Prompt Budget
Domain: Models & Providers
Motivation
Prompt budget is fitting the assembled prompt — system prompt, history, tools, and images — within a model’s context window. The token meter measures contextPressure and projectedTokens (what the next request’s prompt would cost), and the DeepSeek adapter requires that a model’s context window exceed the effective maxTokens plus the compaction policy’s headroomTokens.
Concrete Example
contextPressure.projectedTokens estimates the next request’s prompt cost; when pressure nears the window, proactive compaction shrinks the context before CONTEXT_WINDOW_EXCEEDED.
Analogy
Budgeting the desk space before you lay out the papers, so nothing overflows.