We click "Yes" without reading
Agents ask for permission again and again. Tired users approve without looking, so one blind "Yes" can delete a folder or upload your .env.
93% of permission prompts get approved (Anthropic, 2026)
Free · open source · runs on your PC
Your secrets stay on your PC.
Zuko is a privacy firewall and guardian for AI agents. It masks API keys and personal data before they leave your computer, enforces your rules on every action, and explains risky permissions in plain English.
Download for Windows
Version 0.1.1 · 4 MB · Windows 10 and 11
Get the browser extension
Works with
Claude CodeVS CodeChatGPTclaude.aiDeepSeek
The problem
We trust AI with everything, and we stopped looking.
AI agents now read our files, run commands and browse the web for us. Chatbots hear about our bills, health and bank accounts.
We paste private info into AI
API keys, phone numbers, card and bank details go straight to cloud servers and stay in chat logs. Once they are sent, you cannot take them back.
23.8M secrets leaked on GitHub in 2024 (GitGuardian, 2025)
We cannot set the rules
There is no simple way to say "never open my Personal folder" or "never upload to pastebin". Files and web chats have no guard at all.
OWASP lists data leaks and excessive agency as top LLM risks
Demo
See Zuko in action
Secrets masked, a risky delete explained, a blocked site, and ChatGPT protected, in about three minutes.
How it works
The AI does the work. It never sees the secret.
Zuko swaps every secret for a placeholder on your PC, and puts the real value back when the answer comes home.
Your PC
You type as usual
Real keys, cards and phone numbers, in Claude Code or a web chat.
My key is sk-proj-7Qm4…, put it in .env
Your PC
Zuko masks it
Each secret is stored in an encrypted vault and replaced with a placeholder.
My key is {{API_KEY_1}}, put it in .env
The cloud
The AI answers
The model only ever sees placeholders, and answers with them.
OPENAI_API_KEY={{API_KEY_1}}
Your PC
You get the real thing
Zuko puts the real value back, so your file and your screen show it.
OPENAI_API_KEY=sk-proj-7Qm4…
What Zuko does
One small guardian, four big jobs.
01 · Privacy
Your secrets never reach the model
Everything Claude Code sends goes through Zuko's local gateway: prompts, files the agent reads, command output and IDE selections.
- 50+ secret formats: OpenAI, Anthropic, AWS, GitHub, Stripe, Google, JWTs, private keys, passwords and more.
- Personal data: emails, phone numbers, cards, IBANs and your own custom words. Optional local AI finds names and addresses.
- The same value always gets the same placeholder, so conversations stay consistent.
02 · Permissions
Look before you say yes
Every action gets a risk level and a headline that leads with the consequence, like "DELETES the folders dist/ and .cache/".
- Low risk passes silently, so you are not asked all day.
- High risk needs you to hold the Allow button. A reflex click does nothing.
- Approve risky actions faster than anyone could read them, and Zuko slows you down.
03 · Your rules
Your rules, enforced
Block websites, folders, commands and tools. Zuko stops the call on the spot and tells the AI exactly why.
- Chain rules catch a secret that was read from
.envand then sent out, even base64 or hex encoded. - Self-protection: the agent cannot edit Zuko's policy or switch Zuko off.
- Every decision goes into a tamper-evident audit log that never holds secret values.
04 · Files and web chats
Files and web chats too
The browser extension protects ChatGPT, claude.ai and DeepSeek, and the app cleans any document you want to share.
- Prompts and uploaded files are masked before you hit send. You still see the real values on your screen.
- Drop a
.txt,.md,.pdfor code file on Zuko to get a masked copy. - Ctrl+Alt+M masks the clipboard for any app; Ctrl+Alt+U restores it.
100%detection on our 51-scenario attack benchmark
0%false blocks on the same benchmark
0.3 msper firewall decision
450+automated tests passing
Private by design
Nothing to sign up for. Nothing to pay.
No account
Download it and use it. There is nothing to register.
No server
Masking, rules and the vault all run on your own PC.
No telemetry
Zuko does not phone home. The optional local AI runs offline.
Open source
MIT licensed. Read every line on GitHub.
Ready to keep your secrets?
Install the app in a minute, switch protection on, and keep working the way you do now.