---
name: principle-guard-the-context-window
description: "Apply when large files, logs, or broad exploration threaten reasoning focus."
license: MIT
metadata:
  author: jstack-maintainers
  source: michael-denyer/pstack-claude
  source-version: "0.9.30"
  source-commit: 45f768349a6d7d7e71509fee3f5bccfad54b3bad
  owner: software-factory
  risk: low
  capabilities: jstack,engineering-principle
user-invocable: false
---

# Guard the Context Window

The context window is finite and non-renewable within a session. Every token should be worth its cost.

**Why:** Context overflow degrades reasoning quality, creates compression artifacts, and halts progress.

**Pattern:**
- **Isolate large payloads.** Route verbose outputs, screenshots, and large documents to subagents. The main context gets summaries, not raw data.
- **Don't read what you won't use.** Read selectively based on relevance. If a file isn't needed for the current task, skip it.
- **Keep frequently used content inline.** Templates and references used on every invocation belong in the skill file, not in separate files that cost a read each time.
- **Size phases and cap scope.** Limit files per phase, set turn budgets, account for mechanism costs.