")
+			changed = true
+		}
+	}
+	return changed
+}
+
+func grokComposerTextFromPart(part any) string {
+	partMap, ok := part.(map[string]any)
+	if !ok {
+		return ""
+	}
+	partType := strings.TrimSpace(strings.ToLower(fmt.Sprint(partMap["type"])))
+	switch partType {
+	case "text", "input_text":
+		text, _ := partMap["text"].(string)
+		return strings.TrimSpace(text)
+	default:
+		return ""
+	}
+}
+
+func addOpenAIUsage(dst *OpenAIUsage, usage OpenAIUsage) {
+	if dst == nil {
+		return
+	}
+	dst.InputTokens += usage.InputTokens
+	dst.ImageInputTokens += usage.ImageInputTokens
+	dst.OutputTokens += usage.OutputTokens
+	dst.CacheCreationInputTokens += usage.CacheCreationInputTokens
+	dst.CacheReadInputTokens += usage.CacheReadInputTokens
+	dst.ImageOutputTokens += usage.ImageOutputTokens
+}
+
 func buildGrokResponsesRequest(ctx context.Context, c *gin.Context, account *Account, body []byte, token string) (*http.Request, error) {
 	targetURL, err := xai.BuildResponsesURL(account.GetGrokBaseURL())
 	if err != nil {
diff --git a/backend/internal/service/openai_gateway_grok_test.go b/backend/internal/service/openai_gateway_grok_test.go
index eae424ce9a..d012ab533a 100644
--- a/backend/internal/service/openai_gateway_grok_test.go
+++ b/backend/internal/service/openai_gateway_grok_test.go
@@ -651,6 +651,76 @@ func TestForwardAsChatCompletionsForGrokStreamingUsesRawXAIChatCompletions(t *te
 	require.NotNil(t, repo.updates[53][grokQuotaSnapshotExtraKey])
 }
 
+func TestForwardAsChatCompletionsForGrokComposerBridgesImageInput(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	body := []byte(`{"model":"grok-composer-2.5-fast","messages":[{"role":"system","content":"You are concise."},{"role":"user","content":[{"type":"text","text":"What is shown?"},{"type":"image_url","image_url":{"url":"data:image/png;base64,QUJD"}}]}],"stream":false}`)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/chat/completions", bytes.NewReader(body))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	account := &Account{
+		ID:          55,
+		Name:        "grok",
+		Platform:    PlatformGrok,
+		Type:        AccountTypeOAuth,
+		Concurrency: 1,
+		Credentials: map[string]any{
+			"access_token": "access-token",
+			"expires_at":   time.Now().Add(time.Hour).UTC().Format(time.RFC3339),
+			"base_url":     xai.DefaultCLIBaseURL,
+		},
+	}
+	repo := &grokQuotaAccountRepo{
+		mockAccountRepoForPlatform: &mockAccountRepoForPlatform{
+			accountsByID: map[int64]*Account{55: account},
+		},
+	}
+	upstream := &httpUpstreamRecorder{responses: []*http.Response{
+		{
+			StatusCode: http.StatusOK,
+			Header:     http.Header{"Content-Type": []string{"application/json"}, "xai-request-id": []string{"vision-req"}},
+			Body:       io.NopCloser(strings.NewReader(`{"id":"resp_vision","object":"response","model":"grok-build-0.1","output":[{"type":"message","role":"assistant","content":[{"type":"output_text","text":"A small diagram with ABC letters."}]}],"usage":{"input_tokens":11,"output_tokens":7,"total_tokens":18}}`)),
+		},
+		{
+			StatusCode: http.StatusOK,
+			Header: http.Header{
+				"Content-Type":                   []string{"application/json"},
+				"X-Request-Id":                   []string{"composer-req"},
+				"X-Ratelimit-Limit-Requests":     []string{"10"},
+				"X-Ratelimit-Remaining-Requests": []string{"9"},
+				"X-Ratelimit-Limit-Tokens":       []string{"1000"},
+				"X-Ratelimit-Remaining-Tokens":   []string{"980"},
+			},
+			Body: io.NopCloser(strings.NewReader(`{"id":"chatcmpl_composer","object":"chat.completion","model":"grok-composer-2.5-fast","choices":[{"index":0,"message":{"role":"assistant","content":"It shows ABC."},"finish_reason":"stop"}],"usage":{"prompt_tokens":3,"completion_tokens":5,"total_tokens":8}}`)),
+		},
+	}}
+	svc := &OpenAIGatewayService{
+		cfg:               rawChatCompletionsTestConfig(),
+		httpUpstream:      upstream,
+		grokTokenProvider: NewGrokTokenProvider(repo, nil),
+		accountRepo:       repo,
+	}
+
+	result, err := svc.ForwardAsChatCompletions(context.Background(), c, account, body, "", "")
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Len(t, upstream.requests, 2)
+	require.Equal(t, xai.DefaultCLIBaseURL+"/responses", upstream.requests[0].URL.String())
+	require.Equal(t, "grok-build-0.1", gjson.GetBytes(upstream.bodies[0], "model").String())
+	require.Equal(t, "input_image", gjson.GetBytes(upstream.bodies[0], "input.0.content.1.type").String())
+	require.Equal(t, xai.DefaultCLIBaseURL+"/chat/completions", upstream.requests[1].URL.String())
+	require.Equal(t, "grok-composer-2.5-fast", gjson.GetBytes(upstream.bodies[1], "model").String())
+	require.False(t, strings.Contains(string(upstream.bodies[1]), "image_url"))
+	require.Contains(t, gjson.GetBytes(upstream.bodies[1], "messages.1.content").String(), "Image 1 description")
+	require.Contains(t, gjson.GetBytes(upstream.bodies[1], "messages.1.content").String(), "A small diagram with ABC letters.")
+	require.Equal(t, 14, result.Usage.InputTokens)
+	require.Equal(t, 12, result.Usage.OutputTokens)
+	require.Equal(t, "It shows ABC.", gjson.Get(recorder.Body.String(), "choices.0.message.content").String())
+	require.NotNil(t, repo.updates[55][grokQuotaSnapshotExtraKey])
+}
+
 func TestForwardAsAnthropicForGrokUsesXAIResponses(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 
diff --git a/backend/internal/service/openai_gateway_service.go b/backend/internal/service/openai_gateway_service.go
index 645b31992a..fd104db8b6 100644
--- a/backend/internal/service/openai_gateway_service.go
+++ b/backend/internal/service/openai_gateway_service.go
@@ -5668,7 +5668,13 @@ func (s *OpenAIGatewayService) handleNonStreamingResponse(ctx context.Context, r
 	if isEventStreamResponse(resp.Header) {
 		return s.handleSSEToJSON(resp, c, body, originalModel, mappedModel)
 	}
-	bodyLooksLikeSSE := bytes.Contains(body, []byte("data:")) || bytes.Contains(body, []byte("event:"))
+	// bodyLooksLikeSSE is a line-level heuristic: real SSE framing requires
+	// "data:"/"event:" field names at the very start of a physical line. A
+	// plain bytes.Contains scan would also match ordinary JSON responses
+	// whose string content merely echoes the literal text "data:" or
+	// "event:" (e.g. compact tool output), causing those JSON bodies to be
+	// misrouted into handleSSEToJSON and lose their usage accounting.
+	bodyLooksLikeSSE := bodyHasSSEFraming(body)
 
 	// For OAuth accounts, also fall back to a body-content heuristic because
 	// the upstream may omit the Content-Type header while still sending SSE.
@@ -5718,6 +5724,22 @@ func isEventStreamResponse(header http.Header) bool {
 	return strings.Contains(contentType, "text/event-stream")
 }
 
+// bodyHasSSEFraming reports whether body contains genuine SSE framing by
+// scanning for physical lines that begin with the "data:" or "event:"
+// field names, per the SSE spec. Unlike a raw substring scan, this does not
+// match when those strings only appear embedded inside JSON string values
+// (e.g. "data: foo" quoted as part of an assistant text field), since such
+// occurrences never start a physical line in a valid JSON encoding.
+func bodyHasSSEFraming(body []byte) bool {
+	for _, line := range bytes.Split(body, []byte("\n")) {
+		line = bytes.TrimRight(line, "\r")
+		if bytes.HasPrefix(line, []byte("data:")) || bytes.HasPrefix(line, []byte("event:")) {
+			return true
+		}
+	}
+	return false
+}
+
 func (s *OpenAIGatewayService) handleSSEToJSON(resp *http.Response, c *gin.Context, body []byte, originalModel, mappedModel string) (*openaiNonStreamingResult, error) {
 	bodyText := string(body)
 	finalResponse, ok := extractCodexFinalResponse(bodyText)
diff --git a/backend/internal/service/openai_gateway_service_test.go b/backend/internal/service/openai_gateway_service_test.go
index c11d78e55c..b3e9889a7d 100644
--- a/backend/internal/service/openai_gateway_service_test.go
+++ b/backend/internal/service/openai_gateway_service_test.go
@@ -2739,6 +2739,41 @@ func TestHandleNonStreamingResponse_APIKeyFallsBackToSSEBodyWhenContentTypeIsWro
 	require.Equal(t, "hello", gjson.Get(rec.Body.String(), "output.0.content.0.text").String())
 }
 
+func TestHandleNonStreamingResponse_OAuthJSONBodyWithDataEventTextKeepsJSONUsage(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses/compact", nil)
+
+	svc := &OpenAIGatewayService{cfg: &config.Config{}}
+	// Plain JSON compact response whose output text happens to contain the
+	// literal substrings "data:" and "event:" (e.g. echoing shell/log output).
+	// This must NOT be misdetected as SSE framing: it has a top-level usage
+	// object and no upstream text/event-stream Content-Type.
+	jsonBody := `{"id":"resp_oauth_compact","object":"response","model":"gpt-5.4","status":"completed",` +
+		`"output":[{"type":"message","content":[{"type":"output_text",` +
+		`"text":"processing data: 1,2,3 then event: click finished"}]}],` +
+		`"usage":{"input_tokens":11,"output_tokens":22,"total_tokens":33}}`
+	resp := &http.Response{
+		StatusCode: http.StatusOK,
+		Header:     http.Header{"Content-Type": []string{"application/json"}},
+		Body:       io.NopCloser(strings.NewReader(jsonBody)),
+	}
+	account := &Account{ID: 146, Type: AccountTypeOAuth}
+
+	result, err := svc.handleNonStreamingResponse(context.Background(), resp, c, account, "gpt-5.4", "gpt-5.4")
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.Equal(t, 11, result.InputTokens)
+	require.Equal(t, 22, result.OutputTokens)
+	// Response must remain the original JSON body (not routed through the SSE
+	// path, which would rewrite/lose the body or usage).
+	require.Equal(t, "application/json", rec.Header().Get("Content-Type"))
+	require.Equal(t, "resp_oauth_compact", gjson.Get(rec.Body.String(), "id").String())
+	require.Equal(t, int64(33), gjson.Get(rec.Body.String(), "usage.total_tokens").Int())
+	require.Contains(t, rec.Body.String(), "processing data: 1,2,3 then event: click finished")
+}
+
 func TestHandleSSEToJSON_ReconstructsImageGenerationOutputItemDone(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	rec := httptest.NewRecorder()
diff --git a/deploy/Dockerfile b/deploy/Dockerfile
index aacd121c12..d83b0e25b8 100644
--- a/deploy/Dockerfile
+++ b/deploy/Dockerfile
@@ -18,9 +18,11 @@ ARG GOSUMDB=sum.golang.google.cn
 FROM ${NODE_IMAGE} AS frontend-builder
 
 WORKDIR /app/frontend
+ENV NODE_OPTIONS=--max-old-space-size=1536
 
-# Install pnpm. Keep this aligned with CI to avoid lockfile metadata drift.
-RUN corepack enable && corepack prepare pnpm@9 --activate
+# Install pnpm. Keep this pinned to the lockfile-compatible major version so
+# Docker builds remain reproducible when pnpm changes config validation rules.
+RUN corepack enable && corepack prepare pnpm@9.15.9 --activate
 
 # Install dependencies first (better caching)
 COPY frontend/package.json frontend/pnpm-lock.yaml ./
diff --git a/frontend/src/composables/useModelWhitelist.ts b/frontend/src/composables/useModelWhitelist.ts
index deb6f9d83d..28bc1d28ad 100644
--- a/frontend/src/composables/useModelWhitelist.ts
+++ b/frontend/src/composables/useModelWhitelist.ts
@@ -137,12 +137,14 @@ const metaModels = [
 const xaiModels = [
   'grok-4.3',
   'grok-build-0.1',
+  'grok-composer-2.5-fast',
   'grok-4.20-0309-reasoning',
   'grok-4.20-0309-non-reasoning',
   'grok-4.20-multi-agent-0309',
   'grok',
   'grok-latest',
   'grok-build',
+  'grok-composer',
   'grok-4.20-reasoning',
   'grok-4.20-non-reasoning',
   'grok-imagine',
@@ -297,6 +299,7 @@ const grokPresetMappings = [
   { label: 'Grok 4.3', from: 'grok-4.3', to: 'grok-4.3', color: 'bg-slate-100 text-slate-700 hover:bg-slate-200 dark:bg-slate-800/50 dark:text-slate-300' },
   { label: 'Grok Latest', from: 'grok-latest', to: 'grok-4.3', color: 'bg-emerald-100 text-emerald-700 hover:bg-emerald-200 dark:bg-emerald-900/30 dark:text-emerald-400' },
   { label: 'Build 0.1', from: 'grok-build', to: 'grok-build-0.1', color: 'bg-cyan-100 text-cyan-700 hover:bg-cyan-200 dark:bg-cyan-900/30 dark:text-cyan-400' },
+  { label: 'Composer 2.5', from: 'grok-composer', to: 'grok-composer-2.5-fast', color: 'bg-teal-100 text-teal-700 hover:bg-teal-200 dark:bg-teal-900/30 dark:text-teal-400' },
   { label: '4.20 Reasoning', from: 'grok-4.20-reasoning', to: 'grok-4.20-0309-reasoning', color: 'bg-indigo-100 text-indigo-700 hover:bg-indigo-200 dark:bg-indigo-900/30 dark:text-indigo-400' },
   { label: '4.20 Non Reasoning', from: 'grok-4.20-non-reasoning', to: 'grok-4.20-0309-non-reasoning', color: 'bg-violet-100 text-violet-700 hover:bg-violet-200 dark:bg-violet-900/30 dark:text-violet-400' },
   { label: 'Imagine Image', from: 'grok-imagine', to: 'grok-imagine-image-quality', color: 'bg-sky-100 text-sky-700 hover:bg-sky-200 dark:bg-sky-900/30 dark:text-sky-400' },