fix(session): ignore malformed model costs (#43248)

packages/opencode/src/session/session.ts

@@ -336,10 +336,8 @@ export function plan(input: { slug: string; time: { created: number } }, instanc
 }
 
 export const getUsage = (input: { model: Provider.Model; usage: Usage; metadata?: ProviderMetadata }) => {
-  const safe = (value: number) => {
+  const finite = (value: number) => (Number.isFinite(value) ? value : 0)
-    if (!Number.isFinite(value)) return 0
+  const safe = (value: number) => Math.max(0, finite(value))
-    return Math.max(0, value)
-  }
   const inputTokens = safe(input.usage.inputTokens ?? 0)
   const outputTokens = safe(input.usage.outputTokens ?? 0)
   const reasoningTokens = safe(input.usage.reasoningTokens ?? 0)
@@ -393,13 +391,13 @@ export const getUsage = (input: { model: Provider.Model; usage: Usage; metadata?
         ? new Decimal(totalNanoAiu).div(100_000_000_000).toNumber()
         : safe(
             new Decimal(0)
-              .add(new Decimal(tokens.input).mul(costInfo?.input ?? 0).div(1_000_000))
+              .add(new Decimal(tokens.input).mul(finite(costInfo?.input ?? 0)).div(1_000_000))
-              .add(new Decimal(tokens.output).mul(costInfo?.output ?? 0).div(1_000_000))
+              .add(new Decimal(tokens.output).mul(finite(costInfo?.output ?? 0)).div(1_000_000))
-              .add(new Decimal(tokens.cache.read).mul(costInfo?.cache?.read ?? 0).div(1_000_000))
+              .add(new Decimal(tokens.cache.read).mul(finite(costInfo?.cache?.read ?? 0)).div(1_000_000))
-              .add(new Decimal(tokens.cache.write).mul(costInfo?.cache?.write ?? 0).div(1_000_000))
+              .add(new Decimal(tokens.cache.write).mul(finite(costInfo?.cache?.write ?? 0)).div(1_000_000))
               // TODO: update models.dev to have better pricing model, for now:
               // charge reasoning tokens at the same rate as output tokens
-              .add(new Decimal(tokens.reasoning).mul(costInfo?.output ?? 0).div(1_000_000))
+              .add(new Decimal(tokens.reasoning).mul(finite(costInfo?.output ?? 0)).div(1_000_000))
               .toNumber(),
           ),
     tokens,

packages/opencode/test/session/compaction.test.ts

@@ -1782,6 +1782,22 @@ describe("SessionNs.getUsage", () => {
     expect(Number.isNaN(result.cost)).toBe(false)
   })
 
+  test("ignores malformed cost fields", () => {
+    const model = createModel({
+      context: 100_000,
+      output: 32_000,
+      cost: { input: 3, output: 15, cache: { read: 0.3, write: 3.75 } },
+    })
+    Object.assign(model.cost, { input: {} })
+
+    const result = SessionNs.getUsage({
+      model,
+      usage: usage({ inputTokens: 1_000_000, outputTokens: 100_000, totalTokens: 1_100_000 }),
+    })
+
+    expect(result.cost).toBe(1.5)
+  })
+
   test("calculates cost correctly", () => {
     const model = createModel({
       context: 100_000,