fix(web): surface terminal turn failures

packages/client/runtime/src/client/index.ts

@@ -47,7 +47,7 @@ export type {
   AssistantTiming, CodeSubCall, CommandNode, CompactionSummaryNode, ComposerPhase,
   ContextMessageNode, ConversationNode, ConversationSnapshot, ModelRetryNode, QueuedMessage,
   RunningToolCall,
-  SteeringMessageNode, TodoItem, ToolResultNode, UnknownSurfaceNode, UserMessageNode,
+  SteeringMessageNode, TodoItem, ToolResultNode, TurnErrorNode, UnknownSurfaceNode, UserMessageNode,
 } from './sessions/conversation.ts'
 export type {
   ConversationContext, ConversationContextOriginKind,

packages/client/runtime/src/client/sessions/conversation.ts

@@ -135,6 +135,19 @@ export type ModelRetryNode = LlmRetryEventData & {
   retryState: 'scheduled' | 'started' | 'cancelled'
 }
 
+/** Durable terminal failure for a turn that has no scheduled retry. */
+export interface TurnErrorNode {
+  kind: 'turn-error'
+  /** Seq of the owning turn/end event. */
+  seq: number
+  /** Unix epoch ms from the turn/end event. */
+  time: number
+  turn: number
+  step: number
+  message: string
+  code?: string
+}
+
 /** A tool result paired (when in-window) with its call head. */
 export interface ToolResultNode {
   kind: 'tool-result'
@@ -223,6 +236,7 @@ export type ConversationNode =
   | SteeringMessageNode
   | ContextMessageNode
   | ModelRetryNode
+  | TurnErrorNode
   | ToolResultNode
   | CommandNode
   | CompactionSummaryNode

packages/client/runtime/src/client/sessions/failure-display.ts

@@ -0,0 +1,10 @@
+/**
+ * Convert a durable failure into copy that is safe to expose in the GUI.
+ * @param failure - Structured failure preserved by the session event.
+ * @returns Display-safe copy for client projections.
+ */
+export function displayFailureMessage(failure: { code?: string; message: string }): string {
+  // Provider AUTH messages may echo a masked or partially preserved credential.
+  // Keep the raw diagnostic in the session log, but never project it into UI state.
+  return failure.code === 'AUTH' ? 'API key is invalid' : failure.message
+}

packages/client/runtime/src/client/sessions/request-inspection.ts

@@ -8,6 +8,7 @@ import type { SessionEvent } from '@deepseek-ai/dsh-session/types'
 import type {
   AssistantProvenanceView, AssistantRequestConfig,
 } from './conversation.ts'
+import { displayFailureMessage } from './failure-display.ts'
 
 export type {
   AssistantProvenanceView, AssistantRequestConfig,
@@ -319,7 +320,7 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
       const event = sourceEvent as unknown as RetryEvent
       update(ordinaryByStep.get(requestKey(event.data.turn, event.data.step)), {
         status: 'error',
-        error: event.data.failure.message,
+        error: displayFailureMessage(event.data.failure),
         retry: event.data.retry,
         maxRetries: event.data.maxRetries,
         retryDelayMs: event.data.delayMs,
@@ -330,7 +331,7 @@ function deriveRequests(events: readonly SessionEvent[]): readonly RequestView[]
       const reason = sourceEvent.data.reason
       update(ordinaryByStep.get(requestKey(sourceEvent.data.turn, reason.step)), {
         status: 'error',
-        error: 'failure' in reason ? reason.failure.message : reason.message,
+        error: displayFailureMessage('failure' in reason ? reason.failure : reason),
       })
       continue
     }

packages/client/runtime/src/client/sessions/session.ts

@@ -19,6 +19,7 @@ import type {
 import type { PendingInteraction } from './pending.ts'
 import { PendingWait } from './pending.ts'
 import { TranscriptAdapter } from './transcript-adapter.ts'
+import { displayFailureMessage } from './failure-display.ts'
 import { Notifier } from './notifier.ts'
 import { PartialAccumulator } from './partial.ts'
 import { ProjectionValueStore } from './projection-store.ts'
@@ -749,6 +750,22 @@ export class Session implements SessionFace {
         if (event.data.reason.kind === 'aborted' || event.data.reason.kind === 'disposed') {
           this.settleScheduledRetry('cancelled', event.data.turn)
         }
+        if (
+          event.data.reason.kind === 'error'
+          && !this.derivedNodes.some(node => node.kind === 'model-retry' && node.turn === event.data.turn)
+        ) {
+          const failure = 'failure' in event.data.reason ? event.data.reason.failure : event.data.reason
+          this.derivedNodes.push({
+            kind: 'turn-error',
+            seq: event.seq,
+            time: event.time,
+            turn: event.data.turn,
+            step: event.data.reason.step,
+            message: displayFailureMessage(failure),
+            ...(failure.code === undefined ? {} : { code: failure.code }),
+          })
+          this.derivedRev++
+        }
         // Aborted turns never finalize. The accumulated partial is VALUE, not residue: freeze it
         // into an interrupted terminal node (pulse stops, text survives) instead of deleting it.
         // Shared by live and window-replay paths, so a refresh reconstructs the same frozen node