anthropics_skills/skills/claude-api/shared/models.md

Claude Model Catalog

Only use exact model IDs listed in this file. Never guess or construct model IDs — incorrect IDs will cause API errors. Use aliases wherever available. For the latest information, WebFetch the Models Overview URL in shared/live-sources.md, or query the Models API directly (see Programmatic Model Discovery below).

Programmatic Model Discovery

For live capability data — context window, max output tokens, feature support (thinking, vision, effort, structured outputs, etc.) — query the Models API instead of relying on the cached tables below. Use this when the user asks "what's the context window for X", "does model X support vision/thinking/effort", "which models support feature Y", or wants to select a model by capability at runtime.

m = client.models.retrieve("claude-opus-4-8")
m.id                 # "claude-opus-4-8"
m.display_name       # "Claude Opus 4.8"
m.max_input_tokens   # context window (int)
m.max_tokens         # max output tokens (int)

# capabilities is an untyped nested dict — bracket access, check ["supported"] at the leaf
caps = m.capabilities
caps["image_input"]["supported"]                       # vision
caps["thinking"]["types"]["adaptive"]["supported"]     # adaptive thinking
caps["effort"]["max"]["supported"]                     # effort: max (also low/medium/high)
caps["structured_outputs"]["supported"]
caps["context_management"]["compact_20260112"]["supported"]

# filter across all models — iterate the page object directly (auto-paginates); do NOT use .data
[m for m in client.models.list()
 if m.capabilities["thinking"]["types"]["adaptive"]["supported"]
 and m.max_input_tokens >= 200_000]

Top-level fields (id, display_name, max_input_tokens, max_tokens) are typed attributes. capabilities is a dict — use bracket access, not attribute access. The API returns the full capability tree for every model with supported: true/false at each leaf, so bracket chains are safe without .get() guards. TypeScript SDK: same method names, also auto-paginates on iteration.

Raw HTTP

curl https://api.anthropic.com/v1/models/claude-opus-4-8 \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01"

{
  "id": "claude-opus-4-8",
  "display_name": "Claude Opus 4.8",
  "max_input_tokens": 1000000,
  "max_tokens": 128000,
  "capabilities": {
    "image_input": {"supported": true},
    "structured_outputs": {"supported": true},
    "thinking": {"supported": true, "types": {"enabled": {"supported": false}, "adaptive": {"supported": true}}},
    "effort": {"supported": true, "low": {"supported": true}, …, "max": {"supported": true}},
    …
  }
}

Current Models (recommended)

Friendly Name	Alias (use this)	Full ID	Context	Max Output	Status
Claude Fable 5	claude-fable-5	—	1M	128K	Active
Claude Mythos 5	claude-mythos-5	—	1M	128K	Active (Project Glasswing only)
Claude Opus 5	claude-opus-5	—	1M	128K	Active
Claude Opus 4.8	claude-opus-4-8	—	1M	128K	Active
Claude Opus 4.7	claude-opus-4-7	—	1M	128K	Active
Claude Opus 4.6	claude-opus-4-6	—	1M	128K	Active
Claude Sonnet 5	claude-sonnet-5	—	1M	128K	Active
Claude Sonnet 4.6	claude-sonnet-4-6	-	1M	128K	Active
Claude Haiku 4.5	claude-haiku-4-5	claude-haiku-4-5-20251001	200K	64K	Active

Model Descriptions

• Claude Fable 5 — Anthropic's most capable widely released model, for the most demanding reasoning and long-horizon agentic work. Same API surface as Opus 4.7/4.8 with one new breaking change: an explicit thinking: {type: "disabled"} returns a 400 — omit the thinking parameter instead (thinking is always on; the raw chain of thought is never returned — summaries via display: "summarized"). Same tokenizer as Opus 4.8 (token counts roughly unchanged vs Opus 4.7/4.8). Safety classifiers may return stop_reason: "refusal". No assistant prefill. Requires 30-day data retention (not available under ZDR). $10/$50 per MTok; 1M context window (default), 128K max output. See shared/model-migration.md → Migrating to Claude Fable 5.
• Claude Mythos 5 — Same capabilities, pricing, limits, and API behavior as Claude Fable 5; only the model ID differs. Available exclusively through Project Glasswing, where it joins (and succeeds) the invitation-only Claude Mythos Preview (claude-mythos-preview). Use it only when the org participates in Project Glasswing; otherwise use claude-fable-5.
• Claude Opus 5 — For complex agentic coding and enterprise work; a step-change over Claude Opus 4.8, strongest on deep reasoning, agentic and long-horizon work, and test-time compute scaling, at half the cost of Claude Fable 5 (Claude Fable 5 remains the highest-capability tier). Safety classifiers can return stop_reason: "refusal" — handle it before reading content. A drop-in upgrade at Opus 4.8's pricing ($5/$25 per MTok) with the same feature set. Thinking is on by default (omitting thinking runs adaptive; {type: "adaptive"} is equivalent), and thinking: {type: "disabled"} is available only at effort high or lower — pairing it with xhigh/max returns a 400. Raw thinking tokens are never returned. Full effort ladder through max; 512-token prompt-cache minimum (down from 1024 on Opus 4.8); fast mode on the Claude API only. Elevated cybersecurity safeguards. Separate rate-limit bucket from the combined Opus 4.x pool. 1M context window (default and maximum), 128K max output. See shared/model-migration.md → Migrating to Claude Opus 5.
• Claude Opus 4.8 — The most capable model in the Opus 4 series — highly autonomous, state-of-the-art on long-horizon agentic work, knowledge work, and memory; clearer, warmer writing. Same API surface as Opus 4.7 (adaptive thinking only; sampling parameters and budget_tokens removed). 1M context window at standard API pricing (no long-context premium). See shared/model-migration.md → Migrating to Opus 4.8 — a 4.7 → 4.8 move is a model-ID swap plus prompt re-tuning, no new breaking changes.
• Claude Opus 4.7 — Previous-generation Opus. Highly autonomous; strong on long-horizon agentic work, knowledge work, vision, and memory. Adaptive thinking only; sampling parameters and budget_tokens removed. 1M context window. See shared/model-migration.md → Migrating to Opus 4.7.
• Claude Opus 4.6 — Older Opus. Supports adaptive thinking (recommended), 128K max output tokens (requires streaming for large outputs). 1M context window.
• Claude Sonnet 5 — The best combination of speed and intelligence in the Sonnet tier; near-Opus quality on coding and agentic work. Adaptive thinking on by default (omitting thinking runs adaptive); manual budget_tokens removed; non-default sampling parameters rejected. effort supports low/medium/high/xhigh/max. New tokenizer (~30% more tokens for the same text vs Sonnet 4.6). High-resolution vision (2576px). 1M context window, 128K max output. See shared/model-migration.md → Migrating to Claude Sonnet 5.
• Claude Sonnet 4.6 — Previous-generation Sonnet. Supports adaptive thinking (recommended). 1M context window. 128K max output tokens.
• Claude Haiku 4.5 — Fastest and most cost-effective model for simple tasks.

Legacy Models (still active)

Friendly Name	Alias (use this)	Full ID	Status
Claude Opus 4.5	claude-opus-4-5	claude-opus-4-5-20251101	Active
Claude Opus 4.1	claude-opus-4-1	claude-opus-4-1-20250805	Deprecated (retires 2026-08-05 — migrate to claude-opus-5)
Claude Sonnet 4.5	claude-sonnet-4-5	claude-sonnet-4-5-20250929	Active

Deprecated Models (retiring soon)

Friendly Name	Alias (use this)	Full ID	Status	Retires
Claude Sonnet 4	claude-sonnet-4-0	claude-sonnet-4-20250514	Deprecated	TBD
Claude Opus 4	claude-opus-4-0	claude-opus-4-20250514	Deprecated	TBD
Claude Haiku 3	—	claude-3-haiku-20240307	Deprecated	Apr 19, 2026

Retired Models (no longer available)

Friendly Name	Full ID	Retired
Claude Sonnet 3.7	claude-3-7-sonnet-20250219	Feb 19, 2026
Claude Haiku 3.5	claude-3-5-haiku-20241022	Feb 19, 2026
Claude Opus 3	claude-3-opus-20240229	Jan 5, 2026
Claude Sonnet 3.5	claude-3-5-sonnet-20241022	Oct 28, 2025
Claude Sonnet 3.5	claude-3-5-sonnet-20240620	Oct 28, 2025
Claude Sonnet 3	claude-3-sonnet-20240229	Jul 21, 2025
Claude 2.1	claude-2.1	Jul 21, 2025
Claude 2.0	claude-2.0	Jul 21, 2025

Resolving User Requests

When a user asks for a model by name, use this table to find the correct model ID:

User says...	Use this model ID
"fable", "most capable model"	claude-fable-5
"most powerful"	claude-fable-5
"mythos", "mythos 5"	claude-mythos-5 (Project Glasswing participants only; otherwise use claude-fable-5)
"mythos preview"	claude-mythos-5 (successor to claude-mythos-preview — see migration guide)
"opus"	claude-opus-5
"opus 5"	claude-opus-5
"opus 4.8"	claude-opus-4-8
"opus 4.7"	claude-opus-4-7
"opus 4.6"	claude-opus-4-6
"opus 4.5"	claude-opus-4-5
"opus 4.1"	claude-opus-4-1 (deprecated, retires 2026-08-05 — suggest claude-opus-5)
"opus 4", "opus 4.0"	claude-opus-4-0 (deprecated — suggest claude-opus-5)
"sonnet", "balanced"	claude-sonnet-5
"sonnet 5"	claude-sonnet-5
"sonnet 4.6"	claude-sonnet-4-6
"sonnet 4.5"	claude-sonnet-4-5
"sonnet 4", "sonnet 4.0"	claude-sonnet-4-0 (deprecated — suggest claude-sonnet-5)
"sonnet 3.7"	Retired — suggest claude-sonnet-5
"sonnet 3.5"	Retired — suggest claude-sonnet-5
"haiku", "fast", "cheap"	claude-haiku-4-5
"haiku 4.5"	claude-haiku-4-5
"haiku 3.5"	Retired — suggest claude-haiku-4-5
"haiku 3"	Deprecated — suggest claude-haiku-4-5