# Volatile Context Belongs at the Event Where It Changes ## Claim Volatile context should be injected at the lifecycle event that refreshes it, not captured once when a session starts. <!-- atomicity: 1 idea ✓ --> ## Scope & conditions - This holds for facts such as time, branch, working directory, or external state that can change while a session remains open. - Per-event injection should stay small and relevant; refreshing stable facts every turn only consumes context. - A hook supplies observation, not reasoning: the model can still misuse a correct timestamp. ## Evidence [[3. Resources/Readwise/Articles/Keep Claude Code Up to Date on Time and Date]] shows why `SessionStart` couldn't solve elapsed-time errors and moves the timestamp to `UserPromptSubmit`, which fires after every idle interval when the user resumes work. ## Links - [[Context Not Constraints Is What Unhobbles an Agent]] — applies-in: the missing current fact is situation the model cannot infer, not a behavior rule. - [[Intent Written on the Outside Compounds While Re-Derived Intent Is Debt]] — contrasts: durable intent belongs in stable files, while volatile state must be refreshed at use time. - [[The Harness Now Outpaces the Model as the Source of Agent Capability Gains]] — evidence-for: a small lifecycle hook repairs a capability gap without changing the model. - [[3. Resources/MOCs/AI & the Future of Knowledge Work MOC]] — applies-in: the MOC lists this note under Amplifier thesis & the harness. - [[3. Resources/MOCs/Personal Knowledge Management MOC]] — applies-in: the MOC lists this note under Synthesis additions.