A spending cap can only be set on the command line: not in the builder, on a host, or shown on the job page #45

Priority

high

Components

• app/nullius (backend)
• app/web (routes)
• templates and static files
• docs and the site
• catalogue (benchmarks, agents, capabilities)
• the standard (ports, kits, relay, runs)
• CI, workflows and skills

Today

A spending cap exists only on the command line: nullius standard run --max-usd USD (#14). A run started from the builder's Review step has no cap, on this machine or on a host. A capped job's result.json carries budget (the cap, what was spent, whether it stopped the run, the units cut off and those not run), but no page shows it: a unit the cap cut off reads as an API error with SpendingCapError beside it, and the units never begun appear nowhere. With shards, each shard's cap is its own and merge drops budget from the merged result.

Wanted

• A cap in the builder for a Nullius recipe, sent with the run on this machine and on a host; not offered for a Harbor recipe, whose calls do not pass the relay.
• One cap for the whole run: its jobs that call a model (each dataset with each participant, on each machine) take equal shares, and Review says the cap and each job's share.
• The merged job of a launch says the cap and what all its shards spent.
• The job page says the cap stopped the run, what was spent, and which units were cut off or not run.

Acceptance

• A Nullius recipe can be given a spending cap in the builder, and the run it starts, here or on a host, stops at it as the command line's does.
• A Harbor recipe is not offered the cap.
• A run of several jobs (participants, datasets, shards) shares the cap in equal parts, and the merged job's result carries the cap and the total spent.
• The job page of a capped run shows the cap, what was spent, and, when the cap stopped it, the units cut off and those not run.

Dependencies and related

Follows #14 (the cap on the command line) and #38 (the user's price list, which a cap books calls from). A cap per unit is #47: it changes how a unit counts, which is to be decided first.