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internal/multiagent/tool_error_middleware.go

@@ -0,0 +1,131 @@
+package multiagent
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/cloudwego/eino/compose"
+)
+
+// softRecoveryToolCallMiddleware returns an InvokableToolMiddleware that catches
+// specific recoverable errors from tool execution (JSON parse errors, tool-not-found,
+// etc.) and converts them into soft errors: nil error + descriptive error content
+// returned to the LLM. This allows the model to self-correct within the same
+// iteration rather than crashing the entire graph and requiring a full replay.
+//
+// Without this middleware, a JSON parse failure in any tool's InvokableRun propagates
+// as a hard error through the Eino ToolsNode → [NodeRunError] → ev.Err, which
+// either triggers the full-replay retry loop (expensive) or terminates the run
+// entirely once retries are exhausted. With it, the LLM simply sees an error message
+// in the tool result and can adjust its next tool call accordingly.
+func softRecoveryToolCallMiddleware() compose.InvokableToolMiddleware {
+	return func(next compose.InvokableToolEndpoint) compose.InvokableToolEndpoint {
+		return func(ctx context.Context, input *compose.ToolInput) (*compose.ToolOutput, error) {
+			output, err := next(ctx, input)
+			if err == nil {
+				return output, nil
+			}
+			if !isSoftRecoverableToolError(err) {
+				return output, err
+			}
+			// Convert the hard error into a soft error: the LLM will see this
+			// message as the tool's output and can self-correct.
+			msg := buildSoftRecoveryMessage(input.Name, input.Arguments, err)
+			return &compose.ToolOutput{Result: msg}, nil
+		}
+	}
+}
+
+// isSoftRecoverableToolError determines whether a tool execution error should be
+// silently converted to a tool-result message rather than crashing the graph.
+func isSoftRecoverableToolError(err error) bool {
+	if err == nil {
+		return false
+	}
+	s := strings.ToLower(err.Error())
+
+	// JSON unmarshal/parse failures — the model generated truncated or malformed arguments.
+	if isJSONRelatedError(s) {
+		return true
+	}
+
+	// Sub-agent type not found (from deep/task_tool.go)
+	if strings.Contains(s, "subagent type") && strings.Contains(s, "not found") {
+		return true
+	}
+
+	// Tool not found in ToolsNode indexes
+	if strings.Contains(s, "tool") && strings.Contains(s, "not found") {
+		return true
+	}
+
+	return false
+}
+
+// isJSONRelatedError checks whether an error string indicates a JSON parsing problem.
+func isJSONRelatedError(lower string) bool {
+	if !strings.Contains(lower, "json") {
+		return false
+	}
+	jsonIndicators := []string{
+		"unexpected end of json",
+		"unmarshal",
+		"invalid character",
+		"cannot unmarshal",
+		"invalid tool arguments",
+		"failed to unmarshal",
+		"must be in json format",
+		"unexpected eof",
+	}
+	for _, ind := range jsonIndicators {
+		if strings.Contains(lower, ind) {
+			return true
+		}
+	}
+	return false
+}
+
+// buildSoftRecoveryMessage creates a bilingual error message that the LLM can act on.
+func buildSoftRecoveryMessage(toolName, arguments string, err error) string {
+	// Truncate arguments preview to avoid flooding the context.
+	argPreview := arguments
+	if len(argPreview) > 300 {
+		argPreview = argPreview[:300] + "... (truncated)"
+	}
+
+	// Try to determine if it's specifically a JSON parse error for a friendlier message.
+	errStr := err.Error()
+	var jsonErr *json.SyntaxError
+	isJSONErr := strings.Contains(strings.ToLower(errStr), "json") ||
+		strings.Contains(strings.ToLower(errStr), "unmarshal")
+	_ = jsonErr // suppress unused
+
+	if isJSONErr {
+		return fmt.Sprintf(
+			"[Tool Error] The arguments for tool '%s' are not valid JSON and could not be parsed.\n"+
+				"Error: %s\n"+
+				"Arguments received: %s\n\n"+
+				"Please fix the JSON (ensure double-quoted keys, matched braces/brackets, no trailing commas, "+
+				"no truncation) and call the tool again.\n\n"+
+				"[工具错误] 工具 '%s' 的参数不是合法 JSON，无法解析。\n"+
+				"错误：%s\n"+
+				"收到的参数：%s\n\n"+
+				"请修正 JSON（确保双引号键名、括号配对、无尾部逗号、无截断），然后重新调用工具。",
+			toolName, errStr, argPreview,
+			toolName, errStr, argPreview,
+		)
+	}
+
+	return fmt.Sprintf(
+		"[Tool Error] Tool '%s' execution failed: %s\n"+
+			"Arguments: %s\n\n"+
+			"Please review the available tools and their expected arguments, then retry.\n\n"+
+			"[工具错误] 工具 '%s' 执行失败：%s\n"+
+			"参数：%s\n\n"+
+			"请检查可用工具及其参数要求，然后重试。",
+		toolName, errStr, argPreview,
+		toolName, errStr, argPreview,
+	)
+}