Claude 4.8 vs Codex 5.5: Which Code‑Generation Model Performs Better?

Claude Code – Strong on Complex Work

Claude Code runs on the newly released Opus 4.8 (May 28). On the cheat‑resistant SWE‑bench Pro it scores 69.2%, whereas GPT‑5.5 (the engine behind Codex) scores 58.6%, a gap of nearly 11 points. The author therefore keeps Claude Code as the primary assistant for daily development, using GPT‑5.5 only for bug‑fixes.

For multi‑file refactoring, vague requirements, or front‑end tasks that need visual polish, Claude Code shows a much lower chance of deviating from the intended outcome and feels very stable.

Claude Code can retain up to 1 million tokens of context, compared with Codex’s 256 k tokens, which makes cross‑file edits noticeably smoother. The author notes that Opus 4.8 costs more than twice as much as GPT‑5.5, making it expensive for heavy daily use.

Codex – Terminal Tasks and Cost Efficiency

Codex runs on GPT‑5.5. On Terminal‑Bench 2.1 it achieves 78.2% versus Claude Code’s 74.6%, indicating better performance for command‑line, CI, and pure terminal workloads.

Codex is also faster—roughly half the latency of Claude Code—and its price is about half that of Opus 4.8, offering a cheaper alternative for batch testing or automated scripts.

Running Codex in the cloud feels low‑maintenance: jobs can be dispatched and the user can attend to other tasks while waiting for results.

Choosing Between Them

The author installs both models and routes work based on requirements: use Claude Code for high‑quality code, ambiguous or multi‑file changes, and when visual output matters; use Codex 5.5 for terminal‑centric tasks, bulk test runs, and when budget is a concern.

He invites readers to share their own preferences in the comments.