MCP gives agents access to tools — databases, file systems, APIs. The problem is there's no access control layer. An agent with a database tool can run any query. An agent with file access can read anything. The only safeguard right now is a user clicking "Allow" on a prompt they probably won't read.
Sentinel Gate is a proxy that sits between your MCP client and servers. Every tool call gets checked against RBAC policies before it reaches the server.
The key design decision: *deterministic rules, not AI*. Policies are written in CEL (Common Expression Language). If a rule says deny, it denies. No LLM in the security path, no prompt injection possible against the firewall itself. You get a full audit log of every tool call — what was requested, what was allowed, what was blocked.
Built in Go. Self-hosted. PostgreSQL for audit logs, Redis for sessions. AGPL-3.0.
It's early — we're looking for feedback from teams running MCP in production or planning to. What's missing? What would make this useful for your setup?
Comments
Hi HN,
MCP gives agents access to tools — databases, file systems, APIs. The problem is there's no access control layer. An agent with a database tool can run any query. An agent with file access can read anything. The only safeguard right now is a user clicking "Allow" on a prompt they probably won't read.
Sentinel Gate is a proxy that sits between your MCP client and servers. Every tool call gets checked against RBAC policies before it reaches the server.
The key design decision: *deterministic rules, not AI*. Policies are written in CEL (Common Expression Language). If a rule says deny, it denies. No LLM in the security path, no prompt injection possible against the firewall itself. You get a full audit log of every tool call — what was requested, what was allowed, what was blocked.
Built in Go. Self-hosted. PostgreSQL for audit logs, Redis for sessions. AGPL-3.0.
It's early — we're looking for feedback from teams running MCP in production or planning to. What's missing? What would make this useful for your setup?