# System Prompt Assembly

The [system-prompt package](../../packages/core/system-prompt) owns the data exchanged between prompt contributors and one assembly call. The package [README](../../packages/core/system-prompt/README.md) documents registration, ordering, scoping, and rendering behavior; this page pins the literal cross-package shapes that plugins implement or pass.

Source: [`packages/core/system-prompt/src/index.ts`](../../packages/core/system-prompt/src/index.ts).

## Assembly context

`AssembleContext` identifies the scope layer one assembly resolves. It is merge-extensible: `dsh-agent` adds the optional live `agent` field, and `assembleContextFor(agent)` sets that field and `scope` together.

```ts type-equiv
interface AssembleContext {
  scope?: ScopeKey
}
```

## Tool-provider result

`ToolProviderResult.schemas` is the model-visible set for the current assembly. `knownNames` is the provider's pre-restriction name universe used to distinguish a configured-name typo from a known tool that is deliberately hidden in this scope.

```ts type-equiv
interface ToolProviderResult {
  schemas: ToolSchema[]
  knownNames?: readonly string[]
}
```

## Canonical contribution protection

`PromptProtection` names section and tool contributions whose canonical registry output remains authoritative after the assembly waterfall. Either field may be omitted, but a registration with no names is rejected.

```ts type-equiv
interface PromptProtection {
  sections?: readonly string[]
  tools?: readonly string[]
}
```