Weft — cross-product addressing (URI scheme status)

Status: Authoritative for which addressing scheme is canonical. The short answer: there is no live federation URI scheme. Cross-tool binding is done by SEI (opaque identity) plus the per-product association/contract surfaces in contracts-index.md — not by a URI grammar.

The weft:// URI scheme is closed

A richer cross-tool addressing standard — the Weft URI scheme (weft://… + a component registry + /api/weft/multi-fetch) — was specified in ~/filigree/docs/plans/2026-05-17-weft-uri-spec.md (per-component schemes like shuttle://elspeth/plan/…, with weft:// reserved for future federation-level resources).

It was never implemented and was formally closed by the SEI standard (§0, §0.2, §9): its registry / multi-fetch apparatus was over-built and never shipped; the stable identity it reached for is now delivered by SEI instead. SEI explicitly lists "the Weft-URI scheme, a federation registry, /api/weft/multi-fetch" as out of scope, ever.

Drift note. The previous hub (federation-map.md, shuttle.md) described shuttle://… Weft URIs as "the federation's nascent cross-product addressing scheme." That framing is stale: the scheme it referred to is the closed one above. Recorded as a fixed drift item in conflict-register.md §A-8.

shuttle:// is RESERVED (not active)

Filigree's planning-deprecation work used shuttle://… URIs as a lightweight way for a milestone to reference a (future) Shuttle plan/step (~/filigree/docs/plans/2026-05-17-weft-uri-spec.md, 2026-05-17-filigree-planning-deprecation.md). This is a thin reference convenience, distinct from the closed weft:// registry/multi-fetch apparatus.

Status: RESERVED. The shuttle:// prefix is reserved for a future change-execution authority and is not an active scheme — Shuttle is a speculative roadmap thought-bubble with no repo (see members/shuttle.md), so there is nothing for a shuttle:// URI to resolve to today. Reserving it keeps the prefix from being reused for something else; it confers no live behaviour. Whether a thin reference scheme is actually adopted is decided if/when a change-execution authority is built (which may not be called "Shuttle"). Owned by Filigree + whoever designs that authority. Tracked in conflict-register.md §B-3.

Guidance for now: treat shuttle:// as reserved-but-inert; do not build on it. Use SEI for entity identity and the documented association/contract surfaces for cross-tool bindings.