ANTHROPIC

Anthropic received an export control directive at 5:21pm ET and had to disable Fable 5 and Mythos 5 for every customer. Here is what we know, what still works, and what to do if Fable is in your stack.

A narrow jailbreak that other models can match does not get a frontier model recalled. So what actually happened? The plausible explanations, ranked.

Claude agents vs skills, untangled: agents are workers with their own context window, skills are instructions loaded on demand. Here is the decision table.

Claude Code dynamic workflows turn orchestration into a JavaScript script that runs up to 1,000 agents per run - here is how scripts, schemas, budgets, and resume actually work.

Anthropic's docs say the tokenizer introduced with Opus 4.7 can use up to 35% more tokens for the same text. Here is what that does to per-request cost, max_tokens, and cross-model comparisons.

Fable 5 1M context workflows that actually work: whole-repo reviews, log archaeology, multi-doc synthesis - plus the honest math on when RAG still wins.

Fable 5 effort levels explained: what low, medium, high, xhigh and max change, which models support each, what each costs, and where the defaults differ.

Fable 5 long-running requests can run for many minutes per turn and hours per autonomous run. Here is how to configure client timeouts, streaming keepalive, batch polling, and background patterns so they actually finish.

Anthropic says persistent file-based memory improved Fable 5 three times more than it improved Opus 4.8. Here is the full memory tool setup - handlers, security, and context editing included.

A practical playbook for running Claude Fable 5 as the orchestrator over Sonnet and Haiku workers, with verified cost math on when the premium pays off.

Fable 5 prompt caching economics: cache-write vs cache-read pricing, 5-minute vs 1-hour TTL break-even math, and worked agent-loop examples.

Task budgets give Claude a token countdown for the whole agentic loop, so the model paces itself instead of discovering the limit when max_tokens truncates it. Here is how the beta works on Fable 5, what it does not enforce, and where it fits next to effort and the Usage API.

How to use Claude Fable 5 across every access path: claude.ai plans through June 22, the Claude API, Amazon Bedrock, Vertex AI, and Microsoft Foundry, with setup effort and first-prompt tips.

Claude Fable 5 latency measured: 109 seconds to first token at max effort vs 1.4s for Sonnet 4.6. When slow is fine, when it hurts, and how to route around it.

In one 48-hour window Anthropic shipped Fable 5, Dario Amodei called for FAA-style model testing, and the Anthropic Institute published internal data on AI building AI. Here is what recursive self-improvement actually means, and how far along the loop really is.

Rewriting prompts and skills for Fable 5: what changes when you migrate agents from Opus 4.x, how effort interplay works, and which old workarounds now hurt.

Ultracode is a prompt keyword that runs one task as a dynamic workflow, and an /effort setting that pairs xhigh reasoning with automatic orchestration.

Twelve documented Claude Fable 5 use patterns - agent orchestration, overnight runs, 1M-context refactors, effort tuning - each with a how-to seed and doc link.

Anthropic's first generally available Mythos-class model, released June 9, 2026. 1M context, 128K max output, $10/$50 per million tokens. Built for long-horizon agentic work.

Anthropic's recommended default for complex work, released May 28, 2026. 1M context, 128K output, $5/$25 per million tokens. Defaults to high effort on all surfaces.