Is Claude Mythos better than GPT-5.4?

Likely yes for certain tasks. Anthropic calls Mythos a 'step change' in capabilities, and internal benchmarks show multi-step autonomous task execution. However, it's not publicly available yet, so direct comparisons aren't possible.

When can I use Claude Mythos?

No public release date. As of April 2026, only select early access customers have access. Anthropic is conducting extensive safety testing, particularly around cybersecurity risks, before wider release.

What makes Claude Mythos different?

Mythos can autonomously execute multi-step research tasks without intermediate human input — a capability that current models like GPT-5.4 and Claude Opus 4.6 can only partially achieve. This represents a qualitative leap in agentic capabilities.

Quick Answer

Claude Mythos vs GPT-5.4 vs Gemini 3.1 Pro (2026)

Published: April 6, 2026

Claude Mythos vs GPT-5.4 vs Gemini 3.1 Pro

Anthropic’s leaked next-gen model vs the current frontier. Here’s what we can compare — and what we can’t.

Last verified: April 2026

What We Know

Feature	Claude Mythos	GPT-5.4	Gemini 3.1 Pro
Status	Early access only	Public	Public
By	Anthropic	OpenAI	Google
Released	Leaked Mar 2026	Mar 2026	Feb 2026
Capability level	”Step change” above Opus 4.6	Frontier	Frontier
Autonomous tasks	Multi-step without human input	Thinking mode	Deep Think
Safety concern	Cyberattack risk flagged	Standard	Standard
Price	Unknown	$15/$60 per M tokens	$7/$21 per M tokens

What’s Actually Different About Mythos

The key differentiator is autonomous multi-step execution. Current frontier models can:

Answer complex questions (all three)
Write and debug code (all three)
Follow multi-turn conversations (all three)

Mythos reportedly can:

Plan and execute multi-step research autonomously — without human checkpoints
Self-correct and iterate at a level beyond current models
Handle complex workflows that would normally require human orchestration

This is a qualitative leap, not just a benchmark improvement.

The Safety Question

Anthropic’s private warnings to government officials about Mythos enabling cyberattacks suggest the model’s agentic capabilities are significantly more powerful than anything currently available. This aligns with Anthropic’s “Responsible Scaling” approach — flagging risks before release.

Neither OpenAI nor Google have issued similar warnings about GPT-5.4 or Gemini 3.1 Pro.

Current Best Options (Available Now)

While Mythos remains unreleased, here’s what to use today:

Use Case	Best Available
Coding	Claude Opus 4.6 (Claude Code)
Reasoning	GPT-5.4 Thinking
Multimodal	Gemini 3.1 Pro (2M context)
Budget	DeepSeek V3/V4 or Gemini 3.1 Pro
Autonomous agents	Claude Opus 4.6 (with orchestration)

When Mythos Launches

If Anthropic follows their pattern:

More safety testing (weeks to months)
API access for approved developers first
Claude.ai integration shortly after
Likely premium pricing above Opus 4.6

The model will likely leapfrog current frontier models on benchmarks — but practical advantage depends on how it handles real-world coding, writing, and reasoning tasks.

Last verified: April 2026