[MarkusNeusinger]

Summary

• One source for the per-mark label rule. feat(agents): gates for per-mark label density and the plot language's number format #12184 gave the agent adapter a rule for elements the catalogue draws once per bar or point (value labels, dots on bar ends, shadows): keep them only while each fits its mark, which rarely holds past about 25 marks; otherwise drop them or label the extremes. Per the owner's decision of 2026-10-15, the rule now lives in prompts/default-style-guide.md ("Per-mark Labels and Decorations"), so the catalogue pipeline applies it too.
• Rubric, proportional and soft. prompts/quality-criteria.md VQ-03 gains a "Per-mark labels and decorations count as elements" paragraph (deduct VQ-03 in proportion to how much of the plot they bury, VQ-02 where they overlap; labels that fit, or a few labelled extremes, are no deduction), and the 5d proportional sizing check of ai-quality-review.md gets a matching bullet. No new hard threshold: "about 25 marks" is a heuristic like the data-density heuristic's "< 50 points"; the agent's G11 gate keeps its own measured thresholds in code.
• Agent prompts. agents/anyplot/prompts/adapter.md keeps its agent-specific framing ("the same style" covers fixed-count elements) and points at the shared rule instead of repeating it; the adapter reads the style guide and the VQ-03 rubric verbatim. The scorer's and reviewer's narrowed house-style exemption stays as is (it is the agent-only exception, not the rule). A unit test holds that the "about 25 marks" wording appears once in the adapter's instruction. docs/concepts/agent-network.md names the new source.

Review retest

The last all-Opus set v1 arm (37233543394, rules c64630aa7) predates the claude-code-action pin bump (#11975/#12099) and the rubric change of #12102, so a fresh baseline was run on main's rules (e2a63d6, run 38702205512). To keep the spend near one core arm, both arms ran the 15 fresh core items plus f-bar-stacked-labeled-d3 and f-heatmap-basic-seaborn (labelled plots, as false-alarm probes), 3 runs each, all on claude-opus-5-5, without the bubble regen pairs, which carry no per-mark labels.

Review retest — set v1 f-bubble-basic-ggplot2,f-area-elevation-profile-seaborn,f-bar-horizontal-makie,f-bode-basic-altair,f-bar-diverging-plotnine,f-pie-basic-highcharts,f-bar-pareto-letsplot,f-waterfall-basic-muix,f-line-win-probability-chartjs,f-bubble-basic-d3,f-network-basic-bokeh,f-bar-diverging-likert-matplotlib,f-acf-pacf-plotly,f-line-stock-comparison-pygal,f-gantt-basic-echarts,f-bar-stacked-labeled-d3,f-heatmap-basic-seaborn (17 fresh × 3)

Fresh: claude-opus-5-5 · rules e2a63d6 → 35caaaf · harness v1

Metric	Baseline	Candidate	Δ (95% CI)
Total mean / pooled within-item SD (typed)	79.2 / 1.4	79.3 / 1.5	0.0 (-0.8…+0.9) / 0.1 (-0.5…+0.8)
Items with split verdict at 90	0/17	0/17
Noisiest criteria (SD)	VQ-01 0.5 · DE-02 0.5 · LM-02 0.4	VQ-01 0.5 · VQ-03 0.5 · VQ-05 0.5
Weakness-topic Jaccard	0.61	0.62
Silent deductions (technical items, fresh)	0/178 (0%)	0/174 (0%)
Named-defect miss rate	17/69	15/69
False alarms on permitted features	0/9	1/9
Sessions / API-equivalent cost	51/51 / $37	51/51 / $41

run · set v1 lock sha256 a6831a315a11

Reading. Neutral, as intended for a set with no crowded labels. No candidate weakness cites per-mark label density; the labelled plots (f-bar-stacked-labeled-d3, f-bar-horizontal-makie value labels, f-bar-diverging-plotnine value labels, f-heatmap-basic-seaborn cell text) keep their VQ-03 scores (6/6/6, 6/6/6, 6/6/6, 5–6). VQ-03's mean stays at 5.4. VQ-03's within-item SD (0.31 → 0.46) moves on f-bode-basic-altair (one 4) and f-line-stock-comparison-pygal (4 to 6), whose VQ-03 comments name a bright dark-theme grid, thin lines and small legend swatches, not labels. The one false alarm is f-bubble-basic-ggplot2 A1, run 1: an SC-01 line about the off-spec top-3 callout layer says the callouts "sit on top of the dense bubble clusters", which the probe's overlap regex catches; it is not a per-mark label deduction. The set has no crowded-label item, so the retest shows that the rule does not take points from plots that pass it, but it cannot measure detection. G11's fixtures in #12184 cover the crowded case on the agent side.

Plan

N/A

Test plan

• uv run pytest tests/unit -n 4 (11,037 passed)
• ruff check, ruff format --check, tools.changelog check --base origin/main
• Review retest candidate vs baseline: no per-mark label deductions on the labelled plots, no rise in silent deductions, total within ±0.9 points

[Copilot]

🔵 Needs a closer look

The required baseline-versus-candidate review retest remains pending, leaving catalogue scoring regressions unverified.

0 open findings

What changed in this PR

Centralizes per-mark label density guidance so the catalogue pipeline and agent adapter share the same rule.

Changes:

• Adds shared guidance and proportional scoring deductions for crowded labels and decorations.
• Replaces duplicated adapter guidance with a reference to the shared rule.
• Adds a prompt consistency test and updates documentation.

File	Description
tests/​unit/​agents/​runtime/​test_density_locale_gates.py	Checks shared guidance appears once in adapter instructions.
prompts/​workflow-prompts/​ai-quality-review.md	Adds the label-density review check.
prompts/​quality-criteria.md	Defines proportional deductions for crowding.
prompts/​default-style-guide.md	Establishes the shared per-mark density rule.
docs/​concepts/​agent-network.md	Documents the shared rule’s source.
changelog.d/​style-guide-label-density.md	Records the rubric and adapter changes.
agents/​anyplot/​prompts/​adapter.md	References shared guidance instead of duplicating it.

🧠 Review effort: Balanced

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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