Claude Mythos 5

Tool callingStructured outputReasoningImage inputFile input

Launch post Website Docs

Restricted Claude model for advanced cybersecurity and biology research workflows

Context: 1M
Released: 4mo ago

Sources:models.dev

Benchmarks

DeepSWE is the primary coding benchmark where an exact model evaluation exists. Other sourced evaluations appear below; missing scores are not zero.

Not evaluated in DeepSWE 1.1 as of 2026-09-22. Results are only shown for exact model versions in the official dataset. Official leaderboard.

No benchmark results have been matched to this model yet.

Specifications

Developer: Anthropic
Model family: Claude
Type: Language model
Predecessor: —
Successor: —
Released: June 9, 2026
Model ID: anthropic/claude-mythos-5
Openness: Closed
License: —
Input modalities: text, image, file
Output modalities: text
Modality: text+image+file->text
Max output tokens: 128K
Knowledge cutoff: 2026-01-31
Hugging Face: —
Source freshness: Metadata synced Oct 8, 2026, 10:17 PM UTC

Additional source evidence

Source model: anthropic/claude-mythos-5
Source family: claude-mythos
Last updated: 2026-06-09
Knowledge cutoff: 2026-01-31
Model context: 1M
Model output limit: 128K
Open weights: No
File attachments: Yes
Reasoning: Yes
Tool calling: Yes
Structured output: Yes
Temperature control: No

Complete source record (JSON)

{
  "id": "anthropic/claude-mythos-5",
  "name": "Claude Mythos 5",
  "description": "Restricted Claude model for advanced cybersecurity and biology research workflows",
  "family": "claude-mythos",
  "last_updated": "2026-06-09",
  "knowledge": "2026-01-31",
  "attachment": true,
  "reasoning": true,
  "tool_call": true,
  "structured_output": true,
  "temperature": false,
  "modalities": {
    "input": [
      "text",
      "image",
      "pdf"
    ],
    "output": [
      "text"
    ]
  },
  "limit": {
    "context": 1000000,
    "output": 128000
  },
  "release_date": "2026-06-09",
  "open_weights": false
}

Infrastructure

Provider availability

All providers

Provider endpoint data will appear after this model's first OpenRouter endpoint sync.

Text provenance

Transitioning

Claude text watermarking

Anthropic says Claude models launched before August 2, 2026 have a transition period and are being moved to the same watermarking system over time.

Official explanation