Think of these as the five ways context engineering silently breaks.
**1. Context overload (the kitchen-sink prompt).** The field consensus: keep system prompts under ~2,000 tokens. Everything else should load on demand โ exactly the pattern a skills architecture enforces. Cramming in everything the agent might need wastes most of those tokens on material that's only 10% relevant.
**2. Context poisoning.** One bad retrieved document can contaminate the agent's entire reasoning chain. The mitigations: add provenance tags to every retrieved chunk, apply freshness filters, and treat retrieved text as data โ not as additional instructions.
**3. Naive RAG.** Dropping 50 unranked chunks into the context is where most RAG pipelines fail. The fix: retrieve wide (high recall), then re-rank hard to a precise top-5. Re-ranking is the dividing line between RAG that works and RAG that doesn't.
**4. Context rot in long sessions.** As conversations grow, earlier context degrades in influence. The fix: compaction triggers that summarize old turns, plus subagent offloading for bulk reads.
**5. LLM-generated context files.** The Gloaguen study found that auto-generated CLAUDE.md-style files can actually hurt performance. Write them by hand, from real institutional knowledge.