What is Claude Fable 5.2?
Claude Fable 5.2 is Anthropic's model for long-running agents, deep research and finished documents, released November 9, 2026. The API ID is claude-fable-5-2. It costs $8 per million input tokens and $40 per million output, down from $10 and $50 on Fable 5.1, with an optional fast mode at $16 and $80. Anthropic recommends starting with Claude Opus 5.5 for most work and moving to Fable 5.2 when Opus at higher effort still falls short.
What you use Fable 5.2 for
Anthropic's documentation describes Claude Fable 5.2 as built for demanding reasoning and long-horizon agentic work, including agent sessions that run for hours, multistep deep research, and analysis finished as a document, spreadsheet or deck. The November 9 announcement says Fable and Mythos are the same underlying model; Fable adds cybersecurity and biology safeguards so it can be offered to all users, while Mythos 5.2 is for organizations in Anthropic's Life Sciences or Cyber Verification Programs and shares the same specs and price.
Anthropic still positions Opus 5.5 as the starting point for most coding and knowledge tasks, with Fable 5.2 as a step up for more ambitious work, or as an Advisor or Orchestrator for other Claude models. The announcement also reports that the new models generate outputs up to 30% faster than Fable 5.1. That speed claim is Anthropic's.
Plans, prices and access
On the Claude API the model ID is claude-fable-5-2. Docs list $8 per million input tokens and $40 per million output, with 5-minute cache writes at $10, one-hour cache writes at $16, cache reads at $0.20, and a 50% Batch API discount. Fast mode costs $16 input and $80 output per million tokens and, according to the announcement, speeds up token generation by up to 2.5 times. It is available on Claude Code, in Messages API requests on the Claude API, on Claude Models on Google Cloud, and on Microsoft Foundry for Anthropic-hosted deployments as claude-fable-5-2-fast. Context is 1M tokens, max output 128K, default effort high, latency class Moderate, knowledge cutoff June 2026, and retirement not sooner than November 9, 2027. Fable 5.2 requires 30-day data retention unless Anthropic authorizes otherwise.
In the Claude apps, Anthropic's pricing page lists Fable as available through usage credits on Pro and included for up to half of weekly limits on Max and Ultra. A launch offer, documented in Claude Help and running from November 9, 2026, gives Pro plans and standard Team seats one week of Fable included up to 50% of weekly limits through November 16, plus one Fable reset; Max, Ultra and some premium seats get one to three resets based on subscription length, expiring March 8, 2027. Offers do not apply to Free or several Enterprise types. After the week, Fable on Pro returns to usage credits.
A first workflow to try
Suggested workflow: take a task where Claude Opus 5.5 at high or max effort already missed your checks, such as a research memo that must reconcile conflicting sources. Run the same prompt and files on claude-fable-5-2 at its default high effort, then score both with the same checklist, for example correct citations, no unsupported numbers and every source addressed, and note token counts and cost. Switch only if Fable 5.2 passes checks that Opus missed. If you migrate from Fable 5.1, read Anthropic's What's new page first: four changes can break existing code, including prefix checks on thinking blocks for every account. AppFor.ai has not run this comparison.
Fable 5.2 or Opus 5.5?
The two models share a 1M context window, 128K max output and June 2026 knowledge cutoff. Opus lists $4 input and $20 output per million tokens with default effort medium; Fable 5.2 lists $8 and $40 with default effort high, twice the token price of Opus and 20% below Fable 5.1's $10 and $50. Both have Moderate latency in the current docs table. Anthropic's own FrontierSWE v2 scores are 69.9% for Fable 5.2 and 62.3% for Opus 5.5; those are vendor results. For most daily work, Anthropic still says to start with Opus 5.5.
What stands out
- 1M-token context window and 128K max output
- Adaptive thinking always on, default effort high
- Optional fast mode for up to 2.5x token generation, at 2x standard prices
- Same underlying model as Claude Mythos 5.2, which is limited to verified organizations
- Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry and Claude Platform on AWS
Before you choose
- Anthropic recommends starting with Opus 5.5 for most workloads.
- Launch offers on Claude apps are time-limited; confirm dates in Claude Help.
- Four breaking changes can affect Fable 5.1 integrations.
- Benchmark and speed claims come from Anthropic, not independent tests.
- AppFor.ai has not called the Fable 5.2 API.
Go to the source
Sources & further reading
Based on the official documentation below. Features and access can change; check the provider before making a decision.
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