refactor(api): converge the Remote failure vocabulary and client surface

Single RemoteError with a merge-extensible, domain-prefixed code map; owners throw at the failure point; streams surface marked failures; clients consume ctx.remote directly with isRemoteFailure as the only discrimination point and construct no failure instances.
2026-09-11 04:00:38 +00:00 · 2026-08-28 22:37:36 +08:00
parent 12d7b4ed0c
commit 804b1ffbfc
252 changed files with 3182 additions and 3832 deletions
@@ -1,29 +0,0 @@
-/** Client operation results spanning the Session and subagent Remote calls. */
-
-import type { RpcError } from '@deepseek-ai/dsh-client-connection/client'
-import type { SubagentControlError } from '@deepseek-ai/dsh-subagent/client'
-import type { SessionError } from '../../types.ts'
-
-/** Failure surfaced by the Client Session object layer. */
-export type ClientFailure = RpcError | SessionError | SubagentControlError
-
-/** Success or failure returned by a Client Session operation. */
-export type ClientResult<T> =
-  | { readonly ok: true; readonly value: T }
-  | { readonly ok: false; readonly error: ClientFailure }
-
-/**
- * Fold a rejected carrier operation into the Client Session failure vocabulary.
- * @param error - rejection from a Remote or local carrier call.
- * @returns the failure branch of a Client Session result.
- */
-export function transportResult<T>(error: unknown): ClientResult<T> {
-  return {
-    ok: false,
-    error: {
-      code: 'internal',
-      message: error instanceof Error ? error.message : String(error),
-      details: {},
-    },
-  }
-}
@@ -13,7 +13,6 @@ import type { SessionId } from '@deepseek-ai/dsh-session/types'
 import type { RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
 import type { ObservableSnapshot } from '@deepseek-ai/dsh-client-store'
 import type { PromptContentPart, QueueAction, SessionRequestId } from '../../types.ts'
-import type { ClientResult } from './result.ts'
 import type { PendingSubmissionImage, SessionSnapshot } from './snapshot.ts'

 /**
@@ -84,7 +83,7 @@ export interface ISession {
    mode: 'queue' | 'steer',
    signal?: AbortSignal,
    requestId?: SessionRequestId,
-  ): Promise<ClientResult<{ accepted: true }>>
+  ): Promise<RemoteResult<{ accepted: true }>>
  /**
   * Resolve one durable image referenced by this session.
   * @param attachmentId - opaque id found in the folded session log.
@@ -92,27 +91,27 @@ export interface ISession {
   */
  readAttachment(
    attachmentId: AttachmentIdType,
-  ): Promise<ClientResult<{ attachment: ImageAttachmentRef; data: Uint8Array }>>
+  ): Promise<RemoteResult<{ attachment: ImageAttachmentRef; data: Uint8Array }>>
  /**
   * Apply one edit, remove, or strict steer action to a still-pending queue occurrence.
   * @param itemId - agent-owned inbox occurrence identity.
   * @param action - requested queue operation.
   * @returns acceptance, or a business/transport error.
   */
-  updateQueue(itemId: MessageId, action: QueueAction): Promise<ClientResult<{ accepted: true }>>
+  updateQueue(itemId: MessageId, action: QueueAction): Promise<RemoteResult<{ accepted: true }>>
  /**
   * Cancel the running turn. Pending queued work remains and resumes in FIFO
   * order after the Host reaches cancellation quiescence.
   * @returns acceptance, or the business error.
   */
-  cancel(): Promise<ClientResult<{ accepted: true }>>
+  cancel(): Promise<RemoteResult<{ accepted: true }>>
  /**
   * Rename this session (explicit user title; pins it against automatic
   * regeneration).
   * @param title - raw title text (the host normalizes acceptance).
   * @returns the normalized accepted title and its event seq, or the business error.
   */
-  rename(title: string): Promise<ClientResult<{ title: string; seq: number }>>
+  rename(title: string): Promise<RemoteResult<{ title: string; seq: number }>>
  /**
   * Extend the history window backwards (older messages pagination).
   * @returns completion; failures land in snapshot.openState/loadingOlder.
@@ -8,10 +8,10 @@ import type { Context } from '@deepseek-ai/cordis'
 import type { SubagentAddress } from '@deepseek-ai/dsh-subagent/client'
 import type { SessionId } from '@deepseek-ai/dsh-session/types'
 import type { WorkspaceId } from '@deepseek-ai/dsh-workspace/types'
+import type { RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
 import type { AgentContext } from '../scope.ts'
 import type { SessionSearchResultItem } from '../sessions/manager.ts'
 import type { SessionBinding, SessionListState } from '../sessions/service.ts'
-import type { ClientResult } from './result.ts'
 import type { SessionFace } from './session.ts'
 import type { ObservableSnapshot } from '@deepseek-ai/dsh-client-store'

@@ -83,7 +83,7 @@ export interface ISessions {
  search(
    query: string,
    signal: AbortSignal,
-  ): Promise<ClientResult<{ items: SessionSearchResultItem[]; hasMore: boolean }>>
+  ): Promise<RemoteResult<{ items: SessionSearchResultItem[]; hasMore: boolean }>>
  /**
   * Fork a session from a completed-turn prefix of the source; on resolution
   * the child is in the list store and `open()` can target it.
@@ -3,8 +3,8 @@ import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
 import type { MessageId } from '@deepseek-ai/dsh-llm/brand'
 import type { SessionId } from '@deepseek-ai/dsh-session/types'
 import type { SubagentAddress } from '@deepseek-ai/dsh-subagent/client'
+import type { RemoteFailure } from '@deepseek-ai/dsh-typert-protocol'
 import type { SessionRequestId } from '../../types.ts'
-import type { ClientFailure } from './result.ts'

 /** One transient inbox occurrence from the authoritative queue snapshot. */
 export interface QueuedMessage {
@@ -53,7 +53,7 @@ export type OpenState = 'cold' | 'loading' | 'open' | 'error'
 /** Send/stop failure surfaced by Session consumers. */
 export interface PromptError {
  readonly op: 'send' | 'stop'
-  readonly error: ClientFailure
+  readonly error: RemoteFailure
 }

 /** Immutable Session lifecycle and control snapshot. */
@@ -70,7 +70,7 @@ export interface SessionSnapshot {
  } | null
  readonly removed: boolean
  readonly openState: OpenState
-  readonly openError: ClientFailure | null
+  readonly openError: RemoteFailure | null
  readonly hasMore: boolean
  readonly loadingOlder: boolean
  readonly promptError: PromptError | null
@@ -2,7 +2,6 @@

 import type { Context } from '@deepseek-ai/cordis'
 import type {} from '@deepseek-ai/dsh-agent/types'
-import type { ConnectionHandle } from '@deepseek-ai/dsh-client-connection/client'
 import { createSessionControlStream } from './transport.ts'
 import { ClientSessions } from './sessions/service.ts'
 import type { SessionRemotes } from './sessions/remotes.ts'
@@ -13,7 +12,6 @@ export {
  SessionEventStream,
  SESSION_SEARCH_RESULT_LIMIT,
  SESSION_SEARCH_SNIPPET_MAX_CODE_POINTS,
-  sessionStreamFailure,
 } from './transport.ts'
 export type {
  ClientSessionPageRequest,
@@ -66,7 +64,6 @@ export type {
  QueuedMessage,
  SessionSnapshot,
 } from './contract/snapshot.ts'
-export type { ClientFailure, ClientResult } from './contract/result.ts'

 declare module '@deepseek-ai/cordis' {
  interface Context {
@@ -75,9 +72,8 @@ declare module '@deepseek-ai/cordis' {
  }
 }

-/** Required wire, Remote, and Context projection services. */
+/** Required Remote and Context projection services. */
 export const inject = [
-  'connection',
  'typert',
  'remote',
  'remote.commands',
@@ -90,7 +86,6 @@ export const inject = [
 * @param ctx - Client Cordis context.
 */
 export function apply(ctx: Context): void {
-  const connection = ctx.get('connection') as ConnectionHandle
  const remotes = ctx.remote as unknown as SessionRemotes
  const sessions = new ClientSessions(ctx, remotes)
  ctx.remote.$on('api-session/added', (summary) => { sessions.handleSessionAdded(summary) })
@@ -111,7 +106,7 @@ export function apply(ctx: Context): void {
  })
  control.start()
  ctx.on('connection/reset', () => { sessions.handleConnected() })
-  if (connection.generation.getSnapshot() !== undefined) sessions.handleConnected()
+  if (ctx.remote.$host.home !== undefined) sessions.handleConnected()
  ctx.typert.contexts.registerClient('agent', {
    identity: candidate => sessions.scopeOf(candidate),
    resolve: sessionId => sessions.resolveAgentScope(sessionId),
@@ -9,13 +9,12 @@ import type {
  SessionControlBaseline,
  SessionControlFrame,
  SessionQueuedItem,
-  SessionError,
  SessionSummary,
  SessionJob as JobView,
 } from '../../types.ts'
 import { mergeOrderedBaseline } from '../ordered-baseline.ts'
-import type { ClientFailure, ClientResult } from '../contract/result.ts'
-import { transportResult } from '../contract/result.ts'
+import { isRemoteFailure } from '@deepseek-ai/dsh-api-gateway/client'
+import type { RemoteFailure, RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
 import type { SessionListEntry, TitledSessionSummary } from './lineage.ts'
 import { flattenLineage } from './lineage.ts'
 // Type-only merge edge: the title domain's client-namespace outlet declares
@@ -51,7 +50,7 @@ export interface SessionListSnapshot {
  state: 'idle' | 'loading' | 'error'
  /** Arrival lifecycle (see {@link SessionListPhase}); `state` stays the pull-activity axis. */
  phase: SessionListPhase
-  error: ClientFailure | null
+  error: RemoteFailure | null
  subagentsByParent: Readonly<Record<SessionId, SubagentCatalogSnapshot>>
  /** Background jobs per session; an absent key is an empty set. */
  jobsBySession: Readonly<Record<SessionId, readonly JobView[]>>
@@ -63,7 +62,7 @@ export type SubagentCatalogSnapshot = Omit<SubagentCatalog, 'parentAvailable'> &
  /** Absent until the first successful catalog read. */
  readonly parentAvailable?: boolean
  state: 'loading' | 'ready' | 'error'
-  error: ClientFailure | null
+  error: RemoteFailure | null
 }

 function catalogAvailability(parentAvailable: boolean | undefined): {
@@ -112,7 +111,7 @@ export class SessionManager {
  private listState: 'idle' | 'loading' | 'error' = 'idle'
  /** Arrival phase; the pending → ready edge fires on the first successful pull (see SessionListPhase). */
  private listPhase: SessionListPhase = 'pending'
-  private listError: ClientFailure | null = null
+  private listError: RemoteFailure | null = null
  private listInflight: Promise<void> | null = null
  /** Mutations arriving after a list request starts are replayed over its response. */
  private listMutations: SessionListMutation[] | null = null
@@ -366,7 +365,7 @@ export class SessionManager {
    this.notifier.markDirty()
    const operation = (async () => {
      try {
-        const result = toSessionResult(await this.remote.subagents.list(parentSessionId))
+        const result = await this.remote.subagents.list(parentSessionId)
        if (result.ok) {
          const parentAvailable = this.catalogInflight.get(parentSessionId)?.parentAvailableOverride
            ?? result.value.parentAvailable
@@ -395,7 +394,7 @@ export class SessionManager {
          })
        }
      } catch (error: unknown) {
-        const folded = transportResult<never>(error)
+        if (!isRemoteFailure(error)) throw error
        this.catalogs.set(parentSessionId, {
          entries: this.withCatalogMutations(
            previous?.entries ?? [], expandableRows, activityRows,
@@ -405,7 +404,7 @@ export class SessionManager {
              ?? previous?.parentAvailable,
          ),
          state: 'error',
-          error: folded.ok ? null : folded.error,
+          error,
        })
      } finally {
        this.catalogInflight.delete(parentSessionId)
@@ -457,7 +456,7 @@ export class SessionManager {
    this.notifier.markDirty()
    this.listInflight = (async () => {
      try {
-        const result = toSessionResult(await this.remote.session.list({}))
+        const result = await this.remote.session.list({})
        if (result.ok) {
          const baseline: SessionSummary[] = this.listPhase === 'pending'
            ? [...result.value.items]
@@ -506,10 +505,9 @@ export class SessionManager {
          this.listError = result.error
        }
      } catch (error) {
+        if (!isRemoteFailure(error)) throw error
        this.listState = 'error'
-        const folded = transportResult<never>(error)
-        /* v8 ignore next -- the `? null` arm is unreachable: transportResult always returns ok:false. */
-        this.listError = folded.ok ? null : folded.error
+        this.listError = error
      } finally {
        this.listMutations = null
        this.listInflight = null
@@ -529,19 +527,15 @@ export class SessionManager {
  async search(
    query: string,
    signal: AbortSignal,
-  ): Promise<ClientResult<{ items: SessionSearchResultItem[]; hasMore: boolean }>> {
-    try {
-      const result = toSessionResult(await this.remote.session.search({ query }, signal))
-      if (!result.ok) return result
-      return {
-        ok: true,
-        value: {
-          items: [...result.value.items],
-          hasMore: result.value.hasMore,
-        },
-      }
-    } catch (error: unknown) {
-      return transportResult(error)
+  ): Promise<RemoteResult<{ items: SessionSearchResultItem[]; hasMore: boolean }>> {
+    const result = await this.remote.session.search({ query }, signal)
+    if (!result.ok) return result
+    return {
+      ok: true,
+      value: {
+        items: [...result.value.items],
+        hasMore: result.value.hasMore,
+      },
    }
  }

@@ -558,36 +552,32 @@ export class SessionManager {
      cwd?: string
      sessionId?: SessionId
    } = {},
-  ): Promise<ClientResult<{ sessionId: SessionId }>> {
-    try {
-      const shared = opts.sessionId === undefined ? {} : { sessionId: opts.sessionId }
-      const payload = opts.workspaceId !== undefined
-        ? { workspaceId: opts.workspaceId, ...shared }
-        : { ...(opts.cwd === undefined ? {} : { cwd: opts.cwd }), ...shared }
-      const result = toSessionResult(await this.remote.session.create(payload))
-      if (result.ok) {
+  ): Promise<RemoteResult<{ sessionId: SessionId }>> {
+    const shared = opts.sessionId === undefined ? {} : { sessionId: opts.sessionId }
+    const payload = opts.workspaceId !== undefined
+      ? { workspaceId: opts.workspaceId, ...shared }
+      : { ...(opts.cwd === undefined ? {} : { cwd: opts.cwd }), ...shared }
+    const result = await this.remote.session.create(payload)
+    if (result.ok) {
+      this.recordMutation({ kind: 'upsert', summary: {
+        sessionId: result.value.sessionId, updatedAt: Date.now(), running: false, blank: true,
+        ...(opts.cwd !== undefined ? { cwd: opts.cwd } : {}),
+      } })
+    } else {
+      const publishedSessionId = workspaceAttachSessionId(result.error)
+      // Publication precedes attachment. The error's id is a real Session,
+      // so expose it immediately as Ungrouped while the caller keeps the
+      // prompt buffer and decides whether to retry attachment.
+      if (publishedSessionId !== undefined) {
        this.recordMutation({ kind: 'upsert', summary: {
-          sessionId: result.value.sessionId, updatedAt: Date.now(), running: false, blank: true,
-          ...(opts.cwd !== undefined ? { cwd: opts.cwd } : {}),
+          sessionId: publishedSessionId,
+          updatedAt: Date.now(),
+          running: false,
+          blank: true,
        } })
-      } else {
-        const publishedSessionId = workspaceAttachSessionId(result.error)
-        // Publication precedes attachment. The error's id is a real Session,
-        // so expose it immediately as Ungrouped while the caller keeps the
-        // prompt buffer and decides whether to retry attachment.
-        if (publishedSessionId !== undefined) {
-          this.recordMutation({ kind: 'upsert', summary: {
-            sessionId: publishedSessionId,
-            updatedAt: Date.now(),
-            running: false,
-            blank: true,
-          } })
-        }
      }
-      return result
-    } catch (error) {
-      return transportResult(error)
    }
+    return result
  }

  /**
@@ -601,27 +591,23 @@ export class SessionManager {
   */
  async fork(
    opts: { sessionId: SessionId; atSeq?: number },
-  ): Promise<ClientResult<{ sessionId: SessionId }>> {
-    try {
-      const source = this.summaries.find(s => s.sessionId === opts.sessionId)
-      const result = toSessionResult(await this.remote.session.fork({
-        sessionId: opts.sessionId,
-        ...opts.atSeq === undefined ? {} : { atSeq: opts.atSeq },
-      }))
-      const childId = result.ok
-        ? result.value.sessionId
-        : workspaceAttachSessionId(result.error)
-      if (childId !== undefined) {
-        this.recordMutation({ kind: 'upsert', summary: {
-          sessionId: childId, updatedAt: Date.now(), running: false, blank: false,
-          parentSessionId: opts.sessionId,
-          ...(source?.cwd !== undefined ? { cwd: source.cwd } : {}),
-        } })
-      }
-      return result
-    } catch (error) {
-      return transportResult(error)
+  ): Promise<RemoteResult<{ sessionId: SessionId }>> {
+    const source = this.summaries.find(s => s.sessionId === opts.sessionId)
+    const result = await this.remote.session.fork({
+      sessionId: opts.sessionId,
+      ...opts.atSeq === undefined ? {} : { atSeq: opts.atSeq },
+    })
+    const childId = result.ok
+      ? result.value.sessionId
+      : workspaceAttachSessionId(result.error)
+    if (childId !== undefined) {
+      this.recordMutation({ kind: 'upsert', summary: {
+        sessionId: childId, updatedAt: Date.now(), running: false, blank: false,
+        parentSessionId: opts.sessionId,
+        ...(source?.cwd !== undefined ? { cwd: source.cwd } : {}),
+      } })
    }
+    return result
  }

  /**
@@ -1010,13 +996,6 @@ function applyMutation(summaries: readonly SessionSummary[], mutation: SessionLi
 }

 /** Temporary source-plane bridge while the Host contract and client project build independently. */
-function workspaceAttachSessionId(error: ClientFailure): SessionId | undefined {
-  return error.code === 'workspace-attach-failed' ? error.details.sessionId : undefined
-}
-
-/** Narrow a generated Session Remote failure to its service-owned error vocabulary. */
-function toSessionResult<T>(
-  result: import('@deepseek-ai/dsh-typert-protocol').RemoteResult<T>,
-): ClientResult<T> {
-  return result.ok ? result : { ok: false, error: result.error as SessionError }
+function workspaceAttachSessionId(error: RemoteFailure): SessionId | undefined {
+  return error.code === 'session/workspace-attach-failed' ? error.details.sessionId : undefined
 }
@@ -25,7 +25,7 @@ import type { SessionProjectionMap } from '@deepseek-ai/dsh-session-projection/t
 import {
  createSnapshotStore, type SnapshotStore,
 } from '@deepseek-ai/dsh-client-store'
-import type { ClientFailure, ClientResult } from '../contract/result.ts'
+import type { RemoteFailure, RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
 import type { SessionEventSource } from '../contract/events.ts'
 import type { SessionFace } from '../contract/session.ts'
 import type { AgentContext, ISessions } from '../contract/sessions.ts'
@@ -101,7 +101,7 @@ export class SessionCreateError extends Error {
   * @param requestedSessionId - caller-preallocated id used for later stream/list reconciliation.
   */
  constructor(
-    readonly rpcError: ClientFailure,
+    readonly rpcError: RemoteFailure,
    readonly requestedSessionId: SessionId | undefined,
  ) {
    super(`session create failed: ${rpcError.code}: ${rpcError.message}`)
@@ -117,7 +117,7 @@ export class SessionForkError extends Error {
   * @param sourceSessionId - the session the fork was cut from.
   */
  constructor(
-    readonly rpcError: ClientFailure,
+    readonly rpcError: RemoteFailure,
    readonly sourceSessionId: SessionId,
  ) {
    super(`session fork failed: ${rpcError.code}: ${rpcError.message}`)
@@ -335,7 +335,7 @@ export class ClientSessions implements ISessions {
  search(
    query: string,
    signal: AbortSignal,
-  ): Promise<ClientResult<{ items: SessionSearchResultItem[]; hasMore: boolean }>> {
+  ): Promise<RemoteResult<{ items: SessionSearchResultItem[]; hasMore: boolean }>> {
    return this.manager.search(query, signal)
  }

@@ -6,10 +6,7 @@ import type { AttachmentIdType, ImageAttachmentRef } from '@deepseek-ai/dsh-atta
 import type { SubagentAddress } from '@deepseek-ai/dsh-subagent/client'
 import type { MessageId } from '@deepseek-ai/dsh-llm/brand'
 import type { SessionId } from '@deepseek-ai/dsh-session/types'
-import {
-  SessionEventStream,
-  sessionStreamFailure,
-} from '../transport.ts'
+import { SessionEventStream } from '../transport.ts'
 import type { SessionJournalChange } from '../transport.ts'
 import type {
  PromptContentPart,
@@ -18,10 +15,7 @@ import type {
  SessionControlFrame,
  SessionQueuedItem,
  SessionRequestId,
-  SessionError,
 } from '../../types.ts'
-import type { ClientFailure, ClientResult } from '../contract/result.ts'
-import { transportResult } from '../contract/result.ts'
 import type {
  BeginSubmissionInput, PendingSubmissionRetirement, SessionFace, SubmissionHandle,
 } from '../contract/session.ts'
@@ -33,7 +27,8 @@ import type {
  SessionEventLikeEntry, SessionLiveEventEntry,
 } from '../contract/events.ts'
 import { Notifier } from './notifier.ts'
-import type { RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
+import { isRemoteFailure } from '@deepseek-ai/dsh-api-gateway/client'
+import type { RemoteFailure, RemoteResult } from '@deepseek-ai/dsh-typert-protocol'
 import type { SessionRemotes } from './remotes.ts'
 import { ProjectionValueStore } from './projection-store.ts'
 import type { ProjectionsBaseline } from './projection-store.ts'
@@ -77,7 +72,7 @@ export class Session implements SessionFace {
  private baseSeq = 0
  private hasMore = false
  private openState: OpenState = 'cold'
-  private openError: ClientFailure | null = null
+  private openError: RemoteFailure | null = null
  private openPromise: Promise<void> | null = null
  /** Bumped by stream replacement to invalidate an in-flight doOpen. Stale
   *  passes drop all writes once the generation moves on. */
@@ -214,7 +209,7 @@ export class Session implements SessionFace {
    mode: 'queue' | 'steer',
    signal?: AbortSignal,
    requestId?: SessionRequestId,
-  ): Promise<ClientResult<{ accepted: true }>> {
+  ): Promise<RemoteResult<{ accepted: true }>> {
    this.promptError = null
    this.lastAgentError = null
    // Synchronous, before the first await: the blank → engaging edge must be
@@ -223,52 +218,26 @@ export class Session implements SessionFace {
    this.promptAttempted = true
    if (this.blankBit) this.firstPromptPendingTurn = true
    this.notifier.markDirty()
-    let result: ClientResult<{ accepted: true }>
-    try {
-      if (this.address === undefined) {
-        const clientTimeZone = resolvedClientTimeZone()
-        result = toSessionResult(await this.remote.session.prompt({
-          requestId: requestId ?? randomUUID() as SessionRequestId,
-          sessionId: this.sessionId,
-          mode,
-          content,
-          clientTimeZone,
-        }, signal))
-      } else if (this.address.mode === 'one-shot') {
-        result = {
-          ok: false,
-          error: {
-            code: 'subagent-not-resumable',
-            message: 'one-shot subagent conversations are read-only',
-            details: { childSessionId: this.address.childSessionId },
-          },
-        }
-      } else {
-        if (content.some(part => part.type === 'image')) {
-          result = {
-            ok: false,
-            error: {
-              code: 'attachment-error',
-              message: 'Image input is unavailable for subagent continuations.',
-              details: { reason: 'SUBAGENT_IMAGE_UNSUPPORTED' },
-            },
-          }
-        } else {
-          const routed = toSessionResult(await this.remote.subagents.prompt({
-            requestId: randomUUID() as SessionRequestId,
-            parentSessionId: this.address.parentSessionId,
-            childSessionId: this.address.childSessionId,
-            mode: this.address.mode,
-            content: content.flatMap(part => part.type === 'text'
-              ? [{ type: 'text' as const, text: part.text }]
-              : []),
-            clientTimeZone: resolvedClientTimeZone(),
-          }, signal))
-          result = routed.ok ? { ok: true, value: { accepted: true } } : routed
-        }
-      }
-    } catch (error) {
-      result = transportResult(error)
+    let result: RemoteResult<{ accepted: true }>
+    if (this.address === undefined) {
+      const clientTimeZone = resolvedClientTimeZone()
+      result = await this.remote.session.prompt({
+        requestId: requestId ?? randomUUID() as SessionRequestId,
+        sessionId: this.sessionId,
+        mode,
+        content,
+        clientTimeZone,
+      }, signal)
+    } else {
+      const routed = await this.remote.subagents.prompt({
+        requestId: randomUUID() as SessionRequestId,
+        parentSessionId: this.address.parentSessionId,
+        childSessionId: this.address.childSessionId,
+        mode: 'continuable',
+        content,
+        clientTimeZone: resolvedClientTimeZone(),
+      }, signal)
+      result = routed.ok ? { ok: true, value: { accepted: true } } : routed
    }
    if (!result.ok) {
      if (requestId !== undefined) this.retireFailedSubmission(requestId)
@@ -299,66 +268,38 @@ export class Session implements SessionFace {
   */
  async readAttachment(
    attachmentId: AttachmentIdType,
-  ): Promise<ClientResult<{ attachment: ImageAttachmentRef; data: Uint8Array }>> {
-    try {
-      const result = await this.remote.session.attachment({
-        sessionId: this.sessionId,
-        attachmentId,
-      })
-      if (!result.ok) return toSessionResult(result)
-      const binary = atob(result.value.data)
-      const data = Uint8Array.from(binary, char => char.charCodeAt(0))
-      return { ok: true, value: { attachment: result.value.attachment, data } }
-    } catch (error) {
-      return transportResult(error)
-    }
+  ): Promise<RemoteResult<{ attachment: ImageAttachmentRef; data: Uint8Array }>> {
+    const result = await this.remote.session.attachment({
+      sessionId: this.sessionId,
+      attachmentId,
+    })
+    if (!result.ok) return result
+    const binary = atob(result.value.data)
+    const data = Uint8Array.from(binary, char => char.charCodeAt(0))
+    return { ok: true, value: { attachment: result.value.attachment, data } }
  }

  /** Apply one operation to a still-pending queue occurrence. */
-  async updateQueue(itemId: MessageId, action: QueueAction): Promise<ClientResult<{ accepted: true }>> {
-    try {
-      return toSessionResult(await this.remote.session.updateQueue({ sessionId: this.sessionId, itemId, action }))
-    } catch (error) {
-      return transportResult(error)
-    }
+  async updateQueue(itemId: MessageId, action: QueueAction): Promise<RemoteResult<{ accepted: true }>> {
+    return this.remote.session.updateQueue({ sessionId: this.sessionId, itemId, action })
  }

  /**
   * Stop the active turn while the Host preserves pending inbox work; failures
-   * land in promptError (same error-strip display slot). A continuable
-   * subagent address routes through `subagents.interruptByParent`, whose durable
-   * parent-address authority works without a live parent Agent; a one-shot
-   * address stays uncancellable (the UI offers no stop action, so this arm is
-   * defensive).
+   * land in promptError (same error-strip display slot). A subagent address
+   * routes through `subagents.interruptByParent`, whose durable parent-address
+   * authority works without a live parent Agent.
   * @returns the cancel result.
   */
-  async cancel(): Promise<ClientResult<{ accepted: true }>> {
+  async cancel(): Promise<RemoteResult<{ accepted: true }>> {
    const address = this.address
-    if (address !== undefined && address.mode === 'one-shot') {
-      const result: ClientResult<{ accepted: true }> = {
-        ok: false,
-        error: {
-          code: 'subagent-delivery-unavailable',
-          message: 'subagent activation cancellation is unavailable',
-          details: { childSessionId: address.childSessionId },
-        },
-      }
-      this.promptError = { op: 'stop', error: result.error }
-      this.notifier.markDirty()
-      return result
-    }
-    let result: ClientResult<{ accepted: true }>
-    try {
-      result = address !== undefined
-        ? toSessionResult(await this.remote.subagents.interruptByParent(
-          address.childSessionId,
-          address.parentSessionId,
-          address.mode,
-        ))
-        : toSessionResult(await this.remote.session.cancel({ sessionId: this.sessionId }))
-    } catch (error) {
-      result = transportResult(error)
-    }
+    const result = address !== undefined
+      ? await this.remote.subagents.interruptByParent(
+        address.childSessionId,
+        address.parentSessionId,
+        'continuable',
+      )
+      : await this.remote.session.cancel({ sessionId: this.sessionId })
    if (!result.ok) {
      this.promptError = { op: 'stop', error: result.error }
      this.notifier.markDirty()
@@ -375,14 +316,10 @@ export class Session implements SessionFace {
   * @param title - raw title text (the host normalizes acceptance).
   * @returns the rename result (normalized accepted title + title event seq).
   */
-  async rename(title: string): Promise<ClientResult<{ title: string; seq: number }>> {
-    try {
-      const result = toSessionResult(await this.remote.session.rename({ sessionId: this.sessionId, title }))
-      if (result.ok) this.projections.apply('title', result.value.title, result.value.seq)
-      return result
-    } catch (error) {
-      return transportResult(error)
-    }
+  async rename(title: string): Promise<RemoteResult<{ title: string; seq: number }>> {
+    const result = await this.remote.session.rename({ sessionId: this.sessionId, title })
+    if (result.ok) this.projections.apply('title', result.value.title, result.value.seq)
+    return result
  }

  /**
@@ -390,7 +327,7 @@ export class Session implements SessionFace {
   * admission semantics (the host executor durably logs the lifecycle;
   * outcomes render as flow nodes, never as a response echo).
   * @param line - the full command line, leading slash included.
-   * @returns the admission result, or the error branch on transport failure.
+   * @returns the admission result.
   */
  async command(line: string): Promise<RemoteResult<{ matched: boolean }>> {
    const result = await this.remote.commands.execute(this.sessionId, line, [])
@@ -420,7 +357,7 @@ export class Session implements SessionFace {
    try {
      await events.prepend({ beforeSeq: this.baseSeq, maxMessages: PAGE_MESSAGES })
    } catch (error) {
-      if (sessionStreamFailure(error) === undefined) {
+      if (!isRemoteFailure(error)) {
        console.error('[session-controller] loadOlder failed:', error)
      }
    } finally {
@@ -600,9 +537,10 @@ export class Session implements SessionFace {
      this.openState = 'open'
    } catch (error) {
      if (generation !== this.openGeneration || this.events !== events) return
+      if (!isRemoteFailure(error)) throw error
      this.events = undefined
      this.openState = 'error'
-      this.openError = openFailure(error)
+      this.openError = error
    } finally {
      if (generation === this.openGeneration) this.notifier.markDirty()
    }
@@ -714,11 +652,12 @@ export class Session implements SessionFace {
  /** Publish a terminal background failure only while this stream still owns the Session. */
  private failEventStream(events: SessionEventStream, generation: number, error: unknown): void {
    if (generation !== this.openGeneration || this.events !== events) return
+    if (!isRemoteFailure(error)) throw error
    this.openGeneration++
    this.events = undefined
    this.openPromise = null
    this.openState = 'error'
-    this.openError = openFailure(error)
+    this.openError = error
    void events.dispose()
    this.notifier.markDirty()
  }
@@ -774,17 +713,3 @@ function imageRefsIn(content: unknown): readonly ImageAttachmentRef[] {
  }
  return refs
 }
-
-/** Convert a terminal Session stream failure to the Client error vocabulary. */
-function openFailure(error: unknown): ClientFailure {
-  const failure = sessionStreamFailure(error)
-  if (failure !== undefined) return failure as SessionError
-  const folded = transportResult<never>(error)
-  /* v8 ignore next -- transportResult never returns an ok result. */
-  if (folded.ok) throw new Error('transportResult returned an unexpected success')
-  return folded.error
-}
-/** Narrow a generated Session Remote failure to its service-owned error vocabulary. */
-function toSessionResult<T>(result: RemoteResult<T>): ClientResult<T> {
-  return result.ok ? result : { ok: false, error: result.error as SessionError }
-}
@@ -1,12 +1,10 @@
 /** Session-specific adapters for Gateway-owned Remote stream lifecycles. */

 import type {} from '@deepseek-ai/dsh-api-session-controller/remote'
-import type { RemoteFailure } from '@deepseek-ai/dsh-typert-protocol'
 import {
  RemoteJournalStream,
  RemoteSnapshotStream,
  RemoteStreamCarrierError,
-  RemoteStreamError,
  type ClientRemote,
  type RemoteJournalChange,
  type RemoteJournalFrame,
@@ -25,6 +23,7 @@ import {
  historyRecordLastSeq,
 } from './sessions/history-records.ts'
 import type { SessionEventLikeEntry, SessionLiveEventEntry } from './contract/events.ts'
+import type { SessionRemotes } from './sessions/remotes.ts'

 export {
  SESSION_SEARCH_RESULT_LIMIT,
@@ -80,8 +79,6 @@ export type SessionControlStream = RemoteSnapshotStream<
  SessionControlDeltaFrame
 >

-type SessionStreamRemote = Pick<ClientRemote, '$stream' | 'session'>
-
 /** Domain sinks used by the Host-wide Session control stream. */
 export interface SessionControlStreamOptions {
  /** Apply a complete baseline or one later update. */
@@ -109,7 +106,7 @@ export interface SessionEventStreamOptions {
 * @returns an unstarted stream owned by the Client Session runtime.
 */
 export function createSessionControlStream(
-  remote: SessionStreamRemote,
+  remote: SessionRemotes,
  options: SessionControlStreamOptions,
 ): SessionControlStream {
  const stream = remote.$stream<SessionControlFrame>({
@@ -142,7 +139,7 @@ export class SessionEventStream extends RemoteJournalStream<
   * @param options - Session event-window destinations.
   */
  constructor(
-    private readonly remote: SessionStreamRemote,
+    private readonly remote: SessionRemotes,
    private readonly address: SessionAddress,
    options: SessionEventStreamOptions,
  ) {
@@ -198,13 +195,7 @@ export class SessionEventStream extends RemoteJournalStream<
      { address: this.address, throughSeq, ...request },
      signal,
    )
-    if (!result.ok) {
-      throw new RemoteStreamError(
-        result.error.code,
-        result.error.message,
-        result.error.details,
-      )
-    }
+    if (!result.ok) throw result.error
    return result.value
  }

@@ -215,13 +206,3 @@ export class SessionEventStream extends RemoteJournalStream<
    return request.maxMessages === undefined ? {} : { maxMessages: request.maxMessages }
  }
 }
-
-/**
- * Recover a Host Session failure from a Remote stream terminal error.
- * @param error - value thrown while opening or consuming a Session stream.
- * @returns the Host failure, or `undefined` for carrier and local failures.
- */
-export function sessionStreamFailure(error: unknown): RemoteFailure | undefined {
-  if (!(error instanceof RemoteStreamError)) return undefined
-  return { code: error.code, message: error.message, details: error.details }
-}