# Policies

> Control who can perform an action on an exact Constal Resource and constrain the operation that is allowed.

A Policy evaluates normalized identity, an action, an exact Constal Resource Name, and bounded request context. Authorization is deny by default, explicit deny wins, and scopes can narrow existing grants but cannot manufacture authority. Policies can allow, deny, require approval, substitute safe values, constrain arguments or context, and grant short-lived capabilities.

Policies are ordinary versioned Resources deployed as deterministic executable packages. Each package manifest selects exactly one authorization-target kind and zero, one, or many targets of that kind with the shared label-selector syntax. Targets include managed Resources and platform addresses such as sessions, bindings, and deployments. There is no public declarative Policy type. Runs pin the effective Policy hashes accepted at admission so replay does not silently gain new authority when a current Policy changes.

## Where Policies apply {#where-policies-apply}

| Boundary | Examples |
| --- | --- |
| Platform API | Read, create, update, control, export, or deploy actions |
| Agent execution | Start a Run, call a model, use a Tool, commit or deliver a result |
| Resource invocation | Exact Resource, operation, arguments, effect, and Credential use |
| Channel ingress | Authenticated principal, customer mapping, target, and dispatch |
| Runtime control | Resolve a wait, steer, pause, rebind, truncate, or cancel |

## Choose an interface {#choose-an-interface}

| Interface | Use it for |
| --- | --- |
| Console | Reviewing deployed Policies, attachments, and decisions |
| [SDK](/docs/policies/sdk.md) | Authoring deterministic executable Policy behavior |
| [CLI](/docs/policies/cli.md) | Deploying packages and evaluating exact test requests |
| [Platform API](/docs/api/resources-and-bindings.md) | Policy-aware administration and scoped assignments |

Use [Author a Policy](/docs/policies/author.md) to build and test deterministic behavior. Use [Govern Resource usage](/docs/policies/governance.md) for typed controls and hard limits. Use [Operate Policies](/docs/policies/operate.md) to evaluate, select, version, and inspect effective decisions.