feat(pricing): weekends bill off-peak, and the vision model is on the card

[lroolle]

Two upstream changes since 2026-08-17, neither of which reached us through a changelog.

Weekends are off-peak

From 16:00 UTC on 2026-08-22 (00:00 Beijing, Sun 23 Aug), a Saturday or Sunday bills off-peak for all 24 hours. Peak is 35 hours a week, not 49 — so anything reading the hour alone reports peak for 14 hours a week the account is charged half for.

DeepSeek published no changelog entry. The announcement sat in the pricing-page footnote for a few days before it took effect, and the live page now carries only the settled rule, so it exists nowhere on api-docs.deepseek.com today. The citable source is the archived copy, recorded next to the constant in all three places that hold it:

Effective 00:00 (Beijing Time) on Sunday, August 23, 2026, we will adjust our peak/off-peak billing rules, with off-peak rates applying throughout the day on weekends (Saturdays and Sundays, Beijing Time).

The weekday is read on the vendor's clock, because that last parenthesis is the rule as written — which puts the turnover at 16:00 UTC, not midnight UTC. A Friday evening in Europe is already Saturday upstream.

That choice is untestable by ordinary means and worth being explicit about. Both windows close at 10:00 UTC, well before the 16:00 UTC point where a UTC date and a Beijing date diverge, so the two readings label all 168 hours of the week identically and any test written against the published windows passes with the shift deleted. The tests therefore pin the instants that do discriminate. Verified by mutation, per copy:

copy	mutation	result
internal/deepseek	weekday read in UTC	1 failed — TestWeekendTurnsOverOnTheVendorClock
internal/deepseek	boundary gate removed	1 failed — TestWeekendRuleDoesNotRepriceHistory
gateway/…/meter	weekday read in UTC	1 failed — TestWeekendIsReadOnTheVendorClock
site/pricing.js	BEIJING_OFFSET_MS = 0	2 failed — the two onDay vectors

Each dies to a targeted test and nothing else, which is the point: without those vectors every mutant passes the whole suite.

The boundary is kept, not backdated

Gated on its own instant rather than folded into RepriceAt. Working it through, exactly one weekend day ever billed peak under time-of-use:

Sun 2026-08-16   windows had already passed when time-of-use began  -> flat
Sat 2026-08-22   time-of-use live, weekend rule not yet             -> PEAK
Sun 2026-08-23   weekend rule live from 00:00 Beijing               -> off-peak

A ledger that refunds that Saturday is inventing money the account never got back. TestWeekendRuleDoesNotRepriceHistory pins all three rows.

The vision model was metering at zero

deepseek-v4-flash-vision-exp shipped 2026-08-21, priced exactly as flash on every bucket in both currencies, and was absent from the card — so a call to it cost nothing, in the CLI's estimates and in the gateway's budget.

Added, plus a single deepseek.Models list, because it was missing from three separate hardcoded []string{ModelFlash, ModelPro} iterations. The next model reaches every table at once.

It lands in three copies, on purpose

copy	why it is separate
internal/deepseek	the CLI's card and clock
gateway/…/meter	separate Go module, no shared import. make price-check guarded the numbers; nothing guarded the clock, so it now has tests that do
site/build.py	the schedule gained a days axis; pricing.js reads it, pricing.test.js pins it

The gateway's drift ran the safe direction — over-charging our own budget rather than under — but it still made /economics report a cost-per-task nobody paid.

One process note worth keeping: I first edited the generated site/pricing/index.html directly. make site-check caught it and I redid the work in build.py. That check earned its keep.

Also in here

• The embedded docs corpus is repacked from the freshened mirror (docs: PRICING TRIPWIRE: weekends off-peak; plus vision, Files API, and 57 NUL bytes deepseek-docs#16), so ds docs show quick_start/pricing carries the Monday-through-Friday footnote and the third pricing column offline. 75 pages.
• Two news entries — the weekend rule and the vision release.
• site/llms.txt and the FAQ/OG metadata, which all still described a daily schedule and a two-model API.

Verified

• make check — green end to end: fmt, vet, go test ./..., corpus-check, price-check (5 matching rate-card rows across both modules), build, gateway-check, site-check, bans.
• ds pricing prints the vision row and peak hours … Mon-Fri; all other hours, and all weekend, off-peak.
• The pricing page rendered headless on a faked Beijing Saturday: off-peak, next peak in 46h59m. dsh-meter, written independently, gives the same answer for the same instant.

🤖 Generated with Claude Code