Context
Domain: DSH Fundamentals
Motivation
Context is the window of messages the model sees each turn, derived from the session log by dsh-session and bounded by the model’s context window. dsh-token-meter estimates current context pressure (measure()) so compaction, occupancy displays, and telemetry share one replay-based result without model calls, and dsh-compaction condenses history when pressure grows. Developers care because fitting the prompt to the window — and knowing when to compact — is the core of long-session behavior.
Concrete Example
ctx.tokenMeter.measure(session) returns totalTokens (request-and-response pressure) and surfaceTokens (surface-only total).
Analogy
It is a whiteboard of limited size: you can only keep the recent work visible, so you erase and summarize the oldest.