Anthropic's Claude Fable 5 general model for demanding reasoning and long-horizon agentic work.
Anthropic's Fable 5 safeguard documentation requires 30-day safety retention and states that zero-data retention is unavailable, directly affecting regulated data and sensitive-code deployments.
ActionConfirm data classification with legal and security teams; choose another model when ZDR is mandatory.
Open sourceA preprint reported a 6.1% worst-case attack success rate for Fable 5 under its test setup. The figure applies only to that methodology and sample, not a general real-world risk rate.
ActionHigh-risk deployments still require independent red teaming and output isolation.
Open sourceOfficial integration guidance requires applications to detect stop_reason=refusal and retry through server-side, SDK, or manual fallback paths.
ActionIgnoring the refusal branch can misclassify a successful HTTP response as completed work.
Open sourceTechCrunch summarized reports from security researchers that some routine code-review and security-reading requests triggered Fable safeguards or fallback behavior.
ActionThis is feedback from a specific professional cohort, not all workloads; security teams should run workflow-specific trials.
Open sourceAccess was suspended on June 12 and restored globally on July 1. The interruption ended and is retained as a supply-continuity record.
ActionNo active outage response is required; retain provider-switching and model-fallback plans.
Open source| Company | Anthropic |
|---|---|
| Release | 2026-06-09 |
| Release type | Model release |
| Parameters | Not disclosed |
| Architecture | Not disclosed |
| Context | 1,000,000 |
| Input modalities | text / image |
| Output modalities | text |
| Tool use / function calling | Confirmed: Tool use, Function calling |
| Structured output / reasoning | Confirmed: Structured output, Reasoning |
| Vision / audio / video | Confirmed: Vision; Not shown: Audio, Video |
| Open weights / License | No open weights currently / weight license not disclosed anthropic-claude-fable-5-current · License not applicable |
| Vendor API | Available Introducing Claude Fable 5 and Claude Mythos 5anthropic-claude-fable-5-current · 2026-06-09 |
| OpenRouter | OpenRouter listed |
| Pricing | Official · 2026-06-09: $10 / $50 OpenRouter · 2026-08-11: $10 / $50 input / output, per 1M tokens |
| Benchmark | No reliable public source |
| Public signals | No reliable public source |
| Use cases | Long-horizon agents / Complex coding / Enterprise knowledge work / Vision analysis |
| Claim evidence | Release event / Model specificationsIntroducing Claude Fable 5 and Claude Mythos 5claude-fable-5 · 2026-06-09 · Claude Fable 5 · claude-fable-5 OpenRouter context / capabilities / pricingOpenRouter public models APIanthropic/claude-fable-5 · 2026-08-11T06:28:09.895Z |
| OpenRouter | OpenRouter listed |
|---|---|
| OpenRouter listing | anthropic/claude-fable-5 |
| Mapped version | claude-fable-5 anthropic-claude-fable-5-current |
| Pricing | Official · 2026-06-09: $10 / $50 OpenRouter · 2026-08-11: $10 / $50 input / output, per 1M tokens |
| Context | 1000000 |
| Speed/Latency | No reliable public source |
| Snapshot time | 2026-08-11T06:28:09.895Z |
| Source | View source |
| Source | Model / version | Metric | Rank | Value | Checked | Link |
|---|---|---|---|---|---|---|
| OpenRouter | Anthropic: Claude Fable 5 0609 anthropic-claude-fable-5-current | Weekly token usage on OpenRouter public rankings API | 38 | 226,192,932,974 tokens | 2026-08-11 | View source |
OpenRouter weekly prompt-plus-completion token usage only; this is not a model-quality or whole-market ranking.