D1099 — The only live page of an archive is no orphan, and concept_write takes index_entry

Decision. (1) orphan is not emitted for a concept that is the only live (not deprecated, superseded, archived) concept of its archive, nor for the only live concept of the KB. The count is over the whole KB graph, whatever the scope of the call or the caller's visibility; an archive is a first-level directory of data/ (services/ is not one). orphan stays AvoidableAtWrite: what changes is when the finding exists. (2) concept_write accepts index_entry: true with the concept_new semantics (D714): creation only, refused before anything is written on an existing id or with if_match, the entry under ## New pages, curated_indexes in the response, a failed index edit after the write a note. The write-gate refusal text names concept_write among the tools that take it.

Why. D907: the gate refuses only what a write can avoid. The first page of an archive cannot link to anything, so the one finding blocking it was not avoidable; and the second blocker, the index entry, existed on two tools but not on the one a generic agent reaches for first. The refusal named concept_new, which needs a template a fresh KB does not have. A host that gives the model only tools (no managed block, no skills) could therefore never write its first page.

Alternatives rejected. - Always adding an index entry on creation: already rejected in D714 (the caller asks explicitly). - A way to bypass or accept a finding: removed by D907. - Leaving the exemption off and sending the agent to a two-page concept_batch: fails for a one-page start. - Exempting every archive-top page with no incoming link: reverts D306 (an isolated top-level page is a node connected to nothing).

Consequences. - Once a second live page exists and nothing links the first, a whole-KB lint reports the first as orphan. The write that added the second is not blamed (it did not write the first), and a second page that links the first clears both. An archive whose other pages are all retired exempts its last live page. - index_entry on a satellite of an expanded concept adds the entry to the map's index, as concept_new does; the dossier's own index is not extended. - Authorization is unchanged and deliberately not widened or narrowed: no code reads index_entry for authorization, so it edits the map's index on the concept-level grant, as concept_new and concept_batch already do, whereas index_patch needs the map-level grant. Closing that gap for all three tools is a separate decision. - ScopedCheck builds the live census lazily, only when an orphan candidate asks, so an ordinary write pays nothing; Run and ScopedCheck share orphanFinding and must agree (pinned by internal/lint/lone_live_test.go). - changes_since became_orphan is an in-degree delta of its own and is unchanged.