diff --git a/backend/internal/app/cloud_agent_pi_coordinator.go b/backend/internal/app/cloud_agent_pi_coordinator.go
index cfd5723cd..e0980299a 100644
--- a/backend/internal/app/cloud_agent_pi_coordinator.go
+++ b/backend/internal/app/cloud_agent_pi_coordinator.go
@@ -356,18 +356,21 @@ func (s *Service) runCloudAgentPiSession(ctx context.Context, userID, runID stri
 		},
 	})
 	if err != nil {
-		// 已经因审批暂停的会话，收尾阶段再报错不影响运行：状态停在等审批，
-		// 由审批结论接管。把它当失败处理会让用户还没来得及审批就整轮中断。
-		if pausedForApproval.Load() && !errors.Is(err, context.Canceled) {
-			log.Printf("[Agent] session error after approval pause ignored run=%s: %v", runID, err)
+		// The runtime can abort a prompt before the in-process pause flag is set
+		// (for example when the SDK races into a second model request). The durable
+		// run state is authoritative: an approval/user wait owns the next action
+		// and must never be converted into a terminal runtime failure.
+		paused := pausedForApproval.Load() || s.cloudAgentRunPausedForInput(userID, runID)
+		if paused {
+			log.Printf("[Agent] session error after durable pause ignored run=%s: %v", runID, err)
 			return nil
 		}
 		return err
 	}
 
-	// 本轮因审批暂停：运行由审批决定接管，不能在这里完成。用户可能在会话退出前
-	// 就已批准，此时状态已回到 running，若继续会把未恢复的运行误标为完成。
-	if pausedForApproval.Load() {
+	// The same durable check covers a clean runtime exit after an asynchronous
+	// abort, when the local atomic flag was not observed by this coordinator.
+	if pausedForApproval.Load() || s.cloudAgentRunPausedForInput(userID, runID) {
 		return nil
 	}
 
@@ -382,6 +385,17 @@ func (s *Service) runCloudAgentPiSession(ctx context.Context, userID, runID stri
 	return s.completeCloudAgentPiRun(userID, runID)
 }
 
+func (s *Service) cloudAgentRunPausedForInput(userID, runID string) bool {
+	if s == nil || s.repo == nil || userID == "" || runID == "" {
+		return false
+	}
+	run, err := s.repo.CloudAgent(userID, runID)
+	if err != nil {
+		return false
+	}
+	return run.Status == "waiting_approval" || run.Status == "waiting_user"
+}
+
 // cloudAgentPiTurnSettled 判断本轮是否已在会话里完整结束：本轮已有成功的助手回复，
 // 没有挂着的任务或审批，且会话最后一条消息是不带工具调用的正常结束回复。
 // 只能用于本轮自己落库的快照：运行时的事件按顺序提交，助手回复计数增长之前，
diff --git a/backend/internal/app/image_parameters.go b/backend/internal/app/image_parameters.go
index 8b4c14fec..7d3e603c6 100644
--- a/backend/internal/app/image_parameters.go
+++ b/backend/internal/app/image_parameters.go
@@ -262,6 +262,14 @@ func imageParameterValue(p protocol.ImageParameter, value any) any {
 	return value
 }
 
+func imageParameterAdmissionError(field, issue, message string) error {
+	return NewModelError(ErrCodeModelCapabilityNotSupported, message).WithDetails(map[string]any{
+		"field":   field,
+		"issue":   issue,
+		"message": message,
+	})
+}
+
 func resolveImageParameterValues(parameters []protocol.ImageParameter, values map[string]any) (map[string]any, error) {
 	allowed := map[string]protocol.ImageParameter{}
 	result := imageParameterDefaults(parameters)
@@ -273,11 +281,11 @@ func resolveImageParameterValues(parameters []protocol.ImageParameter, values ma
 	for name, value := range values {
 		p, ok := allowed[name]
 		if !ok {
-			return nil, ModelCapabilityNotSupported("当前图片模型未启用参数：" + name)
+			return nil, imageParameterAdmissionError(name, "unsupported_value", "当前图片模型未启用参数："+name)
 		}
 		value = imageParameterValue(p, value)
 		if !p.Accepts(value) {
-			return nil, ModelCapabilityNotSupported("图片参数超出支持范围：" + p.Label)
+			return nil, imageParameterAdmissionError(p.Name, "unsupported_value", "图片参数超出支持范围："+p.Label)
 		}
 		if value != nil && value != "" {
 			result[name] = value
@@ -285,7 +293,7 @@ func resolveImageParameterValues(parameters []protocol.ImageParameter, values ma
 	}
 	for _, p := range parameters {
 		if p.IsEnabled() && p.Required && (result[p.Name] == nil || result[p.Name] == "") {
-			return nil, ModelCapabilityNotSupported("请填写图片参数：" + p.Label)
+			return nil, imageParameterAdmissionError(p.Name, "required", "请填写图片参数："+p.Label)
 		}
 	}
 	return result, nil
diff --git a/backend/internal/app/model_capability_argument.go b/backend/internal/app/model_capability_argument.go
index a57f157fa..0174729df 100644
--- a/backend/internal/app/model_capability_argument.go
+++ b/backend/internal/app/model_capability_argument.go
@@ -28,7 +28,7 @@ func newModelCapabilityArgumentError(field, issue string, cause error) error {
 func modelCapabilityMismatchError(match CapabilityMatch) error {
 	details := map[string]any{"capabilityIssues": match.Issues}
 	for _, issue := range match.Issues {
-		if issue.Kind != "option" {
+		if issue.Kind != "option" && issue.Kind != "image_parameter" {
 			continue
 		}
 		field := issue.Name
diff --git a/backend/internal/app/model_router_capability.go b/backend/internal/app/model_router_capability.go
index 3c3d61186..b56159b5c 100644
--- a/backend/internal/app/model_router_capability.go
+++ b/backend/internal/app/model_router_capability.go
@@ -8,6 +8,7 @@ package app
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"math"
 	"strconv"
@@ -325,7 +326,21 @@ func MatchCapability(spec CapabilitySpec, intent ModelRequestIntent) CapabilityM
 			}
 		}
 		if _, err := resolveImageParameterValues(parameters, values); err != nil {
-			addIssue("image_parameter", "imageParameters", err.Error())
+			var modelErr *ModelError
+			if errors.As(err, &modelErr) && modelErr != nil {
+				field, _ := modelErr.Details["field"].(string)
+				message, _ := modelErr.Details["message"].(string)
+				if field != "" {
+					if message == "" {
+						message = modelErr.Error()
+					}
+					addIssue("image_parameter", field, message)
+				} else {
+					addIssue("image_parameter", "imageParameters", err.Error())
+				}
+			} else {
+				addIssue("image_parameter", "imageParameters", err.Error())
+			}
 		}
 	}
 	if normalizeCapability(intent.Capability) != normalizeCapability(spec.Capability) {