Darwinian Creativity.
PROTOCOL v0.1Read as Markdown

Fitness Functions v0.1

Fitness functions turn design judgment into numbers. Every function has an ID, a type, a method, a normalized score from 0 to 1, and a version. Scores are only comparable within the same function version.

Types

Type Cost Runs on
Gate Seconds Every variant. Fail means composite = 0.
Measured Seconds to minutes Every variant that passes gates.
Judged Model calls Top 20% after measured scoring.
Field Days, real users Top 2 or 3 finalists, when the target allows it.

Gates

ID Check Pass condition Tool
G-A11Y Automated accessibility Zero critical or serious violations axe-core
G-CONTRAST Text and UI contrast WCAG 2.2 AA: 4.5:1 body text, 3:1 large text and UI components axe-core plus computed styles
G-OVERFLOW Horizontal overflow No horizontal scroll at 320 px width Playwright: scrollWidth <= clientWidth
G-RENDER Render health No console errors, no failed requests Playwright
G-LOCK Locked genes untouched Locked values identical to genome Diff against genome.json

Measured functions

ID Measures Method Score
M-TOKEN Token fidelity Share of computed color, spacing, radius and font values that map to a genome token Ratio, 0 to 1
M-RHYTHM Spacing rhythm Share of vertical gaps on the spacing scale; variance of section spacing 1 minus normalized deviation
M-TYPE Typographic health Body size at least 16 px, line length 45 to 75 characters, line height 1.4 to 1.7 for body Share of text blocks in range
M-TARGET Touch targets Interactive elements at least 44 by 44 px at 320 and 768 px Share passing
M-PERF Performance Lighthouse performance, LCP, CLS, JS weight Weighted, normalized against budget
M-RESP Responsive stability Layout keeps reading order and hierarchy across 4 widths Structural diff score
M-DIVERSITY Novelty vs parents Perceptual distance from parents and siblings Used for selection bonus, not composite

Default performance budget: LCP under 2.0 s on mobile emulation, CLS under 0.05, first-load JS under 120 kB gzip.

Judged functions

Judged functions cover what cannot be measured yet. Each uses a written rubric, a 1 to 5 scale, and 3 independent model judges. The score is the median, normalized to 0 to 1.

ID Question the rubric answers
J-HIERARCHY Is it obvious what to look at first, second and third?
J-CLARITY Can a first-time visitor say what this is and what to do within 5 seconds?
J-BRAND Does it read as this brand and no other?
J-CRAFT Alignment, optical balance, detail. Would a senior designer ship it?

Rules:

  • Judges see screenshots plus the target profile, never other variants' scores.
  • Judge model names and versions are logged in the run record.
  • Calibration: before a run, judges score 10 human-rated reference designs. A judge is used only if its rank correlation with human ratings is at least 0.6.
  • Any judged function that repeatedly disagrees with Stage 6 human review is flagged for rubric revision.

Field functions

ID Measures
F-CONVERT Primary conversion rate vs baseline
F-TASK Task success rate in moderated or unmoderated tests
F-TIME Time on task

Field results are reported separately and never mixed into the lab composite.

Composite score

composite = gates_pass * sum(weight_i * score_i) / sum(weight_i)
  • gates_pass is 1 if every gate passes, else 0.
  • Weights live in target.json and are fixed before Stage 2. Changing weights mid-run starts a new run.

Default weights:

Function Weight
M-TOKEN 1.0
M-RHYTHM 0.75
M-TYPE 0.75
M-TARGET 0.5
M-PERF 1.0
M-RESP 1.0
J-HIERARCHY 1.5
J-CLARITY 1.5
J-BRAND 1.0
J-CRAFT 1.0

Adding a function

  1. Propose it with ID, method, scoring and the human review reasons that motivated it.
  2. Validate on at least one past run: does it separate accepted from rejected finalists?
  3. Ship it in a minor version bump. Old runs keep their old version label.