Filesystem-Based Context Engineering

Use the filesystem as the primary overflow layer for agent context because context windows are limited while tasks often require more information than fits in a single window. Files let agents store, retrieve, and update an effectively unlimited amount of context through a single interface.

Prefer dynamic context discovery -- pulling relevant context on demand -- over static inclusion, because static context consumes tokens regardless of relevance and crowds out space for task-specific information.

When to Activate

Activate this skill when:

• Tool outputs are bloating the context window
• Agents need to persist state across long trajectories
• Sub-agents must share information without direct message passing
• Tasks require more context than fits in the window
• Building agents that learn and update their own instructions
• Implementing scratch pads for intermediate results
• Terminal outputs or logs need to be accessible to agents

Do not activate this skill for adjacent work owned by other skills:

• Semantic cross-session memory, entity tracking, or temporal knowledge graphs: memory-systems.
• Conversation summarization, compaction, or durable handoff wording: context-compression.
• Token-efficiency tactics that do not require file-backed storage: context-optimization.
• Multi-agent topology or handoff protocol design: multi-agent-patterns.
• Model edits that evict content from the live window itself: self-managed-context.

Core Concepts

Diagnose context failures against these four modes, because each requires a different filesystem remedy: