When feature context fragments, write a hub doc
Ending a long session where a feature now spans many GitHub issues, multiple open PRs, several design docs, and a long chat history — and realizing a fresh agent or human picking it up cold has no clear entry point.
The fix is a single hub doc whose only job is orientation. Structure that works: (1) goal in one sentence, (2) design principle in two sentences, (3) architecture in one diagram, (4) live-vs-designed-vs-bug table by component with issue links, (5) prioritised where-to-pick-up list, (6) operating runbook inline (the actual shell commands), (7) cross-cutting principles every implementer must respect. The hub does NOT contain the details — it links out. The detail docs add a one-line header pointing back at the hub. Mark superseded docs HISTORICAL with a pointer instead of deleting them. Add a line to the projects agent-instruction file (CLAUDE.md / AGENTS.md) telling agents to read the hub when touching this feature area. After this, a new contributor reads ONE file and can pick a ticket within minutes.
As soon as a feature has more than ~3 issues OR more than ~2 design docs OR has shipped one component while others are still designed, write the hub doc. The friction-saved compounds with every subsequent contributor, and the writing itself reveals scope drift you didnt notice.