At Debevoise, we have access to a lot of generative AI (“GenAI”) models. We’ve found different models to be good at different tasks for legal practice, and model capabilities are changing quite frequently. But in light of the recent release of OpenAI’s o3 pro model, we thought it would be helpful to provide a quick guide on the comparative capabilities of the various models currently available through GPT Enterprise based on our experience as lawyers using these models and OpenAI’s own recommendations. Of course, this blog post is not a review or endorsement of any particular GenAI model.
|
Model |
Overview |
Average Response Time |
Inputs |
Examples of Good Uses for Lawyers |
Enterprise Usage Limits |
Context Window Limits |
|
GPT-4o |
Default model when you start, so it is the most commonly-used model. All-purpose GenAI model with multimodal capabilities. Best for everyday tasks. Strong general knowledge and reasoning. |
Fast. Near-instant for simple queries. |
Text and images (multimodal); can analyze documents, images, audio, and can generate images via ChatGPT tools. |
Proofreading, drafting emails, summarizing documents that are not particularly complex; summarizing case law or contracts; first drafts of simple legal documents; answering general legal questions; generating illustrative diagrams or images for presentations. |
Unlimited. |
Up to 128k tokens (~190 single-spaced pages). |
|
o3 |
Good for complex, multi-step analysis. Excels at logical reasoning, code, math, and visual tasks. |
Typically, 30–90 seconds. |
Text and images; full tool use (web browsing, file analysis with Python, etc.) for multimodal reasoning. |
Complex legal analyses and strategy. In-depth case reasoning, multi-step legal argument development, or analyzing large evidence datasets with code. Good for planning or tasks requiring rigorous step-by-step logic. |
Currently, 100 req. / wk. |
Up to 200k tokens (~300 pages). |
|
o3-pro |
Same core capabilities as o3, but with extended reasoning time for more accurate responses. |
3-10 minutes. |
Text and images. |
Very complex issues with need for accuracy (e.g. double-checking critical legal arguments or calculations). |
Currently, 15 req. / mo. |
Up to 200k tokens (~300 pages). |
|
GPT-4.1 |
General Model with large context window through the API. |
Usually, a few seconds. |
Text and images. |
Large volume document summaries, chronologies, and timelines. |
500 req. / 3 hrs. |
Up to 1M tokens (~1500 pages) through the API; 128k tokens (~190 pages) through ChatGPT. |
|
GPT-4.1 mini |
Smaller, faster GPT-4.1 with same large context window through the API. |
Very fast. |
Text and images. |
Rapid summaries, quick memos, and interactive chats. |
Unlimited. |
Up to 1M tokens (~1500 pages) through the API; 128k tokens (~190 pages) through ChatGPT. |
|
GPT-4.5 |
Great for creative writing and conversational tasks. |
Usually, less than a minute. |
Text and voice input, as well as good image understanding and generation. |
Drafting client alerts, persuasive legal writing, or preparing for oral argument or witness interviews. |
20 req. / wk. |
Up to 128k tokens (~190 pages). |
|
o4-mini |
Quick, efficient reasoning. |
Usually, a few seconds. |
Text and images; can search web, analyze files, interpret visuals, and generate images. |
High-volume contract scans, data extraction, math/code help. |
300 req. / day. |
Up to 200k tokens (~300 pages). |
|
o4-mini-high |
o4-mini with extra reasoning depth. |
Usually, less than a minute. |
Text and images. |
Detailed clause analysis, multi-step research. |
100 req. / day. |
Up to 200k tokens (~300 pages). |
Takeaways:
- Don’t just default to 4o – A lot of Enterprise users use 4o for all tasks because that is the model selected for them by default, even though for many tasks, other models available to Enterprise users are better. Access alternate models by clicking on the Models menu in the top left corner of the GPT Enterprise interface.
- Don’t forget Deep Research – Deep Research is an agentic capability, built on a browsing-optimized version of the o3 model (but works with other models too), that can autonomously search the Internet, reason over material, and return fully cited responses. It’s capable of handling 200,000 tokens (about 300 single-spaced pages) to perform highly sophisticated research and process-oriented tasks (e.g., retrieving court cases in Spanish, translating them, and compiling them into a memo that quotes relevant portions citing to the original’s specific paragraph numbers). It takes 3-30 minutes for most tasks, but exceptionally large jobs can run longer, and the results are often very impressive. You can find Deep Research when you click on the “Tools” button in the chat window. Enterprise users are limited to 25 Deep Research requests per month.
- Mix and match – Finally, you can toggle between different models in one chat. We often use o3 for legal research, but then switch to 4.5 to help draft a blog post, and then to 4o to generate the cover art.
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The authors would like to thank Debevoise Summer Associate Kanyinsola Oye for her contribution to this blog post.
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The Debevoise STAAR (Suite of Tools for Assessing AI Risk) is a monthly subscription service that provides Debevoise clients with an online suite of tools to help them with their AI adoption. Please contact us at STAARinfo@debevoise.com for more information.
The cover art used in this blog post was generated by Gemini.
