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Evaluate AI agent response relevance using OpenAI and cosine similarity

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Evaluate AI agent response relevance using OpenAI and cosine similarity preview
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Important notice

This workflow is provided as-is. Please review and test before using in production.

1. Workflow Overview

This n8n template demonstrates how to calculate the evaluation metric "Relevance" which in this scenario, measures the relevance of the agent's response to the user's question. The scoring approach...

Best for

  • Engineering automation workflows
  • AI Summarization automation workflows
  • advanced n8n builders looking for reusable templates

Tools used

@n8n/n8n-nodes-langchain.lmchatopenai, n8n-nodes-base.evaluationtrigger, n8n-nodes-base.set, n8n-nodes-base.evaluation, n8n-nodes-base.noop, @n8n/n8n-nodes-langchain.agent, @n8n/n8n-nodes-langchain.chattrigger, @n8n/n8n-nodes-langchain.outputparserstructured

Source and attribution

This workflow is cataloged by N8N Workflows and links back to its original n8n.io source page by Jimleuk.

Original n8n.io source

1.1 Workflow description

Title
Evaluate AI agent response relevance using OpenAI and cosine similarity
Workflow name
Evaluate AI agent response relevance using OpenAI and cosine similarity

This n8n template demonstrates how to calculate the evaluation metric "Relevance" which in this scenario, measures the relevance of the agent's response to the user's question.

The scoring approach is adapted from the open-source evaluations project RAGAS and you can see the source here https://github.com/explodinggradients/ragas/blob/main/ragas/src/ragas/metrics/_answer_relevance.py

How it works

  • This evaluation works best for Q&A agents.
  • For our scoring, we analyse the agent's response and ask another AI to generate a question from it. This generated question is then compared to the original question using cosine similarity.
  • A high score indicates relevance and the agent's successful ability to answer the question whereas a low score means agent may have added too much irrelevant info, went off script or hallucinated.

Requirements

1.2 Logical Blocks

This catalog entry is organized from the workflow JSON. The node-level section below shows the executable blocks available for review before importing the template.

2. Block-by-Block Analysis

Block 1 - OpenAI Chat Model1

Type / Role
@n8n/n8n-nodes-langchain.lmChatOpenAi - lmChatOpenAi
Config choices
Version 1.2

Block 2 - When fetching a dataset row

Type / Role
n8n-nodes-base.evaluationTrigger - evaluationTrigger
Config choices
Version 4.6

Block 3 - Remap Input

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 4 - Evaluation

Type / Role
n8n-nodes-base.evaluation - evaluation
Config choices
Version 4.6

Block 5 - Set Input Fields

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

Block 6 - No Operation, do nothing

Type / Role
n8n-nodes-base.noOp - noOp
Config choices
Version 1

Block 7 - AI Agent

Type / Role
@n8n/n8n-nodes-langchain.agent - agent
Config choices
Version 2

Block 8 - When chat message received

Type / Role
@n8n/n8n-nodes-langchain.chatTrigger - chatTrigger
Config choices
Version 1.1

Block 9 - Update Output

Type / Role
n8n-nodes-base.evaluation - evaluation
Config choices
Version 4.6

Block 10 - Update Metrics

Type / Role
n8n-nodes-base.evaluation - evaluation
Config choices
Version 4.6

Block 11 - OpenAI Chat Model

Type / Role
@n8n/n8n-nodes-langchain.lmChatOpenAi - lmChatOpenAi
Config choices
Version 1.2

Block 12 - Structured Output Parser

Type / Role
@n8n/n8n-nodes-langchain.outputParserStructured - outputParserStructured
Config choices
Version 1.2

Block 13 - Answer Relevance

Type / Role
@n8n/n8n-nodes-langchain.chainLlm - chainLlm
Config choices
Version 1.7

Block 14 - Sticky Note1

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 15 - Sticky Note

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 16 - Sticky Note3

Type / Role
n8n-nodes-base.stickyNote - stickyNote
Config choices
Version 1

Block 17 - Get Embeddings

Type / Role
n8n-nodes-base.httpRequest - httpRequest
Config choices
Version 4.2

Block 18 - Calculate Similarity Score

Type / Role
n8n-nodes-base.code - code
Config choices
Version 2

Block 19 - Questions to Items

Type / Role
n8n-nodes-base.code - code
Config choices
Version 2

Block 20 - Calculate Relevance Score

Type / Role
n8n-nodes-base.set - set
Config choices
Version 3.4

3. Summary Table

Workflow Evaluate AI agent response relevance using OpenAI and cosine similarity
Complexity advanced
Nodes 20
Categories Engineering, AI Summarization
Author Jimleuk
Published 27 May 2025

4. Reproducing the Workflow from Scratch

  1. 1. Download the workflow JSON

    Use the JSON export at /data/workflows/4425/4425.json as the source template for this automation.

  2. 2. Import the template into n8n

    Open n8n, import the downloaded JSON, and review each node before activating the workflow.

  3. 3. Configure credentials and variables

    Replace placeholder credentials, API keys, webhook URLs, account IDs, and environment-specific values with your own settings.

  4. 4. Test with sample data

    Run the workflow manually or in a staging workspace, inspect node output, and confirm downstream systems receive the expected data.

  5. 5. Activate and monitor

    Enable the workflow only after testing, then monitor executions, errors, and rate limits during the first production runs.

5. General Notes & Resources

Review imported nodes carefully before activation. This catalog entry is intended to help you inspect the workflow structure, understand required services, and find related templates faster.

Node names, credentials, schedules, webhook paths, and external service limits may need adjustment for your workspace.

Frequently asked questions

What does Evaluate AI agent response relevance using OpenAI and cosine similarity do?

This n8n template demonstrates how to calculate the evaluation metric "Relevance" which in this scenario, measures the relevance of the agent's response to the user's question. The scoring approach...

What do I need before importing this workflow?

Review the workflow JSON, configure any required credentials in n8n, and test the automation in a safe workspace before using it in production.

Can I customize this workflow?

Yes. Use the block-by-block analysis and the downloadable JSON to inspect each node, then adjust credentials, prompts, schedules, filters, or destinations for your Engineering, AI Summarization use case.