Layer stack · Diagram Design
AI app stack · Where the work actually happens
ABSTRACTION
SILICON
L5
UI surface
chat, editor, canvas
L4
Agent harness
tools, memory, loop
L3
Prompt layer
system, few-shot, caching
L2
SDK / client
auth, retries, streaming
L1
Model weights
opus, sonnet, haiku
FOCAL LAYER
The harness is where most product differentiation actually lives — tools, memory, and the loop that stitches model calls into useful work.