LLM context windows

Can Too Much Context Make Your AI Dumber?

More context does not always improve AI performance. Learn how LLM context length affects reliability and how to use long-context AI effectively.

By Avi Santoso5 min read

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Article Summary

  1. 01

    Retrieval and task completion are separate capabilities. A model can find every required fact and still fail to use those facts correctly.

  2. 02

    In our 30K payroll test, Llama 3.1 8B retrieved the required facts in 5 out of 5 trials but completed the task correctly in 0 out of 5.

  3. 03

    Context-window performance depends on the model and task. Test retrieval and task completion separately before changing a production AI workflow.

You want AI to perform a task for you, and its pretty complicated. So, you dump every piece of information, even the smallest details, thinking that your AI assistant will execute the task better if you do so.

Sometimes, it succeeds. Other times? It falls over flat. At this point, “Maybe it needs more information?” could cross your mind.

Let’s stop there for a second. The problem isn't necessarily with the information you dumped. Your AI can retrieve the right information and still fail to use it correctly. Why? Because more information can make it harder for AI to focus on the main task you’ve requested.

Think about it this way. If you throw a 100-page policy book at someone and ask them to use it to answer an open book test, that's a difficult task, right? (Even when it's open-book...)

It’s the same with AI, and this is where LLM context length becomes important.

So, What Exactly is LLM Context Length Again?

The information you put into your AI model to process is called context. The amount of that information (measured in tokens) is its context length. This can include your prompt, instructions, documents, previous messages, and other information provided to the model.

And that’s why AI companies are always improving their models to handle longer context. User demand for AI applications is growing, and some models can now process hundreds of thousands to millions of tokens in a single context window. 1

If AI models can process longer contexts, then the best way to get better output should be to give it more information… right?

Well, not necessarily. If you keep feeding your AI with too much information–even the unimportant stuff–research has found that it can become harder for the model to determine which parts actually matter. 2

Why More Context Can Make AI Less Reliable

To answer whether or not we should give our AI assistants more information, we ran our own small-scale experiment based on the method used by Du et al. 3 We measured two things separately:

  • Retrieval = Did the model recover the required facts and rules from the information provided?
  • Task completion = Did it actually produce the correct final result?

We designed our experiment to find out whether giving an AI more context affected its ability to complete a task, and whether successfully retrieving the right information necessarily meant the model could use it correctly.

So, what exactly did we test? We put three AI models through four fictional business tasks using short prompts and long contexts of around 30K and 60K tokens. For each model and task, we ran five trials for retrieval and five trials for task completion. Across the experiment, we recorded 720 results. 4

Here are the details:

Three models

  • Mistral Nemo
  • Llama 3.1 8B
  • GPT-4.1 Nano

Four tasks

  • Payroll calculation
  • Payroll exception word problem
  • Transaction-coding policy decision
  • Payroll calculation function

Three context conditions

  • Short
  • Long
  • Long-blank

Two context lengths

  • ~30K
  • ~60K tokens

To put this into perspective, consider one of our payroll tasks. We asked the model to calculate an employee’s wages using a company policy. First, we checked whether the model found the correct pay rate, overtime rules, and allowance figures. We call this retrieval.

Then, we checked whether it used those figures and rules to calculate the correct salary. We call this task completion.

More Context, Different Results

ModelKey resultWhat it tells us
Llama 3.1 8B30K Payroll: retrieval 5/5, task completion 0/5Could find the information but failed to use it
Mistral NemoResults were low/inconsistent; e.g. 30K Transaction Coding: retrieval 0/5, task completion 5/5Retrieval and task completion can diverge in either direction
GPT-4.1 NanoLong-context task completion stayed at/near 20/20Longer context did not reduce performance for this model

From our results, the takeaway isn’t that more context will always make your AI “dumber.” Instead, our experiment shows that a model’s ability to retrieve information and its ability to use that information to complete a task can behave independently. And, of course, our results varied depending on the model and the task. 4

The Better Way to Use Your AI Models

Now that you know where the problem is, how can you get your AI to run tasks more precisely? Here are three practical things you can do:

1. Stop. Dumping. Everything.

Oversharing won't necessarily help your AI. It might make the task harder instead.

Seriously, just give your AI the relevant information rather than every piece of information you have. This can make it easier for the model to focus on the information that actually matters for the task.

2. Separate Information from Instructions

Make the important evidence and actual task clear. Don’t make the model hunt through a giant wall of text to figure out what you’re asking. Give it a chance to chew through the information before asking it to execute the task.

3. Break Complex Tasks into Smaller Steps

Instead of asking your AI to retrieve, reason, calculate, validate, and format everything in one go, consider splitting the workflow into smaller steps. Give the model one clear objective at a time.

The goal isn't to make your AI process less information. It's to make the information it processes more useful.

More Information is Good, but Relevant Information is Better for Your AI

So, does this mean you should stop dumping information into your AI? Not exactly.

Our experiment doesn’t show that longer context will always make an AI model perform worse. Our results varied across models and tasks, with GPT-4.1 Nano remaining at or near the ceiling in its long-context tests while other models showed more inconsistent behaviour.

What it does show is that retrieving information and using that information correctly are two different things. Your AI might have access to everything it needs and still struggle to turn that information into the right result.

That’s why understanding LLM context length matters so your AI can do the task you ask more precisely.

If you’re working with a long-context AI, the goal shouldn’t be to fit everything into one prompt just because you can. 5 Instead, give the model the information that actually matters, make your instructions clear, and break complicated tasks into manageable steps when necessary.

In the end, AI reliability isn’t just about how much information a model can hold, but about how well it can turn that information into action. Your AI doesn’t need to know everything. It just needs to know what matters.

Footnotes

  1. Google DeepMind. Gemini 2.5 Technical Report.

  2. Shi et al. Large Language Models Can Be Easily Distracted by Irrelevant Context. ICML 2023.

  3. Du et al. Context Length Alone Hurts LLM Performance Despite Perfect Retrieval. Findings of EMNLP 2025.

  4. Avi Santoso. Why More Context Can Make AI Less Reliable: Data Pack. August 2026. Controlled business-task experiment containing 720 scored API records across the 30K and 60K baselines. Each task-level cell used five repeated requests and one fixed task item, so the results are descriptive rather than conclusive. 2

  5. Hsieh et al. RULER: What’s the Real Context Size of Your Long-Context Language Models?. 2024.

LLM Context Length: Why More Context Can Hurt AI | Avi Santoso