pi-deepseek-pricing-by-time

Time-of-day-aware DeepSeek cost accounting for pi.

DeepSeek prices every request with peak/off-peak (valley) rates that depend on the hour of day, but pi's cost display is static: it applies one fixed rate set from the model metadata to every message. This extension fixes that by re-pricing each DeepSeek assistant message with what was actually in effect when the message was produced — the effective-dated rate schedule and the peak/off-peak tier for that message's own UTC timestamp — so everything pi derives from per-message cost — session totals, the footer, the statusline cost segment, /usage, exports — matches what DeepSeek bills.

How it works

• Hooks message_end (the same event pi's own docs use for cost correction) and, for assistant messages from the deepseek provider, resolves the model id against the rate period in effect at the message's own timestamp (UTC), then recomputes usage.cost from the message's token counts (input, output, cacheRead, cacheWrite) at that period's peak or off-peak rate.
• pi's session totals are the sum of per-message usage.cost.total, so the corrected values flow into every cost display automatically — no other state to sync.
• Also registers the /deepseek-tier command to show which tier is active right now, and sets a footer status (peak ⚠️/off-peak) that only updates when the tier flips (disableable, see Configuration).

Official rate schedule (as of 2026-09-12)

Peak hours: 01:00–04:00 & 06:00–10:00 UTC, Monday–Friday (09:00–12:00 & 14:00–18:00 Beijing). All other hours — including weekends — are off-peak. Off-peak rates are exactly half of peak. DeepSeek does not charge for cache writes.

Model	Tier	Input (cache miss)	Output	Cache hit (input)	Cache write
deepseek-flash (V4.1-Flash)	peak	$0.30 /M	$1.20 /M	$0.006 /M	$0
deepseek-flash (V4.1-Flash)	off-peak	$0.15 /M	$0.60 /M	$0.003 /M	$0
deepseek-v4-flash, deepseek-v4-flash-vision-exp (legacy ids, routed to V4.1 Flash)	peak	$0.30 /M	$1.20 /M	$0.006 /M	$0
deepseek-v4-flash, deepseek-v4-flash-vision-exp (legacy ids, routed to V4.1 Flash)	off-peak	$0.15 /M	$0.60 /M	$0.003 /M	$0
deepseek-v4-pro (DeepSeek-V4-Pro-0813)	peak	$1.32 /M	$3.96 /M	$0.044 /M	$0
deepseek-v4-pro (DeepSeek-V4-Pro-0813)	off-peak	$0.66 /M	$1.98 /M	$0.022 /M	$0

Timeline

• 2026-08-16 — peak/off-peak (valley) pricing introduced: 01:00–04:00 & 06:00–10:00 UTC, Monday–Friday. Unchanged since.
• 2026-09-10 04:00 UTC — DeepSeek-V4.1-Flash ships as deepseek-flash at lower rates (peak input $0.44 → $0.30 per M, output $1.32 → $1.20; off-peak exactly half). deepseek-v4-flash and deepseek-v4-flash-vision-exp are retired but temporarily routed to V4.1 Flash and billed at Flash rates.
• 2026-09-14 04:00 UTC (cancelled) — DeepSeek had announced that deepseek-v4-pro would retire at this instant and route to V4.1 Flash, then reversed the decision: Pro keeps serving — and billing — unchanged past that instant until further notice. No retirement period is encoded.

Effective-dated schedules and id routing

The schedule is not a snapshot: in deepseek-pricing-by-time.ts each model id maps to an ordered list of rate periods (SCHEDULES), each with an inclusive from instant plus the peak/off-peak rates from that instant on. A period applies until the next one begins, and the first (from-less) period applies to every earlier instant. The message's timestamp selects the period; the timestamp's UTC day and hour then select peak vs. off-peak inside it. Only forward-looking boundaries are encoded — today there are none: every model has a single from-less period, and the mechanism stays ready for the next price change or retirement.

There is deliberately no 2026-09-10 boundary in the schedule. pi persists the corrected cost on every message at message_end, and history is never re-priced, so no message this extension can see predates the V4.1-Flash price cut: an old message keeps the rate that was correct when it completed, and its session totals stay consistent with what DeepSeek billed. (A replay-based re-pricing path would have to reintroduce a pre-2026-09-10 V4-Flash period; until then it would be dead code.)

Each message is looked up by responseModel first, falling back to model. The fallback is what keeps the legacy flash ids priced: DeepSeek echoes a deepseek-v4-flash (or -vision-exp) request as "model": "deepseek-flash", but pi's bundled catalog (0.85.1) has no deepseek-flash entry, and an unknown id would otherwise disable re-pricing entirely and leave pi's stale static catalog cost in place. deepseek-v4-pro echoes its own id.

Install

pi install npm:pi-deepseek-pricing-by-time

or from a local clone of this repo:

pi install ./extensions/deepseek-pricing-by-time

Usage

When a DeepSeek response completes, its cost is re-priced at the period and tier in effect for that message's timestamp:

• message_end corrects the stored per-message cost before it is summed into session totals, so the footer/statusline cost segment is accurate in real time.
• /deepseek-tier reports the currently active tier, the rates in effect for the active model, and the routing note for a retired/legacy id (useful for deciding when to run a batch).

Configuration

The footer tier status is on by default. It can be disabled from project settings (when the project is trusted) or global settings, with project settings taking precedence:

{
  "deepseekPricingByTime": false
}

or the object form:

{
  "deepseekPricingByTime": {
    "showTierStatus": false
  }
}

Cost re-pricing itself is always on; only the footer status indicator is affected.

Optionally: keep models.json as the fallback

If you also override DeepSeek rates in ~/.pi/agent/models.json (e.g. with the off-peak Flash values — 0.15 input, 0.60 output, 0.003 cache hit, in USD per million tokens — since most of the day is off-peak), keep them: they remain the baseline for any message this extension does not touch, for example other frontends that consume your config, or a model id newer than its schedule. This extension corrects the display on top of them.

Customizing

The peak windows and the effective-dated schedules live at the top of deepseek-pricing-by-time.ts (PEAK_HOURS_UTC and SCHEDULES). Edit them there if DeepSeek changes the schedule or prices, or to add other models. The peak windows are defined in UTC on purpose — DeepSeek publishes them in UTC and your local timezone must not affect the tier. A period's optional note is what /deepseek-tier appends for a retired or routed id.

Append a period to express a future price change, keeping each list in ascending from order — e.g. when V4.1 Pro ships, add a second period to deepseek-v4-pro (with placeholders standing in for the real launch instant and rates):

"deepseek-v4-pro": [
  { rates: V4_PRO },
  { from: V41_PRO_LAUNCH, rates: V41_PRO },
],

A brand-new model id is just a new entry with its own list (even a single from-less period). Add a row to the rate table above when the published prices change.

Compatibility

• pi 0.85+ (uses the message_end extension event and ctx.ui status API).
• Tested with deepseek-flash (V4.1 Flash, the canonical id), the legacy ids deepseek-v4-flash / deepseek-v4-flash-vision-exp (routed to V4.1 Flash), and deepseek-v4-pro (Pro rates — the announced 2026-09-14 retirement was reversed) on the official DeepSeek API.
• Cost correctness is display-side: like all pi cost accounting, it is an estimate based on reported usage tokens and published rates, not an invoice.
• Compaction and branch-summary entries still carry pi's static catalog cost: session_compact exposes no way to replace them, so those entries are not re-priced. Every actual assistant message is, so the residual error is limited to those summary entries.

License

MIT