Evidence

Every number, with the run behind it.

We do not ask you to trust a skill. Each one was measured on held-out cases it never saw, by a machine, and the results are here. Every number here has a run behind it.

Office skills

Sixteen held-out specifications per row, best of two samples. Cheap model: DeepSeek-chat. Strong model: claude-sonnet-5. Prices at the time of the run.

skill, contextcheap model alonecheap model + skillstrong model alonecents per success, skill vs strongskill
docx, portrait then landscape section with header and table25%100%87.5%0.15 vs 4.83 (32x)docx_landscape_rungs
pptx, combo chart on a secondary axis12.5%100%100%0.32 vs 4.66 (15x)pptx_combo_chart_rung
pdf, fillable AcroForm43.8%100%100%0.15 vs 2.92 (19x)pdf_fillable_form_rungs
xlsx, validated sheet: frozen header, dropdown, named range, conditional format (checker forged, not hand-written)56.2%87.5%100%0.18 vs 3.58 (20x)xlsx_validated_sheet_rungs
pdf, real form, the real CRA TD1 tax form, filled from human labels18.8%93.8%100%0.34 vs 27.17 (80x)real_form_fill_td1_rungs

How the shelf grows

13 contexts were described in plain words. No code was written for any of them: a strong model wrote the reference, the exact checker, deliberate corruptions that must fail, and a specification generator, and a mutation gate decided whether to trust the result. 12 checkers passed, for $1.35 in total. A skill is then built and listed only where it measurably beats the model working on its own, so the shelf stays worth reading.

contextcheap model alonecheap model + skillinterval on the liftchecker
calendar, RFC 5545 with a weekly recurrence and a display alarm38%88%+0.250..+0.750$0.13
email, MIME with a non-ASCII subject and an attachment31%75%+0.188..+0.688$0.17

Small and local models

With a skill wrapped as a single call, the model only fills in a JSON argument schema. Qwen3 runs in bf16 with thinking off on one consumer GPU.

skillexecutorheld-out setcents per item
pdf fillable formDeepSeek-chat (API)16/160.059
pptx combo chartDeepSeek-chat (API)16/160.065
pdf fillable formQwen3-1.7B, local, no API15/160
pptx combo chartQwen3-1.7B, local, no API16/160
pdf fillable formQwen3-0.6B, local, no API16/160
pptx combo chartQwen3-0.6B, local, no API16/160
calendar with recurrenceQwen3-0.6B, local, no API8/80

A public benchmark: 134 unseen games

A public benchmark of household tasks, run on its own unseen evaluation split. Our library was built from 24 training games and never touched the unseen split.

executorsuccessmodel turns per gamecents per game
DeepSeek cold (ReAct over admissible commands, 50 steps)70/13431.40.389
DeepSeek + rungs v4134/1341.000.033
Local Qwen3-1.7B + rungs v4, no API133/1341.070
Local Qwen3-1.7B + rungs v4 + parser rung134/1341.000
Parser rung alone, no model134/13400
The best published baseline on this split (GPT-4o with a skill library)99.3%3.2n/a

Autopilot

60 mixed office tasks with no human in the loop: 58 correct for 8.3 cents in total, 0.15 cents per task from first to last, because every skill the workload needed had already been forged once.