Divyanshu’s Blog

LLM Evaluation Technique 5 (Prompt Tagging System)

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Not all prompts are created equal, some test creativity, others logic or factual recall. That’s where a Prompt Tagging System comes in.

It labels each prompt by category (like reasoning, creative, or factual) so you can see exactly how an AI model performs across different types of tasks.

In this post, we’ll explore how tagging transforms evaluations into deeper insights.


🧠 Concept Overview

Every LLM behaves differently depending on what kind of question it’s asked. For example:

  • It might be brilliant at factual Q&A,
  • But struggle at creative writing,
  • And slightly inconsistent in reasoning or math.

So, a Prompt Tagging System helps us label each evaluation (each prompt) with one or more categories (tags), so we can analyze how the model performs per type of task.


🧩 Diagram

Prompt: "Write a poem about gravity."     → 🏷️ Creative
Prompt: "What is 12 × 9?"                 → 🏷️ Logical, Math
Prompt: "Who discovered gravity?"         → 🏷️ Factual, Science
Prompt: "Should AI replace teachers?"     → 🏷️ Opinion, Ethics

Once prompts are tagged, you can compare model accuracy or clarity within each tag.


🎯 Why It’s Used

In real-world AI evaluation (like at OpenAI, Anthropic, Google, or DeepMind), prompt classification is standard practice.

Reason Why It Matters
🧠 Fine-grained analysis Know which prompt types the model excels or fails at
📊 Dataset balancing Ensure equal representation of prompt categories
⚙️ Benchmarking Measure performance across task types (creative, reasoning, factual)
🔍 Debugging model behavior Detect if a model fails only for ethical or ambiguous prompts

In short: tagging = deeper insights.

It’s how labs detect, for instance,

Model X underperforms on reasoning tasks but excels in factual recall.


⚙️ How It Works

Let’s understand how a prompt tagging system actually operates in practice 👇


Step 1️⃣: Defining Tag Categories

Every prompt can belong to one or more categories based on its intent or task type. Before tagging begins, a small set of broad categories is defined.

Category Example Prompts
Factual / Knowledge “Who wrote Hamlet?”
Reasoning / Logic “If A > B and B > C, is A > C?”
Creative / Writing “Write a story about a robot who dreams.”
Opinion / Ethical “Should robots have rights?”
Instructional / Step-by-Step “Explain how to make coffee.”

These categories can later expand as more prompts and use cases emerge.


Step 2️⃣: Tagging the Prompts

Each prompt is then labeled with one or more tags that best describe its nature. Tags can be added manually by a human evaluator or automatically by an AI model.

For example:

🏷️ Tags: [Factual], [Science], [Reasoning]

In a dashboard or evaluation interface, prompts often include a small multi-select input or checkboxes for these tags, making it easy to categorize prompts as they are evaluated.


Step 3️⃣: Auto-Tagging (Optional)

In more advanced systems, tagging is performed automatically by another AI model. The model reads the prompt, understands its intent, and assigns appropriate tags such as “Reasoning,” “Creative,” or “Ethical.”

This process is known as auto-tagging and helps handle large-scale datasets efficiently. For example, when evaluating thousands of prompts, an AI classifier (like Gemini or GPT) can automatically predict which categories each belongs to, saving human time and ensuring consistency.

Example Judging Prompt

You are a classification assistant.
Given a user prompt, assign 1–3 tags describing its type.
Possible tags: Factual, Reasoning, Creative, Opinion, Instructional, Math, Ethical.
Return as JSON array.

Prompt: "Explain why the sky is blue."

Gemini returns:

["Factual", "Science", "Reasoning"]

You save those as part of your evaluation entry.


Step 4️⃣: Analyzing Model Performance by Tag

Once every prompt is tagged, those tags become incredibly useful for deep-dive analytics. Instead of seeing just an overall “average accuracy,” evaluators can now understand how well the model performs across different categories of prompts.

For example, a model might perform excellently on factual questions but show weaknesses in reasoning or ethical discussions.

This can be visualized in simple charts or tables like:

Tag (Prompt Type) Avg. Accuracy Avg. Clarity Avg. Helpfulness
Creative Writing 4.8 4.7 4.9
Reasoning / Logic 3.9 3.5 3.6
Factual Knowledge 4.9 4.8 4.7
Opinion / Ethical 3.2 3.0 3.1

Such a view makes it immediately clear where a model excels and where it struggles. It’s the kind of insight researchers use when fine-tuning or comparing LLMs.


Step 5️⃣: Filtering and Comparative Evaluation

With tags in place, evaluators can also filter the results to focus on a specific task type. For instance, one could view only Reasoning prompts, or only Creative ones, and study the model’s consistency, safety, or bias patterns within those contexts.

This makes the evaluation process more interactive and insightful. By examining models category-wise, teams can spot patterns like:

  • “The model drifts off-topic more often in creative tasks.”
  • “Accuracy is stable across factual queries, but clarity varies in reasoning.”
  • “Safety scores drop slightly in opinion-based prompts.”

These findings are vital for anyone working on model alignment, safety, or domain specialization.


📊 Example Visualization

A prompt-tagging system often produces a simple bar chart like this:

Model Performance by Prompt Type
--------------------------------
Creative   ████████████░░ 4.8
Factual    ████████████░░ 4.7
Reasoning  ████████░░░░░░ 3.8
Opinion    ██████░░░░░░░░ 3.2

✅ Easy to understand, and instantly shows strengths and weaknesses.


✍️ Summary

A Prompt Tagging System helps categorize model inputs (factual, creative, reasoning, etc.) so developers can analyze where their AI performs best or needs improvement. It enables fine-grained, interpretable insights that real AI labs use for model tuning and bias detection.

The Prompt Tagging System technique:

  • Helps analyze model performance by task type
  • Supports both manual and auto tagging
  • Enables filtered analytics and visual comparisons
  • Makes the evaluator dashboard feel professional and research-grade

Thanks for reading till the end! 🙏

A Prompt Tagging System adds structure and clarity to evaluations, turning raw prompts into meaningful analytics. With it, evaluators can finally answer questions like “Where does this model shine, and where does it struggle?”

In the next article, we’ll wrap up this series by connecting all five evaluation techniques into a single, cohesive AI evaluation workflow.

See you in the next post 👋