# Context Isolation
Context isolation is the practice of separating different types or trust levels of context so that problems in one domain don't contaminate another. It's the security boundary within [[Context Engineering]].
## Isolation boundaries
### Trust-based isolation
Separate context by trustworthiness:
- **Trusted**: human-authored instructions, reviewed rules, curated knowledge (CLAUDE.md, skills, identity notes)
- **Semi-trusted**: AI-generated memories, previous conversation context, internally retrieved documents
- **Untrusted**: external tool outputs, web search results, RAG-retrieved content from unverified sources, user-uploaded documents
The model should treat these differently, but it can't unless the context explicitly marks trust boundaries. This is the core challenge of preventing [[Context Poisoning]].
### Scope-based isolation
Separate context by scope to prevent cross-contamination:
- Project A's context shouldn't leak into Project B's agent
- Personal context (health, finances) shouldn't appear in work-related agent outputs
- Customer data shouldn't flow between different customer contexts
### Temporal isolation
Separate current context from historical context:
- Current task instructions shouldn't be diluted by old conversation context
- Fresh tool results should take precedence over cached/stale results
## Why isolation matters
Without isolation:
- A poisoned RAG result can override trusted instructions
- Agent memories from one project bleed into another
- [[Context Entropy]] in one layer degrades the entire system
- Security and compliance boundaries become impossible to enforce
## Implementation patterns
- **Separate context windows**: use different conversations or agents for different trust levels
- **Context tagging**: mark each piece of context with its source and trust level (cfr [[Context Provenance]])
- **Agent specialization**: dedicated agents with focused context rather than one agent with everything (cfr [[Receptionist AI Design Pattern]])
- **[[Context Layering]]**: architectural separation into enterprise/team/personal/task layers
## References
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## Related
- [[Context Layering]]
- [[Context Inheritance]]
- [[Context Poisoning]]
- [[Context Engineering]]
- [[AI Context Governance]]
- [[Context Provenance]]
- [[Context Entropy]]
- [[Receptionist AI Design Pattern]]
- [[Separation of Concerns]]
- [[Harness Engineering]]
- [[Personal Context Management (PCM)]]
- [[Enterprise Context Management (ECM)]]