weichen
c0baa342fc
Why: the adjudicated preview plan needs server-side OG fetching for link cards, and the proposal's reserved-capability items call for the fs tool family to exist behind a default-off gate (implemented, not offered). Evidence: GET /api/url-preview fetches and parses og:title/description/ site_name/image/favicon with a 5s timeout, 256KB body cap, text/html content check, TTL cache, and SSRF guards enforced at dial time (loopback /private/link-local/multicast/reserved/CGNAT rejected per hop, anti DNS- rebind; AS_URL_PREVIEW_ALLOW_PRIVATE=1 exists for local testing only, default fail-closed; errors return sanitized cards, never internal addresses). fs_read_file/fs_write_file/fs_list_dir register as Hidden tools sandboxed under <root>/<owner>/<conversationId>: traversal, absolute paths, backslashes, and symlink escape rejected; 1MB/2MB size caps; writes register an artifact so workspace files stay visible in the panel. ToolDesc.Hidden gates both model visibility (runctx.Tools) and /api/tools listing on runtime.fsTools, and registry.Execute re-checks fail-closed. ToolExecCtx gains OwnerID/WorkspaceRoot/SettingBool. go test ./... green (fs negative matrix, SSRF negatives, endpoint fail-closed, cache). Impact: link previews work end to end once the frontend wires the fetcher; fs tools are inert until runtime.fsTools is enabled. Refs: task feature/file-preview-caps; core 4d29301.
Agent-System-Backend
对话系统后端：Go 模块化单体，默认构建为单二进制（go:embed 内嵌前端与嵌入式 SQLite 存储）。组合 Agent-Native / Agent-Squad / Agent-Intent 生态，依赖 agent-system-core 契约。
契约与架构见 Agent-System-Documents 设计方案与架构文档；开发规范见 development-guidelines（Dev 仓 development/guidelines）。本仓为 Agent-System 多仓组合的组成部分。