{
  "name": "Claude Fable 5",
  "vendor": "Anthropic",
  "model_id": "claude-fable-5",
  "model_id_note": "Use this exact string. No date suffix exists.",
  "released": "2026-06-09",
  "tier": "Above Opus — Anthropic's most intelligent model. A Mythos-class model made safe for general use.",
  "context_window_tokens": 1000000,
  "max_output_tokens": 128000,
  "streaming_required_above_output_tokens": 16000,
  "pricing_per_million_tokens_usd": {"input": 10.0, "output": 50.0},
  "pricing_comparison_per_million_tokens_usd": {
    "claude-opus-4-8": {"input": 5.0, "output": 25.0},
    "claude-sonnet-4-6": {"input": 3.0, "output": 15.0},
    "claude-haiku-4-5": {"input": 1.0, "output": 5.0}
  },
  "thinking": {
    "mode": "adaptive_only",
    "enable": {"thinking": {"type": "adaptive"}},
    "disable": "Omit the thinking field entirely. An explicit {\"type\": \"disabled\"} returns HTTP 400 (Fable-specific).",
    "display_default": "omitted",
    "display_visible_reasoning": {"thinking": {"type": "adaptive", "display": "summarized"}}
  },
  "effort": {
    "parameter": "output_config.effort",
    "levels": ["low", "medium", "high", "xhigh", "max"],
    "default": "high",
    "recommended": {"coding_and_agentic": "xhigh", "general": "high", "correctness_critical": "max"}
  },
  "structured_outputs": true,
  "prompt_caching": {"supported": true, "minimum_cacheable_prefix_tokens": 2048},
  "task_budgets": {"beta_header": "task-budgets-2026-03-13", "parameter": "output_config.task_budget", "minimum_total_tokens": 20000},
  "vision": "State-of-the-art, high-resolution image input",
  "availability": {
    "api": "Fully available from 2026-06-09",
    "consumption_enterprise": "Fully available from 2026-06-09",
    "subscriptions_included_free": {"from": "2026-06-09", "to": "2026-06-22"},
    "subscriptions_usage_credits_from": "2026-06-23",
    "claude_code": "Fable 5 powers Claude Code (CLI, desktop, web, IDE extensions)"
  },
  "mythos_5": {
    "what": "Same underlying model with safeguards lifted in specific areas",
    "access": "Restricted: Project Glasswing partners (cyber), select biology researchers (bio/chem); broader trusted-access program planned",
    "data_retention_days": 30,
    "generally_available": false
  },
  "sources": [
    "https://www.anthropic.com/news/claude-fable-5-mythos-5",
    "https://platform.claude.com/docs"
  ],
  "disclaimer": "Independent guide, not affiliated with Anthropic. Verify against platform.claude.com/docs.",
  "last_verified": "2026-06-10"
}