Compare AI models

Specifications
Context windowHow much text the model can hold in mind at once — your question, any documents you attach, the conversation so far, and its own reply. Go past it and the earliest part falls out of view.
9k128k
Overview
CompanyAnthropicOpenAI
Release dateMar 14 2023Feb 12 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude 1 and GPT-5.3-Codex-Spark don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude 1 shipped 1066 days before GPT-5.3-Codex-Spark, so benchmark comparisons should account for the intervening progress.

Context windows are 9k (Claude 1) vs 128k (GPT-5.3-Codex-Spark).

Direct benchmark comparisons are unavailable — Claude 1 and GPT-5.3-Codex-Spark don't publish scores on any of the same benchmarks.