Merge origin/master (regenerate the event producer-consumer graph)

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

@@ -0,0 +1,56 @@
+/**
+ * The outward session face. Feature packages never see the concrete Session
+ * class: components read conversation state through `useSession` (the
+ * ObservableSnapshot half), and orchestration code calls the behavior verbs
+ * below — nothing else. Widening this interface is the explicit act of
+ * widening what features may do to a session (and what every test fixture
+ * must stub); runtime-internal entry points (history staging, wire-frame
+ * dispatch) stay on the class, invisible out here.
+ */
+import type { ContentBlock } from '@deepseek-ai/dsh-llm/types'
+import type { RpcResult, SessionId } from '@deepseek-ai/dsh-client-connection/client'
+import type { ConversationSnapshot } from '../sessions/conversation.ts'
+import type { ObservableSnapshot } from './store.ts'
+
+/** Key-addressed projection read face (the useProjection resolution path; see ProjectionValueStore). */
+export interface ProjectionsFace {
+  /**
+   * The identity-stable bare observable for one projection key (absence is
+   * an `undefined` snapshot, never a missing face).
+   * @param key - projection key.
+   * @returns the key's value face.
+   */
+  faceOf(key: string): ObservableSnapshot<unknown>
+}
+
+/** Identity plus the behavior verbs features may invoke on a session. */
+export interface ISession {
+  /** The session's host identity (agent id — same axis). */
+  readonly sessionId: SessionId
+  /** Host-computed projection values by key (the useProjection seat). */
+  readonly projections: ProjectionsFace
+  /**
+   * Send a prompt into the session.
+   * @param content - model-facing content blocks.
+   * @param mode - 'queue' appends a turn; 'steer' interrupts the running one.
+   * @returns acceptance, or the business error (also mirrored into snapshot.promptError).
+   */
+  prompt(content: ContentBlock[], mode: 'queue' | 'steer'): Promise<RpcResult<{ accepted: true }>>
+  /**
+   * Cancel the running turn.
+   * @returns acceptance, or the business error.
+   */
+  cancel(): Promise<RpcResult<{ accepted: true }>>
+  /**
+   * Extend the history window backwards (older messages pagination).
+   * @returns completion; failures land in snapshot.openState/loadingOlder.
+   */
+  loadOlder(): Promise<void>
+}
+
+/**
+ * The full outward face: behavior verbs plus the conversation read side
+ * (the `useSession` hook source). This is the type carried by
+ * `SessionBinding.session` and the provide channel.
+ */
+export type SessionFace = ISession & ObservableSnapshot<ConversationSnapshot>

packages/client/runtime/src/client/contract/sessions-port.ts

@@ -0,0 +1,47 @@
+/**
+ * Cross-domain sessions face: the contract surface sibling domains (today:
+ * workspaces) consume instead of the sessions implementation. The sessions
+ * domain satisfies it structurally — SessionsService is assignable, checked
+ * wherever the assembly layer or a test injects the real service — so
+ * widening this face is the explicit act of widening the inter-domain
+ * dependency.
+ */
+
+import type { SessionId, WorkspaceId } from '@deepseek-ai/dsh-client-connection/client'
+import type { ObservableSnapshot } from './store.ts'
+
+/** Session-list row facts sibling domains read: recency, blank-reuse eligibility, and its cwd canon. */
+export interface SessionsPortSummary {
+  id: SessionId
+  /** Empty-log bit (blank sessions are reused by New Session instead of minting another). */
+  blank: boolean
+  cwd?: string
+  updatedAt: number
+}
+
+/** Session-list facts sibling domains read: readiness, selection, and the row map. */
+export interface SessionsPortList {
+  ids: SessionId[]
+  byId: Record<SessionId, SessionsPortSummary>
+  current: SessionId | undefined
+  phase: 'pending' | 'ready'
+}
+
+/** The sessions-service face injected into sibling domains. */
+export interface SessionsPort {
+  /** Observable list snapshot (read face only; writes stay inside the sessions domain). */
+  readonly list: ObservableSnapshot<SessionsPortList>
+  /**
+   * Create a session on the host.
+   * @param opts - target workspace.
+   * @returns the new session id.
+   */
+  create(opts: { workspaceId: WorkspaceId }): Promise<SessionId>
+  /**
+   * Select a session as current.
+   * @param id - session id (must exist in the list store).
+   */
+  open(id: SessionId): void
+  /** Clear the current selection into the no-session view state. */
+  clear(): void
+}

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

@@ -0,0 +1,64 @@
+/**
+ * The outward sessions-service face — what `ctx.sessions` exposes to feature
+ * packages and the renderer host, and therefore exactly what the test
+ * runtime's sessions double must implement. Wire-pump entry points
+ * (handleMuxEnvelope/handleConnected/refresh) and runtime internals stay on
+ * the concrete class; cross-domain consumers keep the narrower
+ * [SessionsPort](./sessions-port.ts). Widening this interface is the
+ * explicit act of widening what features may do to the sessions domain.
+ */
+import type { Context } from 'cordis'
+import type { SessionId } from '@deepseek-ai/dsh-client-connection/client'
+import type { HostObservable, SessionMaybeProvideInfo } from '@deepseek-ai/dsh-client-ui-slots'
+import type {
+  SessionBinding, SessionListState, SessionProvideDescriptor,
+} from '../sessions/service.ts'
+import type { SessionFace } from './session.ts'
+import type { ObservableSnapshot } from './store.ts'
+
+/** The sessions-service face injected as `ctx.sessions`. */
+export interface ISessions {
+  /** The useSessions standard feed (list rows + current selection; read face — writes stay inside the domain). */
+  readonly list: ObservableSnapshot<SessionListState>
+  /** Atomic current-session provide projection (the renderer host's `sessions.provideInfo` feed). */
+  readonly currentProvideInfo: HostObservable<SessionMaybeProvideInfo>
+  /**
+   * Select a session as current.
+   * @param id - session id (must exist in the list; unknown ids fail loud).
+   */
+  open(id: SessionId): void
+  /** Clear the current selection into the no-session view state. */
+  clear(): void
+  /**
+   * Register a per-session standard-props provider (hooks become `use<Name>`
+   * selector hooks on the render side; props spread verbatim).
+   * @param descriptor - static member roster plus per-session resolver.
+   * @returns disposer removing the provider.
+   */
+  provide(descriptor: SessionProvideDescriptor): () => void
+  /**
+   * Resolve an Agent-scoped context view (use-and-discard).
+   * @param id - session id.
+   * @returns scoped ctx, or undefined for a session neither listed nor already scoped.
+   */
+  scope(id: SessionId): Context | undefined
+  /**
+   * Read the Agent scope tag off a context (service-method seam: fetch
+   * bundles must reach scope resolution through ctx.sessions).
+   * @param ctx - any client context.
+   * @returns the session id, or undefined on root contexts.
+   */
+  scopeOf(ctx: Context): SessionId | undefined
+  /**
+   * Resolve the session face behind an Agent-scoped context.
+   * @param ctx - an Agent-scoped context.
+   * @returns the session face, or undefined when the ctx is untagged or its scope was pruned.
+   */
+  sessionOf(ctx: Context): SessionFace | undefined
+  /**
+   * Resolve the stable session binding (scope-addressed assembly feed).
+   * @param id - session id.
+   * @returns binding, or undefined for a session neither listed nor already scoped.
+   */
+  binding(id: SessionId): SessionBinding | undefined
+}

packages/client/runtime/src/client/contract/workspaces.ts

@@ -0,0 +1,65 @@
+/**
+ * The outward workspaces-service face — what `ctx.workspaces` exposes to
+ * feature packages and the renderer host, and therefore exactly what the
+ * test runtime's workspaces double must implement. Wire-pump entry points
+ * (handleHostEnvelope/handleConnected/refresh/startInitialSelection) stay on
+ * the concrete class. Widening this interface is the explicit act of
+ * widening what features may do to the workspaces domain.
+ */
+import type { SessionId, WorkspaceId, WorkspaceView } from '@deepseek-ai/dsh-client-connection/client'
+import type { WorkspaceListState } from '../workspaces/service.ts'
+import type { ObservableSnapshot } from './store.ts'
+
+/** The workspaces-service face injected as `ctx.workspaces`. */
+export interface IWorkspaces {
+  /** The useWorkspaces standard feed (read face — writes stay inside the domain). */
+  readonly list: ObservableSnapshot<WorkspaceListState>
+  /**
+   * Connect a Workspace to its reusable or freshly created blank session.
+   * @param workspaceId - target workspace.
+   * @returns the connected session id.
+   */
+  connectWorkspace(workspaceId: WorkspaceId): Promise<SessionId>
+  /**
+   * The New Session flow: connect the target (or recent) Workspace and open
+   * the resulting session; failures surface on the session list state.
+   * @param workspaceId - explicit target; omitted uses the recency projection.
+   */
+  startSession(workspaceId?: WorkspaceId): void
+  /**
+   * Create a Workspace by name or register an existing path.
+   * @param input - exactly one Host create spelling.
+   * @returns the created or idempotently resolved Workspace.
+   */
+  create(input: { name: string } | { path: string }): Promise<WorkspaceView>
+  /**
+   * Open the Host's native directory picker.
+   * @returns the selected path, or null when the user cancelled.
+   */
+  pickDirectory(): Promise<string | null>
+  /**
+   * Open a filesystem path with the Host operating system's default application.
+   * @param path - absolute or host-resolvable path.
+   */
+  openPath(path: string): Promise<void>
+  /**
+   * Rename a Workspace.
+   * @param workspaceId - target workspace.
+   * @param title - the new display title.
+   * @returns the updated Workspace view.
+   */
+  rename(workspaceId: WorkspaceId, title: string): Promise<WorkspaceView>
+  /**
+   * Delete a Workspace (its sessions fall back to the unaccounted group).
+   * @param workspaceId - target workspace.
+   */
+  delete(workspaceId: WorkspaceId): Promise<void>
+  /**
+   * Move an accounted session within/into a Workspace's ordered list.
+   * @param workspaceId - target workspace.
+   * @param sessionId - accounted session to move.
+   * @param beforeSessionId - accounted anchor to insert before; omitted appends.
+   * @returns the updated Workspace view.
+   */
+  insertSessionBefore(workspaceId: WorkspaceId, sessionId: SessionId, beforeSessionId?: SessionId): Promise<WorkspaceView>
+}

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

@@ -12,10 +12,17 @@ import type { UseProjection } from './sessions/projection-store.ts'
 export { SlotsService } from './slots.ts'
 export type { RootOwnerProps } from './slots.ts'
 export { SessionCreateError, SessionsService, scopeOf, workspaceTitleOf } from './sessions/service.ts'
+// The provide channel is shared with the client test runtime (one
+// materialization/projection implementation; no test-side mirror to drift).
+export { SessionProvideChannel } from './sessions/provide.ts'
+export type { SessionProvideChannelHost } from './sessions/provide.ts'
 export { createScope } from './agents/scope.ts'
 export type { AgentScopeHandle } from './agents/scope.ts'
 export { WorkspaceCreateError, WorkspacesService } from './workspaces/service.ts'
 export type { Session } from './sessions/session.ts'
+export type { ISession, ProjectionsFace, SessionFace } from './contract/session.ts'
+export type { ISessions } from './contract/sessions.ts'
+export type { IWorkspaces } from './contract/workspaces.ts'
 export type {
   SessionBinding, SessionListState, SessionProvideContribution, SessionProvideDescriptor, SessionSummary,
 } from './sessions/service.ts'
@@ -109,8 +116,10 @@ declare module 'cordis' {
   }
   interface Context {
     slots: import('./slots.ts').SlotsService
-    sessions: import('./sessions/service.ts').SessionsService
-    workspaces: import('./workspaces/service.ts').WorkspacesService
+    /** The outward face only; the concrete service stays inside the runtime. */
+    sessions: import('./contract/sessions.ts').ISessions
+    /** The outward face only; the concrete service stays inside the runtime. */
+    workspaces: import('./contract/workspaces.ts').IWorkspaces
   }
 }
 

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

@@ -212,6 +212,19 @@ export class SessionManager {
             session.handleBlank(s.blank)
             session.handleRunning(s.running)
           }
+          // Seed each row's projection baseline into the per-session value
+          // store (cold titles surface without opening the session). Per-key
+          // apply, not seed(): the list block is a partial baseline — the
+          // cold cache serves only version-matching keys — so an absent key
+          // must not clear; higher-seq-wins still keeps a stale list block
+          // from overwriting a newer push frame or tail baseline.
+          for (const s of result.value.items) {
+            const block = s.projections
+            if (block === undefined) continue
+            const store = this.projectionStore(s.sessionId)
+            const values = block.values as Record<string, unknown>
+            for (const key of Object.keys(values)) store.apply(key, values[key], block.asOfSeq)
+          }
         } else {
           this.listState = 'error'
           this.listError = result.error

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

@@ -0,0 +1,190 @@
+/**
+ * The session standard-props provide channel: provider roster, bundle
+ * materialization (fail-loud on undeclared/missing/duplicate members), the
+ * static no-session projection, and the atomic current-session projection
+ * observable. One implementation — SessionsService drives it from wire
+ * truth, the test runtime's sessions double drives it from fixtures — so
+ * the materialization rules and the projection semantics cannot drift
+ * between production and the test bench.
+ */
+import type { HostObservable, SessionMaybeProvideInfo, SessionProvideInfo } from '@deepseek-ai/dsh-client-ui-slots'
+import type { SessionBinding, SessionProvideDescriptor } from './service.ts'
+
+/** The owner-side hooks: how the channel reaches the owner's live bundles and current selection. */
+export interface SessionProvideChannelHost {
+  /**
+   * Re-materialize every already-materialized bundle against the new roster
+   * (call {@link SessionProvideChannel.materializeInfo} per live binding).
+   * Lazily-materialized sessions pick the new roster up on first resolve.
+   */
+  rebuildBundles(): void
+  /** Resolve the current selection's bundle (the owner's maybe-provide lookup). */
+  resolveCurrent(): SessionMaybeProvideInfo
+}
+
+/**
+ * Provider roster + materialization + current projection. The channel owns
+ * every rule a provider contribution must satisfy; owners keep only their
+ * per-session bundle storage and the definition of "current".
+ */
+export class SessionProvideChannel {
+  private readonly providers: SessionProvideDescriptor[] = []
+  private maybeInfoCache: SessionMaybeProvideInfo
+  /** Latest published current bundle (identity comparison dedupes republish). */
+  private currentSnapshot: SessionMaybeProvideInfo
+  /** Projection subscribers (plain cell: bundles hold live session sources, so no store freeze may touch them). */
+  private readonly listeners = new Set<() => void>()
+
+  /**
+   * Atomic current-session provide projection: selection changes and
+   * provider-roster changes publish through this one source, so a roster
+   * change under a stable current id republishes the bundle instead of
+   * stranding mounted entries.
+   */
+  readonly currentProvideInfo: HostObservable<SessionMaybeProvideInfo>
+
+  /**
+   * @param host - owner-side bundle storage and current-selection resolution.
+   */
+  constructor(private readonly host: SessionProvideChannelHost) {
+    // The runtime's own contribution comes first: useSession rides the same
+    // provide channel every plugin uses (no renderer special case).
+    this.providers.push({
+      hooks: ['session'],
+      resolve: binding => ({ hooks: { session: binding.session } }),
+    })
+    this.maybeInfoCache = this.materializeMaybeInfo()
+    this.currentSnapshot = this.maybeInfoCache
+    this.currentProvideInfo = {
+      getSnapshot: () => this.currentSnapshot,
+      subscribe: (fn) => {
+        this.listeners.add(fn)
+        return () => { this.listeners.delete(fn) }
+      },
+    }
+  }
+
+  /** The static no-session projection under the current roster (declared names present, values undefined). */
+  get maybeInfo(): SessionMaybeProvideInfo {
+    return this.maybeInfoCache
+  }
+
+  /**
+   * Register a per-session standard-props provider (see
+   * SessionsService.provide for the product contract). Live bundles rebuild
+   * immediately; misdeclared providers fail loud here, at the registration
+   * edge, and the registration rolls back — the channel never stays on a
+   * roster it cannot materialize.
+   * @param descriptor - static member roster plus per-session resolver.
+   * @returns disposer removing the provider.
+   */
+  provide(descriptor: SessionProvideDescriptor): () => void {
+    this.providers.push(descriptor)
+    try {
+      this.applyRosterChange()
+    } catch (error) {
+      this.providers.splice(this.providers.indexOf(descriptor), 1)
+      // Restore the previous (valid) roster's bundles; cannot rethrow — the
+      // pre-push roster materialized successfully before.
+      this.applyRosterChange()
+      throw error
+    }
+    return () => {
+      const at = this.providers.indexOf(descriptor)
+      if (at >= 0) this.providers.splice(at, 1)
+      this.applyRosterChange()
+    }
+  }
+
+  /**
+   * Re-derive the current selection's bundle and publish it when it changed.
+   * Bundles are identity-stable per (scope, roster) materialization, so an
+   * identity compare is exact; synchronous notify — call sites (the owner's
+   * list subscription, provide()) already sit behind their own batching or
+   * registration edges.
+   */
+  publishCurrent(): void {
+    const next = this.host.resolveCurrent()
+    if (next === this.currentSnapshot) return
+    this.currentSnapshot = next
+    for (const fn of [...this.listeners]) {
+      try {
+        fn()
+      } catch (error) {
+        // Contain subscriber failures: this notify runs inside the list
+        // notification, where a throwing render-side subscriber would starve
+        // later listeners and abort the projection pass that scheduled it.
+        console.error('sessions.currentProvideInfo subscriber failed:', error)
+      }
+    }
+  }
+
+  /**
+   * Materialize the standard-props bundle for one session (fails loud on
+   * undeclared, missing, and duplicate member names).
+   * @param binding - session assembly handle fed to every resolver.
+   * @returns the materialized bundle (identity-stable until the next materialization).
+   */
+  materializeInfo(binding: SessionBinding): SessionProvideInfo {
+    const hooks: Record<string, HostObservable<unknown>> = {}
+    const props: Record<string, unknown> = {}
+    for (const descriptor of this.providers) {
+      const contribution = descriptor.resolve(binding)
+      const contributedHooks = contribution.hooks ?? {}
+      const contributedProps = contribution.props ?? {}
+      for (const name of Object.keys(contributedHooks)) {
+        if (!(descriptor.hooks ?? []).includes(name)) {
+          throw new Error(`sessions.provide: undeclared hook "${name}"`)
+        }
+      }
+      for (const name of Object.keys(contributedProps)) {
+        if (!(descriptor.props ?? []).includes(name)) {
+          throw new Error(`sessions.provide: undeclared prop "${name}"`)
+        }
+      }
+      for (const name of descriptor.hooks ?? []) {
+        const source = contributedHooks[name]
+        if (source === undefined) throw new Error(`sessions.provide: missing hook "${name}"`)
+        if (Object.hasOwn(hooks, name)) throw new Error(`sessions.provide: duplicate hook "${name}"`)
+        hooks[name] = source
+      }
+      for (const name of descriptor.props ?? []) {
+        if (!Object.hasOwn(contributedProps, name)) throw new Error(`sessions.provide: missing prop "${name}"`)
+        if (Object.hasOwn(props, name)) throw new Error(`sessions.provide: duplicate prop "${name}"`)
+        props[name] = contributedProps[name]
+      }
+    }
+    return {
+      sessionId: binding.sessionId,
+      hooks,
+      props,
+      // The useProjection seat: key-addressed bare value faces off the
+      // session's projection store (open key space — never a static roster member).
+      projections: { faceOf: key => binding.session.projections.faceOf(key) },
+    }
+  }
+
+  /** Rebuild the static projection and the owner's live bundles, then republish the current one. */
+  private applyRosterChange(): void {
+    this.maybeInfoCache = this.materializeMaybeInfo()
+    this.host.rebuildBundles()
+    this.publishCurrent()
+  }
+
+  /** Build the static no-session kit and reject duplicate declared names. */
+  private materializeMaybeInfo(): SessionMaybeProvideInfo {
+    const hooks: Record<string, undefined> = {}
+    const props: Record<string, undefined> = {}
+    for (const descriptor of this.providers) {
+      for (const name of descriptor.hooks ?? []) {
+        if (Object.hasOwn(hooks, name)) throw new Error(`sessions.provide: duplicate hook "${name}"`)
+        hooks[name] = undefined
+      }
+      for (const name of descriptor.props ?? []) {
+        if (Object.hasOwn(props, name)) throw new Error(`sessions.provide: duplicate prop "${name}"`)
+        props[name] = undefined
+      }
+    }
+    return { sessionId: undefined, hooks, props } // no projections face: every key reads absent without a session
+  }
+}

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

@@ -22,9 +22,12 @@ import type {
 } from '@deepseek-ai/dsh-client-ui-slots'
 import type { SnapshotStore } from '../contract/store.ts'
 import { createSnapshotStore } from '../contract/store.ts'
+import type { SessionFace } from '../contract/session.ts'
+import type { ISessions } from '../contract/sessions.ts'
 import { createScope, scopeOf as scopeTagOf } from '../agents/scope.ts'
 import { SessionManager } from './manager.ts'
 import type { SessionListPhase } from './manager.ts'
+import { SessionProvideChannel } from './provide.ts'
 import type { Session } from './session.ts'
 
 /** Session list row projected from the host list RPC plus live stream increments. */
@@ -79,7 +82,8 @@ export class SessionCreateError extends Error {
 /** Session assembly handle for SessionProvider/inject factories (identity-stable per session). */
 export interface SessionBinding {
   readonly sessionId: SessionId
-  readonly session: Session
+  /** The outward session face only — feature code never sees the concrete class. */
+  readonly session: SessionFace
   readonly ctx: Context
 }
 
@@ -119,6 +123,8 @@ interface ScopeRecord {
   fiber: Fiber
   ctx: Context
   binding: SessionBinding
+  /** The concrete Session for runtime-internal entry points (staging open()); the binding carries only the outward face. */
+  session: Session
   /** Render-layer standard-props bundle (identity-stable per scope; the renderer's per-info caches key off it). */
   provideInfo: SessionProvideInfo
 }
@@ -146,7 +152,7 @@ export interface SessionProvideDescriptor {
 }
 
 /** Root sessions service: list store, current selection, object-layer manager, scope tree, bindings, ancestry. */
-export class SessionsService {
+export class SessionsService implements ISessions {
   /** List snapshot store (list RPC + host stream increments; re-pulled on reconnect) — the useSessions standard feed, current included. */
   readonly list: SnapshotStore<SessionListState>
   /** The object-layer instance cluster and frame dispatch entry. */
@@ -170,14 +176,8 @@ export class SessionsService {
   private readonly selection: SnapshotStore<{ sessionId?: SessionId }>
 
   private readonly scopes = new Map<SessionId, ScopeRecord>()
-  /** Registered per-session standard-props providers, in registration order. */
-  private readonly providers: SessionProvideDescriptor[] = []
-  /** Static no-session projection, rebuilt only when the provider roster changes. */
-  private maybeInfo: SessionMaybeProvideInfo
-  /** Latest published {@link SessionsService.currentProvideInfo} bundle (identity comparison dedupes republish). */
-  private currentProvideInfoSnapshot: SessionMaybeProvideInfo
-  /** currentProvideInfo subscribers (plain cell: bundles hold live Session sources, so no store freeze may touch them). */
-  private readonly currentProvideInfoListeners = new Set<() => void>()
+  /** The provide channel (roster, materialization rules, current projection) — shared with the test runtime's double. */
+  private readonly provideChannel: SessionProvideChannel
   /**
    * The staged session id — follows `list.current` exactly, holding its last
    * defined value across masked gaps (a transiently absent selection blanks
@@ -212,23 +212,17 @@ export class SessionsService {
     // The current-provide projection follows the same current writes.
     this.list.subscribe(() => {
       this.followCurrent()
-      this.updateCurrentProvideInfo()
+      this.provideChannel.publishCurrent()
     })
-    // The runtime's own contribution comes first: useSession rides the same
-    // provide channel every plugin uses (no renderer special case).
-    this.providers.push({
-      hooks: ['session'],
-      resolve: binding => ({ hooks: { session: binding.session } }),
-    })
-    this.maybeInfo = this.materializeMaybeProvideInfo()
-    this.currentProvideInfoSnapshot = this.maybeInfo
-    this.currentProvideInfo = {
-      getSnapshot: () => this.currentProvideInfoSnapshot,
-      subscribe: (fn) => {
-        this.currentProvideInfoListeners.add(fn)
-        return () => { this.currentProvideInfoListeners.delete(fn) }
+    this.provideChannel = new SessionProvideChannel({
+      rebuildBundles: () => {
+        for (const record of this.scopes.values()) {
+          record.provideInfo = this.provideChannel.materializeInfo(record.binding)
+        }
       },
-    }
+      resolveCurrent: () => this.maybeProvideInfo(this.list.getSnapshot().current),
+    })
+    this.currentProvideInfo = this.provideChannel.currentProvideInfo
     rootCtx.reflect.provide('sessions', this, undefined)
   }
 
@@ -243,105 +237,10 @@ export class SessionsService {
    * @returns disposer removing the provider (already-materialized bundles keep their members until their scope drops).
    */
   provide(descriptor: SessionProvideDescriptor): () => void {
-    this.providers.push(descriptor)
     // Scopes may already exist (boot order: the list lands and resolves
-    // scopes before later plugins register) — their bundles must include
-    // every provider by first render, so re-materialize on roster change.
-    this.rematerializeProvideBundles()
-    return () => {
-      const at = this.providers.indexOf(descriptor)
-      if (at >= 0) this.providers.splice(at, 1)
-      this.rematerializeProvideBundles()
-    }
-  }
-
-  /** Rebuild every live scope's standard-props bundle after a provider roster change. */
-  private rematerializeProvideBundles(): void {
-    this.maybeInfo = this.materializeMaybeProvideInfo()
-    for (const record of this.scopes.values()) {
-      record.provideInfo = this.materializeProvideInfo(record.binding)
-    }
-    this.updateCurrentProvideInfo()
-  }
-
-  /**
-   * Re-derive the current selection's provide bundle and publish it when it
-   * changed. Bundles are identity-stable per (scope, roster)
-   * materialization, so an identity compare is exact; synchronous notify —
-   * both call sites (list.subscribe, provide()) already sit behind their own
-   * batching or registration edges.
-   */
-  private updateCurrentProvideInfo(): void {
-    const next = this.maybeProvideInfo(this.list.getSnapshot().current)
-    if (next === this.currentProvideInfoSnapshot) return
-    this.currentProvideInfoSnapshot = next
-    for (const fn of [...this.currentProvideInfoListeners]) {
-      try {
-        fn()
-      } catch (error) {
-        // Contain subscriber failures: this notify runs inside the list
-        // notification, where a throwing render-side subscriber would starve
-        // later listeners and abort the projection pass that scheduled it.
-        console.error('sessions.currentProvideInfo subscriber failed:', error)
-      }
-    }
-  }
-
-  /** Build the static no-session kit and reject duplicate declared names. */
-  private materializeMaybeProvideInfo(): SessionMaybeProvideInfo {
-    const hooks: Record<string, undefined> = {}
-    const props: Record<string, undefined> = {}
-    for (const descriptor of this.providers) {
-      for (const name of descriptor.hooks ?? []) {
-        if (Object.hasOwn(hooks, name)) throw new Error(`sessions.provide: duplicate hook "${name}"`)
-        hooks[name] = undefined
-      }
-      for (const name of descriptor.props ?? []) {
-        if (Object.hasOwn(props, name)) throw new Error(`sessions.provide: duplicate prop "${name}"`)
-        props[name] = undefined
-      }
-    }
-    return { sessionId: undefined, hooks, props } // no projections face: every key reads absent without a session
-  }
-
-  /** Materialize the standard-props bundle for one session (fails loud on duplicate member names). */
-  private materializeProvideInfo(binding: SessionBinding): SessionProvideInfo {
-    const hooks: Record<string, HostObservable<unknown>> = {}
-    const props: Record<string, unknown> = {}
-    for (const descriptor of this.providers) {
-      const contribution = descriptor.resolve(binding)
-      const contributedHooks = contribution.hooks ?? {}
-      const contributedProps = contribution.props ?? {}
-      for (const name of Object.keys(contributedHooks)) {
-        if (!(descriptor.hooks ?? []).includes(name)) {
-          throw new Error(`sessions.provide: undeclared hook "${name}"`)
-        }
-      }
-      for (const name of Object.keys(contributedProps)) {
-        if (!(descriptor.props ?? []).includes(name)) {
-          throw new Error(`sessions.provide: undeclared prop "${name}"`)
-        }
-      }
-      for (const name of descriptor.hooks ?? []) {
-        const source = contributedHooks[name]
-        if (source === undefined) throw new Error(`sessions.provide: missing hook "${name}"`)
-        if (Object.hasOwn(hooks, name)) throw new Error(`sessions.provide: duplicate hook "${name}"`)
-        hooks[name] = source
-      }
-      for (const name of descriptor.props ?? []) {
-        if (!Object.hasOwn(contributedProps, name)) throw new Error(`sessions.provide: missing prop "${name}"`)
-        if (Object.hasOwn(props, name)) throw new Error(`sessions.provide: duplicate prop "${name}"`)
-        props[name] = contributedProps[name]
-      }
-    }
-    return {
-      sessionId: binding.sessionId,
-      hooks,
-      props,
-      // The useProjection seat: key-addressed bare value faces off the
-      // session's projection store (open key space — never a static roster member).
-      projections: { faceOf: key => binding.session.projections.faceOf(key) },
-    }
+    // scopes before later plugins register) — the channel rebuilds their
+    // bundles through the host hooks so every provider lands by first render.
+    return this.provideChannel.provide(descriptor)
   }
 
   /**
@@ -439,9 +338,9 @@ export class SessionsService {
    * `agent.session`). Same service-method seam as
    * {@link SessionsService.scopeOf}.
    * @param ctx - an Agent-scoped context.
-   * @returns the Session, or undefined when the ctx is untagged or its scope was pruned.
+   * @returns the session face, or undefined when the ctx is untagged or its scope was pruned.
    */
-  sessionOf(ctx: Context): Session | undefined {
+  sessionOf(ctx: Context): SessionFace | undefined {
     const id = scopeTagOf(ctx)
     if (id === undefined) return undefined
     return this.scopes.get(id)?.binding.session
@@ -473,7 +372,7 @@ export class SessionsService {
    * return the static no-session projection rather than removing hook props.
    */
   private maybeProvideInfo(id: string | undefined): SessionMaybeProvideInfo {
-    return (id === undefined ? undefined : this.provideInfo(id)) ?? this.maybeInfo
+    return (id === undefined ? undefined : this.provideInfo(id)) ?? this.provideChannel.maybeInfo
   }
 
   /**
@@ -497,7 +396,7 @@ export class SessionsService {
      * validates and the projection masks absent selections), so resolve
      * cannot miss; kept so a future current writer cannot crash the notify. */
     if (record !== undefined) {
-      void record.binding.session.open()
+      void record.session.open()
     }
   }
 
@@ -540,8 +439,9 @@ export class SessionsService {
       fiber,
       ctx,
       binding,
+      session,
       // Sources are bare observables; React binds selector hooks at its own seam.
-      provideInfo: this.materializeProvideInfo(binding),
+      provideInfo: this.provideChannel.materializeInfo(binding),
     }
     this.scopes.set(id, record)
     return record
@@ -608,7 +508,7 @@ export class SessionsService {
     void record.fiber.dispose()
     // Release the Session's dispatch point with the scope it belongs to (a
     // surviving instance — the live Intent — rebinds when resolve re-mints).
-    record.binding.session.unbindScope()
+    record.session.unbindScope()
     // Optional lookup: slots and sessions are sibling services with no
     // declared dependency; a slots-less boot (object-layer tests) skips.
     this.rootCtx.get('slots')?.pruneStoreScope(id)

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

@@ -10,7 +10,7 @@ import type {
 // Value import from the inline-safe wire layer (not the connection plugin):
 // plugin-to-plugin value imports are a bundle purity error.
 import { transportError } from '@deepseek-ai/dsh-host-apiproxy/api'
-import type { ObservableSnapshot } from '../contract/store.ts'
+import type { SessionFace } from '../contract/session.ts'
 import type {
   CodeSubCall, ComposerPhase, ConversationNode, ConversationSnapshot, OpenState,
   PromptError, QueuedMessage, RunningToolCall,
@@ -67,9 +67,11 @@ function queuePreviewOf(content: readonly ContentBlock[]): string {
 
 /**
  * Owns a session's event window, derived conversation state, and observable
- * snapshot. React bindings remain outside this data layer.
+ * snapshot. React bindings remain outside this data layer. Features see only
+ * the {@link SessionFace} slice (ISession verbs + the snapshot source); the
+ * remaining public members are manager/runtime entry points.
  */
-export class Session implements ObservableSnapshot<ConversationSnapshot> {
+export class Session implements SessionFace {
   // ---- Window and derived state (all private; the snapshot is the only read surface) ----
   private events: SessionEvent[] = []
   /** Wire views aligned with `events` by index (envelope-level annotations; undefined = no view).

packages/client/runtime/src/client/workspaces/service.ts

@@ -6,7 +6,8 @@ import type {
 } from '@deepseek-ai/dsh-client-connection/client'
 import type { SnapshotStore } from '../contract/store.ts'
 import { createSnapshotStore } from '../contract/store.ts'
-import type { SessionsService } from '../sessions/service.ts'
+import type { SessionsPort, SessionsPortList } from '../contract/sessions-port.ts'
+import type { IWorkspaces } from '../contract/workspaces.ts'
 import { WorkspaceManager, type WorkspaceListPhase } from './manager.ts'
 
 /** Workspace list plus the two-baseline readiness and default-target projection. */
@@ -30,7 +31,7 @@ export class WorkspaceCreateError extends Error {
 }
 
 /** Real Workspace object layer and Host actions. */
-export class WorkspacesService {
+export class WorkspacesService implements IWorkspaces {
   /** UI-facing immutable projection; the manager remains wire truth. */
   readonly list: SnapshotStore<WorkspaceListState>
   /** Workspace baseline and frame owner. */
@@ -43,9 +44,9 @@ export class WorkspacesService {
   /**
    * @param ctx - client root context.
    * @param api - shared wire client.
-   * @param sessions - lower-level Session service used for recency and blank-session reuse.
+   * @param sessions - cross-domain sessions face used for recency and blank-session reuse.
    */
-  constructor(ctx: Context, private readonly api: IApiClient, private readonly sessions: SessionsService) {
+  constructor(ctx: Context, private readonly api: IApiClient, private readonly sessions: SessionsPort) {
     this.manager = new WorkspaceManager(api)
     this.list = createSnapshotStore<WorkspaceListState>({
       items: [], state: 'idle', phase: 'pending', error: null,
@@ -271,7 +272,7 @@ export class WorkspacesService {
 /** Stable tie-breaking follows Host Workspace order. */
 function recentWorkspace(
   workspaces: readonly WorkspaceView[],
-  sessions: ReturnType<SessionsService['list']['getSnapshot']>['byId'],
+  sessions: SessionsPortList['byId'],
 ): WorkspaceId | undefined {
   let selected: WorkspaceId | undefined
   let selectedTime = Number.NEGATIVE_INFINITY

packages/client/runtime/tests/manager.spec.ts

@@ -160,6 +160,28 @@ describe('list lifecycle', () => {
     expect(manager.getListSnapshot().items.find(item => item.sessionId === S1)?.title).toBeUndefined()
   })
 
+  it('seeds cold titles from the list rows\' projections block under higher-seq-wins', async () => {
+    const api = new FakeApiClient()
+    const manager = new SessionManager(api)
+    // A push frame landed before the list (S2's title is newer than the block's cut).
+    manager.handleMuxEnvelope({
+      rpcId: 'push-newer' as never,
+      payload: { type: 'session/projection', sessionId: S2, key: 'title', value: 'Pushed', seq: 9 } as never,
+    })
+    api.onList = () => Promise.resolve(ok({
+      items: [
+        { ...summary(S1), projections: { asOfSeq: 4, values: { title: 'Cold cached' } } },
+        { ...summary(S2, { updatedAt: 200 }), projections: { asOfSeq: 5, values: { title: 'List stale' } } },
+      ] as never[],
+    }))
+    await manager.refreshList()
+    const items = manager.getListSnapshot().items
+    // Cold row: title surfaces straight from the list block — no open, no history.
+    expect(items.find(item => item.sessionId === S1)?.title).toBe('Cold cached')
+    // The stale list block (seq 5) cannot overwrite the newer push frame (seq 9).
+    expect(items.find(item => item.sessionId === S2)?.title).toBe('Pushed')
+  })
+
   it('drops a projection row beyond the subscription baseline before accepting its durable replay', async () => {
     const api = new FakeApiClient()
     api.onList = () => Promise.resolve(ok({ items: [summary(S1)] as never[] }))