Mythos Model

Sources#

• Anthropic's Boris Cherny: Why Coding Is Solved, and What Comes Next
• Claude Mythos Preview red.anthropic.com
• How Anthropic's product team moves faster than anyone else | Cat Wu (Head of Product, Claude Code)

Summary#

Anthropic's preview-tier frontier model. Notably described as "incredibly powerful" and gated behind safety review (the Mythos Preview / red.anthropic.com publication that established the LLM-Driven Vulnerability Research story). Used internally at Anthropic alongside Claude Opus 4.7. As of May 2026, not GA.

What's known publicly#

• Mythos Preview demonstrated emergent cybersecurity capabilities — autonomous zero-day discovery, full exploit chains. See LLM-Driven Vulnerability Research for the detailed analysis from the Mythos Preview publication.
• Anthropic's response: Project Glasswing safeguards (referenced in 4.7 release as "first post-Glasswing safeguards").
• Boris Cherny: "We use a little bit of Mythos to try it and then a lot of Opus 4.7 to dog food it and to write most of our code." — Mythos is preview-tier, not the workhorse.
• Cat Wu: "Mythos is an incredibly powerful model. But we do use the models internally and I think this has increased our rate of shipping a little bit but I don't think it explains the bulk of the increase." — confirms internal use; explicitly disclaims it as the cadence explanation.

Why kept gated#

The combination of:

• Cybersecurity capability gap vs prior models (per Mythos Preview publication)
• Safety mechanisms still being evaluated and hardened
• Anthropic's stated mission posture

Means the model is used internally and previewed selectively rather than shipped broadly. Some descendant of Mythos is expected to ship publicly later — Boris Cherny: "It will become some version of some descendant of that will become available at some point to everyone."

Connections#

• Anthropic — vendor
• Claude Opus 4.7 — current GA model; Mythos is the next-tier preview
• LLM-Driven Vulnerability Research — primary public account of capability profile
• Harness Shrinkage as Models Improve — Mythos-class capability is what makes Boris's "100 lines" prediction conceivable
• AI Native Product Cadence — explicitly disclaimed as the cadence explanation, but contributes

Open questions#

• Public release timeline: not in source.
• Capability profile beyond cybersecurity: Mythos Preview focused on the safety story; other capability dimensions not well-documented externally.
• Internal access controls: who at Anthropic actually uses Mythos for daily work, vs Opus 4.7? Boris implies infrequent (try-it use); not detailed.

Sources#

• Claude Mythos Preview red.anthropic.com
• How Anthropic's product team moves faster than anyone else | Cat Wu (Head of Product, Claude Code)
• Anthropic's Boris Cherny: Why Coding Is Solved, and What Comes Next