Interface: ExtensionHost¶

The registration-time surface the Kernel offers to Extension.register().

This is the explicit contract of what an extension may call while it is being loaded (s-dna-extension-host-contract). It is a narrow slice of the Kernel — the registration vocabulary — NOT the whole Kernel API. Derived from actual usage across every builtin extension:

kind(kp) — register a KindPort (identity + composition)
kindFromDescriptor() — register a record Kind from a kinds/*.kind.yaml descriptor (F3 — Kinds as data). Pair with loadDescriptors() from ./descriptor-loader.js.
reader(r) — register a ReaderPort (detect/scan a format)
writer(w) — register a WriterPort (write a format)
on(hook, fn) — subscribe to an event (e.g. post_save)
onVeto(hook, fn) — register a veto listener (e.g. pre_save write guards — throwing vetoes the operation)
tool(td) — register a ToolDefinition (DNA tool discovery metadata; queried via kernel.getTools())
compositionProfile() — register orchestrator kind wiring
hooks — the HookRegistry itself, for advanced listener management (kernel.hooks.onVeto(..., {key}))

The real Kernel satisfies this interface structurally (statically asserted in tests/extension-host-contract.test.ts). Py twin: ExtensionHost in dna/kernel/protocols.py.

Properties¶

hooks¶

readonly hooks: HookRegistry;

The HookRegistry the on/onVeto conveniences delegate to.

Methods¶

compositionProfile()¶

compositionProfile(profile): void;

Parameters¶

Parameter	Type
`profile`	`CompositionProfile`

Returns¶

void

kind()¶

kind(kp): void;

Parameters¶

Parameter	Type
`kp`	`KindPort`

Returns¶

void

kindFromDescriptor()¶

kindFromDescriptor(raw): KindPort;

Parameters¶

Parameter	Type
`raw`	`Record`\<`string`, `unknown`>

Returns¶

KindPort

on()¶

on(hook, fn): void;

Parameters¶

Parameter	Type
`hook`	`HookNameArg`
`fn`	(`ctx`) => `void`

Returns¶

void

onVeto()¶

onVeto(
   hook, 
   fn, 
   opts?): void;

Parameters¶

Parameter	Type
`hook`	`HookNameArg`
`fn`	`VetoHandler`
`opts?`	{ `key?`: `string`; `priority?`: `number`; }
`opts.key?`	`string`
`opts.priority?`	`number`

Returns¶

void

reader()¶

reader(r): void;

Parameters¶

Parameter	Type
`r`	`ReaderPort`

Returns¶

void

tool()¶

tool(td): void;

Parameters¶

Parameter	Type
`td`	`ToolDefinition`

Returns¶

void

writer()¶

writer(w): void;

Parameters¶

Parameter	Type
`w`	`WriterPort`

Returns¶

void