The Narrow Window

Level 2 · Course 14

Every model advertises a context window. 200K. 400K. 1M. Those numbers are real, but they are not the same as judgment. A model can still hold the conversation while getting worse at the work. It remembers the words and loses the plot. It connects unrelated projects. It speaks with confidence from stale context. It keeps going because continuing is what it was trained to do.

Course 10 gave you bands. Course 13 taught you to control what enters the room. This course teaches you where the best work actually happens. The useful window is narrower than the technical window. Fresh sessions are fast but shallow. Loaded sessions synthesize. Heavy sessions get conversational and dangerous. The job is not to max out context. The job is to choose the right band for the work.

Your agent installs a narrow-window protocol: plan when light, execute in the productive band, stop new work before judgment degrades, and use fresh sessions for new domains. You stop asking, "How much context is left?" and start asking, "Is this the right instance for this job?" That question saves projects.

Three Scenarios, One Agent

Take a hypothetical operator: Marcus runs a general contracting business and also manages a small portfolio of rental properties. Same agent, two different domains. Both involve decisions, deadlines, and money — but they draw on completely different context.

Scenario A — Fresh session (under 50K tokens). Fast, rules are loud, agent is sharp on instructions. Good for bounded tasks: checking tomorrow's job site schedule, sending a follow-up email to a subcontractor, confirming a rental payment came through. No synthesis needed. Speed is the feature.

Scenario B — Loaded session (100–250K tokens). This is where the best work happens. The agent has enough context to connect things, hold multiple threads, and think ahead. Marcus uses this band for deep work: researching whether a property deal makes sense, planning a full renovation scope, drafting a contract. The session has weight. Use it.

Scenario C — Heavy session (300K-plus). The session keeps going. Technically fine. But something shifts. The agent starts connecting the rental deal research to a contracting bid that has nothing to do with it. It hedges on a commitment it was firm about two hours ago. Judgment fades while confidence holds steady. This is the danger band.

The protocol: fresh session for domain switches — contracting work to rental work means /new between them. Loaded sessions for anything requiring depth. /new before entering new heavy territory. The session doesn't tell you when to stop. You set the rule in advance.

You decide: at what context level do you /new for a domain switch? Most operators land between 200–300K. Test it. Your number might be different.