# Build glossary

The words a contributor meets that a user never does. The user's words are in the
[user glossary](../reference/glossary.md); a word in neither is not allowed in a page, a flag or a
message.

**core** — `packages/world-core`, `@volter/world-core`: the state kernel and shared runtime
libraries. One entry model, checkpoints, parent-position branches and head execution; vendor
semantics stay in the packages. See [architecture](./architecture.md).

**kernel** — `packages/world-*`: the runtime (`world-runtime`), the remote (`twins-host`), the
dev-only tooling, the shared UI assets. Vendor-agnostic; few writers; kernel process.

**pack** — a twin's package as the build sees it: `<vendor>/` in `twin-packs-p3`, created from the vendor's spec by
[Creating a pack](./architecture.md#creating-a-pack). A user says twin, or package.

**unit** — a directory holding `src/manifest.ts`: a pack, or one lane of a pack of lanes. The pack tools take one.

**lane** — one API of a vendor with several (its own spec, manifest and handlers), `<vendor>/<lane>/`, keeping the
vendor's one store.

**catalog** — every pack: the `@volter/twin-*` packages a World resolves from its sources (a pack repository's checkout,
or the installed packages in an app).

**demand** — what the products volter.ai names call: the scan's ranking of vendors (`generated/DEMAND.md`), and a
pack's own reading of its applications' calls (`journeys/demand.json`).

**life** — a pack's customer life (`journeys/customer-life.json`): one believable customer's story, walked through the
pack's fetch, the pack's proof. Its **outline** is the story's acts, before any handler.

**decision table** — per operation served, what it does, decided before any handler is written; its outcome is
`journeys/decisions.json`.

**blitz** — writing every handler of a pack in one pass from its decision table.

**report** — a pack's walked life, coverage, examples and breadth (`scripts/score-pack.ts`).

**door** — an HTTP endpoint a twin or a remote serves beside the vendor's API. A user reads
"HTTP API".

**backing** — which of local and remote stands behind a vendor on a remote. A user reads local
and remote as nouns.

**shape** — a vendor's wire, as the code names it. A user reads "the vendor's API".

**placeholder** — the default data's origin, as the code names it (`PLACEHOLDER_REMOTE`,
`placeholder-pull`). A user reads "default data".

**observed** — vendor state admitted through `observeResource` into a root’s log; default
seeding supplies inherited state through the seed window.

**landing** — an entry added to the parent with a receipt; its branch copy is not applied twice.

**admission** — the reservation of memory and disk `up` makes before starting; refused by name.

**instance** — the running world's record: `instance.json` and the directory around it.

**manifest** (world) — the document a world publishes for attachments: vendors, CA, proxy, env.
**manifest** (capability) — a pack's enumeration of the vendor's surface with a `verify()` per
capability; the completeness number's denominator.
**manifest** (pack) — a derived pack's `src/manifest.ts`: the vendor facts no spec
carries, and the surfaces outside the spec.

**derived pack** — a pack with `src/manifest.ts` and `src/generated/`: its wire, schemas, generic CRUD,
perform, refresh and coverage are generated from the vendor's spec; only its semantics are
hand-written.

**semantics** — a derived pack's hand-written behaviour: state machines as data and handlers by
operationId. Write semantics run wherever the head does not perform a write now; read semantics
run under every head.

**cell** — a value of a state field paired with an operation on its resource; the unit a derived
pack's completion is counted in.

**attestation** — a signed judgment (a journey's plausibility, a transition's source, a ruling on a
cell, a review), keyed by the hash of what it depends on and stale when that changes.

**attachment** — applying a world's vendor map to one consumer. A user reads `run`, `activate`,
`shell`.

**narration** — a changeset's generated summary, as the code names it. A user reads "summary".

**basis** — a change’s recorded assumptions, as compatibility code names them. A user reads "base"
for the branch’s parent position.

**sealed** — the sandbox mode for cooperating HTTP/Fetch and guarded Node connections
([transport coverage](./architecture.md#outbound-transport-coverage)); native traffic requires
an enforced Machine boundary. Also a credential at rest on the remote.

**recipe** (cookbook) — a runnable example, as the cookbook's tooling names it. A user reads
"example". **procedure** (building a twin) — [Creating a pack](./architecture.md#creating-a-pack).

**skin** — the composed front a remote presents: one URL, every twin a path.

**R-numbers** (R2a, R14, …) — identifiers retained in the invariant runners and older design
records. Current implementation rules live in [architecture](./architecture.md), and unresolved
work is on Volter's board.

**history descriptor** — an immutable view's verified segment ranges, storage generations and
projection layout. The descriptor's content hash identifies it; its dependencies participate in
World cleanup. Local views share payloads; a remote cache deduplicates complete entry contents.