Session Guard Overview Long sessions corrupt silently. Context compaction drops instructions unannounced. Hooks don't fix it (confirmed by multiple developers on GitHub issues #19471, #9796, #64171). This skill prevents both through behavioral self-enforcement: monitor health, anchor critical rules through compaction, split before damage occurs. No packages, no databases - pure behavioral enforcement that works in every harness. When to Use - Session exceeds 40 tool calls - Agent contradicts earlier decisions - Style/naming conventions start drifting - After any context compaction event - Tas…