For a live model catalog, use Anthropic’s GET /v1/models endpoint. It returns model IDs and lifecycle information; use that response rather than treating a copied list as a live availability check. Anthropic documents the endpoint as a way to determine which models are available for use in the API. (List Models API reference)
Anthropic News announced Claude Fable 5.2 and Claude Mythos 5.2 on November 9, 2026, but that announcement does not provide API IDs. Don’t infer IDs from model names. (Anthropic News: Models)
Anthropic API model IDs
The Anthropic-maintained skills repository’s catalog lists the aliases below. Treat them as a catalog snapshot, not a complete or live availability check: the repository recommends querying the Models API for live data, and its captured table does not include the 5.2 announcement. Before deploying, check the API response and confirm that the model’s lifecycle and access conditions fit your use. The repository warns against guessing or constructing IDs. (Claude Model Catalog)
| Model in the captured catalog | Alias shown | Catalog note |
|---|---|---|
| Claude Fable 5.1 | claude-fable-5-1 |
Listed as active in the snapshot |
| Claude Mythos 5.1 | claude-mythos-5-1 |
Snapshot restricts it to approved Project Glasswing customers |
| Claude Fable 5 | claude-fable-5 |
Listed as active in the snapshot |
| Claude Mythos 5 | claude-mythos-5 |
Snapshot marks it Project Glasswing-only |
| Claude Opus 5.5 | claude-opus-5-5 |
Listed as active in the snapshot |
| Claude Opus 5 | claude-opus-5 |
Listed as active in the snapshot |
| Claude Opus 4.8 | claude-opus-4-8 |
Listed as active in the snapshot |
| Claude Opus 4.7 | claude-opus-4-7 |
Listed as active in the snapshot |
| Claude Opus 4.6 | claude-opus-4-6 |
Listed as active in the snapshot |
| Claude Sonnet 5.5 | claude-sonnet-5-5 |
Listed as active in the snapshot |
| Claude Sonnet 5 | claude-sonnet-5 |
Listed as active in the snapshot |
| Claude Sonnet 4.6 | claude-sonnet-4-6 |
Listed as active in the snapshot |
| Claude Haiku 5.5 | claude-haiku-5-5 |
Listed as active in the snapshot |
| Claude Haiku 4.5 | claude-haiku-4-5 |
Snapshot also gives full ID claude-haiku-4-5-20251001 |
The table’s status labels are not a guarantee of live availability. Anthropic’s API reference defines active models as available and open to new adopters; deprecated models remain callable only for organizations with existing access and are closed to new adopters; retired models are no longer available. A model appearing in the list—especially with a deprecated lifecycle—does not by itself establish that your organization can call it. (List Models API reference)
Retrieve the live list with HTTP
Set ANTHROPIC_API_KEY to an API key for your application, then request the list endpoint:
curl https://api.anthropic.com/v1/models -H "x-api-key: $ANTHROPIC_API_KEY"
Anthropic documents GET /v1/models as the list operation. The reference says the anthropic-version header is optional. The list is paginated: the documented limit defaults to 20 and ranges from 1 to 1,000; use after_id or before_id as cursors. By default, the endpoint includes active and deprecated models; request the retired lifecycle explicitly to include retired entries. (List Models API reference)
List models with the Python SDK
With the Anthropic Python SDK installed and an API key configured, iterate the list to inspect model IDs and display names:
from anthropic import Anthropic
client = Anthropic()
for model in client.models.list():
print(model.id, model.display_name)
Anthropic’s maintained repository documents client.models.list() and says to iterate the page object directly; iteration auto-paginates. The API response also includes a lifecycle field, which you can use when checking lifecycle status. (Claude Model Catalog; List Models API reference)
To inspect one model rather than list them all, use the retrieve operation. This SDK pattern is shown in Anthropic’s repository:
model = client.models.retrieve("claude-opus-4-8")
print(model.id, model.display_name)
print(model.max_input_tokens, model.max_tokens)
print(model.capabilities)
The example ID demonstrates retrieval; it is not a recommendation to select that model. Anthropic documents GET /v1/models/{model_id} for retrieving one model, separately from GET /v1/models for listing. For live capability information, query the Models API rather than relying on cached catalog limits. (Models API reference; Claude Model Catalog)
Which endpoint should you use?
- Need to list models? Use
GET /v1/modelsorclient.models.list(). Inspect each returnedidandlifecycle; don’t assume that listing a deprecated model proves your organization has existing access. (List Models API reference) - Need details for one known ID? Use
GET /v1/models/{model_id}orclient.models.retrieve(model_id). This retrieves one model; it is not the list operation. (Models API reference) - Need capability or limit data? Retrieve the model and inspect the returned fields. The catalog recommends querying the Models API for live capability information. (Models API reference; Claude Model Catalog)
- Considering Mythos? The captured catalog describes access restrictions, but check current API lifecycle information and your organization’s eligibility rather than assuming the snapshot reflects current access. (Claude Model Catalog)
Third-party listings are not enough to confirm an official API ID. For example, third-party pages show claude-fable-5-2, while Anthropic News announces Fable 5.2 but does not provide an API ID. Use Anthropic’s Models API to check the current catalog; don’t treat the third-party ID as officially confirmed. (Anthropic News: Models; List Models API reference)
Sources
List Models — Claude API Reference