Pattern: Context Selection Is Consolidating Into Its Own Layer Beneath the Agent

GitHub·high signal

Four distinct projects now sit between the agent and its context rather than inside it: LeanCTX gates reads at the filesystem, graphify replaces grep with graph traversal, PageIndex does reasoning-based retrieval with no vector store at all, and Claude Code's own /doctor now prunes the context file you hand it. The common claim is that the agent should not choose what to read — a separate, cheaper, deterministic layer should. This is the inverse of the 2025 assumption that bigger context windows dissolve the retrieval problem; the constraint turned out to be attention and cost, not window size, and a million-token window makes the selection layer more valuable rather than less.