fix(pricing): DeepSeek V4 static defaults stale by 4 days, off by ~1.6-2.4x (#10635)

Merged — locally validated (28/28 focused pricing tests, gates green). Appreciate the conservative off-peak-only scope and the live verification against the pricing page. Thanks!

src/shared/constants/pricing/frontier-labs.ts

@@ -317,20 +317,28 @@ export const DEFAULT_PRICING_FRONTIER = {
       reasoning: 2.19,
       cache_creation: 0.55,
     },
-    // DeepSeek official API list prices, checked 2026-08-13.
+    // DeepSeek official API list prices, checked 2026-08-18. Superseded the
+    // prior 2026-08-13 flat prices below: DeepSeek switched v4-pro/v4-flash to
+    // peak/off-peak dynamic pricing on 2026-08-17 (peak = exactly 2x off-peak;
+    // peak hours 01:00-04:00 and 06:00-10:00 UTC — see
+    // https://api-docs.deepseek.com/quick_start/pricing/). This static table has
+    // no time-of-day dimension, so these are the OFF-PEAK (lower-bound) prices —
+    // a deliberate, documented undercount during the two peak windows, never an
+    // overcount. True peak-awareness would need a time dimension threaded through
+    // getPricingForModel() and every call site; out of scope for this fix.
     "deepseek-v4-pro": {
-      input: 0.435,
-      output: 0.87,
-      cached: 0.003625,
-      reasoning: 0.87,
-      cache_creation: 0.435,
+      input: 0.66,
+      output: 1.98,
+      cached: 0.022,
+      reasoning: 1.98,
+      cache_creation: 0.66,
     },
     "deepseek-v4-flash": {
-      input: 0.14,
-      output: 0.28,
-      cached: 0.0028,
-      reasoning: 0.28,
-      cache_creation: 0.14,
+      input: 0.22,
+      output: 0.66,
+      cached: 0.007,
+      reasoning: 0.66,
+      cache_creation: 0.22,
     },
   },
   blackbox: {

tests/unit/pricing-deepseek-v4-static-regression.test.ts

@@ -0,0 +1,44 @@
+// Regression guard for the corrected DeepSeek V4 static pricing defaults (#10635): DeepSeek
+// switched deepseek-v4-pro/deepseek-v4-flash to peak/off-peak dynamic pricing on 2026-08-17;
+// the static table carries the off-peak (lower-bound) values. Asserts the exact corrected
+// figures and the documented output=3x-input / peak=2x-off-peak internal consistency so a
+// future accidental revert to the stale 2026-08-13 numbers is caught by CI.
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+const { DEFAULT_PRICING_FRONTIER } = await import(
+  "../../src/shared/constants/pricing/frontier-labs.ts"
+);
+
+test("deepseek-v4-pro carries the corrected off-peak static prices", () => {
+  const entry = (DEFAULT_PRICING_FRONTIER as Record<string, Record<string, Record<string, number>>>)
+    .deepseek["deepseek-v4-pro"];
+  assert.ok(entry, "deepseek-v4-pro entry must exist under DEFAULT_PRICING_FRONTIER.deepseek");
+  assert.equal(entry.input, 0.66);
+  assert.equal(entry.output, 1.98);
+  assert.equal(entry.cached, 0.022);
+  assert.equal(entry.reasoning, 1.98);
+  assert.equal(entry.cache_creation, 0.66);
+});
+
+test("deepseek-v4-flash carries the corrected off-peak static prices", () => {
+  const entry = (DEFAULT_PRICING_FRONTIER as Record<string, Record<string, Record<string, number>>>)
+    .deepseek["deepseek-v4-flash"];
+  assert.ok(entry, "deepseek-v4-flash entry must exist under DEFAULT_PRICING_FRONTIER.deepseek");
+  assert.equal(entry.input, 0.22);
+  assert.equal(entry.output, 0.66);
+  assert.equal(entry.cached, 0.007);
+  assert.equal(entry.reasoning, 0.66);
+  assert.equal(entry.cache_creation, 0.22);
+});
+
+test("deepseek-v4 entries keep DeepSeek's documented output=3x-input ratio", () => {
+  const deepseek = (DEFAULT_PRICING_FRONTIER as Record<string, Record<string, Record<string, number>>>)
+    .deepseek;
+  for (const model of ["deepseek-v4-pro", "deepseek-v4-flash"]) {
+    const entry = deepseek[model];
+    assert.equal(entry.output, entry.input * 3, `${model}: output should be 3x input`);
+    assert.equal(entry.reasoning, entry.output, `${model}: reasoning should match output`);
+    assert.ok(entry.cached < entry.input, `${model}: cached must be cheaper than input`);
+  }
+});