Tier above Opus
Anthropic places Mythos-class models, including Fable, above its Opus class in capability. Use it for the hardest reasoning, planning and review steps in your stack.
The Claude Fable 5 API, Anthropic's first Fable model, at 65% below list price.
claude-fable-5Updated from openai import OpenAIclient = OpenAI( base_url="https://api.zurelay.com/v1", api_key="YOUR_ZURELAY_KEY",)stream = client.chat.completions.create( model="claude-fable-5", messages=[ {"role": "user", "content": "Explain quicksort briefly."}, ], stream=True,)for chunk in stream: if chunk.choices: print(chunk.choices[0].delta.content or "", end="")Base URL https://api.zurelay.com/v1. Works with any OpenAI SDK, and the Anthropic SDK and Claude Code. Chat API docs
Pricing
Pay as you go from prepaid credit, with no subscription. Top up from $10. Requests that fail are never billed.
| Rate | Zurelay | Anthropic list | You save |
|---|---|---|---|
Input per 1M tokens | $3.50 | 65%off | |
Output per 1M tokens | $17.50 | 65%off | |
Cached input per 1M tokens | $0.35 | 65%off | |
Cache writes (5 min) per 1M tokens | $4.375 | 65%off | |
Cache writes (1 h) per 1M tokens | $7.00 | 65%off |
One rate at every prompt length, up to the full 1M context window. Streaming, tool calls and structured outputs cost nothing extra.
Every Claude model and priceMove the sliders to your monthly usage.
$7,800 a year
Cost
Typical workloads at Zurelay's live prices next to the list price, and what other places charge for the same model.
50,000 requests a month, 1,500 tokens in and 300 out, 30% of the input cached. $0.00908 a request.
20,000 requests a month, 8,000 tokens in and 500 out, 20% of the input cached. $0.0317 a request.
5,000 requests a month, 40,000 tokens in and 1,500 out, 85% of the input cached. $0.0592 a request.
1,000,000 requests a month, 400 tokens in and 5 out. $0.00149 a request.
Prices per 1M tokens
| Seller | Input | Output | vs Anthropic |
|---|---|---|---|
Anthropic List price, direct | $10.00 | $50.00 | — |
List price, plus 5.5% on card top-ups | $10.00 | $50.00 | +5.5% |
Zurelay No fee to add credit | $3.50 | $17.50 | 65%off |
OpenRouter's fee as its pricing page listed it on October 28, 2026. Zurelay's prices are live. Some labs also discount batch or off-peak requests.
Overview
Claude Fable 5 is Anthropic's first Fable model, part of the Mythos-class tier that Anthropic places above Opus in capability. The Zurelay Claude Fable 5 API serves it through OpenAI-compatible and Anthropic-compatible endpoints at 65% below Anthropic's list price. It suits teams that tuned prompts and evals on Fable 5 and want to keep them running for less.
Claude Fable 5 launched on June 9, 2026 as the first model in Anthropic's Fable line. Anthropic calls it a Mythos-class model made safe for general use, and says Mythos-class models sit above its Opus class in capability. It is built for demanding reasoning and long-horizon agentic work. On Zurelay, the Claude Fable 5 API uses the model ID claude-fable-5 and costs $3.50 per 1M input tokens and $17.50 per 1M output tokens.
The specs: a 1M-token context window by default, up to 128K output tokens per request, text and image input, and text output. Its reliable knowledge cutoff is January 2026. Adaptive thinking is always on and cannot be disabled, and the raw chain of thought is never returned. You steer depth, latency and cost with effort: low, medium, high (the default), xhigh or max. Anthropic says Fable 5 at lower effort still performs well and often beats earlier models running at xhigh.
Claude Fable 5.1 replaced it on September 1, 2026, Claude Fable 5.2 followed on November 9, 2026, and Anthropic now lists Fable 5 as a legacy model. Legacy means it is still served but no longer updated, with retirement no sooner than June 9, 2027. There are practical reasons to stay on it: Fable 5 accepts forced tool choice, which Fable 5.1 and 5.2 reject, and in agent loops it tends to batch several tool calls per turn where Fable 5.1 may issue one at a time.
A few API rules apply. Sampling parameters (temperature, top_p, top_k) have no effect, so Zurelay leaves them out of the request, and prefilling the assistant reply returns an error. Anthropic runs safety classifiers on Fable 5 that can decline some requests in areas such as cybersecurity and biology, and says more than 95% of Fable sessions involve no fallback at all. Prompt caching works from a 512-token minimum prompt.
Strengths
Anthropic places Mythos-class models, including Fable, above its Opus class in capability. Use it for the hardest reasoning, planning and review steps in your stack.
Built for long-running agentic work. Anthropic says Fable 5 stays focused across millions of tokens in long-running tasks.
Adaptive thinking is always on, and effort sets how hard it works. Anthropic says lower effort on Fable 5 often beats earlier models at xhigh, so test low and medium first.
As a legacy model, Fable 5 gets no further updates, so prompts and evals tuned on it keep behaving the same until you choose to move.
Use cases
Keep production prompts and evals tuned on Fable 5 while cutting the per-token bill, then move to Fable 5.2 on your own schedule.
Workflows that force a specific tool call with tool_choice get a true forced call on Fable 5. Anthropic's API rejects forced tool use on Fable 5.1 and 5.2, where Zurelay can only ask the model to call the tool.
Load a big repository or document collection into the 1M-token window and ask for analysis, plans or migrations across all of it.
Anthropic names software engineering, knowledge work, vision and life sciences research as Fable 5's strongest areas.
Get started
No waitlist and no new SDK. If your code already talks to OpenAI, it already talks to Zurelay.
Sign up, add credit and create an API key. Set a monthly budget or a rate limit per key if you like.
Change the base URL. Everything else in your code stays the same.
https://api.zurelay.com/v1Send chat completions as usual. Streaming, tool calls and usage reporting work as you expect.
claude-fable-5Works with the tools you already use
Compare
$3.20 / $16.00 per 1M tokens
Pick Claude Fable 5.2 for new work: it is Anthropic's newest Fable model, stronger at coding, reasoning and vision, at a list price 20% lower per token.
Claude Fable 5.2 API$1.40 / $7.00 per 1M tokens
Pick Claude Opus 5.5 for most workloads at a lower price; Anthropic suggests starting there and moving up to Fable only when your evals fall short.
Claude Opus 5.5 API$0.79 / $3.95 per 1M tokens
Pick Claude Sonnet 5.5 for fast, well-scoped tasks where latency and cost matter more than peak reasoning.
Claude Sonnet 5.5 APIZurelay charges $3.50 per 1M input tokens and $17.50 per 1M output tokens, with cached input at $0.35. Anthropic's list price is $10.00 input and $50.00 output, so you save 65%. The rate is the same at every prompt length, up to the full 1M-token window.
Yes. Zurelay serves claude-fable-5 at 65% below Anthropic's list price, paid from prepaid credit with no subscription. It is the same model, not a smaller substitute. You keep your code and change the base URL and key.
Create a Zurelay API key, set the base URL to https://api.zurelay.com/v1 and set the model to claude-fable-5. Chat completions, streaming and tool calls use the request shapes you know from OpenAI. Temperature and top_p have no effect: Fable 5 refuses them, so Zurelay leaves them out of the request.
Yes. Zurelay also serves the Anthropic Messages API. Set the Anthropic SDK's base URL, or ANTHROPIC_BASE_URL for Claude Code, to https://api.zurelay.com with no /v1, because the client adds /v1/messages itself. Authenticate with your Zurelay key and choose claude-fable-5 as the model.
For new work, use Claude Fable 5.2, the newest Fable model: Anthropic reports gains in coding, reasoning and vision at a list price 20% lower per token. Stay on Fable 5 if your code forces tool choice, which Fable 5.1 and 5.2 reject, or if you need results that match evals you already ran.
Claude Fable 5 has a 1M-token context window and returns up to 128K output tokens per request. Thinking counts toward the output limit, so set a large max_tokens at high effort and stream long responses.
No. Anthropic lists Claude Fable 5 as a legacy model: still active, no longer updated, with retirement no sooner than June 9, 2027. Claude Fable 5.1 succeeded it, and Claude Fable 5.2 is the newest Fable model.
Yes. Streaming works on chat completions and on the Messages API; on chat completions, set stream_options.include_usage to get token counts at the end of the stream. Each key can have its own monthly budget and requests-per-minute cap. If a route fails, Zurelay retries on another route, and failed requests are never billed.
Yes. Your requests run on Claude Fable 5 itself. Zurelay doesn't swap in a different or smaller model. Only smart routing, which you turn on yourself, can answer with a close alternative when the model is down, and the x-zurelay-model header names the model that answered. Output is sampled, so exact wording varies between calls on any API. Zurelay is an independent service and is not affiliated with or endorsed by Anthropic.
Create a key in seconds, point the SDK you already use at Zurelay, and every request costs up to 90% less from the first token.