core: track retry attempts with detailed error context on assistant entries

users can now see when transient failures occur during assistant responses,
such as rate limits or provider overloads, giving visibility into what
issues were encountered and automatically resolved before the final response

packages/opencode/src/v2/session-entry-stepper.ts

@@ -1,4 +1,4 @@
-import { castDraft, produce, type WritableDraft } from "immer"
+import { produce, type WritableDraft } from "immer"
 import { SessionEvent } from "./session-event"
 import { SessionEntry } from "./session-entry"
 
@@ -235,7 +235,15 @@ export function stepWith<Result>(adapter: Adapter<Result>, event: SessionEvent.E
         )
       }
     },
-    retried: () => {},
+    retried: (event) => {
+      if (currentAssistant) {
+        adapter.updateAssistant(
+          produce(currentAssistant, (draft) => {
+            draft.retries = [...(draft.retries ?? []), SessionEntry.AssistantRetry.fromEvent(event)]
+          }),
+        )
+      }
+    },
     compacted: (event) => {
       adapter.appendEntry(SessionEntry.Compaction.fromEvent(event))
     },

packages/opencode/src/v2/session-entry.ts

@@ -104,6 +104,24 @@ export class AssistantReasoning extends Schema.Class<AssistantReasoning>("Sessio
   text: Schema.String,
 }) {}
 
+export class AssistantRetry extends Schema.Class<AssistantRetry>("Session.Entry.Assistant.Retry")({
+  attempt: Schema.Number,
+  error: SessionEvent.RetryError,
+  time: Schema.Struct({
+    created: Schema.DateTimeUtc,
+  }),
+}) {
+  static fromEvent(event: SessionEvent.Retried) {
+    return new AssistantRetry({
+      attempt: event.attempt,
+      error: event.error,
+      time: {
+        created: event.timestamp,
+      },
+    })
+  }
+}
+
 export const AssistantContent = Schema.Union([AssistantText, AssistantReasoning, AssistantTool]).pipe(
   Schema.toTaggedUnion("type"),
 )
@@ -113,6 +131,7 @@ export class Assistant extends Schema.Class<Assistant>("Session.Entry.Assistant"
   ...Base,
   type: Schema.Literal("assistant"),
   content: AssistantContent.pipe(Schema.Array),
+  retries: AssistantRetry.pipe(Schema.Array, Schema.optional),
   cost: Schema.Number.pipe(Schema.optional),
   tokens: Schema.Struct({
     input: Schema.Number,
@@ -137,6 +156,7 @@ export class Assistant extends Schema.Class<Assistant>("Session.Entry.Assistant"
         created: event.timestamp,
       },
       content: [],
+      retries: [],
     })
   }
 }

packages/opencode/src/v2/session-event.ts

@@ -53,6 +53,15 @@ export namespace SessionEvent {
     source: Source.pipe(Schema.optional),
   }) {}
 
+  export class RetryError extends Schema.Class<RetryError>("Session.Event.Retry.Error")({
+    message: Schema.String,
+    statusCode: Schema.Number.pipe(Schema.optional),
+    isRetryable: Schema.Boolean,
+    responseHeaders: Schema.Record(Schema.String, Schema.String).pipe(Schema.optional),
+    responseBody: Schema.String.pipe(Schema.optional),
+    metadata: Schema.Record(Schema.String, Schema.String).pipe(Schema.optional),
+  }) {}
+
   export class Prompt extends Schema.Class<Prompt>("Session.Event.Prompt")({
     ...Base,
     type: Schema.Literal("prompt"),
@@ -386,14 +395,16 @@ export namespace SessionEvent {
   export class Retried extends Schema.Class<Retried>("Session.Event.Retried")({
     ...Base,
     type: Schema.Literal("retried"),
-    error: Schema.String,
+    attempt: Schema.Number,
+    error: RetryError,
   }) {
-    static create(input: BaseInput & { error: string }) {
+    static create(input: BaseInput & { attempt: number; error: RetryError }) {
       return new Retried({
         id: input.id ?? ID.create(),
         type: "retried",
         timestamp: input.timestamp ?? DateTime.makeUnsafe(Date.now()),
         metadata: input.metadata,
+        attempt: input.attempt,
         error: input.error,
       })
     }