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Illustration 8.1 — Routing matrix

Referenced in Chapter 8. Four routing qualities (Fit / Acceptable / Poor / Do-not-route) are encoded by four monochrome fill techniques: solid fill, dot pattern, diagonal hatch, and diagonal strike. No colour.

Fit Acceptable Poor Do-not-route
0
Human		 1
Rules		 2
Classical ML		 3
LLM feature		 4
RAG		 5
Single agent		 6
Tool-using agent		 7
Multi-agent
Judgment callwho is accountable; what is fair Fit
Codified decisionstable rule, auditable Acc Fit Poor Poor Poor Poor Poor Poor
Prediction on tabular datalabels available Poor Acc Fit Poor Poor Poor Poor Poor
Open-ended text transformationsummary, rewrite, classify Poor Poor Acc Fit Acc Acc Poor Poor
Question over a proprietary corpusfresh or niche knowledge Poor Poor Poor Acc Fit Acc Acc Poor
Bounded task with one external calllookup, fetch, compute Poor Acc Poor Poor Poor Fit Acc Poor
Multi-step task with tools and side effectsbook, refund, file Poor Poor Poor Poor Poor Acc Fit Acc
Coordination across specialistsparallel sub-tasks, handoffs Poor Poor Poor Poor Poor Poor Acc Fit

Fit: cheapest option that carries the job. Acceptable: works but pays a tax. Poor: try only with a stated reason. Do-not-route: the row must stay on its Fit column.

Four categories, four fill techniques

  • Fit — solid fill in fg colour; label inverted (bg text on fg ground). Reads loudest. The diagonal from top-left to bottom-right traces the spine of the matrix.
  • Acceptable — dotted pattern, 6-pixel grid. Reads as present but not emphatic.
  • Poor — 45° hatch, light density. Reads as visible but recessive.
  • Do-not-route — empty cell with a single diagonal strike. Reads as crossed off.

The four techniques are visually distinct at a glance, distinguishable when printed on a black-and-white office laser printer, and — critically — flip cleanly between light and dark mode because every stroke and fill references the theme's fg/bg variables.

Dark-mode check

Toggle theme (top right). The Fit band inverts to solid-white-on-black; hatches and dots re-draw in white on black; the strike marks stay. Same diagram, no second asset.

Three-technique cheat sheet (monochrome edition)

Illustration shape Technique House-rule encoding
Flow, sequence, hierarchy Mermaid Border weight, dash, arrow thickness
Emphasis, strike, contrast Inline SVG Strike marks, frame weight, opacity tiers
Grid of categorical data HTML + CSS Solid fill, dots, hatches, strikes

Every rendering agent for this book follows the same rule: two colours from theme variables, emphasis through technique rather than hue, third colour only with a written justification in the spec.