diff --git a/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.i18n.yaml b/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.i18n.yaml
index 223ad912f1..7b6ad0fc3e 100644
--- a/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.i18n.yaml
+++ b/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.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 .agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.md
-2026-08-19-projection-cache-per-session-files.md: 1b5b0f3d3df95fd8193e6674ca09f0806bd82db6
-2026-08-19-projection-cache-per-session-files.zh.md: adf4ed1261680f11366b38225885a3bce7e71bc4
+2026-08-19-projection-cache-per-session-files.md: 62ba71bf1f33461ab0e43fa87d3177bd6649ef28
+2026-08-19-projection-cache-per-session-files.zh.md: e3af483711953fd5c1c471c105725eca8e0c300c
diff --git a/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.md b/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.md
index 1b5b0f3d3d..62ba71bf1f 100644
--- a/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.md
+++ b/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.md
@@ -10,20 +10,20 @@ The persisted projection cache was one global `session_projcache.json` — a `se
 
 ## Decision
 
-The cache becomes one `projection_cache.json` per session, stored inside the session's own persistence directory. The location comes from the persistence seam — `sessionPersistence.locate(meta)` — so the persistence backend owns the session-directory layout (the jsonl backend places the file beside the session log); the cache service never imports a backend's path helpers. The cache service keeps every other responsibility: checkpoint fold, write policy (turn/end + disposal mandatory, count/interval throttle), fail-soft durability, and the cold-read ladder.
+The cache becomes one `projection_cache.json` per session, stored under the cache's own storage root — `<root>/<session-id>/projection_cache.json` (the session id is a code-generated string, used directly as the directory name). The cache owns its directory tree and never consults the persistence layer: no `locate`, no dependency on which backend is mounted. The cache service keeps every other responsibility: checkpoint fold, write policy (turn/end + disposal mandatory, count/interval throttle), fail-soft durability, and the listing read.
 
-Reading a cache row is now one file read, so `cachedSnapshot(meta)` is async; `coldSnapshot` takes the session header (it needs the header to locate the file — the stored log's header remains the identity witness). A persistence backend without a per-session directory (e.g. sqlite) disables the durable cache: writes no-op and cold reads fall to the full-log rung.
+Reading a cache row is one file read, so `cachedSnapshot(meta)` is async. The cache no longer runs a cold-refold ladder (that would require reading the session log, which belongs to the persistence layer); a consumer that needs a guaranteed cold snapshot refolds from the log itself. Session directories and cache files are created owner-only (`0o700`/`0o600`) via `@deepseek-ai/dsh-atomic-write`.
 
 ## Consequences
 
-- Per-session write isolation: each throttled write replaces only that session's small file, removing the global write amplification.
+- Per-session write isolation: each throttled write replaces only that session's small file, removing the global write amplification. Writes to one cache file serialize, so a newer cut never lands before an older one; plugin disposal drains in-flight writes.
 - Listing pays N small file reads instead of one big load; a session without a cache file simply lacks the projection column.
-- No migration: the cache is derived data, never an authority. An obsolete global cache (or any earlier format) is never read — the first cold read refolds from the log and writes the current format.
-- The cache file is bound to the same log lifecycle as before: the stored `{createdAt, cwd}` identity guards against a recreated id or a swapped store.
+- No migration: the cache is derived data, never an authority. An obsolete cache (any earlier format) is never read — the first cold read refolds from the log and writes the current format.
+- The cache file is bound to the same log lifecycle as before: the stored `{createdAt, cwd}` identity guards against a recreated id.
 
 ## Alternatives considered
 
-- **Keep the global sessions table.** Preserves one-load listing and a synchronous `cachedSnapshot`, but keeps the global write amplification and single-file blast radius that motivated the change.
-- **One storage-domain unit per session in the storage root** (flat `session_projcache_<id>.json`). Rejected: unit names must match `[a-z0-9_]` (session ids cannot), and the files would sit outside the session's own directory, scattering the storage root instead of living beside the log.
-- **Replicate the session-directory layout inside the cache.** Rejected: the persistence backend already owns that layout through `locate`; duplicating the path helpers couples the cache to a backend's internals.
-- **Reuse `@deepseek-ai/dsh-atomic-write`** (the zero-dependency `writeFileAtomic` with `mode`/`dirMode`). Adopted: the cache writes through it with `{ mode: 0o600, dirMode: 0o700 }`, keeping the session tree owner-only like the jsonl backend's own 0o700 directories, instead of exporting a second atomic-write primitive from the storage-json backend plugin.
+- **Keep the global sessions table.** Preserves one-load listing, but keeps the global write amplification and single-file blast radius that motivated the change.
+- **Resolve the path through `sessionPersistence.locate(meta)`** (the file beside the session log). Rejected: the cache would have to guess "beside the log" from a log artifact path (`dirname` + fixed filename), coupling the cache to the persistence service and to a backend's layout. The cache keeps its own tree instead.
+- **Replicate the session-directory layout inside the cache.** Rejected: the persistence backend already owns that layout; the cache does not need the log's project/session directory structure for its own derived files.
+- **Use the existing `@deepseek-ai/dsh-atomic-write`.** Adopted: it is the repo's single atomic whole-file write primitive (owner-only modes included); exporting a second one from the storage-json backend was rejected.
diff --git a/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.zh.md b/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.zh.md
index adf4ed1261..e3af483711 100644
--- a/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.zh.md
+++ b/.agents/notes/implemented/architecture/2026-08-19-projection-cache-per-session-files.zh.md
@@ -10,20 +10,20 @@ Status: implemented
 
 ## Decision
 
-缓存改为每会话一个 `projection_cache.json`，存放在该会话自己的持久化目录内。位置来自持久化 seam——`sessionPersistence.locate(meta)`——因此会话目录布局由持久化后端所有（jsonl 后端将其放在会话日志旁）；缓存服务绝不 import 后端的路径 helper。缓存服务保留其余全部职责：检查点折叠、写策略（turn/end + dispose 强制点、count/interval 节流）、fail-soft 持久化与冷读阶梯。
+缓存改为每会话一个 `projection_cache.json`，存放在缓存自己的存储根下——`<root>/<session-id>/projection_cache.json`（session id 是代码生成的字符串，直接用作目录名）。缓存拥有自己的目录树，绝不咨询持久化层：没有 `locate`、不依赖挂载的是哪个后端。缓存服务保留其余全部职责：检查点折叠、写策略（turn/end + dispose 强制点、count/interval 节流）、fail-soft 持久化与列表读。
 
-读取缓存行现在是一次文件读取，因此 `cachedSnapshot(meta)` 变为异步；`coldSnapshot` 改为接收会话 header（定位文件需要 header——存储日志的 header 仍是身份见证）。没有每会话目录的持久化后端（如 sqlite）会禁用持久缓存：写入变为 no-op，冷读落到全量日志那一级。
+读取缓存行现在是一次文件读取，因此 `cachedSnapshot(meta)` 变为异步。缓存不再运行冷重折叠阶梯（那需要读取会话日志，属于持久化层的职责）；需要保证冷快照的消费方自行从日志重折叠。会话目录与缓存文件经 `@deepseek-ai/dsh-atomic-write` 以仅属主权限（`0o700`/`0o600`）创建。
 
 ## Consequences
 
-- 每会话写入隔离：每次节流写入只替换该会话的小文件，消除全局写放大。
+- 每会话写入隔离：每次节流写入只替换该会话的小文件，消除全局写放大。同一缓存文件的写入被串行化，新切面绝不会先于旧切面落盘；插件释放时会排空在途写入。
 - 列表读取从一次大加载变为 N 次小文件读取；没有缓存文件的会话只是缺少投影列。
-- 无需迁移：缓存是派生数据，绝非权威。过时的全局缓存（或任何更早格式）从不被读取——首次冷读从日志重折叠并写出当前格式。
-- 缓存文件仍绑定同一日志生命周期：存储的 `{createdAt, cwd}` 身份防止被重建的 id 或替换的存储误导。
+- 无需迁移：缓存是派生数据，绝非权威。过时的缓存（任何更早格式）从不被读取——首次冷读从日志重折叠并写出当前格式。
+- 缓存文件仍绑定同一日志生命周期：存储的 `{createdAt, cwd}` 身份防止被重建的 id 误导。
 
 ## Alternatives considered
 
-- **保留全局 sessions 表。** 保留一次加载式列表与同步 `cachedSnapshot`，但保留了促成此改动的全局写放大与单文件爆炸半径。
-- **存储根目录下每会话一个 storage-domain unit**（扁平 `session_projcache_<id>.json`）。未采用：unit 名必须匹配 `[a-z0-9_]`（会话 id 做不到），且文件会落在会话目录之外，散落在存储根目录而不是日志旁。
-- **在缓存内复刻会话目录布局。** 未采用：持久化后端已通过 `locate` 拥有该布局；复刻路径 helper 会把缓存耦合到后端的内部实现。
-- **复用 `@deepseek-ai/dsh-atomic-write`**（零依赖的 `writeFileAtomic`，带 `mode`/`dirMode`）。已采纳：缓存以 `{ mode: 0o600, dirMode: 0o700 }` 经其写入，使会话目录树与 jsonl 后端自己的 0o700 目录保持一致、仅属主可读，而不是从 storage-json 后端插件再导出一套原子写原语。
+- **保留全局 sessions 表。** 保留一次加载式列表，但保留了促成此改动的全局写放大与单文件爆炸半径。
+- **经 `sessionPersistence.locate(meta)` 解析路径**（文件放在会话日志旁）。未采用：缓存得从日志 artifact 路径"猜"日志旁边（`dirname` + 固定文件名），把缓存耦合到持久化服务与后端的布局。缓存改用自有目录树。
+- **在缓存内复刻会话目录布局。** 未采用：持久化后端已拥有该布局；缓存为自己派生的文件不需要日志的 project/session 目录结构。
+- **使用现有 `@deepseek-ai/dsh-atomic-write`。** 采纳：它是仓库唯一的原子整文件写入原语（含仅属主权限）；从 storage-json 后端再导出一套并行实现被否决。
diff --git a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml
index 3b39d84067..db2f7170e0 100644
--- a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.i18n.yaml
+++ b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.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 .agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
-2026-07-28-storage-root-and-derived-medium-recovery.md: 9650b43a2493a36658a410e93cc76ec0050974ae
-2026-07-28-storage-root-and-derived-medium-recovery.zh.md: 0d944f017ce3187c1c1238893c8b83423f615d20
+2026-07-28-storage-root-and-derived-medium-recovery.md: c06226c34518a6971a313cc5b7e78c9750a90a17
+2026-07-28-storage-root-and-derived-medium-recovery.zh.md: 6082bc78729f2270840bb7e07860af227370f632
diff --git a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
index 9650b43a24..c06226c345 100644
--- a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
+++ b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.md
@@ -10,7 +10,7 @@ The persisted projection cache ([note](2026-07-27-session-projection-and-command
 
 **Where the files actually live (root mismatch closed; resolve-once residual still open).** The shared base defaults the session store to the global harness home (`$DSH_HOME/sessions`, default `~/.dsh/sessions`), while the shipped Web overlay used to give the json backend the relative root `./.storages`: `workspace.json` and `session_projcache.json` landed under `<launch dir>/.storages/` — two launches from different directories shared their sessions yet saw different workspace registries and different projection caches, and the cache exists precisely to serve the cross-session cold listing, which missed for every session last cached under another launch directory. That mismatch is now closed: the overlay anchors `storage-json.root` to `$DSH_HOME/storages` with the same `!!js` expression the session root uses (`apps/cli/config/web.cordis.yml`). The residual hazard: `JsonStorageBackend` still never resolves its root — each unit open joins the path against whatever `process.cwd()` is at that moment (packages/storage/storage-json/src/index.ts); the shipped overlay root is already absolute and unaffected, but any relative root (bare Loader boots, tests) still splits on a later cwd change — the exact hazard the JSONL session backend resolves-once to prevent ("later process.cwd() changes cannot split one backend across roots", packages/session/session-persistence-jsonl/src/index.ts).
 
-**How recovery works today.** Inside a healthy medium the cache is fully self-healing by design: a `stateVersion`-mismatched row is discarded and refolded, a log shrunk below a row's watermark is detected by the anchored restore floor and answered with one full re-read, and every background write is fail-soft. But at the *medium* level there is no recovery at all: a truncated, hand-edited, or version-bumped `session_projcache.json` fails `openJsonUnit` with `malformed-medium`/`version-mismatch` (packages/storage/storage-json/src/format.ts), a schema-drifted record fails domain open with `invalid-record` (packages/storage/storage-domain/src/index.ts), the rejection propagates through `SessionProjectionCache[Service.init]`, and under the CLI's fail-loud boot the assembly refuses to start. A file whose entire content is rebuildable from session logs can brick boot. This contradicts the cache package's own stated stance ("a stale or unreadable cache costs a longer tail replay, never a wrong value") and the cache domain spec's JSDoc ("version bumps discard the whole medium"), which today describes an aspiration, not the implementation. Partially superseded for the projection cache: [the per-session cache files note](../implemented/architecture/2026-08-19-projection-cache-per-session-files.md) removed the global `session_projcache` domain, so the cache half of this proposal (recovery on that domain) no longer applies; the `workspace.json` half remains current. The same fail-loud path is *correct* for `workspace.json` — workspace records are authoritative, not derivable — so the missing concept is a per-domain declaration of authority, not a global behavior change.
+**How recovery works today.** Inside a healthy medium the cache is fully self-healing by design: a `stateVersion`-mismatched row is discarded and refolded, a log shrunk below a row's watermark is detected by the anchored restore floor and answered with one full re-read, and every background write is fail-soft. But at the *medium* level there is no recovery at all: a truncated, hand-edited, or version-bumped `session_projcache.json` fails `openJsonUnit` with `malformed-medium`/`version-mismatch` (packages/storage/storage-json/src/format.ts), a schema-drifted record fails domain open with `invalid-record` (packages/storage/storage-domain/src/index.ts), the rejection propagates through `SessionProjectionCache[Service.init]`, and under the CLI's fail-loud boot the assembly refuses to start. A file whose entire content is rebuildable from session logs can brick boot. This contradicts the cache package's own stated stance ("a stale or unreadable cache costs a longer tail replay, never a wrong value") and the cache domain spec's JSDoc ("version bumps discard the whole medium"), which today describes an aspiration, not the implementation. Partially superseded for the projection cache: [the per-session cache files note](../../implemented/architecture/2026-08-19-projection-cache-per-session-files.md) removed the global `session_projcache` domain, so the cache half of this proposal (recovery on that domain) no longer applies; the `workspace.json` half remains current. The same fail-loud path is *correct* for `workspace.json` — workspace records are authoritative, not derivable — so the missing concept is a per-domain declaration of authority, not a global behavior change.
 
 ## Proposal
 
diff --git a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md
index 0d944f017c..6082bc7872 100644
--- a/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md
+++ b/.agents/notes/proposed/architecture/2026-07-28-storage-root-and-derived-medium-recovery.zh.md
@@ -10,7 +10,7 @@ Status: proposed
 
 **文件到底存在哪（根错位已收口，resolve-once 残余仍开放）。** 共享 base 将会话存储默认为全局 harness home（`$DSH_HOME/sessions`，默认 `~/.dsh/sessions`），而出厂 Web overlay 曾给 json 后端相对根 `./.storages`：`workspace.json` 和 `session_projcache.json` 落在 `<启动目录>/.storages/` 下——从两个不同目录启动，会话相同，工作区注册表和投影缓存却各是一份，而缓存存在的意义恰恰是跨会话冷列表，凡上次在别的启动目录下缓存过的会话全部 miss。这一错位已消除：overlay 现以与会话根同一段 `!!js` 表达式把 `storage-json.root` 锚定到 `$DSH_HOME/storages`（`apps/cli/config/web.cordis.yml`）。残余隐患：`JsonStorageBackend` 仍从不 resolve 根——每次打开 unit 都把路径 join 到当时的 `process.cwd()` 上（packages/storage/storage-json/src/index.ts）；出厂 overlay 的根已是绝对路径不受影响，但任何相对根（裸 Loader 启动、测试）仍会被后续 cwd 变化劈开，JSONL 会话后端用「构造时 resolve 一次」防住的正是它（"later process.cwd() changes cannot split one backend across roots"，packages/session/session-persistence-jsonl/src/index.ts）。
 
-**现在是怎么恢复的。** 在健康介质内部，缓存按设计完全自愈：`stateVersion` 不匹配的行被丢弃重折，日志缩短到行水位以下由带锚的 restore floor 检出并以一次全量重读回答，每次后台写都是 fail-soft。但在*介质*层面完全没有恢复：被截断、被手改或版本被 bump 的 `session_projcache.json` 会让 `openJsonUnit` 以 `malformed-medium`/`version-mismatch` 失败（packages/storage/storage-json/src/format.ts），schema 漂移的记录让域 open 以 `invalid-record` 失败（packages/storage/storage-domain/src/index.ts），拒绝一路穿过 `SessionProjectionCache[Service.init]`，在 CLI 的 fail-loud 启动下整个组装拒绝启动。一个内容完全可从会话日志重建的文件能把启动搞死。这与缓存包自己声明的立场（"a stale or unreadable cache costs a longer tail replay, never a wrong value"）和缓存域 spec 的 JSDoc（"version bumps discard the whole medium"）相矛盾——后者今天描述的是愿望而非实现。投影缓存半边已被[每会话缓存文件 note](../implemented/architecture/2026-08-19-projection-cache-per-session-files.md) 部分取代：全局 `session_projcache` domain 已移除，本提案的缓存恢复半边不再适用；`workspace.json` 半边仍然有效。同一条 fail-loud 路径对 `workspace.json` 却是*正确*的——工作区记录是权威数据，不可派生——所以缺的概念是按域声明权威性，而不是全局改行为。
+**现在是怎么恢复的。** 在健康介质内部，缓存按设计完全自愈：`stateVersion` 不匹配的行被丢弃重折，日志缩短到行水位以下由带锚的 restore floor 检出并以一次全量重读回答，每次后台写都是 fail-soft。但在*介质*层面完全没有恢复：被截断、被手改或版本被 bump 的 `session_projcache.json` 会让 `openJsonUnit` 以 `malformed-medium`/`version-mismatch` 失败（packages/storage/storage-json/src/format.ts），schema 漂移的记录让域 open 以 `invalid-record` 失败（packages/storage/storage-domain/src/index.ts），拒绝一路穿过 `SessionProjectionCache[Service.init]`，在 CLI 的 fail-loud 启动下整个组装拒绝启动。一个内容完全可从会话日志重建的文件能把启动搞死。这与缓存包自己声明的立场（"a stale or unreadable cache costs a longer tail replay, never a wrong value"）和缓存域 spec 的 JSDoc（"version bumps discard the whole medium"）相矛盾——后者今天描述的是愿望而非实现。投影缓存半边已被[每会话缓存文件 note](../../implemented/architecture/2026-08-19-projection-cache-per-session-files.md) 部分取代：全局 `session_projcache` domain 已移除，本提案的缓存恢复半边不再适用；`workspace.json` 半边仍然有效。同一条 fail-loud 路径对 `workspace.json` 却是*正确*的——工作区记录是权威数据，不可派生——所以缺的概念是按域声明权威性，而不是全局改行为。
 
 ## 提案
 
diff --git a/apps/cli/composition.md b/apps/cli/composition.md
index 4d37b9186a..d82beeb5ed 100644
--- a/apps/cli/composition.md
+++ b/apps/cli/composition.md
@@ -44,6 +44,8 @@ flowchart LR
   cfg --> plugin_dsh_base_llm_pi_ai
   plugin_dsh_base_session_persistence_jsonl["session-persistence-jsonl<br/>@deepseek-ai/dsh-session-persistence-jsonl"]
   cfg --> plugin_dsh_base_session_persistence_jsonl
+  plugin_dsh_base_session_projection_cache["session-projection-cache<br/>@deepseek-ai/dsh-session-projection-cache"]
+  cfg --> plugin_dsh_base_session_projection_cache
   plugin_dsh_base_attachment_local["attachment-local<br/>@deepseek-ai/dsh-attachment-local"]
   cfg --> plugin_dsh_base_attachment_local
   plugin_dsh_base_session_query_sqlite["session-query-sqlite<br/>@deepseek-ai/dsh-session-query-sqlite"]
@@ -186,6 +188,7 @@ flowchart LR
 | `credentials` | `@deepseek-ai/dsh-credentials-local` |
 | `llm-pi-ai` | `@deepseek-ai/dsh-llm-pi-ai` |
 | `session-persistence-jsonl` | `@deepseek-ai/dsh-session-persistence-jsonl` |
+| `session-projection-cache` | `@deepseek-ai/dsh-session-projection-cache` |
 | `attachment-local` | `@deepseek-ai/dsh-attachment-local` |
 | `session-query-sqlite` | `@deepseek-ai/dsh-session-query-sqlite` |
 | `session-projection` | `@deepseek-ai/dsh-session-projection` |
diff --git a/docs/config-catalog.i18n.yaml b/docs/config-catalog.i18n.yaml
index 12824b94de..c995d27168 100644
--- a/docs/config-catalog.i18n.yaml
+++ b/docs/config-catalog.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 docs/config-catalog.md
-config-catalog.md: bd15d4c0b548526acd9adb578ba10e6a37f94410
-config-catalog.zh.md: 190500df89c97b68e3fff201e90f51436250ab07
+config-catalog.md: b5c487120f1272ddb1da29d8ed1230a5c1f3d0a9
+config-catalog.zh.md: 435ba990e69f2efc157edc793568cd889e639d0a
diff --git a/docs/config-catalog.md b/docs/config-catalog.md
index bd15d4c0b5..b5c487120f 100644
--- a/docs/config-catalog.md
+++ b/docs/config-catalog.md
@@ -1698,7 +1698,7 @@ Source: [`packages/session/session-persistence-sqlite/src/index.ts:70`](../packa
 
 ## `@deepseek-ai/dsh-session-projection-cache`
 
-Requires: `storageDomain` · `sessionProjections` · `sessionPersistence` · `sessions`
+Requires: `sessionProjections` · `sessions`
 
 ```ts config-catalog
 /**
@@ -1708,6 +1708,8 @@ Requires: `storageDomain` · `sessionProjections` · `sessionPersistence` · `se
  * disposal) are policy, not tunables, and always fire.
  */
 export interface Config {
+  /** Directory holding one `<session-id>/projection_cache.json` per session. */
+  root: string
   /** Committed events per session that force a durable checkpoint write between mandatory points. */
   writeEveryEvents: number
   /** Longest time (milliseconds) a dirty checkpoint may stay unwritten between mandatory points. */
@@ -1715,7 +1717,7 @@ export interface Config {
 }
 ```
 
-Source: [`packages/session/session-projection-cache/src/index.ts:42`](../packages/session/session-projection-cache/src/index.ts)
+Source: [`packages/session/session-projection-cache/src/index.ts:48`](../packages/session/session-projection-cache/src/index.ts)
 
 <a id="deepseek-aidsh-session-query-sqlite"></a>
 
diff --git a/docs/config-catalog.zh.md b/docs/config-catalog.zh.md
index 190500df89..435ba990e6 100644
--- a/docs/config-catalog.zh.md
+++ b/docs/config-catalog.zh.md
@@ -1700,7 +1700,7 @@ export type JournalMode = 'wal' | 'delete' | 'truncate' | 'persist'
 
 ## `@deepseek-ai/dsh-session-projection-cache`
 
-需要：`storageDomain` · `sessionProjections` · `sessionPersistence` · `sessions`
+需要：`sessionProjections` · `sessions`
 
 ```ts config-catalog
 /**
@@ -1710,6 +1710,8 @@ export type JournalMode = 'wal' | 'delete' | 'truncate' | 'persist'
  * disposal) are policy, not tunables, and always fire.
  */
 export interface Config {
+  /** Directory holding one `<session-id>/projection_cache.json` per session. */
+  root: string
   /** Committed events per session that force a durable checkpoint write between mandatory points. */
   writeEveryEvents: number
   /** Longest time (milliseconds) a dirty checkpoint may stay unwritten between mandatory points. */
@@ -1717,7 +1719,7 @@ export interface Config {
 }
 ```
 
-来源：[`packages/session/session-projection-cache/src/index.ts:42`](../packages/session/session-projection-cache/src/index.ts)
+来源：[`packages/session/session-projection-cache/src/index.ts:48`](../packages/session/session-projection-cache/src/index.ts)
 
 <a id="deepseek-aidsh-session-query-sqlite"></a>
 
diff --git a/docs/subsystems/session-projection.i18n.yaml b/docs/subsystems/session-projection.i18n.yaml
index 6ec80ed2a9..477dfdeca3 100644
--- a/docs/subsystems/session-projection.i18n.yaml
+++ b/docs/subsystems/session-projection.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 docs/subsystems/session-projection.md
-session-projection.md: 66543b6bfff666435acb8c00dd2f87d5fb0bccb4
-session-projection.zh.md: 4d99c208a8c54424655ec0b4238dbed37c75603b
+session-projection.md: f17e70d3dd4a4d89381bbe2be1428647a612ff9a
+session-projection.zh.md: cc6a4edf1ba394cf71abfa64ccff6667566f5d9d
diff --git a/docs/subsystems/session-projection.md b/docs/subsystems/session-projection.md
index 66543b6bff..f17e70d3dd 100644
--- a/docs/subsystems/session-projection.md
+++ b/docs/subsystems/session-projection.md
@@ -27,8 +27,6 @@ interface ProjectionDefinition<
   key: K
   /** Validates persisted state before it seeds a fold. */
   stateSchema: ZodType<S>
-  /** Persist a host-only unit. Client-visible units are always persisted. */
-  persist?: boolean
   /**
    * State for the empty log.
    * @returns the initial state.
@@ -114,7 +112,7 @@ Generated from source by `scripts/gen-cordis-catalog.ts` (verified fresh by `pnp
 
 ### `ctx.sessionProjectionCache` — `SessionProjectionCache`
 
-The persisted projection cache service. Checkpoints live sessions on a throttled write-behind (count/interval triggers from Config) plus two mandatory points — `turn/end` and session disposal (the live-to-cold moment) — and serves the cold-read ladder: cached file, persistence `readFrom` tail, registry `restore`, durable write-back. Every durable write is fail-soft: failures log a warning and the cache self-heals on the next write or cold read. A persistence backend without a per-session directory (e.g. sqlite) disables the durable cache: writes no-op, cold reads fall to the full-log rung.
+The persisted projection cache service. Checkpoints live sessions on a throttled write-behind (count/interval triggers from Config) plus two mandatory points — `turn/end` and session disposal (the live-to-cold moment) — and serves the cached rows for a session header. Every durable write is fail-soft: failures log a warning and the cache self-heals on the next write. The cache owns its directory tree and never consults the persistence layer.
 
 ```ts cordis-catalog
 /**
@@ -122,9 +120,7 @@ The persisted projection cache service. Checkpoints live sessions on a throttled
  * (version-matching keys only), each cut carried with its watermark so a
  * client value store can seed under its higher-seq-wins rule — as stale as
  * the last durable checkpoint but never wrong, and never from an unrelated
- * log (the caller's header is the identity witness). Fresher paths (the
- * history tail baseline, {@link coldSnapshot}) supersede these values
- * whenever a session is actually opened.
+ * log (the caller's header is the identity witness).
  * @param meta - the listed session's header (identity witness; no log read).
  * @returns the cut (`asOfSeq` = lowest served-row watermark), or
  *   `undefined` when no usable row exists for this lifecycle.
@@ -141,26 +137,11 @@ async cachedSnapshot(meta: SessionHeader): Promise<ProjectionSnapshot | undefine
  * @returns resolution after durability and event emission.
  */
 async write(session: Session): Promise<void>
-
-/**
- * Cold-read one persisted session's projections with zero full-log load:
- * cached rows + a persistence `readFrom` tail from the registry's restore
- * floor, refolded by the registry and written back (fail-soft) so the next
- * cold read starts closer. A cache row invalidated by a shrunk log
- * (crash-repair truncation) triggers one full re-read from seq 0 — the
- * ladder's slow rung, still no crash. Rejects when the session has no
- * persisted log (`not found` from the persistence seam).
- * @param meta - the persisted session whose projections are read (locates
- *   the cache file and witnesses the stored log identity).
- * @param signal - optional cancellation for the persistence reads.
- * @returns the snapshot cut at the stored log end.
- */
-async coldSnapshot(meta: SessionHeader, signal?: AbortSignal): Promise<ProjectionSnapshot>
 ```
 
 Types: [Session](session.md) · [SessionHeader](persistence.md)
 
-Source: [`packages/session/session-projection-cache/src/index.ts:78`](../../packages/session/session-projection-cache/src/index.ts)
+Source: [`packages/session/session-projection-cache/src/index.ts:80`](../../packages/session/session-projection-cache/src/index.ts)
 
 <a id="ctxsessionprojections--sessionprojectionregistry"></a>
 
diff --git a/docs/subsystems/session-projection.zh.md b/docs/subsystems/session-projection.zh.md
index 4d99c208a8..cc6a4edf1b 100644
--- a/docs/subsystems/session-projection.zh.md
+++ b/docs/subsystems/session-projection.zh.md
@@ -27,8 +27,6 @@ interface ProjectionDefinition<
   key: K
   /** Validates persisted state before it seeds a fold. */
   stateSchema: ZodType<S>
-  /** Persist a host-only unit. Client-visible units are always persisted. */
-  persist?: boolean
   /**
    * State for the empty log.
    * @returns the initial state.
@@ -114,7 +112,7 @@ Generated from source by `scripts/gen-cordis-catalog.ts` (verified fresh by `pnp
 
 ### `ctx.sessionProjectionCache` — `SessionProjectionCache`
 
-The persisted projection cache service. Checkpoints live sessions on a throttled write-behind (count/interval triggers from Config) plus two mandatory points — `turn/end` and session disposal (the live-to-cold moment) — and serves the cold-read ladder: cached file, persistence `readFrom` tail, registry `restore`, durable write-back. Every durable write is fail-soft: failures log a warning and the cache self-heals on the next write or cold read. A persistence backend without a per-session directory (e.g. sqlite) disables the durable cache: writes no-op, cold reads fall to the full-log rung.
+The persisted projection cache service. Checkpoints live sessions on a throttled write-behind (count/interval triggers from Config) plus two mandatory points — `turn/end` and session disposal (the live-to-cold moment) — and serves the cached rows for a session header. Every durable write is fail-soft: failures log a warning and the cache self-heals on the next write. The cache owns its directory tree and never consults the persistence layer.
 
 ```ts cordis-catalog
 /**
@@ -122,9 +120,7 @@ The persisted projection cache service. Checkpoints live sessions on a throttled
  * (version-matching keys only), each cut carried with its watermark so a
  * client value store can seed under its higher-seq-wins rule — as stale as
  * the last durable checkpoint but never wrong, and never from an unrelated
- * log (the caller's header is the identity witness). Fresher paths (the
- * history tail baseline, {@link coldSnapshot}) supersede these values
- * whenever a session is actually opened.
+ * log (the caller's header is the identity witness).
  * @param meta - the listed session's header (identity witness; no log read).
  * @returns the cut (`asOfSeq` = lowest served-row watermark), or
  *   `undefined` when no usable row exists for this lifecycle.
@@ -141,26 +137,11 @@ async cachedSnapshot(meta: SessionHeader): Promise<ProjectionSnapshot | undefine
  * @returns resolution after durability and event emission.
  */
 async write(session: Session): Promise<void>
-
-/**
- * Cold-read one persisted session's projections with zero full-log load:
- * cached rows + a persistence `readFrom` tail from the registry's restore
- * floor, refolded by the registry and written back (fail-soft) so the next
- * cold read starts closer. A cache row invalidated by a shrunk log
- * (crash-repair truncation) triggers one full re-read from seq 0 — the
- * ladder's slow rung, still no crash. Rejects when the session has no
- * persisted log (`not found` from the persistence seam).
- * @param meta - the persisted session whose projections are read (locates
- *   the cache file and witnesses the stored log identity).
- * @param signal - optional cancellation for the persistence reads.
- * @returns the snapshot cut at the stored log end.
- */
-async coldSnapshot(meta: SessionHeader, signal?: AbortSignal): Promise<ProjectionSnapshot>
 ```
 
 Types: [Session](session.md) · [SessionHeader](persistence.md)
 
-Source: [`packages/session/session-projection-cache/src/index.ts:78`](../../packages/session/session-projection-cache/src/index.ts)
+Source: [`packages/session/session-projection-cache/src/index.ts:80`](../../packages/session/session-projection-cache/src/index.ts)
 
 <a id="ctxsessionprojections--sessionprojectionregistry"></a>