AI Governance & Security Vendor Wiki

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Open Policy Agent (OPA)

Researched 2026-06-28. Primary category: authorization-engine. Open-source CNCF Graduated project — not a company. Created by styra; core maintainers acqui-hired by Apple (Aug 2025), project stays under CNCF.

One-liner — The de-facto open-source, general-purpose policy engine: ship your access rules (written in Rego) to a decision point that any app, service, or agent can call for a fast allow/deny.

What it does

OPA is a general-purpose Policy Decision Point. You express policy in Rego, a declarative language for querying complex hierarchical data (JSON), and OPA evaluates a decision given input + data. It started in cloud-native infra — Kubernetes admission control, microservice authz, CI/CD guardrails (policy-as-code) — and the same engine is now pointed at agent/tool authorization: define in code what an agent or MCP tool is allowed to do and enforce it consistently. It is decision-only: it does not store relationship data or do content inspection.

Where it sits in the stack

Dual-primary: authorization-engine (per-request allow/deny) and policy-as-code (infra/CI guardrails) — it is genuinely both. Layer: model-prompt. Lethal-trifecta role: constrains the sensitive-data and egress legs by deciding whether an action is permitted; it does not inspect prompts for injection (that’s ai-runtime-security / agent-runtime-security). The center of gravity for externalized authz — many neighbors wrap or compete with it.

Deployment & architecture

Self-hosted OSS (Apache-2.0); runs as a sidecar/daemon (REST API), an embedded Go library, or WebAssembly. Stateless evaluation — you push policy bundles and supply input/data; pairs with your IdP and data sources rather than replacing them. Widely embedded in K8s (Gatekeeper), service meshes, API gateways, and increasingly MCP/agent gateways that call OPA for decisions.

Positioning & differentiators

The OSS standard PDP — broadest adoption, largest ecosystem, most general-purpose. Rego is powerful but has a learning curve, which is exactly the gap commercial neighbors sell against: styra (enterprise management of OPA), permit-io (developer-friendly hosted layer over OPA/Cedar), cerbos (simpler YAML policies), oso (Polar DSL), authzed (Zanzibar/ReBAC graph). If you want vendor-neutral, embeddable, ubiquitous authz, OPA is the default; if you want managed tooling on top, you buy one of the others.

Ownership, funding & M&A

Not a company — an open-source project created at styra (Tim Hinrichs, Torin Sandall, Teemu Koponen) ~2016, donated to CNCF (accepted 2018, Incubating 2019, Graduated 2021-01-29). Aug 2025: Apple acqui-hired the three OPA creators plus several Styra engineers (see styra). Crucially, OPA stays under CNCF governance — license, governance, and release cadence unchanged — so the project itself is insulated, though some observers note Apple-acqui-hire precedent (FoundationDB) as a watch item. Confidence high.

CTO / hedge-fund lens

Day-2, but often already owned: if your platform/devops team does Kubernetes admission control or policy-as-code, OPA is probably in production already, so “adopting” it for agent authz can be re-use rather than a new buy. SR 11-7 angle is indirect (consistent, auditable access decisions support control documentation). Best fit for shops with engineering depth willing to write Rego; smaller funds may prefer a managed layer (permit-io, cerbos Cloud, oso Cloud).

Competitors / alternatives

styra (commercial OPA), cerbos, permit-io, oso, authzed, hashicorp-sentinel, kyverno (infra-policy neighbors).

Open questions / to verify

  • Long-term health of OPA development under CNCF now that core maintainers are inside Apple — watch release cadence and maintainer diversity through 2026.
  • Status of formerly-Styra enterprise tooling (Enterprise OPA/EOPA, Regal linter) reportedly moving to OSS.

Sources

History

  • [2026-06-28] Stub created from seed registry.
  • [2026-06-28] Researched; confirmed CNCF Graduated project (created by Styra, donated 2018, graduated 2021). Documented Apple acqui-hire of OPA core maintainers (Aug 2025) with OPA remaining under CNCF. Raised ownership_confidence to high; corrected ownership_detail. Cross-linked styra.

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