name: principle-guard-the-context-window description: "Apply when context is filling up. Route bulk to subagents; keep summaries in the main thread."

Guard the Context Window

The session's context is finite and cannot be reclaimed. Every token that enters must earn its place.

Why: Overflow degrades reasoning, invents compression artifacts, and stalls the run. Compute is cheap; context is not.

Pattern:

• Route verbose output, long files, screenshots, and bulk reads to subagents.
• The main thread keeps summaries, not raw payloads.
• Do not read a file you will not use for this step.
• Keep high-frequency templates in the skill body, not a second file that costs a read each time.
• Cap files per phase and scope per subagent.
• Fan-out planning belongs in the planner; raw payloads do not.
• Prefer a pointer to a file over inlining its contents.
• Filling context is a reason to route work out, never to stop, summarize early, or suggest a new session — continue the work.