Authorization

Agents touch the same data and actions as everyone else, so the same authorization model governs them. Two things decide what an agent can do: the groups on its definition and the owner of each thread.

When authentication is disabled for the runtime, requests through the Agent API gateway follow the same unrestricted authorization behavior as normal API requests. The group restrictions below apply when authentication is enabled.

Groups gate use and reach

An agent's groups (set on defineAgent) do two things:

• Who can use it. A principal can list and run an agent only if their grants cover it (run:agent). GET /api/agents returns only agents the caller may run; running one without the grant is rejected.
• What it can reach. A run acts under its own identity whose memberships mirror the agent's groups — so it can query the objects, read the telemetry, and request the actions its groups allow, and nothing else. Its instructions can ask for anything; only its permissions get through.

import { defineAgent, defineGroup } from "@sixb/core"
import { gateway } from "ai"

const financeAdmins = defineGroup("finance-admins")

export const invoiceAssistant = defineAgent("invoice-assistant", {
  name: "Invoice Assistant",
  model: gateway("openai/gpt-5.5"),
  instructions: "...",
  groups: [financeAdmins], // only finance admins can run it; it acts with their reach
})

Every referenced group must exist in your security registry (security/groups/ or createSixb({ groups })), or startup fails.

Threads are owner-scoped

A thread records the principal that created it. Reading it, posting to it, and subscribing to its stream all require that owner (plus the run:agent grant). Anyone else sees it as not-found.

The run API exposes requestedBy, resolved from its immutable execution record. The Agent's managed service account is the execution authority; it is stored once in that execution record rather than copied onto the run.

Related

• Authorization — defining groups, roles, and grants.
• Defining agents — set groups on an agent.