ck-context-engineering

# Context Engineering Context engineering curates the smallest high-signal token set for LLM tasks. The goal: maximize reasoning quality while minimizing token usage. ## When to Activate - Designing/debugging agent systems - Context limits constrain performance - Optimizing cost/latency - Building multi-agent coordination - Implementing memory systems - Evaluating agent performance - Developing LLM-powered pipelines ## Core Principles 1. **Context quality > quantity** - High-signal tokens beat exhaustive content 2. **Attention is finite** - U-shaped curve favors beginning/end positions 3. **Progressive disclosure** - Load information just-in-time 4. **Isolation prevents degradation** - Partition work across sub-agents 5. **Measure before optimizing** - Know your baseline **IMPORTANT:** - Sacrifice grammar for the sake of concision. - Ensure token efficiency while maintaining high quality. - Pass these rules to subagents. ## Quick Reference | Topic | When to Use | Reference | |-------|-------------|-----------| | **Fundamentals** | Understanding context anatomy, attention mechanics | [context-fundamentals.md](./references/context-fundamentals.md) | | **Degradation** | Debugging failures, lost-in-middle, poisoning | [context-degradation.md](./references/context-degradation.md) | | **Optimization** | Compaction, masking, caching, partitioning | [context-optimization.md](./references/context-optimization.md) | | **Compression** | Long sessions, summarization strategies | [context-compression.md](./references/context-compression.md) | | **Memory** | Cross-session persistence, knowledge graphs | [memory-systems.md](./references/memory-systems.md) | | **Multi-Agent** | Coordination patterns, context isolation | [multi-agent-patterns.md](./references/multi-agent-patterns.md) | | **Evaluation** | Testing agents, LLM-as-Judge, metrics | [evaluation.md](./references/evaluation.md) | | **Tool Design** | Tool consolidation, description engineering | [tool-design.md](./references/tool-design.md) | | **Pipelines** | Project development, batch processing | [project-development.md](./references/project-development.md) | | **Runtime Awareness** | Usage limits, context window monitoring | [runtime-awareness.md](./references/runtime-awareness.md) | ## Key Metrics - **Token utilization**: Warning at 70%, trigger optimization at 80% - **Token variance**: Explains 80% of agent performance variance - **Multi-agent cost**: ~15x single agent baseline - **Compaction target**: 50-70% reduction, <5% quality loss - **Cache hit target**: 70%+ for stable workloads ## Four-Bucket Strategy 1. **Write**: Save context externally (scratchpads, files) 2. **Select**: Pull only relevant context (retrieval, filtering) 3. **Compress**: Reduce tokens while preserving info (summarization) 4. **Isolate**: Split across sub-agents (partitioning) ## Anti-Patterns - Exhaustive context over curated context - Critical info in middle positions - No compaction triggers before limits - Single agent for parallelizable tasks - Tools without clear descriptions ## Guidelines 1. Place critical info at beginning/end of context 2. Implement compaction at 70-80% utilization 3. Use sub-agents for context isolation, not role-play 4. Design tools with 4-question framework (what, when, inputs, returns) 5. Optimize for tokens-per-task, not tokens-per-request 6. Validate with probe-based evaluation 7. Monitor KV-cache hit rates in production 8. Start minimal, add complexity only when proven necessary ## Runtime Awareness The system automatically injects usage awareness via PostToolUse hook: ```xml <usage-awareness> Claude Usage Limits: 5h=45%, 7d=32% Context Window Usage: 67% </usage-awareness> ``` **Thresholds:** - 70%: WARNING - consider optimization/compaction - 90%: CRITICAL - immediate action needed **Data Sources:** - Usage limits: Anthropic OAuth API (`https://api.anthropic.com/api/oauth/usage`) - Context window: Statusline temp file (`/tmp/ck-context-{session_id}.json`) ## Scripts - [context_analyzer.py](./scripts/context_analyzer.py) - Context health analysis, degradation detection - [compression_evaluator.py](./scripts/compression_evaluator.py) - Compression quality evaluation