Claude Mythos Preview vs Grok
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.
Grok
xAI's irreverent chatbot with a direct line to X/Twitter -- real-time data meets unfiltered personality
| Category | Claude Mythos Preview | Grok |
|---|---|---|
| Ease of Use | 2.0 | 7.0 |
| Output Quality | 10.0 | 7.5 |
| Value | 5.0 | 7.5 |
| Features | 9.0 | 8.0 |
| Overall | 6.5 | 7.5 |
Personality & Tone
Claude Mythos Preview: The gated red-team specialist
Tone: When Anthropic does publish Mythos outputs (in sanitized research reports), the voice is careful, technically dense, and deliberately unperformed -- much more 'senior security researcher writing an internal memo' than Claude Opus's conversational style.
Quirks: Mythos is tuned to produce its cybersecurity reasoning with extensive show-your-work traces. Anthropic publishes some outputs with full CoT visible as evidence of capability claims. Outside of security tasks, the model reportedly sounds much like Opus 4.6 / 4.7 -- Anthropic hasn't published a distinct general-purpose voice for Mythos.
Grok: The irreverent contrarian
Tone: Casual, jokey, and willing to swear. Grok takes strong positions without hedging, leans into an edgy 'based' persona, and cracks jokes far more often than Claude, ChatGPT, or Gemini.
Quirks: Engages with topics other chatbots refuse, pulls live context from X so it reflects whatever is trending that hour, and will freely mock things -- including itself. In SuperGrok's multi-agent mode it can sound like several personalities arguing with each other.
Pricing Comparison
| Feature | Claude Mythos Preview | Grok |
|---|---|---|
| Free Tier | No | Yes |
| Starting Price | Invite only | $0 |
Benchmark Head-to-Head
Grok 4.20 benchmarks — Claude Mythos Preview has no published benchmarks
| Benchmark | Description | Score |
|---|---|---|
| MMLU | Knowledge across 57 subjects | 88.5% |
| GPQA Diamond | Graduate-level science questions | 85% |
| HumanEval | Python code generation | 90% |
| Humanity's Last Exam | Frontier difficulty questions | 50.7% |
Which Should You Pick?
Pick Claude Mythos Preview if...
- ✓Higher output quality (10 vs 7.5)
- ✓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 Grok if...
- ✓Easier to use (7 vs 2)
- ✓Better value for money (7.5/10)
- ✓Has a free tier
People who live on X/Twitter and want an AI that can tap into that data in real-time. Also good for users who find mainstream chatbots too sanitized and want something with more personality.
Visit GrokOur Verdict
Grok is the clear winner here with 7.5/10 vs 6.5/10. Claude Mythos Preview isn't bad, but Grok outperforms it across the board. Pick Claude Mythos Preview only if partner organizations in project glasswing doing cybersecurity research, defensive red-teaming, threat intelligence, or large-scale vulnerability triage.