The ContextUsed property is an Integer value that returns the
estimated number of context tokens currently used by the active session
history. This includes tokens associated with prompts, responses, system
instructions and other retained conversation content managed by the
control.
As additional messages are exchanged with the model, the amount of
context used by the session will generally increase. When the accumulated
context approaches the maximum context window supported by the model,
older messages may need to be removed or truncated to remain within the
model limits.
The value returned by this property is an estimate calculated by the
control and may differ from the exact token usage reported by the service
provider. Token usage can vary depending on the provider, model,
tokenizer implementation and internal formatting used when constructing
requests.
This property is primarily intended for informational or diagnostic
purposes and should not be interpreted as an exact measurement of the
provider's internal token usage.