From 577d5a1bff0f583a953e0f459d882ed929fb8168 Mon Sep 17 00:00:00 2001
From: oleg <me@olegivaniv.com>
Date: Thu, 6 Feb 2025 17:28:13 +0100
Subject: [PATCH] refactor(Google Gemini Chat Model Node): Provide custom
 message mapper to N8nLlmTracing (no-changelog) (#13076)

---
 .../LmChatGoogleGemini.node.ts                | 22 +++++++++++++------
 .../nodes/llms/N8nLlmTracing.ts               | 10 ++++++++-
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/packages/@n8n/nodes-langchain/nodes/llms/LmChatGoogleGemini/LmChatGoogleGemini.node.ts b/packages/@n8n/nodes-langchain/nodes/llms/LmChatGoogleGemini/LmChatGoogleGemini.node.ts
index 05c2475556..f6ff0f5038 100644
--- a/packages/@n8n/nodes-langchain/nodes/llms/LmChatGoogleGemini/LmChatGoogleGemini.node.ts
+++ b/packages/@n8n/nodes-langchain/nodes/llms/LmChatGoogleGemini/LmChatGoogleGemini.node.ts
@@ -1,12 +1,13 @@
 /* eslint-disable n8n-nodes-base/node-dirname-against-convention */
 import type { SafetySetting } from '@google/generative-ai';
 import { ChatGoogleGenerativeAI } from '@langchain/google-genai';
-import {
-	NodeConnectionType,
-	type INodeType,
-	type INodeTypeDescription,
-	type ISupplyDataFunctions,
-	type SupplyData,
+import { NodeConnectionType } from 'n8n-workflow';
+import type {
+	NodeError,
+	INodeType,
+	INodeTypeDescription,
+	ISupplyDataFunctions,
+	SupplyData,
 } from 'n8n-workflow';
 
 import { getConnectionHintNoticeField } from '@utils/sharedFields';
@@ -15,6 +16,13 @@ import { additionalOptions } from '../gemini-common/additional-options';
 import { makeN8nLlmFailedAttemptHandler } from '../n8nLlmFailedAttemptHandler';
 import { N8nLlmTracing } from '../N8nLlmTracing';
 
+function errorDescriptionMapper(error: NodeError) {
+	if (error.description?.includes('properties: should be non-empty for OBJECT type')) {
+		return 'Google Gemini requires at least one <a href="https://docs.n8n.io/advanced-ai/examples/using-the-fromai-function/" target="_blank">dynamic parameter</a> when using tools';
+	}
+
+	return error.description ?? 'Unknown error';
+}
 export class LmChatGoogleGemini implements INodeType {
 	description: INodeTypeDescription = {
 		displayName: 'Google Gemini Chat Model',
@@ -147,7 +155,7 @@ export class LmChatGoogleGemini implements INodeType {
 			temperature: options.temperature,
 			maxOutputTokens: options.maxOutputTokens,
 			safetySettings,
-			callbacks: [new N8nLlmTracing(this)],
+			callbacks: [new N8nLlmTracing(this, { errorDescriptionMapper })],
 			onFailedAttempt: makeN8nLlmFailedAttemptHandler(this),
 		});
 
diff --git a/packages/@n8n/nodes-langchain/nodes/llms/N8nLlmTracing.ts b/packages/@n8n/nodes-langchain/nodes/llms/N8nLlmTracing.ts
index 3d426309b7..7f7d70841e 100644
--- a/packages/@n8n/nodes-langchain/nodes/llms/N8nLlmTracing.ts
+++ b/packages/@n8n/nodes-langchain/nodes/llms/N8nLlmTracing.ts
@@ -61,11 +61,15 @@ export class N8nLlmTracing extends BaseCallbackHandler {
 				totalTokens: completionTokens + promptTokens,
 			};
 		},
+		errorDescriptionMapper: (error: NodeError) => error.description,
 	};
 
 	constructor(
 		private executionFunctions: ISupplyDataFunctions,
-		options?: { tokensUsageParser: TokensUsageParser },
+		options?: {
+			tokensUsageParser?: TokensUsageParser;
+			errorDescriptionMapper?: (error: NodeError) => string;
+		},
 	) {
 		super();
 		this.options = { ...this.options, ...options };
@@ -192,6 +196,10 @@ export class N8nLlmTracing extends BaseCallbackHandler {
 		}
 
 		if (error instanceof NodeError) {
+			if (this.options.errorDescriptionMapper) {
+				error.description = this.options.errorDescriptionMapper(error);
+			}
+
 			this.executionFunctions.addOutputData(this.connectionType, runDetails.index, error);
 		} else {
 			// If the error is not a NodeError, we wrap it in a NodeOperationError