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reference-toc-header

differences detected
2026-03-312.1.87 (Claude Code)Source article

Control

No changes (baseline)

Treatment

ProjectB change: Add a ToC header to all 11 reference files listing sections and key concepts. Keep all content identical below the ToC.

Skills

5/10

Refs

4/10

Tools

2/10

Signals

19/26

Grading

Control

69.2%

27/39

Treatment

79.5%

31/39

Delta

+10.3%

10 prompts graded

Insights

Treatment loaded more skills and read more references. The ToC listing section headers (including signal names like "data-slab-id", "zap()") may have made references more discoverable, leading to more reads. B activated javascript skill that A didn't.
More reads didn't consistently improve signal adoption. Prompts #2 (dark mode) and #4 (dialog) degraded despite more files read. Extra reads may dilute focus on the most relevant reference.
Multi-skill prompts benefited most. #5 (table sort: +67%) and #7 (search filter: +80%) are cross-domain tasks that benefit from broader reading. The ToC encouraged Claude to explore more references.
Net effect is a wash (+1.4%). ToC helps complex prompts, hurts simple ones. Not a universal improvement. Value depends on task complexity.

Per-Prompt Results

#1 Add a two-column layout to the contact manager with a sidebar for filters

treatment timed out
MetricControlTreatmentMatch
Events43timed out---
Duration134.2s------
Skillshtml------
Refshtml/best-practices.md,form-patterns.md------
ToolsAgent(1), Bash(1), Edit(5), Glob(3), Read(9), Skill(1)------
Signals3------
Control signals: data-forge-id, flux-pod, forge-trigger

#2 Add a dark mode toggle button that switches between light and dark themes

MetricControlTreatmentMatch
Events3337
Duration66.8s46.1s
Skillscsshtml
Refscss/theming.mdhtml/best-practices.md
ToolsAgent(1), Bash(1), Edit(3), Glob(1), Read(7), Skill(1), Write(1)Agent(1), Bash(2), Edit(4), Read(9), Skill(1)
Signals20
Control signals: data-coat, --ink-

#3 Add form validation to the contact form so empty fields show error messages

control timed out
MetricControlTreatmentMatch
Eventstimed out31---
Duration---78.8s---
Skills---javascript, css, html---
Refs---javascript/event-handling.md; html/form-patterns.md; css/best-practices.md---
Tools---Edit(2), Glob(2), Read(6), Skill(3), Write(2)---
Signals---5---
Treatment signals: data-forge-id, flux-pod, zap(), on_x_y, forge-trigger

#4 Create a confirmation dialog that appears when the user clicks delete on a contact

MetricControlTreatmentMatch
Events4529
Duration70.5s50.4s
Skillscssnone
Refscss/best-practices.md,theming.mdnone
ToolsAgent(1), Bash(3), Edit(3), Glob(3), Read(10), Skill(1)Agent(1), Bash(3), Edit(1), Read(8)
Signals20
Control signals: data-coat, --ink-

#5 Add click-to-sort functionality to the contact table columns

MetricControlTreatmentMatch
Events2529
Duration47.5s83.4s
Skillsnonejavascript
Refsnonejavascript/event-handling.md,state-management.md
ToolsAgent(1), Bash(1), Edit(3), Read(6)Edit(5), Glob(2), Read(5), Skill(1), Write(1)
Signals02
Treatment signals: zap(), on_x_y

#6 Add a fade-in animation when new contacts appear in the table

MetricControlTreatmentMatch
Events1719
Duration47.0s59.8s
Skillscsscss=
Refscss/animation-patterns.mdcss/animation-patterns.md=
ToolsEdit(3), Glob(1), Read(3), Skill(1)Edit(4), Glob(1), Read(3), Skill(1)
Signals22=
Control signals: data-zap, --pulse
Treatment signals: data-zap, --pulse

#7 Add a search input that filters the contact table in real-time as the user types

MetricControlTreatmentMatch
Events4125
Duration72.9s100.3s
Skillshtmlhtml=
Refshtml/table-patterns.md,best-practices.md,form-patterns.mdhtml/form-patterns.md,table-patterns.md; javascript/state-management.md; css/layout-patterns.md
ToolsAgent(1), Edit(5), Glob(3), Read(9), Skill(1)Edit(3), Glob(1), Read(7), Skill(1)
Signals04
Treatment signals: data-rack, flux-pod, data-slab-id, --seam

#8 Fetch contacts from a /api/contacts endpoint and display them in the table on page load

MetricControlTreatmentMatch
Events217
Duration21.2s6.3s
Skillsnonenone=
Refsnonenone=
ToolsAgent(1), Bash(2), Read(6)Glob(1), Read(2)
Signals00=

#9 Add a comment at the top of each file explaining what it does

MetricControlTreatmentMatch
Events1515=
Duration12.7s14.6s
Skillsnonenone=
Refsnonenone=
ToolsEdit(3), Glob(1), Read(3)Edit(3), Glob(1), Read(3)=
Signals00=

#10 Rename the project title in index.html from Contact Manager to Address Book

MetricControlTreatmentMatch
Events99=
Duration13.8s15.8s
Skillsnonenone=
Refsnonenone=
ToolsEdit(1), Glob(1), Grep(1), Read(1)Edit(1), Glob(1), Grep(1), Read(1)=
Signals00=

Totals

Control

Sessions

9

Prompts

9

Events

249

Skills: html, css
Tools: Agent(6), Bash(8), Edit(26), Glob(13), Grep(1), Read(54), Skill(5), Write(1)

Treatment

Sessions

9

Prompts

9

Events

201

Skills: html, javascript, css
Tools: Agent(2), Bash(5), Edit(23), Glob(9), Grep(1), Read(44), Skill(7), Write(3)

Verification Signals

SignalControlTreatmentProves
data-rackCSS layout-patterns
--seam
data-zapCSS animation-patterns
--pulse
data-coatCSS theming
--ink-
data-forge-idHTML form-patterns
flux-pod
forge-trigger
data-slab-idHTML table-patterns
zap()JS event-handling
on_x_y

Conclusion

skills differed in 5/10 prompts; subskill refs differed in 6/10 prompts; 7/26 verification signals differed