fix(mothership): sim lows #9,#13-#16 — honest errors, one terminal predicate

#16: Stop during a permission wait no longer reads "Timed out" — the
message names the actual reason.
#13: subscription-plan and sealed-context catches log the caught error.
#14: registerPendingToolPromise's .finally() derived an unhandled
rejection chain; the rejection is now observed and logged.
#15: the attach tail->batch reconnect cycle paces 1s on an empty
non-terminal batch instead of spinning against a prompt-closing middlebox.
#9: the terminal-status predicate (defined 3x, one a drifted Set copy)
lives once in request/session; all consumers import it.

Claude-Session: https://claude.ai/code/session_01CgaxNAaeD3taGdghbXn17w

Author: Sg312

apps/sim/app/api/copilot/chat/stream/route.test.ts

@@ -23,6 +23,8 @@ vi.mock('@/lib/mothership/async-runs/repository', () => ({
 }))
 
 vi.mock('@/lib/mothership/request/session', () => ({
+  isTerminalStreamStatus: (status: string | null | undefined) =>
+    status === 'complete' || status === 'error' || status === 'cancelled',
   readEvents,
   readFilePreviewSessions,
   checkForReplayGap,

apps/sim/app/api/copilot/chat/stream/route.ts

@@ -25,6 +25,7 @@ import {
   createEvent,
   encodeSSEComment,
   encodeSSEEnvelope,
+  isTerminalStreamStatus,
   readEvents,
   readFilePreviewSessions,
   SSE_RESPONSE_HEADERS,
@@ -58,16 +59,6 @@ function extractEnvelopeRequestId(envelope: { trace?: { requestId?: unknown } })
   return extractCanonicalRequestId(envelope.trace?.requestId)
 }
 
-function isTerminalStatus(
-  status: string | null | undefined
-): status is MothershipStreamV1CompletionStatus {
-  return (
-    status === MothershipStreamV1CompletionStatus.complete ||
-    status === MothershipStreamV1CompletionStatus.error ||
-    status === MothershipStreamV1CompletionStatus.cancelled
-  )
-}
-
 function buildResumeTerminalEnvelopes(options: {
   streamId: string
   afterCursor: string
@@ -425,7 +416,7 @@ async function handleResumeRequestBody({
         if (controllerClosed) {
           break
         }
-        if (isTerminalStatus(currentRun.status)) {
+        if (isTerminalStreamStatus(currentRun.status)) {
           emitTerminalIfMissing(currentRun.status, {
             message:
               currentRun.status === MothershipStreamV1CompletionStatus.error

apps/sim/app/workspace/[workspaceId]/home/hooks/stream-protocol.ts

@@ -128,12 +128,6 @@ export function resolveChatIdFromStreamBatch(batch: StreamBatchResponse): string
   return undefined
 }
 
-const TERMINAL_STREAM_STATUSES = new Set(['complete', 'error', 'cancelled'])
-
-export function isTerminalStreamStatus(status: string | null | undefined): boolean {
-  return TERMINAL_STREAM_STATUSES.has(status ?? '')
-}
-
 export function isAlreadyProcessedStreamCursor(
   eventCursor: string | undefined,
   currentCursor: string

apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts

@@ -56,6 +56,7 @@ import {
 import { MOTHERSHIP_CHAT_API_PATH } from '@/lib/mothership/constants'
 import { sendMothershipMessage } from '@/lib/mothership/events'
 import { MothershipStreamV1ToolOutcome } from '@/lib/mothership/generated/mothership-stream-v1'
+import { isTerminalStreamStatus } from '@/lib/mothership/request/session'
 import { parsePersistedStreamEventEnvelopeJson } from '@/lib/mothership/request/session/contract'
 import type { FilePreviewSession } from '@/lib/mothership/request/session/file-preview-session-contract'
 import { canDisplayResource } from '@/lib/mothership/resources/availability'
@@ -159,7 +160,6 @@ import {
   isAlreadyProcessedStreamCursor,
   isStreamGoneError,
   isStreamSchemaValidationError,
-  isTerminalStreamStatus,
   parseStreamBatchResponse,
   resolveChatIdFromStreamBatch,
   type StreamBatchResponse,
@@ -2472,6 +2472,10 @@ export function useChat(
             if (activeAbort.signal.aborted || streamGenRef.current !== expectedGen) {
               return { error: false, aborted: true }
             }
+            /* A middlebox that closes the SSE tail promptly makes this loop spin
+               tail->batch->tail with zero delay. An empty non-terminal batch means
+               nothing new arrived — pace the next cycle instead of hammering. */
+            await sleep(1_000)
           }
         }
 

apps/sim/lib/mothership/chat/effective-transcript.ts

@@ -13,6 +13,7 @@ import {
   MothershipStreamV1ToolOutcome,
   MothershipStreamV1ToolPhase,
 } from '@/lib/mothership/generated/mothership-stream-v1'
+import { isTerminalStreamStatus } from '@/lib/mothership/request/session'
 import type { FilePreviewSession } from '@/lib/mothership/request/session/file-preview-session-contract'
 import type { StreamBatchEvent } from '@/lib/mothership/request/session/types'
 import {
@@ -52,14 +53,6 @@ function asPayloadRecord(value: unknown): Record<string, unknown> | undefined {
   return isRecordLike(value) ? value : undefined
 }
 
-function isTerminalStreamStatus(status: string | null | undefined): boolean {
-  return (
-    status === MothershipStreamV1CompletionStatus.complete ||
-    status === MothershipStreamV1CompletionStatus.error ||
-    status === MothershipStreamV1CompletionStatus.cancelled
-  )
-}
-
 /**
  * Error codes that describe the USER stopping the turn, not a failure.
  *

apps/sim/lib/mothership/request/handlers/types.ts

@@ -1,5 +1,5 @@
 import { createLogger } from '@sim/logger'
-import { toError } from '@sim/utils/errors'
+import { getErrorMessage, toError } from '@sim/utils/errors'
 import { isRecordLike, toRecord } from '@sim/utils/object'
 import type {
   AsyncCompletionSignal,
@@ -131,11 +131,19 @@ export function registerPendingToolPromise(
   pendingPromise: Promise<AsyncCompletionSignal>
 ): void {
   context.pendingToolPromises.set(toolCallId, pendingPromise)
-  pendingPromise.finally(() => {
-    if (context.pendingToolPromises.get(toolCallId) === pendingPromise) {
-      context.pendingToolPromises.delete(toolCallId)
-    }
-  })
+  /* .finally() derives a NEW promise that re-throws the rejection with no handler — an
+     unhandled-rejection crash waiting for the first rejecting tool promise. Observe the
+     chain: cleanup on both settles, rejection logged (the original promise's consumers
+     still see it through the map). */
+  pendingPromise
+    .catch((error) => {
+      logger.warn('Pending tool promise rejected', { toolCallId, error: getErrorMessage(error) })
+    })
+    .finally(() => {
+      if (context.pendingToolPromises.get(toolCallId) === pendingPromise) {
+        context.pendingToolPromises.delete(toolCallId)
+      }
+    })
 }
 
 /**

apps/sim/lib/mothership/request/session/contract.ts

@@ -7,6 +7,7 @@ import type {
   MothershipStreamV1Trace,
 } from '@/lib/mothership/generated/mothership-stream-v1'
 import {
+  MothershipStreamV1CompletionStatus,
   MothershipStreamV1EventType,
   MothershipStreamV1ResourceOp,
   MothershipStreamV1RunKind,
@@ -402,6 +403,17 @@ export function isSyntheticFilePreviewEventEnvelope(
 
 // Stream event type guards
 
+/** The one terminal-status predicate — complete | error | cancelled. */
+export function isTerminalStreamStatus(
+  status: string | null | undefined
+): status is MothershipStreamV1CompletionStatus {
+  return (
+    status === MothershipStreamV1CompletionStatus.complete ||
+    status === MothershipStreamV1CompletionStatus.error ||
+    status === MothershipStreamV1CompletionStatus.cancelled
+  )
+}
+
 export function isToolCallStreamEvent(event: SessionStreamEvent): event is ToolCallStreamEvent {
   return event.type === 'tool' && isRecordLike(event.payload) && event.payload.phase === 'call'
 }

apps/sim/lib/mothership/request/session/index.ts

@@ -46,6 +46,7 @@ export {
   isContractStreamEventEnvelope,
   isSubagentSpanStreamEvent,
   isSyntheticFilePreviewEventEnvelope,
+  isTerminalStreamStatus,
   isToolArgsDeltaStreamEvent,
   isToolCallStreamEvent,
   isToolResultStreamEvent,

apps/sim/lib/mothership/request/tools/billing.ts

@@ -1,4 +1,5 @@
 import { createLogger } from '@sim/logger'
+import { getErrorMessage } from '@sim/utils/errors'
 import { getHighestPrioritySubscription } from '@/lib/billing/core/plan'
 import { isEnterprise, isPaid } from '@/lib/billing/plan-helpers'
 import { isOrgScopedSubscription } from '@/lib/billing/subscriptions/utils'
@@ -59,8 +60,10 @@ export async function handleBillingLimitResponse(
           "You've reached your usage limit for this billing period. Please increase your usage limit from billing settings to continue."
       }
     }
-  } catch {
-    logger.warn('Failed to determine subscription plan, defaulting to upgrade_plan')
+  } catch (error) {
+    logger.warn('Failed to determine subscription plan, defaulting to upgrade_plan', {
+      error: getErrorMessage(error),
+    })
   }
 
   const upgradePayload = JSON.stringify({

apps/sim/lib/mothership/request/tools/client.ts

@@ -124,10 +124,11 @@ export async function waitForClientToolCompletion({
         }
       }
     }
-  } catch {
+  } catch (error) {
     toolRegistry?.markIncomplete('client-tool-seal-failed', {
       origin: 'copilotToolClient.sealedContext',
     })
+    logger.warn('Sealed-context unseal failed', { error: getErrorMessage(error) })
   } finally {
     finishPendingActivation?.()
   }