docs: implement experimental and internal package group

packages/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/README.md
-README.md: f5420b6f2f30837b030a0e832a438c34674a6f23
-README.zh.md: 7beeaadf380a742cbdb6447553f42692a97fad10
+README.md: 706d741b87bd22656580419eb43a493c1ab2933a
+README.zh.md: c41a15dcb743d024348d5a8a8c105b37e694205b

packages/README.md

@@ -44,11 +44,12 @@ Packages live at `packages/<group>/<pkg>/`; groups are containers, while names r
 | [`sdk/`](sdk/README.md) | Project SDK tooling | Product — stable surface |
 | [`acp/`](acp/README.md) | Automation-only Agent Client Protocol server | Product — stable surface |
 | [`ui/`](ui/README.md) | TUI and JSON-RPC integrations, approval/interaction seams, ask-user tool | Product — stable surface |
+| [`experimental/`](experimental/README.md) | Prototypes and internal plugins | Unreleased |
 | [`examples/`](examples/README.md) | Demo bundles (agent-spine + TUI/CLI/ACP/JSON-RPC bins) leaves load | Support — example infra |
 | [`support/`](support/README.md) | Support infrastructure (testkits, invariants, replay, Loader smokes) | Support — lower compatibility expectations |
 | [`util/`](util/README.md) | Low-level zero-dependency utilities shared across groups (`Branded<B>`, Harness home/path helpers, timeout, retention) | Support — small, stable, harness-dep-free |
 
-Groups distinguish product API from support infrastructure. New packages join an existing group; a new group updates its README and this table.
+New packages join existing groups; new groups update their README and this table.
 
 ## Dependencies
 

packages/README.zh.md

@@ -44,11 +44,12 @@
 | [`sdk/`](sdk/README.md) | 项目 SDK 工具 | 产品：稳定表面 |
 | [`acp/`](acp/README.md) | 仅面向自动化的 Agent Client Protocol 服务器 | 产品：稳定表面 |
 | [`ui/`](ui/README.md) | TUI 与 JSON-RPC 集成、批准／交互 seam、用户问答工具 | 产品：稳定表面 |
+| [`experimental/`](experimental/README.md) | 原型和内部插件 | 未发布 |
 | [`examples/`](examples/README.md) | 演示组合包（agent-spine + TUI/CLI/ACP/JSON-RPC bin），由叶节点加载 | 支持：示例基础设施 |
 | [`support/`](support/README.md) | 支持基础设施（testkit、不变式、回放、Loader 冒烟测试） | 支持：兼容性预期较低 |
 | [`util/`](util/README.md) | 组间共享的低层零依赖工具（`Branded<B>`、Harness home／路径辅助函数、超时、保留策略） | 支持：小型、稳定、无 harness 依赖 |
 
-组用于区分产品 API 与支持基础设施。新包加入现有组；新组则更新其 README 和此表。
+新包加入现有组；新组更新其 README 和此表。
 
 ## 依赖
 

packages/experimental/AGENTS.md

@@ -0,0 +1,11 @@
+# AGENTS.md — Experimental and internal packages
+
+These rules supplement the [package rules](../AGENTS.md). The [experimental and internal package group decision](../../.agents/notes/implemented/architecture/2026-07-28-experimental-plugin-package-group.md) owns the rationale.
+
+- All Cordis plugin packages whose whole public contract is experimental or internal-only belong here. An experimental option inside an otherwise stable package stays in that package's product-role group.
+- Use this directory to share engineering and product-manager prototypes across the team so others can discover, run, review, and extend them against the real plugin graph.
+- Official releases exclude this directory. A package enters a release only after moving to its product-role group; do not add packages here to release manifests or bundles.
+- Experimental packages carry no stability, compatibility, migration, or support promise. Internal-only packages may define narrower internal contracts but make no public release promise.
+- Experimental or internal-only status never relaxes repository engineering, security, documentation, lifecycle, testing, or snapshot requirements.
+- Release packages must not take runtime dependencies on packages here. Examples may; every other runtime dependent is also experimental or internal-only and belongs here. Tests may use them as development dependencies.
+- Promotion moves a package to its product-role group without renaming its `@deepseek-ai/dsh-*` package. Require explicit review of its public contract, limitations, test evidence, and a named owner accepting stable-package obligations.

packages/experimental/README.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write packages/experimental/README.md
+README.md: db39af8bb1b1bcfd257e16e4ad1dd112f604ffb1
+README.zh.md: df9b8cb2a91faab7af782e0f53685368e99583ff

packages/experimental/README.md

@@ -0,0 +1,7 @@
+# experimental/ — experimental and internal packages
+
+English | [中文](README.zh.md)
+
+This group hosts team-shared engineering and product-manager prototypes plus internal-only Cordis plugins. It is excluded from official releases; packages move to their product-role group before release.
+
+No packages live here yet. The [subtree rules](AGENTS.md) define the no-warranty, dependency, and promotion boundaries.

packages/experimental/README.zh.md

@@ -0,0 +1,7 @@
+# experimental/：实验性与内部专用包（package）
+
+[English](README.md) | 中文
+
+该分组容纳工程人员与产品经理在团队内共享的原型，以及内部专用 Cordis 插件。该分组不纳入官方发布版本；包在发布前移入对应的产品角色分组。
+
+该分组尚未包含任何包。[子树规则](AGENTS.md)界定不作保证、依赖关系和提升机制的边界。