fix(agent): Agent 运行 - 重复读取改为软收敛并保留可纠正的媒体失败原因

重复只读和同版本识图不再把运行标成失败，下一步暂时收起只读工具。媒体能力错误改为可纠正，准入失败保留安全原因。

backend/internal/app/cloud_agent_runtime_tools.go

@@ -169,6 +169,31 @@ func cloudAgentToolResult(runID string, state *cloudAgentRuntime, call cloudAgen
 	return exhausted
 }
 
+func cloudAgentMarkReadLoopNudge(state *cloudAgentRuntime, call cloudAgentCall, count int) {
+	if state == nil || state.ReadLoopNudge {
+		return
+	}
+	state.ReadLoopNudge = true
+	state.ReadLoopToolName = call.Function.Name
+	state.ReadLoopCount = max(1, count)
+}
+
+func cloudAgentApplyReadLoopNudge(canonical *canonicalAgentRequest, state *cloudAgentRuntime) {
+	if state == nil || !state.ReadLoopNudge {
+		return
+	}
+	toolName := state.ReadLoopToolName
+	if toolName == "" {
+		toolName = "只读工具"
+	}
+	canonical.Tools = cloudAgentToolsWithoutReadTools(canonical.Tools)
+	// 提示只进入下一次模型输入，避免插入尚未收齐结果的工具批次或堆积历史。
+	canonical.Messages = append(append([]map[string]any(nil), canonical.Messages...), cloudAgentRuntimeMessage(cloudAgentRuntimeContext{
+		Kind:   cloudAgentContextReadLoop,
+		Detail: fmt.Sprintf("%s 触发读取收敛（读取或回放计数 %d）；本次模型请求暂时不提供只读工具，运行状态仍为 running。", toolName, max(1, state.ReadLoopCount)),
+	}))
+}
+
 // cloudAgentCompactSupersededReadResult bounds repeated snapshots without
 // changing the transcript shape. A newer read with the same cache key makes an
 // older canvas projection stale; keep the old tool message for provider pairing,
@@ -389,30 +414,22 @@ func (s *Service) advanceCloudAgentReadBatch(run *model.CloudAgentExecution, sta
 		for _, item := range outcomes {
 			var readLoopErr *cloudAgentReadLoopError
 			if errors.As(item.err, &readLoopErr) {
-				// A provider tool-call turn is atomic from the transcript's point of
-				// view: every declared tool_call_id needs a tool message, even when a
-				// read guard terminates the run. Record the triggering error and then
-				// explicit skipped receipts before appending run_failed, otherwise a
-				// later resume/replay produces an invalid provider transcript.
-				cloudAgentToolResult(current.ID, state, item.call, item.result, item.err)
-				for state.CallIndex < len(state.Calls) {
-					pending := state.Calls[state.CallIndex]
-					cloudAgentToolResult(current.ID, state, pending,
-						map[string]any{"skipped": true, "reason": readLoopErr.reasonCode()},
-						nil)
-				}
-				current.Status = "failed"
-				current.FailureMessage = truncateRunes(readLoopErr.Error(), 1000)
-				cloudAgentDropInterjections(run.ID, "本轮已结束："+truncateRunes(current.FailureMessage, 120), state)
-				reason := readLoopErr.reasonCode()
-				state.event(run.ID, "run_failed", map[string]any{
-					"text": current.FailureMessage, "reason": reason,
-					"toolName": item.call.Function.Name, "readCount": readLoopErr.Count,
-				})
+				// 只收敛触发护栏的读取；同批剩余调用仍由调度器处理，不能吞掉写操作。
+				cloudAgentToolResult(current.ID, state, item.call, map[string]any{
+					"readLoopGuard": true,
+					"message":       "重复只读调用已软收敛，请使用已有结果继续；运行仍可继续",
+				}, nil)
+				cloudAgentMarkReadLoopNudge(state, item.call, readLoopErr.Count)
 				break
 			}
 			cloudAgentRecordToolResult(current, state, item.call, item.result, item.err)
 		}
+		if state.ReadLoopNudge && len(outcomes) > 0 {
+			state.event(run.ID, "read_loop_guard", map[string]any{
+				"text":     "重复只读调用已软收敛，运行继续",
+				"toolName": state.ReadLoopToolName, "readCount": state.ReadLoopCount,
+			})
+		}
 		return cloudAgentSave(current, state)
 	})
 	return true, err
@@ -675,7 +692,12 @@ func (s *Service) advanceCloudAgentTool(run *model.CloudAgentExecution, state *c
 	if allowed && call.Function.Name == "canvas_inspect_image" && state.Request.VisionEnabled {
 		inspectionResult, inspectionErr = s.prepareCloudAgentImageInspection(run.UserID, state.Request.CanvasID, state, call)
 		if errors.Is(inspectionErr, errCloudAgentImageInspectionBudget) {
-			return s.failCloudAgent(run, state, cloudAgentImageInspectionBudgetMessage)
+			inspectionErr = &cloudAgentReadLoopError{
+				ToolName:   "canvas_inspect_image",
+				Count:      state.cloudAgentImageInspectionCalls() + 1,
+				Budget:     true,
+				ReasonCode: "vision_read_budget_exceeded",
+			}
 		}
 	}
 	// Service-backed reads may open resources or use domain repositories.
@@ -731,6 +753,9 @@ func (s *Service) advanceCloudAgentTool(run *model.CloudAgentExecution, state *c
 						}
 						state.ImageInspectionReads[inspection.CacheKey]++
 					}
+					if inspection.Receipt["repeat"] == true {
+						cloudAgentMarkReadLoopNudge(state, call, state.ImageInspectionReads[inspection.CacheKey])
+					}
 				}
 			}
 		case call.Function.Name == "skill_read_file", call.Function.Name == "model_list", call.Function.Name == "image_annotation_render", call.Function.Name == "canvas_read_text":
@@ -745,13 +770,13 @@ func (s *Service) advanceCloudAgentTool(run *model.CloudAgentExecution, state *c
 		}
 		var readLoopErr *cloudAgentReadLoopError
 		if errors.As(toolErr, &readLoopErr) {
-			cloudAgentRecordToolResult(current, state, call, result, toolErr)
-			current.Status = "failed"
-			current.FailureMessage = truncateRunes(readLoopErr.Error(), 1000)
-			cloudAgentDropInterjections(run.ID, "本轮已结束："+truncateRunes(current.FailureMessage, 120), state)
-			reason := readLoopErr.reasonCode()
-			state.event(run.ID, "run_failed", map[string]any{
-				"text": current.FailureMessage, "reason": reason,
+			cloudAgentRecordToolResult(current, state, call, map[string]any{
+				"readLoopGuard": true,
+				"message":       "重复只读调用已软收敛，请使用已有结果继续；运行仍可继续",
+			}, nil)
+			cloudAgentMarkReadLoopNudge(state, call, readLoopErr.Count)
+			state.event(run.ID, "read_loop_guard", map[string]any{
+				"text":     "重复只读调用已软收敛，运行继续",
 				"toolName": call.Function.Name, "readCount": readLoopErr.Count,
 			})
 			return cloudAgentSave(current, state)
@@ -774,6 +799,12 @@ func (s *Service) advanceCloudAgentTool(run *model.CloudAgentExecution, state *c
 			return cloudAgentSave(current, state)
 		}
 		cloudAgentRecordToolResult(current, state, call, result, toolErr)
+		if state.ReadLoopNudge {
+			state.event(run.ID, "read_loop_guard", map[string]any{
+				"text":     "重复只读调用已软收敛，运行继续",
+				"toolName": state.ReadLoopToolName, "readCount": state.ReadLoopCount,
+			})
+		}
 		return cloudAgentSave(current, state)
 	})
 }