Distinguished engineer at AWS. AI, agents, databases, and serverless. Views are my own.
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Firecracker is intentionally feature-light.
There are a lot of alternatives with richer feature sets (notably QEMU), many of which predate Firecracker. But small has its advantages, both in security and density.
i still do not understand why so many sandboxes use firecracker
apart from being trendy, it lacks clear features like vfio-pci passthrough, virtio-fs or live migrations
AI made it possible for a lot of people to roll infrastructure. But good infra will still differentiate.
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The Strands Harness team wrote a deeper dive on how we compared our harness to alternatives, running over 94,000 trials, achieving 34% lower cost on average.
Don't miss it: strandsagents.com/blog/we-ra…
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Looking for a great new decider model? Today, we're pleased to share four new strands-decider variants: more accurate, and better calibrated.
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Check them out on HuggingFace: huggingface.co/StrandsAgents
And GitHub: github.com/strands-labs/stra…
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I love virtualization. You can see my name on the Firecracker paper. I've written a bare metal VMM using the CPU manuals (not a very good one, but it works). We picked it for AgentCore Runtime.
So why didn't we pick virtualization for Strands Box?
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Marc Brooker retweeted
Another day, another release from the Strands team! Strands Box was just released as a developer preview.
Most sandboxes are just about what files can be read and if there is network access. This isn't enough granularity for many uses though. Strands Box uses kernel isolation to make a user-space policy layer the only way out of the isolation. This is enforced with Dogwood rules for shell use, Python, MCP and network access. One example shown is for git push being blocked unless npm test recently passed.
Check this out from @MarcJBrooker. If you haven't already checked out Strands, give it a try.
lckhd.eu/DXfzKZ
#Agents #AgentSecurity #Sandboxing #StrandsAgents #AWS
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A few ways:
1/ What it's for. AgentCore Runtime (the 'sandbox') is for running agents in the cloud, providing scalable, secure, highly available compute infrastructure.
Strands Box is a local sandbox, running on whatever compute you already have (e.g. your laptop).
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5/ Size of the TCB. AgentCore Runtime's is quite small (Firecracker, KVM).
Strands Box's is quite big (host kernel, Python and Shell runtimes, Box's policy layer, etc).
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This is one of the core reasons we released a developer preview: for complex local tools like git, command line filtering is hard to get right. A richer model of what git is doing makes writing simple correct policy easier, and we're working on just that.
the git push example also lets git commit -a through: it stages edits made after npm test without a git add, so nothing resets the window. keying it on any file write under the project since the passing test would close that
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