# 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.

```python
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

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

```json
{
  "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` |
