fix(opencode): cap session retries with jitter (#41939)

packages/opencode/src/session/retry.ts

@@ -25,8 +25,10 @@ export type Retryable = {
 
 export const RETRY_INITIAL_DELAY = 2000
 export const RETRY_BACKOFF_FACTOR = 2
+export const RETRY_JITTER_FACTOR = 0.25
 export const RETRY_MAX_DELAY_NO_HEADERS = 30_000 // 30 seconds
 export const RETRY_MAX_DELAY = 2_147_483_647 // max 32-bit signed integer for setTimeout
+export const RETRY_MAX_RETRIES = 5
 
 const RETRYABLE_MESSAGE_PATTERNS = [
   /429|500|502|503|504|524/i,
@@ -41,7 +43,7 @@ function cap(ms: number) {
   return Math.min(ms, RETRY_MAX_DELAY)
 }
 
-export function delay(attempt: number, error?: SessionV1.APIError) {
+export function delay(attempt: number, error?: SessionV1.APIError, random = Math.random()) {
   if (error) {
     const headers = error.data.responseHeaders
     if (headers) {
@@ -67,11 +69,16 @@ export function delay(attempt: number, error?: SessionV1.APIError) {
         }
       }
 
-      return cap(RETRY_INITIAL_DELAY * Math.pow(RETRY_BACKOFF_FACTOR, attempt - 1))
+      return cap(exponential(attempt, random))
     }
   }
 
-  return cap(Math.min(RETRY_INITIAL_DELAY * Math.pow(RETRY_BACKOFF_FACTOR, attempt - 1), RETRY_MAX_DELAY_NO_HEADERS))
+  return cap(Math.min(exponential(attempt, random), RETRY_MAX_DELAY_NO_HEADERS))
+}
+
+function exponential(attempt: number, random: number) {
+  const base = RETRY_INITIAL_DELAY * Math.pow(RETRY_BACKOFF_FACTOR, attempt - 1)
+  return Math.ceil(base + base * RETRY_JITTER_FACTOR * random)
 }
 
 export function retryable(error: Err, provider: string) {
@@ -182,6 +189,7 @@ export function policy(opts: {
       const error = opts.parse(meta.input)
       const retry = retryable(error, opts.provider)
       if (!retry) return Cause.done(meta.attempt)
+      if (meta.attempt > RETRY_MAX_RETRIES) return Cause.done(meta.attempt)
       return Effect.gen(function* () {
         const wait = delay(meta.attempt, SessionV1.APIError.isInstance(error) ? error : undefined)
         const now = yield* Clock.currentTimeMillis