Is Claude Fable 5 still available? The suspension, the return, and what it means for API users

Yes. Claude Fable 5 is available again and can be called today with the model ID claude-fable-5. Anthropic suspended it for all users on June 12, 2026, after a US government export control directive, and restored it on July 1, 2026, once the controls were lifted. Anthropic now lists it as "Active (legacy)", with Claude Fable 5.1 as the current Fable model.

On SeedRouter, both claude-fable-5 and claude-fable-5-1 can be called with one API key.

Why was Claude Fable 5 suspended?

On June 12, 2026, three days after launch, the US government issued an export control directive covering Claude Fable 5 and Claude Mythos 5. In Anthropic's statement that day, the directive suspended "all access to Fable 5 and Mythos 5 by any foreign national, whether inside or outside the United States."

Anthropic had no reliable way to check nationality in real time, so it disabled both models for every customer. Access to its other models was not affected.

According to Anthropic's later account, the directive followed a report by Amazon researchers who had found a way around Fable 5's safeguards: prompting it to identify software vulnerabilities, and in one case to produce code demonstrating an exploit. Anthropic's testing found that many less capable models, including Claude Opus 4.8, could find the same vulnerabilities.

When did Claude Fable 5 come back?

Before the return, Anthropic and the government trained a new safety classifier that, in Anthropic's words, blocks the reported technique "in over 99% of cases." Anthropic also notes the trade-off: the classifier flags benign requests more often during routine coding and debugging.

Is Claude Fable 5 available right now?

Yes. Anthropic's Claude Fable 5 model page lists it as "Active (legacy)", with retirement "not sooner than June 9, 2027". Legacy means it still runs, but Anthropic recommends Claude Fable 5.1 for new work.

Through SeedRouter you reach it at https://api.seedrouter.ai with the Anthropic Messages format, or with the OpenAI Chat Completions and Responses formats:

curl https://api.seedrouter.ai/v1/messages \
  -H "x-api-key: $SEEDROUTER_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-fable-5",
    "max_tokens": 4096,
    "messages": [{"role": "user", "content": "Hello, Claude Fable 5."}]
  }'

The Claude Fable 5.1 API guide walks through keys and SDK setup; the steps are the same for Fable 5.

Should I use Claude Fable 5 or Claude Fable 5.1?

For new work, Claude Fable 5.1. It has the same input and output prices, cache reads at a quarter of the cost, a later knowledge cutoff (June 2026 against January 2026), and higher scores on every benchmark in Anthropic's launch table.

Keep Claude Fable 5 if your code forces a tool call with tool_choice set to any or tool. Claude Fable 5.1 rejects that; Claude Fable 5 still accepts it. The Fable 5.1 vs Fable 5 vs Opus 5.5 comparison covers the other differences.

Why does Claude Fable 5 sometimes refuse a request?

Anthropic runs safety classifiers on the Fable models, tuned with what it calls a "safety margin": some requests that are probably harmless, especially around cybersecurity, are still declined. When that happens over the API, the response ends with stop_reason: "refusal" instead of an answer. Anthropic's guidance is to handle that stop reason in code and, where it fits, retry on another Claude model.

Frequently asked questions

Was Claude Fable 5 banned?

It was suspended, not banned permanently. The June 12 export control directive led Anthropic to disable it for all users, and it returned on July 1, 2026, after the controls were lifted on June 30.

Is Claude Fable 5 available in Europe?

Anthropic's July 1 restoration was global, for users of the Claude Platform, Claude.ai, Claude Code and Claude Cowork.

Will Claude Fable 5 be retired?

Anthropic commits to keeping it running until at least June 9, 2027. Its successor, Claude Fable 5.1, is committed until at least September 1, 2027.

Is Claude Mythos 5 available too?

Only to invited organizations. Anthropic restored Mythos 5 for a set of US organizations after government approval on June 26, 2026. SeedRouter does not sell Claude Mythos models.

Call Claude Fable 5 today

Try a prompt on the Claude Fable 5 page, compare it with Claude Fable 5.1, and see the Claude Fable 5 API reference for every request field.