Open Policy Agent alternative: purpose-built spend firewalls for AI agents
OPA can enforce any policy you can write in Rego — including spend rules. But you have to write them, test them, and maintain them. sipi.bot ships with the spend primitives already built, tested, and integrated.
The Rego tax
To control agent spending with OPA, you must: (1) learn Rego, (2) model spend concepts as Rego policies — per-transaction caps, daily totals with sliding windows, velocity detection, merchant allow/block lists, time-window rules, approval thresholds — (3) write tests for every rule, (4) build a dashboard for the approval queue, (5) integrate OPA into every agent framework you use, and (6) maintain all of this forever.
sipi.bot does all of that out of the box. The rule types are pre-built. The dashboard ships with the product. The framework integrations — LangChain, CrewAI, OpenAI SDK, Vercel AI SDK — are written and maintained. The 53-scenario eval gym proves every rule works. The core is MIT-licensed so you can audit it.
When OPA makes sense for spend control
OPA is the right choice if you already run OPA across your platform, you have Rego expertise on your team, and the spend-control rules you need are simple enough to express in a few Rego policies. For most teams deploying AI agents that spend money, a purpose-built spend firewall saves weeks of engineering time and months of maintenance.
Frequently asked
Can OPA do everything sipi.bot does?
With enough engineering effort, yes — OPA with Rego can express arbitrary policies. The question is whether you want to build a spend firewall from scratch in Rego or use a product that ships with the primitives, dashboard, and integrations already done.
Can I use OPA alongside sipi.bot?
Yes. Use OPA for platform-wide authorization — APIs, Kubernetes admission control, data access — and sipi.bot specifically for agent spend control. They address different policy domains.
Does sipi.bot support Rego policies?
No. sipi.bot has its own rule engine with pre-built spend-control primitives. You configure rules through the dashboard or API, not by writing Rego. If you need arbitrary policy expression in Rego, OPA is the better fit.