The harness is the OS of the intent stack
The dominant frame. As the software stack regrows in natural language, the harness plays the role of the operating system, mapping item-by-item:
| OS | Harness |
|---|---|
| virtual memory / paging | context compaction |
| syscall | tool call |
| privilege rings | permission system |
| process / lifecycle | subagent / session |
| env & rc files | CLAUDE.md |
| POSIX | MCP |
| filesystem | memory / cross-session state |
The OS's defining power is controlling page tables; the harness's is controlling context layout. Its constituency = the 5 OS functions (resource mgmt, hardware abstraction, protection, persistence, lifecycle), admitted by Liedtke's microkernel minimality: a function belongs in the kernel iff it needs an authority bit / external state / trust externality — i.e. the constitutive half of prosthetic-vs-constitutive-scaffolding. Everything else (task decomposition, domain knowledge, reasoning patterns, agentic loops) is userland = skills.
Current harnesses are in the monolithic-kernel era (1980s). Open seams: prompt injection (prompt-injection-is-buffer-overflow), and the economics → architecture-follows-the-tariff.
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