This product was not featured by Product Hunt yet. It will not be visible on their landing page and won't be ranked (cannot win product of the day regardless of upvotes).
Custos is a safety and control layer for AI agents. It sits between an agent and the tools it uses—like APIs, files, databases, shell commands, and MCP servers—and checks every action before it runs. You define what the agent is allowed to do, Custos blocks anything outside those rules, and every action is recorded in a tamper-evident audit trail. It’s open source, works with Python and TypeScript, and is built for teams running AI agents in real-world environments.
Hey PH! Maker here.
I built this after seeing enterprise teams blocked on AI agent deployment because they couldn't answer "what did the agent actually do and can you prove it?"
The MCP ecosystem is growing fast but the governance layer is missing. Custos fills that gap — policy evaluation + cryptographic audit trail in a single library.
The cross-runtime wire compat (Python ↔ Node verified) was the hardest technical piece — had to get byte-identical canonical JSON and Ed25519 wrapping right on both sides.
Would genuinely love feedback on:
- The policy DSL — too simple? too complex?
- What evidence bundle formats regulators actually ask for
- Use cases I haven't thought of
Ask me anything 👇
Gallery assets to create:
1. Hero: dark terminal showing gate.call() → signed ledger record JSON
2. Flow diagram: Agent → Gate (policy check) → Tool → Ledger
3. Cross-runtime diagram: Python sign ↔ Node verify
4. Policy YAML snippet with syntax highlighting
Nice idea. Congrats on the launch, @sanjaynandanj ! This feels especially useful for companies where compliance and auditability matter.
About Custos — The bouncer for your AI agents on Product Hunt
“Stop AI agents from doing things they shouldn't.”
Custos — The bouncer for your AI agents was submitted on Product Hunt and earned 7 upvotes and 2 comments, placing #26 on the daily leaderboard. Custos is a safety and control layer for AI agents. It sits between an agent and the tools it uses—like APIs, files, databases, shell commands, and MCP servers—and checks every action before it runs. You define what the agent is allowed to do, Custos blocks anything outside those rules, and every action is recorded in a tamper-evident audit trail. It’s open source, works with Python and TypeScript, and is built for teams running AI agents in real-world environments.
Custos — The bouncer for your AI agents was featured in Developer Tools (517.4k followers), Artificial Intelligence (475.9k followers), GitHub (41.4k followers) and Security (2.8k followers) on Product Hunt. Together, these topics include over 224.8k products, making this a competitive space to launch in.
Who hunted Custos — The bouncer for your AI agents?
Custos — The bouncer for your AI agents was hunted by Sanjay Nanda N J. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
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Sanjay Nanda N J