GPT-5.3 Codex is OpenAI’s flagship coding model. It leads Terminal-Bench by a wide margin and performs on par with Opus 4.6 on our internal benchmarks, at roughly one-third the price. Much faster than previous GPT generations. A strong default for most coding tasks.

Strengths

  • Leads Terminal-Bench by a wide margin. Competitive with Opus 4.6 on our internal benchmarks.
  • About one-third the price of Opus with comparable quality on most tasks. Good for daily coding, long debugging sessions, and cost-conscious teams.
  • Grinds through complex, multi-step problems and deep debugging sessions.

Limitations

  • Code style is less polished than Opus on architecture-heavy tasks.
  • Terminal-Bench skews toward general reasoning; real-world coding gains may differ.

Tools

GPT-5.3 Codex has access to all agent tools when used with Cursor including:

Learn more about how tools work and tool calling fundamentals.

Pricing

Cursor plans include two usage pools. GPT-5.3 Codex draws from the third-party Other Models pool, which charges at the rates below. All prices are per million tokens.

A high reasoning effort variant (gpt-5.3-codex-high) is available for tasks that need deeper analysis.