Greywall
Kernel-enforced sandbox with live activity feed for AI coding agents
Greywall is the most practical kernel-level guardrail I've seen for local AI agents. The live activity feed and opt-in deny rules are genuinely useful, and it's free for the core. For teams needing SSO or managed governance today, wait—that layer is still on the roadmap. Compared to container sandboxes like Docker-based isolation, Greywall is lighter and less disruptive.
Verified 1d ago · liveness 72/100 · cite: rightaichoice.com/tools/greywall
- Developers using AI coding agents who want to prevent accidental leaks of API keys, .env files, or SSH keys.
- Teams enforcing security boundaries for agent actions without sacrificing speed or requiring container setup.
- Solo developers who want observability into what agents are reading and writing in real time.
- Platform engineers evaluating lightweight, kernel-enforced sandboxing for agent workflows.
- Users who need full container or VM isolation—Greywall is kernel-enforced but not a container.
- Non-developer users who don't run CLI agents.
- Windows users—only Linux and macOS are supported.
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Skip Greywall if you need full container or VM isolation, or if you're on Windows—it's a kernel-enforced sandbox for Linux and macOS only, and it's not a substitute for heavy-duty containment.
No hidden costs in the open-source core—it's free. The managed governance layer (SSO, team rulesets) is under development, so if you need those enterprise features today, you'll have to wait or use a different tool.
Greywall's open-source core is free for individuals and small teams, making it a cost-effective alternative to commercial agent monitoring tools. For enterprise governance (SSO, team rulesets), you'll need to wait for the paid managed layer or consider alternatives like Docker-based sandboxes that may have subscription costs.
In short
Greywall — Kernel-enforced sandbox with live activity feed for AI coding agents. Best for Developers using AI coding agents who want to prevent accidental leaks of API keys, .env files, or SSH keys., Teams enforcing security boundaries for agent actions without sacrificing speed or requiring container setup., Solo developers who want observability into what agents are reading and writing in real time.. Free to use.
What's new in Greywall
Checked yesterdayAcross the latest 1 update: 1 changelog entry.
What people actually say about Greywall — is it worth it?
We ran a structured research pass across product reviews, community discussions, and post-purchase forum threads to surface the patterns vendors won't publish themselves. Below: the recurring strengths, the hidden costs people mention most, and the cohort that consistently regrets adopting this tool.
17 mentions across 2 sources (Hacker News, GitHub) · researched Jul 3, 2026.
- +Kernel-level sandboxing provides stronger isolation than container or VM approaches.
- +Deny-by-default policy prevents agents from accessing sensitive files like .env and SSH keys.
- +Live activity feed shows every read, write, and network request in real time.
- +Supports any CLI agent without modifications, including Claude Code, Codex, and Cursor.
- +Zero config for common development directories reduces setup time.
- −Very early-stage with only ~250 GitHub stars and 22 open issues.
- −A user reported it could be forkbombed by a compromised package, raising reliability doubts.
- −Limited community presence outside Hacker News and GitHub makes support uncertain.
- −No official documentation or tutorials beyond the GitHub repo and website.
- −Cross-platform support may have gaps; macOS implementation relies on Endpoint Security.
Viability Score
How well maintained and how widely used is Greywall? Built from what the vendor actually publishes (docs, changelog, tutorials, integrations, pricing), whether the site is live, and how much real users discuss it. How we calculate this
Last calculated: September 2026
How we score →Key Features
- Live activity feed logs every read, write, and connection in real time
- Kernel-enforced filesystem sandboxing with per-path allow/deny rules
- Network isolation via TUN + SOCKS5 proxy, captures all TCP/UDP traffic
- Seccomp BPF syscall filtering blocks 27+ dangerous system calls
- eBPF monitoring traces syscall exits for full visibility
- Landlock filesystem control enforces granular read/write permissions
- Bubblewrap namespaces isolate process, network, and mount environments
- Switch to ask or deny mode mid-session without restarting
- Deny rules for filesystem paths, network hosts, and commands
- Command blocking works inside pipes, chains, and nested shells
- Learning mode auto-generates least-privilege templates via strace
- Safe defaults deny SSH keys, .env files, and shell configs
- One-line install via Homebrew, curl, Go install, or source
- Works with any local CLI agent without agent-specific config
About Greywall
Greywall is a lightweight, kernel-enforced sandbox that gives developers running local AI coding agents like Claude Code, Codex, Cursor, or Aider a live activity feed of every file read, write, and network connection the agent attempts. Instead of slowing you down with container overhead, it wraps any agent command with a transparent layer that logs everything—then lets you decide what to lock down. You can run in the default allow mode to keep momentum, or switch to ask or deny mode mid-session without restarting, and drop in deny rules for sensitive paths, network destinations, or commands. The tool stacks five security layers—Bubblewrap namespaces, Landlock filesystem control, Seccomp BPF syscall filtering, eBPF monitoring, and TUN + SOCKS5 proxy for network isolation—so that if one mechanism misses something, another catches it at the kernel boundary. This defense-in-depth approach works across Linux and macOS, with graceful degradation on older kernels (you can inspect the active set with `greywall --linux-features`). It also includes a learning mode that uses strace to auto-generate least-privilege permission templates, saving you the effort of hand-crafting rules. Installation is one line—Homebrew, curl, Go install, or build from source—and it works with any local CLI agent without agent-specific configuration, because it sits underneath the process. Safe defaults deny SSH keys, .env files, and shell configs, while command blocking works even inside pipes, chains, and nested shells. Give it a try with `greywall -- claude --dangerously-skip-permissions` to see everything the agent touches in real time. Compared to container-based sandboxes, Greywall is lighter—no image rebuilds—but it provides kernel-level isolation rather than full VM containment. It's for developers who want to prevent accidental data leaks and observe agent behavior without slowing workflows, and for teams that need a lightweight enforcement layer before committing to heavier governance.
Behind the Verdict
Greywall fills a real gap for developers using local AI coding agents: it gives you observability and control without forcing a heavy container workflow. The live activity feed is the standout—you see every read, write, and connection as it happens, and you can react mid-session by switching to ask or deny mode. The five-layer defense (Bubblewrap, Landlock, Seccomp, eBPF, TUN+SOCKS5) is genuinely defense-in-depth, and the learning mode that auto-generates templates from strace is a nice touch. Where it shines is the solo developer or small team who wants to prevent accidental leaks of API keys or .env files while keeping the agent productive. It's also great for platform engineers who need a lightweight enforcement layer before scaling to a full governance system. The compatibility with any CLI agent is a big plus—no agent-specific config needed. Weaknesses: it's not a full container or VM, so if you need complete isolation you'll still need something heavier. The managed governance layer (SSO, team rulesets) is still in development, so larger enterprises may be underwhelmed. Windows isn't supported, which locks out a chunk of developers. Also, advanced functionality depends on kernel capabilities, so older kernels get fewer protections. Where it doesn't fit: anyone needing full container isolation, or teams that need mature governance features today. Non-developers won't get value from a CLI tool. Overall, it's a practical tool that solves a real problem with minimal friction. The open-source core is free, so there's little risk in trying it.
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Real-world workflow fit
Concrete scenarios for the personas Greywall actually fits — and what changes day-one when you adopt it.
You run `greywall -- claude --dangerously-skip-permissions` and watch the live activity feed. You see it attempt to read .env and connect to api.stripe.com. You immediately write deny rules for those, and the agent continues with placeholder values.
Outcome: You prevent a potential API key leak and live API call, gaining peace of mind with zero setup friction.
You install Greywall on a test machine, run it with Aider, and use learning mode to auto-generate a least-privilege template. You inspect the generated rules and enforce them on your team's dev environments.
Outcome: You evaluate the tool's capability to enforce security boundaries without slowing down development, and you have a template ready for rollout.
Your team runs Cursor with Greywall wrapped around it. You set deny rules for .env and SSH keys, and you review the activity feed after each session to catch any risky actions.
Outcome: Your team avoids accidental data leaks, and you have visibility into agent behavior without needing a full governance platform.
Use Cases
- Sandbox Claude Code to prevent it from reading ~/.ssh/ or .env files in production projects.
- Watch every file read/write and network call made by Codex while building a web app, then switch to deny mode for sensitive paths.
- Enforce that your AI agent can only write to src/ and package.json, but never to /etc/ or ~/Documents/.
- Block all outbound connections except to your own staging API, ensuring no data leaks to external services.
- Run Cursor with deny rules for .env and API key files while allowing full access to project source code.
Limitations
- Greywall is a kernel-enforced sandbox that works on Linux and macOS.
- It runs with safe defaults and allows you to deny specific filesystem paths, network hosts, and commands in configuration.
- A managed governance layer for multiple teams is under development.
- Advanced functionality depends on kernel capabilities and is not available on older kernels.
as of 2026-09-01
Verification history
We have re-verified Greywall 7 times since . Each pass re-reads the vendor's own pages and re-checks every listed field against that evidence; passes where nothing had changed are marked as such.
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
- — re-verified summary, description, our verdict, our analysis, pricing model, pricing tiers, features, integrations, who it suits, who should skip it
Showing the 6 most recent of 7 verification passes.
Free to cite with attribution — this page re-verifies continuously.
12-month cost
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
Plans compared
For each published Greywall tier: who it actually fits, and what it adds vs. the previous tier. Cross-reference the cost calculator above for projected annual outlay.
Open Source Core
$0/mo
Ideal for
Solo developers and small teams who want kernel-level agent sandboxing and observability at no cost.
What this tier adds
Free tier includes the full sandbox, live activity feed, and learning mode—no paid upgrades currently.
Where the pricing makes sense
The company stage and team size where Greywall's pricing actually pencils out — and where peers do it cheaper.
Greywall's open-source core is free for individuals and small teams, making it a cost-effective alternative to commercial agent monitoring tools. For enterprise governance (SSO, team rulesets), you'll need to wait for the paid managed layer or consider alternatives like Docker-based sandboxes that may have subscription costs.
Setup time & first value
How long it actually takes to get something useful out of Greywall — broken out by persona, not the marketing-page minute.
Installation takes under a minute with the one-line curl script or Homebrew. After install, you can prefix any agent command immediately. For learning mode, it takes a few seconds to trace and generate a template. No agent-specific configuration is needed.
Integrations
Resources & Guides
Tutorials & Learning
Official links
Featured Head-to-Head Comparisons
Greywall vs Audioeye
Greywall and AudioEye serve entirely different purposes, so the choice depends on your primary need. If you are a developer using AI coding agents and want to prevent data leaks, Greywall's free, kernel-enforced sandbox is ideal. If you need web accessibility compliance to avoid lawsuits, AudioEye's paid platform with automated scanning and expert audits is the better fit.
Greywall vs Temporal Ai
Temporal AI and Greywall solve entirely different problems — one is a durable execution platform for orchestrating resilient server-side workflows, the other a lightweight sandbox for securing local AI coding agents. If you need crash-proof, long-running orchestration with retries and human-in-the-loop, Temporal is the clear choice. If you're a developer running Claude Code or similar CLI agents and want to prevent them from reading your .env files or reaching unknown networks, Greywall's free, zero-config sandbox is exactly what you need.
Greywall vs Push Security
Choose Push Security if you need enterprise-grade browser security against sophisticated attacks like AiTM phishing and OAuth abuse, especially in AI tool governance. Choose Greywall if you're a developer wanting lightweight, kernel-level sandboxing for AI coding agents to prevent accidental data leaks. They solve different problems: Push protects users from external threats; Greywall protects secrets from internal agents.
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Frequently Asked Questions
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