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  1. Home/
  2. Compare/
  3. Mercury 2.5 vs GPT-1
Updated Sep 2026

Mercury 2.5 vs GPT-1

Mercury 2.5 has a larger context window than GPT-1 (260K tokens vs 1K tokens).

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Mercury 2.5
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GPT-1

Which answer wins?

Written rounds

3 prompts
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Mercury 2.5: Setting: A quiet office at a university. Dr. Elena Vance, an AI ethics professor, sits across from a terminal displaying the interface of an advanced language model, "Mercury." Dr. Vance: Thank you for agreeing to this session. I’ve been reviewing your outputs from the last benchmark. Your coherence is striking.

    GPT-1: Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights. the ai model was not very smart ( and the ai model didn't have many laws about things ). the ai models were all very clever and were never completely successful.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    Mercury 2.5: Why did the scarecrow win an award? Because he was outstanding in his field. What do you call a fake noodle? An impasta. Why don't scientists trust atoms? Because they make up everything. What do you call a bear with no teeth? A gummy bear. How do you organize a space party? You planet. All 5 jokes are unique.

    GPT-1: Generate 5 jokes. How many are unique? the one that was asked was in the'the one who didn't have a head and wanted to keep it?'i don't recall whic h one, not that i've ever written anything more. the one who didn't have a head and wanted to keep i t? what did that mean by'the one who '?

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    Mercury 2.5: ( walks to the mic, adjusts the stand) Hey everyone, how we doing? Good? So, I realized something recently. We are living in the future, but we’re acting like we’re still stuck in 1998. Think about it.

    GPT-1: Write a 3-minute stand-up comedy routine that isn't based on puns. the one thing was for sure, no matter how many times he gave this speech, he 'd never be able to remember all of it. he was never sure if he liked the guy or not. the next day, he went out with a band friend and got them started.

    Every model's answer to this prompt

Price and specs

Not enough votes to call it. On the specs, Mercury 2.5 has the edge: bigger model tier, newer, bigger context window.

Mercury 2.5 and GPT-1 compared across 7 shared prompts
SpecMercury 2.5GPT-1
Input price$0.04/M tokens—
Output price$0.15/M tokens—
Context window260K tokens1K tokens
Weights—Open
Free API (OpenRouter)No—
ReleasedSep 2026Jun 2018
At 10M a month$0.40$0.40–not listed
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it1 host
Mercury 2.51 host
HostInOutContextUptime
  • Inception$0.04 in·$0.15 out·260k·99.9% up
GPT-1

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 28 Sep 2026.

Common questions

What is the difference between Mercury 2.5 and GPT-1?

Mercury 2.5 is developed by Inception while GPT-1 is developed by OpenAI. Mercury 2.5 has a 260K token context window vs GPT-1's 1K. You can compare their actual outputs across 7 challenges on Rival to see how they differ in practice.

Which is better, Mercury 2.5 or GPT-1?

It depends on your use case. Mercury 2.5 and GPT-1 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 7 challenges so you can judge which fits your needs best.

How can I compare Mercury 2.5 and GPT-1 on Rival?

This page shows a side-by-side comparison of Mercury 2.5 and GPT-1 across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

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