Web subagent catalogs consume shared projections
Web 子代理目录消费共享 projection
The parent catalog projection already publishes complete membership through the Session control stream. A separate catalog-change event, repeated RPC reads, and a second membership cache duplicate that delivery and require coordination between responses and later events. Historical Sessions still need initial loading when their projection is absent, and parent Agent availability remains independent of durable members
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English
Problem
The parent catalog projection already publishes complete membership through the Session control stream. A separate catalog-change event, repeated RPC reads, and a second membership cache duplicate that delivery and require coordination between responses and later events. Historical Sessions still need initial loading when their projection is absent, and parent Agent availability remains independent of durable membership.
Decision
The Client retains catalog membership only in its standard per-Session projection store. Initial session.projections reads return a complete projection baseline from one live-preferred Session observation. The endpoint accepts any Session id and has no catalog-specific dependency or validation. The same observation supplies the values and sequence cursor. Initial baselines and live control frames use the store's existing sequence ordering, so an older response cannot replace a newer value. The endpoint does not activate an Agent or sample child activity. Opening a conversation uses its follow baseline without scheduling a second projection read; unopened catalog branches still use explicit reads.
Feature consumers select subagentCatalog from projectionsBySession and derive row activity from Session-list baselines and status events. Session summaries report Agent availability separately; Agent creation and disposal republish the existing summary event. Completed subagents retain their summaries and display projections after removal. Generic projection reads own loading and error state; parent availability comes from the Session list independently of membership. Opening a loaded catalog reuses its data; an initial failure can be retried. Reconnect cancels previous reads and starts fresh reads for requested catalogs. Session removal cancels its pending read and marks parent availability false; projection responses cannot change Agent availability.
The parent-catalog decision owns durable creation facts and ordering. This decision supersedes the dedicated membership-refresh mechanism in Web subagent conversations; that note remains active for navigation, control, and presentation decisions.
Host summaries replace running and availability state; local create/fork placeholders only enrich missing metadata. Sharing overwrite behavior would let a late local response erase a newer Host state and generate a false completion reminder. Removed ordinary Sessions retain stores only for nonempty child catalogs; empty catalogs carry no navigation that needs to survive removal. Breadcrumb selectors derive addresses from the Session-list snapshot so their subscriptions cover every dependency.
Alternatives considered
Keep notification-driven reads. Rejected because the shared stream already delivers the changed value. Menu subscriptions, response-local activity replay, and trailing membership reads add no required delivery capability.
Remove the initial-read endpoint. Deferred. Session-list projections are cache hints and may be absent; following a conversation also transfers history and retains observation state. A lightweight read preserves historical catalog access without establishing a conversation follow stream. Parent availability is a live delivery hint, not a durable projection fact.
Consequences
Membership changes use the existing control stream without extra catalog notifications or reads. Whole-value projection publication still costs O(D) for D children; this change does not introduce delta transport. Initial reads return the observation's complete projection baseline, including values beyond the catalog, so they reuse standard baseline semantics at the cost of that additional initial payload. Session sequence ordering does not establish identity across reused Session ids.
Manager tests cover pushed membership, stale initial responses, lazy loading, status composition, retained completion metadata, retry, removal of empty catalogs, late create/fork responses, and reconnect cancellation. Host tests exercise the shared control stream and cold observations. The persisted-subagent Web scenario covers nested historical navigation and continuation through the shipped application.
中文
问题
父目录 projection 已通过 Session control stream 发布完整成员关系。独立的目录变化事件、重复 RPC 读取与第二份成员缓存重复传递同一数据，并要求协调响应与后续事件。历史 Session 的 projection 缺席时仍需初始加载，父 Agent 可用性也独立于持久成员关系。
决策
Client 仅在标准逐 Session projection store 中保留目录成员关系。初始 session.projections 读取通过一次 live-preferred Session observation 返回完整 projection 基线。endpoint 接受任意 Session id，不含目录专用依赖或校验。值与序号游标来自同一次 observation。初始基线与实时 control 帧使用 store 既有的序号排序，因此旧响应不能替换新值。该 endpoint 不激活 Agent，也不采样子代理活动状态。打开会话时使用其 follow baseline，不再额外调度一次投影读取；未打开的目录分支仍使用显式读取。
功能消费者从 projectionsBySession 中选择 subagentCatalog，并从 Session 列表基线与状态事件派生行活动状态。Session 摘要单独报告 Agent 可用性；Agent 创建与销毁重新发布已有摘要事件。完成的子代理在移除后保留摘要与展示 projection。通用 projection 读取拥有加载与错误状态；父 Agent 可用性来自 Session 列表，独立于成员关系。打开已加载目录会复用数据，初始失败可以重试。重连取消此前的读取，并为已请求的目录重新读取。Session 移除会取消其待完成读取并将父 Agent 可用性标为 false；projection 响应不能改变 Agent 可用性。
父目录决策 说明持久创建事实与顺序。本决策取代 Web 子代理会话 中的专用成员刷新机制；该记录继续保留导航、控制与展示决策。
Host 摘要替换运行状态与可用性；本地 create/fork 占位摘要只补充缺失的元数据。若共用覆盖行为，晚到的本地响应会抹去较新的 Host 状态，并生成虚假的完成提醒。普通 Session 移除后，仅为非空子目录保留 store；空目录没有需要保留的导航关系。面包屑 selector 从 Session 列表快照推导地址，使订阅涵盖全部依赖。
考虑过的替代方案
保留通知驱动的读取。 不采用，因为共享流已经传递变化后的值。菜单订阅、请求内活动状态回放与尾随成员读取没有提供额外的必要传递能力。
删除初始读取 endpoint。 暂缓。Session 列表 projection 是可能缺席的缓存提示；跟随会话还会传输历史并保留 observation 状态。轻量读取保留历史目录访问能力，无需建立会话跟随流。父 Agent 可用性是实时投递提示，而非持久 projection 事实。
影响
成员变化使用既有 control stream，无需额外目录通知或读取。对 D 个子级发布完整 projection 值仍需 O(D)；本变更不引入增量传输。初始读取返回 observation 的完整 projection 基线，其中包括目录以外的值，以额外初始载荷换取标准基线语义的复用。Session 序号排序不确立复用 Session id 之间的身份关系。
Manager 测试覆盖成员推送、过时初始响应、按需加载、状态组合、完成元数据保留、重试、空目录移除、晚到的 create/fork 响应与重连取消。Host 测试覆盖共享 control stream 与冷 observation。持久化子代理 Web 场景通过发布应用验证嵌套历史导航与续传。