Anthropic · llm model

Claude Mythos 5

Claude Mythos 5 is an Anthropic language model (limited access) released Jun 9, 2026; Anthropic's newest language model in our dataset is Claude Haiku 5.5. Proprietary, API access only. Anthropic's access-limited Claude model for Project Glasswing participants, launched Jun 9, 2026 alongside Claude Fable 5. Verified against vendor sources on Oct 26, 2026.

Reported Last verified Oct 26, 2026 · All models · JSON · Markdown

ReleasedJun 9, 2026
Context window1M1,000,000 tokens
Max output128K128,000 tokens
LicenceProprietaryProprietary (API)

Modalities not verified

Key facts

Claude Mythos 5: key facts with sources
Fact	Value	Source
Vendor	Anthropic	n/a
Released	Jun 9, 2026 Date of the launch entry in the Claude Platform release notes (API availability).	source
Status	limited access	n/a
API id	claude-mythos-5	source
Context window	1,000,000 tokens (1M)	source
Max output	128,000 tokens	source
Licence	Proprietary (API)	source

Where Claude Mythos 5 sits in our data

Released Jun 9, 2026 (week 24 of 2026), in June 2026. Other models in our data released that month: Claude Sonnet 5, Nano Banana 2 Lite, GLM-5.2, Claude Fable 5, North Mini Code.
The previous Anthropic model we track is Claude Opus 4.8 (May 28, 2026), 12 days earlier.
Of the 60 models in our data with a published context window, Claude Mythos 5 has the number 36 largest (1M tokens). Our data is not every model on the market.
Anthropic tools we cover: Claude Code, Claude.
All releases by date: AI model releases by month · new AI models this week. Choosing for code: best LLM for coding.

How Claude Mythos 5 differs from Claude Mythos 5.1

Read from the recorded facts of the two models, not from a head-to-head test. We have not run either.

We have no recorded price for Claude Mythos 5; Claude Mythos 5.1 has one.
Both list a 1M-token context window.
Claude Mythos 5 came out 84 days before Claude Mythos 5.1.
Facts for the other model: Claude Mythos 5.1.

What we tested

Nothing yet. We have not run Claude Mythos 5 ourselves, so every fact on this page is Reported from the sources below. When we do test it, the scope will be stated here and in our test logs. See methodology.

Not verified, left out

We could not confirm these on a vendor page, so we do not state them.

Price was not captured.
Access is limited to Project Glasswing participants per the release notes.