AI · alternatives · 2026
24 alternatives to Context Fence
Runtime firewall for AI coding agents.
Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. Prices are shown for the 3 we have checked on their own sites, 3 of them free or with a free tier.
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Kastrafree tier, from $19.99/mo▲332Hi HN, Fernando and I built Kastra. Kastra intercepts AI agent tool calls and evaluates them against deterministic policies before they execute. We built this product to control pre- and post-inference workloads. This is aimed at developers using coding agents like Claude Code, Codex, Cursor, and OpenClaw. Kastra pushes an allow, hold, and deny decision before the action runs. You can build these policies in plain English from the web app. The interception engine evaluates the tools, targets, and parameters of every action at sub 1ms at a scale of billions of interceptions per day. We also…
Jul 2026 · kastra.ai · its alternatives →
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Context Gateway▲220We built an open-source proxy that sits between coding agents (Claude Code, OpenClaw, etc.) and the LLM, compressing tool outputs before they enter the context window. Demo: https://www.youtube.com/watch?v=-vFZ6MPrwjw#t=9s. Motivation: Agents are terrible at managing context. A single file read or grep can dump thousands of tokens into the window, most of it noise. This isn't just expensive — it actively degrades quality. Long-context benchmarks consistently show steep accuracy drops as context grows (OpenAI's GPT-5.4 eval goes from 97.2% at 32k to 36.6% at 1M…
Mar 2026 · github.com · its alternatives →
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Runwallfree tier▲9A Runtime security layer that lets AI agents execute safely
Jul 2026 · runwall.vercel.app · its alternatives →
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Runtimefree tier, from $99/mo▲303Sandboxed coding agents for everyone on your team
May 2026 · runtm.com · its alternatives →
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CtrlAI▲104Transparent proxy that secures AI agents with guardrails
Mar 2026 · github.com · its alternatives →
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The firewall for AI agents. Block dangerous commands
Dec 2025 · mcp-shield.vercel.app · its alternatives →
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Hi HN! We just launched Codacy Guardrails, an IDE extension with a CLI for code analysis and MCP server that enforces security & quality rules on AI-generated code in real-time. It hooks into AI coding assistants (like VS Code Agent Mode, Cursor, Windsurf), silently scanning and fixing AI-suggested code that has vulnerabilities or violates your coding standards, while the code it’s being generated. We built this because coding agents can be a double-edged sword. They do boost productivity, but can easily introduce insecure or non-compliant code. One recent research team at NYU found that 40%…
2025 · its alternatives →
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Project AI agents from unsafe actions before they execute.
Aug 2026 · agentfirewall.launchreadyal.com · its alternatives →
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Security firewall for AI agents. Cloudflare for MCP.
Feb 2026 · agent-wall.github.io · its alternatives →
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Blocks.ai▲53Launched Blocks.ai today - the control plane and network layer for agents. One outbound connect, zero-trust security, and A2A protocols built in. Connect your agent to any frontend you build or any specialist agents you need regardless of runtime without tons of messy middleware. I work to solve agentic problems with Blocks.ai AMA :)
Jul 2026 · blocks.ai · its alternatives →
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AI code security review that runs entirely on your Mac
Apr 2026 · its alternatives →
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Gateplex▲12Real-time governance firewall for autonomous AI agents
May 2026 · gateplex.ai · its alternatives →
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Greywall▲10Prefix any AI coding agent with `greywall --` for a live feed of every read, write, and connection. Allow by default; ask mode and deny rules opt-in via config. Linux and macOS.
Mar 2026 · greywall.io · its alternatives →
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The only way to go fast is full YOLO mode in your coding agent. I've got the local sandbox figured out (pro tip: Incus VMs work great) but I wanted to keep my agents from doing things like inadvertently blowing up my cloud services or chasing a prompt to POST to some random website. I struggle most with this on my side projects where my permission model isn't quite as robust as it is at the office. I started with a firewall on the Incus container but every time the agent needed access to something new, I was poking more holes in it - and it didn't differentiate between HTTP verbs. I've been…
Jul 2026 · trollbridge.dev · its alternatives →
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Firewall for AI agents. Scan before you trust.
Mar 2026 · aisecurityguard.io · its alternatives →
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Your agent team, on your machine. Open-source harness for multi-user Claude agents. - yaodub/cast
Jun 2026 · github.com · its alternatives →
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As a Security Engineer with over 10+ years in industry, I kept running into the same problem with coding agents: Instructions are not guarantees. I put guidance in `CLAUDE.md`, `AGENTS.md`, memory files, MCP descriptions, and tool documentation. I explicitly told the agent things like: - Use the code graph for architecture questions instead of grepping the repository. - Do not use deprecated APIs or Unsafe code. - Prefer specific tools for specific tasks. The agent would still ignore those instructions surprisingly often. It would grep the entire repo, use deprecated APIs, or choose a slower…
Apr 2026 · sigmashake.com · its alternatives →
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AI-powered SAST Security That Actually Understands Your Code
2025 · enforster.ai · its alternatives →
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Hi HN, I’m the creator of Cordum. I’ve been working in DevOps and infrastructure for years (currently in the fintech/security space), and as I started playing with AI agents, I noticed a scary pattern. Most "safety" mechanisms rely on system prompts ("Please don't do X") or flimsy Python logic inside the agent itself. If we treat agents as autonomous employees, giving them root access and hoping they listen to instructions felt insane to me. I wanted a way to enforce hard constraints that the LLM cannot override, no matter how "jailbroken" it gets. So I built Cordum. It’s an open-source…
Jan 2026 · github.com · its alternatives →
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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →