One-install GitBook front door over five bounded domain packs and eleven operating workflows. It admits all 333 user-token JSON or bodyless operations from the current 355-operation official OpenAPI contract. The explicit exclusions are 17 internal, staff, integration, or installation-token-only routes and five SSE streaming routes that the static JSON REST composition cannot represent. Coverage includes organizations, members and permissions, spaces and page content, change requests and comments, published sites, analytics and content intelligence, integrations, and hosted OpenAPI specifications. A documentary read-only note Source mirrors top-level pages from one configured space, hydrates every listed page by id, and uses hash-only change detection because the page union exposes no mandatory version field. Enroll a GitBook personal access token as a bearer credential and store the Source target space id in connection config as space_id. Reads are uncached and marked sensitive-read except the Source list/read pair; all mutations are grant-off and require approval every run. The five SSE endpoints remain available through GitBook's native SDK rather than this JSON pack.