Is Codex or GitHub Copilot more reliable?

Based on StupidLLM's incident database, Codex has 3 documented failures (avg severity 5.8/10) while GitHub Copilot has 4 (avg severity 8.2/10). Codex shows better reliability.

What are the main differences between Codex and GitHub Copilot failures?

Codex's most common failure mode is Destructive Action, while GitHub Copilot most commonly fails via Security Vulnerability. Codex has 0 critical incidents vs GitHub Copilot's 3.

Which has more critical-severity failures?

GitHub Copilot has more critical failures (3 vs 0), indicating a higher likelihood of severe, production-impacting incidents.

Should I use Codex or GitHub Copilot for production code?

Codex has a lower average failure severity (5.8/10 vs 8.2/10), making it the statistically safer choice for production environments. However, both agents have documented critical incidents — no AI coding agent is risk-free.

How many verified incidents does each agent have?

Codex has 2 verified incidents out of 3 total, while GitHub Copilot has 4 verified out of 4. Verified incidents are confirmed against source evidence.

Head to head

Codex vs GitHub Copilot

Comparing 3 documented Codex incidents against 4 for GitHub Copilot.

Full Codexreport →Full GitHub Copilotreport →

Verdict

Codex has the lower average failure severity (5.8/10 vs 8.2/10), making it the statistically safer choice of the two — though both agents have documented critical incidents.