Anthropic / Claude

A system prompt template merged into OpenAI's open-source codex repo in late August reveals how Codex Persistent mode actually works: it's not a 24/7 always-on process, but a wake-check-sleep loop every 1–3 minutes. The template requires the agent to record its goal, latest status, completion condition, and next check time before sleeping, then decide what to do upon waking. One hard rule: persistence does not broaden authorization scope—anything beyond scope requires explicit permission. WIRED reported on this mode earlier, but media headlines saying 'always-on' clash with the code's 'sampled again' language. OpenAI hasn't launched it yet; the backend request still shows 'disabled.' ProAgentBench shows models achieve only 64.4% accuracy in judging when to proactively help, and Anthropic's engineering blog reports a 17% miss rate on real overreach during automated review—two numbers that explain the hold. Tasks suited for it are delivery-type jobs like CI, deployment, and builds that execute for one minute and wait for ten. Open-ended tasks like writing proposals or designs are a bad fit. Three discipline rules from the template can be adopted today: write four-element checkpoints, stay silent when nothing has changed, and prefer deterministic mechanisms.

Claude Cowork and Claude Code can now take over your computer in the background—clicking, typing, opening apps—while you switch to other tasks. The post doesn't disclose latency, permission boundaries, or supported operating systems.

Anthropic's post explains how to turn models like Claude into commerce agents that actually work in production, focusing on architecture, latency, and cost. They also open-sourced a reference implementation called commerce-agents. The full article body isn't available yet—only the title and lede are shown—so specific architecture details, latency figures, and cost breakdowns are still missing.

Anthropic launched Claude Fable 5.1 and Mythos 5.1 on Sep 1, claiming SOTA on coding and knowledge work. Fable 5.1 hits 55.8% on Terminal-Bench 4.0 and is pitched for autonomous multi-step tasks. Cache read price dropped 75% to $0.25/MTok, but Artificial Analysis found output tokens rose 1.7x, netting a ~20% per-task cost increase. Community speculation suggests Fable and Mythos may share weights with different safety routing—the post doesn't confirm this. Early praise for coding ability is offset by complaints about rate limits, false safeguard triggers, and subscription UX.

Community members ran two-month SBS comparisons and a week-long 5.1B-token workload on DSH + DeepSeek V4 Flash, concluding it feels better than GPT-5.6 Sol in real tasks. Sol overthinks and produces bloated output; V4 Flash is fast (2.3s first token) and cost ¥362.84 total. A 'subscription gym paradox' theory argues subscription-based harnesses quietly throttle usage while pay-per-token models don't. Anthropic launched Fable 5.1 with 75% cheaper cache reads, but Fable 5 scored below Opus 5. Also: Astra hits Critical cybersecurity tier, Anthropic's $35B compute deal, Qwen 3.8-Max-0902 benchmark run, Microsoft AI secretary setup, and Grok Bot hands-on.

Simon Willison ran his classic 'SVG of a pelican riding a bicycle' prompt against Claude Fable 5.1 at five reasoning levels. Low and medium produced near-identical outputs with no visible reasoning, taking ~23 seconds and ~10 cents. At xhigh the model spent 7m51s and $1.83, adding real detail. Max ran for 13m54s and $3.30, delivering his best Anthropic pelican yet—blue hat, basket with a fish, feet on pedals—though he still says it lacks the flair of Gemini 3.7 Flash. Separately, Fable 5.1 hit 52.6% on the new Terminal-Bench-Science 0.1 benchmark, up from 24.7% for Fable 5.

A long-time Claude Max subscriber at $200/month got banned overnight with a template email citing "suspicious signals" — no clause, no example, no human appeal path. A colleague in the Philippines was banned right after paying $100 for Max. GitHub issues show similar cases in Brazil, Singapore, and Malaysia, some hitting multiple linked accounts within hours of upgrading. The author argues Anthropic's enforcement feels like 2010s Google account bans: automated, opaque, and disproportionately painful for individuals who depend on the product. Enterprise customers get account managers; Max users get a no-reply address and a reference ID. The author filed an appeal but no longer trusts a single frontier lab with their entire workflow, and plans to diversify across other providers and open-weight models.

Anthropic released Fable 5.1 and Mythos 5.1, directly addressing customer complaints about cost, data retention, and overzealous safeguards. Fable 5.1 outperforms Fable 5 while costing ~25% less typically and up to 45% less for complex agentic tasks, driven by lower pricing on cached data. Every CEO Dan Shipper called it the strongest coding model they've used, now fast, token-efficient, and speaking like a normal person. The post doesn't spell out Mythos 5.1 specs or detailed pricing.

OpenAI shared safety details on Astra, its first LLM to hit a 'critical cybersecurity threshold.' Astra can find and exploit unknown security flaws without human guidance. OpenAI plans to release it soon but will limit access to its most advanced cyber capabilities. This mirrors concerns Anthropic raised about its Mythos model earlier this year.

Artificial Analysis tested Claude Fable 5.1 at max effort and it scored 66, hitting #1 on their Intelligence Index. The trade-off: per-task cost is 20% higher than Fable 5. The post doesn't break down task types or latency—just the headline and a one-line result.

Anthropic bumped Fable and Mythos to 5.1. Fable 5.1 is now cheaper and triggers fewer false-positive safety refusals; it's live today on cloud platforms and the API. Mythos 5.1 remains restricted to registered cybersecurity and life sciences partners. A key change is zero data retention—clients can run the model on their own infra with no data outflows, rolling out this fall. The post doesn't disclose specific price cuts or benchmark comparisons.

The author rewrote a 65k-line terminal editor from Go to Rust using Fable 5 for $400. The method has three steps: extract code into a data representation (state machines, graphs, formulas), operate on that representation, then regenerate code in the target language. Fable's precise data-flow tracing is the key enabler. The post doesn't report compilation pass rate or test coverage, so I'd discount the 'fully autonomous' claim until those numbers surface.

Anthropic released Claude Fable 5.1 on OpenRouter as a direct upgrade to Fable 5. The focus areas are agentic coding, long-running workflows, visual code generation, finance, and analytics. The post doesn't disclose benchmark numbers or pricing changes, so I'd wait for third-party evals.

Anthropic shipped Claude Fable 5.1 and Mythos 5.1 together. Pricing matches Fable 5, but API cache reads are 75% cheaper. The model stays autonomous longer on long tasks, flags when it's stuck more proactively, and writes more naturally. The post doesn't disclose latency, context window, or benchmark scores—I'd discount the 'most advanced' claim until numbers land.

Anthropic released two models, Fable 5.1 and Mythos 5.1—same underlying model, different safeguards. Fable 5.1 is generally available; Mythos 5.1 is gated behind trusted access programs for cybersecurity and life sciences. Fable 5.1 beats Fable 5 across coding, knowledge work, and long-horizon tasks, while costing ~25% less on typical workloads and up to ~45% less on highly agentic work. Enterprise Frontier Safeguards (EFS) will let customers keep data in their own cloud infra, rolling out in phases from fall 2026; until then, eligible customers get zero data retention. Cybersecurity false positives dropped 60%, and the model can discover vulnerabilities but not build exploits. The post does not disclose parameter count, context window, or training details.

Anthropic updated its platform docs for Claude Fable 5.1. Pricing matches Fable 5, with cache reads at a quarter of the cost. The focus is stronger long-running agentic coding, multistep research, and document, spreadsheet, and slide work. Three breaking changes: forced tool use now errors, earlier models can't read its thinking blocks, and editing earlier turns invalidates thinking blocks. Five additive features include mid-conversation effort changes, turn-scoped system messages, and readable progress between tool calls—some marked beta. The post doesn't include benchmark scores or latency figures.

Boris from Anthropic walked through Claude Code's full origin story on Lenny's podcast—the internal launch post got just 2 likes. The team used an 'underfund' principle: deliberately starve projects of headcount but give them unlimited tokens, forcing everything to be 'Claudified.' Boris hasn't manually written a line of code since last November. Separately, ChatGPT Ads hit a $1B annualized run rate in under 200 days, but the analysis argues agents and ads are fundamentally at odds—agents compress decision steps that ads depend on. The group also debated whether solo builders beat teams, using Overcooked as the litmus test.

Anthropic released Enterprise Frontier Safeguards (EFS), which pairs zero data retention (ZDR) privacy with safety monitoring for abuse detection. Data sits in the customer's own cloud infrastructure rather than at Anthropic.

In April 2026, Salesforce opened its entire platform to AI agents via Headless 360 and hosted MCP servers. Over the next four months, almost no enterprise adopted it—developers hit config errors, per-user auth bottlenecks, and missing docs. In August, the same underlying capabilities relaunched as Claudeforce, a Claude plugin with 37 sales-specific skills, one-click admin setup, inherited permissions, and native embedding in the Claude UI. The stock jumped 23% on announcement day, though earnings and a short squeeze drove most of it. The product enters public beta in September; pricing and named external customers are still missing. The article frames the gap as a four-layer stack—interface, semantics, governance, distribution—and argues April only delivered the first layer.

Anthropic released Claude Fable 5.1 (successor to Fable 5 for long-running coding and research) and Mythos 5.1 (Project Glasswing only). Both default to 1M context, 128k max output, and the same $10/$50 per MTok pricing as Fable 5. The standout change: cache reads are now $0.25/MTok—2.5% of base input price, far cheaper than other models. tool_choice drops 'any' and 'tool' modes; thinking blocks only work with same-gen or newer models; text watermarking and C2PA credentials are on by default. The post doesn't include benchmark scores or performance comparisons.