Claude API model names: the full list of model IDs (Opus, Sonnet, Haiku, Fable)

Haiku 4.5 is a previous-generation model: Anthropic marks it legacy, with a 200K-token context window and up to 64K output tokens. Anthropic committed not to retire it before 15 Oct 2026. That date has passed, but as of 12 November the model is still Active, and Anthropic gives at least 60 days' notice before retiring a publicly released model.

The current model of this class is Claude Haiku 5.5: claude-haiku-5-5 on Anthropic and anthropic/claude-haiku-5-5 on Kumo, with a 1M-token context window and up to 128K output tokens.

Anthropic opens the Mythos models only to organizations that pass its verification programs, and they are not in the Kumo catalogue. One more model from Anthropic's status table, claude-mythos-preview, is deprecated with no retirement date announced; it is not in the models overview, so it is not here either.

The Kumo catalogue holds 15 Claude models in total. Two of them, Claude Opus 5.5 and Claude Fable 5.2, are currently on the list of free models within a limit. Prices of every Claude model at Anthropic and on Kumo are collected in a separate article.

From the 4.6 generation on, a Claude ID carries no date: claude-{name}-{major}[-{minor}], for example claude-sonnet-4-6 or claude-opus-5-5. Major versions such as Claude Opus 5 have no minor number: claude-opus-5. Models before 4.6 end with a snapshot date: claude-{name}-{major}-{minor}-{YYYYMMDD}, for example claude-haiku-4-5-20251001.

Anthropic guarantees that the model will not change for an ID, not for an alias. That is why production code for models before 4.6 pins the dated snapshot: a re-pointed alias cannot then change behaviour quietly. For models from 4.6 on the dateless ID is enough. Every ID has its own retirement schedule. Anthropic also notes that the serving infrastructure around a model can change even when the weights stay the same.

These strings are for the Anthropic API. Cloud platforms use their own IDs for the same models: Haiku 4.5 is anthropic.claude-haiku-4-5 on Amazon Bedrock and claude-haiku-4-5@20251001 on Google Cloud. Those names do not work through Kumo.

In the Kumo catalogue a Claude model's canonical name carries the vendor prefix: anthropic/claude-opus-5-5. Every model also has aliases, and they are exactly Anthropic's IDs: claude-opus-5-5, plus the dated snapshot for models before 4.6. So code written for the Anthropic API can move to Kumo without touching the model string.

One exception today: Claude Sonnet 5 is listed as claude-sonnet-5 with no prefix, and anthropic/claude-sonnet-5 is its alias. Both names work. The name is matched literally and case-sensitively. If the string is neither a canonical name nor an alias, the gateway refuses at once, before anything is charged.

Every Claude model on Kumo is served over both the Anthropic Messages protocol and the OpenAI-compatible Chat Completions, under the same model name.

On Anthropic the list comes from GET /v1/models. The example from Anthropic's documentation:

The answer is a data array. Each model has id, display_name, max_input_tokens, max_tokens and lifecycle: active, deprecated or retired. Without the lifecycle parameter the list holds active and deprecated models; retired ones appear only when you ask for them explicitly. Newer models come first, a page holds 20 entries by default, and the limit parameter raises that to 1000.

Kumo serves the same path on its gateway: https://api.kumorouter.com/v1/models. A key is not required to read the list, but with a Kumo key the list may be narrowed to the models that key allows. The answer is OpenAI-shaped: object set to list and a data array. Each model has id (the canonical name), aliases, context_window_tokens, max_output_tokens and protocol_codes. The command below prints the Claude models with their aliases:

How to read the rest of the catalogue fields is described in the Kumo documentation.

Claude Code takes its main model from ANTHROPIC_MODEL and the four entries of its /model menu from ANTHROPIC_DEFAULT_FABLE_MODEL, ANTHROPIC_DEFAULT_OPUS_MODEL, ANTHROPIC_DEFAULT_SONNET_MODEL and ANTHROPIC_DEFAULT_HAIKU_MODEL. Through Kumo it looks like this:

The gateway address for the Anthropic protocol has no /v1. Some Claude Code releases name the auxiliary fast model ANTHROPIC_SMALL_FAST_MODEL instead of ANTHROPIC_DEFAULT_HAIKU_MODEL; check the docs of the release you have installed. The last line sends the auto mode classifier's requests through Kumo, and they are paid from your key. Details are in the Kumo Claude Code docs; a script that fills every slot in one command is described in the article about moving to the API.

In OpenAI-compatible clients (the OpenAI SDK, Cursor, Cline) the address is https://api.kumorouter.com/v1 and the model name goes into the model field:

In the Anthropic SDK and Messages-format requests the address is https://api.kumorouter.com and the key goes in the x-api-key header. This example uses the Anthropic alias, which Kumo accepts:

Kumo's answer to an unknown model name on the Anthropic Messages protocol:

On the OpenAI-compatible protocol the code is the same; only the envelope differs:

The nearest dates: Anthropic retires claude-sonnet-4-5-20250929 on 30 Nov 2026 and recommends claude-sonnet-5-5, while claude-opus-4-5-20251101 is promised not to be retired before 24 Nov 2026. Both models are still in the Kumo catalogue.

The four current Claude models on Kumo, with current prices: