What

Adds a Show Cost (USD) toggle to the leaderboard. When on, each score cell gains a muted second line with cost, mirroring how scores are shown at every level (model total / category / subtask). Off by default — the table is byte-for-byte unchanged unless toggled.


Show cost: ☑
 Model            Global Avg   Reasoning   Coding   Agentic Coding
 Claude Opus 4.8   78.8         80.7        71.7     75.0
                   $45.21       $1.48       $1.16    $38.00     ← covered: per-cell USD totals
 Some-OSS-70b      54.2         55.1        48.0     49.9
                   n/a                                          ← not in cost file: single n/a

How it works

• Data: a parallel, feature-detected public/cost_<date>.csv with the same header shape as table_<date>.csv (first col model, then the task columns) but holding USD totals per task.
• Roll-up = SUM (totals, not means): subtask → category → model. Totals are additive, so the per-task costs sum to the category total and categories sum to the model total (the global cell).
• Coverage is data-driven: a model shows cost iff it has a row in the cost file. Everyone else (including non-best variants) shows a single muted n/a — in the Global Average cell, or the first metric cell when only one category is selected. No allowlist or "top-N" logic in the UI.
• Composes with every existing control (category average/subcategories, Show Variants, row filters, sort, organization/API-name) with no new branches — cost renders inside the cells those controls already build.
• Zero impact until data lands: dates with no cost_<date>.csv hide the toggle and render exactly as today (fetch is feature-detected; guards against SPA 200-with-index.html fallbacks).
• c/cost=true URL param, consistent with the other display toggles; reset by Clear Filters.

Files

• src/Table/Averaging.js — sumColumns() (sum twin of calculateAverage)
• src/Table/CSVTable.jsx — state + URL param, cost fetch, checkbox (only when a cost file is loaded), per-cell render, reset
• src/App.css — .cost styling (muted, tabular-nums; hidden < 600px)

Activation

Drop a cost_<date>.csv (same model keys as table_<date>.csv, USD totals per task — key by the displayed model name so variant-collapse matches) into public/. Only those models show cost; the rest show n/a. Initial rollout will populate the top models from a rerun; the file is sparse by construction.

Testing

• npm run build compiles cleanly (only pre-existing lint warnings).
• Verified roll-up math against a sample cost file + the real categories_2026_01_08.json: category totals and the global total reconcile (e.g. Agentic Coding $38.00, python subtask $14.00, global $45.21); uncovered models render a single n/a.
• Adversarially reviewed for regressions: no-cost-file dates unchanged, no URL/render loop, no key-casing mismatch, fetch rejects HTML fallbacks.

🤖 Generated with Claude Code