Claude Mythos Preview vs GPT-5.4-Cyber (OpenAI)
Which one should you pick? Here's the full breakdown.
Claude Mythos Preview
Anthropic's most capable model -- a gated research preview via Project Glasswing, cybersecurity-specialized. 73% success on expert CTF tasks, 32-step autonomous network attacks. Not generally available.
GPT-5.4-Cyber (OpenAI)
OpenAI's defensive-cybersecurity variant of GPT-5.4, launched 2026-04-16. Lowered refusal boundary for security-research tasks and native binary reverse-engineering. Access gated via Trusted Access for Cyber (TAC) program -- thousands of verified defenders, hundreds of teams, no public pricing
| Category | Claude Mythos Preview | GPT-5.4-Cyber (OpenAI) |
|---|---|---|
| Ease of Use | 2.0 | 5.0 |
| Output Quality | 10.0 | 8.5 |
| Value | 5.0 | 7.0 |
| Features | 9.0 | 8.0 |
| Overall | 6.5 | 7.2 |
Pricing Comparison
| Feature | Claude Mythos Preview | GPT-5.4-Cyber (OpenAI) |
|---|---|---|
| Free Tier | No | No |
| Starting Price | Invite only | Not publicly disclosed |
Which Should You Pick?
Pick Claude Mythos Preview if...
- ✓Higher output quality (10 vs 8.5)
- ✓More features (9 vs 8)
Partner organizations in Project Glasswing doing cybersecurity research, defensive red-teaming, threat intelligence, or large-scale vulnerability triage. If your use case is legitimate cybersecurity and you have enterprise Anthropic contact, ask about Glasswing admission.
Visit Claude Mythos PreviewPick GPT-5.4-Cyber (OpenAI) if...
- ✓Easier to use (5 vs 2)
- ✓Better value for money (7/10)
Enterprise SOC teams, established security research orgs, and vetted individual defenders who can qualify for Trusted Access for Cyber. Strongest fit if your work involves binary analysis, vulnerability research, or defensive-security tooling where standard GPT-5.4 refusals actually block the work.
Visit GPT-5.4-Cyber (OpenAI)Our Verdict
GPT-5.4-Cyber (OpenAI) edges out Claude Mythos Preview with a 7.2 vs 6.5 overall score. Both are solid picks, but GPT-5.4-Cyber (OpenAI) has the advantage in value.