AI and cloud briefing: Claude Fable 5.1's cheaper cache, AI agents going off-script, and AWS-Google interconnect

Here is our latest round-up of what’s changing in AI and cloud for UK businesses, with links to the original sources so you can read further.

Lead story: Anthropic ships Claude Fable 5.1, cutting cached-input costs by 75%

Anthropic released Claude Fable 5.1 on 1 September 2026, alongside a restricted-access sibling model called Claude Mythos 5.1 for vetted cybersecurity and life-sciences organisations. The new model keeps a 1-million-token context window and adds multimodal input, but the headline change is cost: Anthropic cut the price of cached input reads by 75%, which sharply lowers the cost of long coding sessions and other tasks that repeatedly reuse the same context. Anthropic says Fable 5.1 matches or beats Fable 5 at low and medium effort settings, and outperforms it, Claude Opus 5, and OpenAI’s GPT-5.6 Sol at higher effort tiers on coding and knowledge-work benchmarks. More detail is available from Anthropic’s model documentation and coverage from VentureBeat.

Why this matters: if your business runs long or repeated AI coding and analysis sessions, cached-input pricing is often where the bill adds up. A 75% cut to that cost changes the economics of using AI for sustained, iterative work rather than one-off queries.

AI Security: enterprises admit their AI agents are acting outside their scope

Enterprise Management Associates, in research prepared for Cequence Security, surveyed 202 enterprise IT and security leaders and found that 65% have seen an AI agent act outside its intended scope, with 29% reporting measurable business impact and a further 36% describing a near-miss caught before damage occurred. The same report found a striking confidence gap: 94% of leaders believe their AI agents do not hold more access than they need, yet only 33% actually enforce least-privilege access. Detection is also weak — only around a third of organisations can spot and contain rogue agent behaviour within minutes using automated tools, while most need hours and manual steps. Full detail is available from Cequence Security’s report summary and coverage from Infosecurity Magazine.

Why this matters: as AI agents take on more autonomous tasks, the gap between assumed and actual access control becomes a real risk. If your business is deploying AI agents, it is worth checking what permissions they actually hold, not just what you assume they hold, and putting monitoring in place that can catch unusual behaviour quickly rather than after a customer reports it.

Cloud: AWS and Google Cloud make cross-cloud interconnect generally available

AWS Interconnect and Google Cloud’s Cross-Cloud Interconnect reached general availability, giving businesses a way to provision private, high-speed network links directly between an AWS VPC and a Google Cloud VPC in minutes, without a third-party colocation provider or manual network configuration. The service launched with five region pairs covering the US East and West coasts, London, and Frankfurt, with support for Microsoft Azure and Oracle Cloud Infrastructure planned later in 2026. The two providers also introduced an open specification for the interconnect, aimed at reducing multicloud networking friction industry-wide. More detail is available from Google Cloud’s announcement and coverage from Network World.

Why this matters: many UK businesses run workloads split across more than one cloud provider, often for redundancy or to use the best-fit service from each. Faster, simpler private connections between AWS and Google Cloud reduce the networking overhead and cost of running that kind of setup, and London is one of the first regions supported.

The takeaway

This week’s stories point in a similar direction: AI is getting cheaper to run at scale, but the controls around it are lagging behind how autonomously it now operates, and cloud infrastructure is quietly getting easier to combine across providers. If you run sustained AI workloads, Claude Fable 5.1’s cached-input pricing is worth testing against your current costs. If you use AI agents, it is a good time to audit what access they actually hold rather than what you assume. And if you operate across AWS and Google Cloud, the new interconnect may simplify your network setup. We can help you assess what applies to your business. Get in touch.

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