文件系统
可选的文件系统能力由四个部分组成：dsh-fs 拥有 ctx.fs 以及带可选守卫的原子文本操作；dsh-fs-local 实现本地磁盘后端；dsh-fs-observation-policy 记录观测到的存在或缺失状态，并通过事件（而非服务）添加新鲜度规则；dsh-tool-fs 直接执行面向模型的 read/write/edit 调用并渲染窗口。它位于 agent loop（智能体循环）主干之外；替换后端不会改变策略或工具 schema。
dsh-fs-observation-policy 是可选插件。没有该插件时，FileSystem 服务定义、一个提供方和 dsh-tool-fs 消费方组成完整且不受约束的文件系统 seam：write 无条件创建或覆盖，edit 无条件替换字面文本。策略插件通过裁决 fs/* waterfall（瀑布式事件）来改变这些操作。移除该插件不会破坏工具，因为工具调用 ctx.fs 并分发事件，而不调用策略方法。加载了 dsh-tool-fs 的部署也应加载 dsh-fs-observation-policy，使默认行为为「先读后写/编辑」。
提供方源码：packages/fs/fs/src/types.ts 与 packages/fs/fs/src/index.ts。策略源码：packages/fs/fs-observation-policy/src/types.ts。读取渲染源码：packages/fs/tool-fs/src/read-render.ts。
目标标识与元数据（提供方约定）
每个操作首先将用户提供的路径解析为不透明的后端目标。消费方可以显示 displayPath，但禁止解析 targetKey（一个品牌化的不透明 id），也不得假设它是本地绝对路径。
与文件系统共享执行世界的消费方通过提供方获取跨能力坐标，而不是解释该身份：processPath(target) 返回子进程可以打开的规范化绝对路径，fileUrl(target) 返回采用提供方平台语法的 file: URI，contains(parent, child) 则检查规范化身份相等或后代包含关系。
/**
* A path resolved by a backend into a stable identity. `resolve()` produces
* this; every other operation takes it.
*/
interface FsTarget {
/** Opaque key for stale guards and target lookup. */
targetKey: FsTargetKey
/**
* Path for model/UI-facing output. May be a local absolute path,
* workspace-relative path, or remote URI depending on the backend.
*/
displayPath: string
}后端拥有文件版本 token，即 write/edit 所守卫的新鲜度 token。策略插件存储它们以进行陈旧检查；消费方不解释其内容。两个 id 都是品牌化的不透明字符串。
/**
* Opaque key for stale guards and target lookup. The local backend uses a
* realpath-like string; a remote backend might use a workspace URI or file id.
* Consumers MUST NOT parse it or assume it is a local absolute path.
*/
type FsTargetKey = Branded<'FsTargetKey'>/**
* Opaque file-version token — the freshness token a write/edit guards against.
* The local backend derives it from high-resolution stat identity and freshness
* fields; a remote backend might use a revision id. The policy layer records it
* for stale checks; consumers may display related metadata but MUST NOT
* interpret this token.
*/
type FsVersion = Branded<'FsVersion'>stat 返回元数据（从不返回内容），目标不存在时返回 undefined。type 让消费方在读取前拒绝目录和特殊文件；size 让文本消费方无需通过失败探测即可选择 readText 还是 streamText。文本消费方在消费 streamText 时执行自己的保留量上限。原始字节消费方调用 readBytes(target, signal, maxBytes)；其必填的完整内容上限会使已知或读取中发现的超限以 FS_TOO_LARGE 失败，不会截断结果或无界缓冲。
/**
* Metadata about a target — what {@link FileSystem.stat} returns. Lets the
* policy layer reject directories/special files before reading and choose
* `readText` vs `streamText` from `size` without probing by failure. `version`
* is the freshness token. `undefined` from `stat` means the target is absent.
*/
interface FsInfo {
/** Opaque freshness token of the target right now. */
version: FsVersion
/** Whether the target is a regular file, a directory, or something else. */
type: 'file' | 'directory' | 'other'
/** Byte size of a regular file, when the backend can report it. */
size?: number
}lstat 是路径级、不跟随链接的元数据原语。它接收路径而不是 FsTarget，因为 resolve 会有意跟随 symlink 以产生稳定标识；需要检查信任边界的消费方可以先调用 lstat，在解析前拒绝 symlink。
/**
* Metadata about a path without following the final path component when it is a
* symbolic link. Unlike {@link FsInfo}, this path-level probe can report
* `symlink` so consumers with trust-boundary rules can reject repository-owned
* links before resolving a target.
*/
interface FsPathInfo {
/** Opaque freshness token of the path entry right now. */
version: FsVersion
/** Whether the path entry is a regular file, directory, symlink, or other. */
type: 'file' | 'directory' | 'symlink' | 'other'
/** Byte size of the path entry, when the backend can report it. */
size?: number
}listDir 按稳定的名称顺序返回直接子条目。每个条目携带子项的 basename、类型、已解析目标，以及后端能报告时的廉价元数据。它禁止读取文件内容，因此 size 仅用于普通文件，version 来自元数据。已损坏或已消失的子项可以作为 other 返回且不带元数据；列出或解析子项元数据时的权限或后端 I/O 失败会以 FS_PERMISSION_DENIED 或 FS_IO_ERROR 使整个列表操作失败。
/**
* One direct child returned by {@link FileSystem.listDir}. Listing returns
* metadata and resolved targets only; it must not read file contents.
*/
interface FsDirEntry {
/** Basename of the child inside the listed directory. */
name: string
/** Whether the child is a regular file, a directory, or something else. */
type: 'file' | 'directory' | 'other'
/** Resolved child target for follow-up operations. */
target: FsTarget
/** Opaque freshness token when the backend can report metadata cheaply. */
version?: FsVersion
/** Byte size of a regular file, when the backend can report it. */
size?: number
}写入与编辑守卫（提供方约定）
writeText 和 editText 的版本守卫都是可选的：省略守卫时执行无条件的裸提供方变更，提供守卫时则执行相应的条件检查。writeText 的守卫是 FsWriteIntent：createIfAbsent 在目标缺失时创建，目标已存在时以 FS_NOT_OBSERVED 拒绝；即使目标在提供方初始探测后才出现，也必须拒绝，因为发布操作本身不得替换。replaceIfVersion 仅在目标存在且版本匹配时替换，否则报 FS_STALE_VERSION。省略 expected 则无条件创建或覆盖。联合类型本身只包含两种有守卫的意图；「无守卫」通过省略表达，因此 write 和 edit 都使用同一个可选的 expected 字段。
/**
* Guarded write intent. `createIfAbsent` rejects an existing target with
* `FS_NOT_OBSERVED`; `replaceIfVersion` rejects absence or mismatch with
* `FS_STALE_VERSION`. Omitting the intent from `writeText` means unconditional
* create-or-overwrite, not a third union arm.
*/
type FsWriteIntent =
| { kind: 'createIfAbsent' }
| { kind: 'replaceIfVersion'; version: FsVersion }/** Outcome of a full-file write. */
interface FsWriteOutcome {
/** Whether the write created a new file or replaced an existing one. */
operation: 'create' | 'update'
/** Opaque version of the file after the write. */
version: FsVersion
/**
* The file's content BEFORE the write, or `null` when the file did not exist
* (a create) or the backend declined a contextual basis (for example, a
* binary/non-UTF-8 prior file or either overwrite side reaching its exclusive limit).
* LF-normalized storage text (the diff basis), never a diff — a consumer
* computes the result-time contextual diff from `before`/`after` when
* `before` is present, else falls back to a whole-file diff.
*/
before: string | null
/** The file's content AFTER the write, LF-normalized to share `before`'s diff basis. */
after: string
}editText 是提供方级别的变更操作，而非在别处组合的 read 加 write。带守卫时，它在字面匹配之前先验证预期版本（因此对陈旧内容的编辑报 FS_STALE_VERSION，而非对更新内容的匹配失败）；不带守卫时，它编辑当前内容。无论哪种路径，它都应用替换并原子写入——将匹配、行尾处理、陈旧检查和原子替换保持在一个变更临界区内——目标缺失时两条路径都报 FS_STALE_VERSION。
/** A literal-replacement edit request. */
interface FsEditRequest {
/** Literal non-empty text to replace. Must match exactly (after line-ending normalization). */
oldString: string
/** Literal replacement text. An empty string deletes the matched text. */
newString: string
/** Replace every match instead of requiring exactly one. */
replaceAll: boolean
}/** Outcome of a literal edit. */
interface FsEditOutcome {
/** Opaque version of the file after the edit. */
version: FsVersion
/**
* The file's content BEFORE the edit. Raw storage text (LF-normalized by the
* backend), never a diff — a consumer computes the result-time contextual diff
* (the applied hunk with context) from `before`/`after`.
*/
before: string
/** The file's content AFTER the edit. */
after: string
}fs 策略事件（提供方约定词汇）
dsh-fs 拥有三个事件，由工具分发、策略插件监听，使事件发出方（dsh-tool-fs）与监听方（dsh-fs-observation-policy）共享词汇，而事件发出方无需依赖策略插件。它们只携带 dsh-fs 词汇加一个不透明的 object actor，不含面向模型的概念，也不含 agent/会话所有者结构。
fs/write-intent 与 fs/edit-intent 是单槽决策 waterfall：工具分发时附带一个默认 thunk（返回 undefined，即裸提供方），监听方完全决策而不调用 next()。该 slot 按注册顺序先到先得——由策略插件占据是部署约定，而非强制不变式。fs/observed 是一个即发即弃的记录事件，携带 FsObservation：存在于某个版本，或确认缺失。该事件通过普通 ctx.emit 分发；其监听方必须是同步的、仅产生副作用，因为工具不会捕获该 emit 抛出的异常——抛出异常的监听方可能取代读取操作原本待返回的错误，或使工具在变更已经成功后返回 isError 结果。下方生成的 cordis surface 展示确切签名。
/**
* One authoritative observation of a target. A present observation carries the
* version used by guarded replacement; an absent observation authorizes only a
* guarded create, never an edit.
*/
type FsObservation =
| { readonly kind: 'present'; readonly version: FsVersion }
| { readonly kind: 'absent' }执行上下文（策略插件）
策略插件只需要足够的执行上下文，通过收窄 fs/* 事件携带的不透明 object actor 来推导观测状态的所有者。ToolExecution 包含必需的字段，因此 dsh-tool-fs 将其执行对象作为 actor 直接传递，而无需让 dsh-fs-observation-policy 导入工具、agent 或会话包。
/**
* Minimal structural view of a tool execution the policy plugin needs to derive
* an observed-state owner. `@deepseek-ai/dsh-tools`' `ToolExecution` contains
* these fields, so the tool passes its `exec` straight through as the opaque
* `object` actor on the `fs/*` events; this plugin narrows that actor to
* `FsObservationActor` without importing `dsh-tools`, `dsh-agent`, or `dsh-session`.
*
* The owner is `agent.session` when present. It is treated as an opaque object
* identity (a `WeakMap` key); this package never reads any of its fields.
*/
interface FsObservationActor {
/** The agent on whose behalf the call runs, when there is one. */
agent?: {
/** The session that owns observed-file state, used as an opaque key. */
session?: object
}
}读取结果（消费方 / 读取渲染）
文本读取受行窗口、字节上限和后端限制约束。达到字节上限后，扫描仍会继续，但不再保留更多行，因此 totalLines 仍为精确值。面向模型的 read 工具渲染的结果纯粹是展示性的；不存在 full/partial 视图区分——授权基于新鲜度（工具发出表示目标存在的 fs/observed 事件，并直接携带 stat 的版本），因此任何窗口化读取在文件未变时都能授权后续的 write/edit。元数据未命中时，工具会在返回 FS_NOT_FOUND 前 emit 缺失观测，使后续带守卫的写入可以重新创建外部删除的目标，但不会授权 edit。拥有读取操作的执行器 dsh-tool-fs 实现读取窗口化并构造该结果；策略插件不执行这些操作。
/** Outcome of a bounded text read — what {@link formatReadOutput} renders. */
interface FileReadOutcome {
/** 1-based first line requested. */
offset: number
/** Returned lines, already numbered. */
lines: FileTextLine[]
/** Exact total line count in the file. */
totalLines: number
/** Whether selected output hit the byte cap. */
truncatedByBytes?: true
}已观测文件状态（策略插件）
已观测状态是 dsh-fs-observation-policy 插件内部持有的 WeakMap<owner, Map<targetKey, FsObservation>>。映射中没有条目表示未见；{ kind: 'absent' } 表示 read 的元数据未命中，或 str_replace_editor 的 view、str_replace、insert 命令发生元数据未命中，从而确认缺失；{ kind: 'present', version } 表示 read、write 或 edit 观测到该版本。写入决策把未见和缺失映射到 createIfAbsent，把存在映射到 replaceIfVersion；编辑决策把未见映射到 FS_NOT_OBSERVED，把缺失映射到 FS_NOT_FOUND，把存在映射到其版本守卫。所有者从事件 actor 推导（通常是 exec.agent.session），被视为不透明且从不读取。dispose（资源释放）时丢弃全部数据（HMR（热模块替换）安全），策略不执行任何文件系统 I/O。
错误分类体系（提供方约定）
文件系统故障使用稳定的 FsErrorCode 字符串，由 FsError（HarnessError）携带。工具注册表在错误结果上保留 { name, code }，使重试、权限和 UI 层可以按 code 分支而无需解析文本。
/**
* Stable, machine-routable codes for filesystem failures. Carried on
* {@link FsError}; the tool registry exposes `{ name, code }` on `isError`
* results so retry/permission/UI layers can branch without parsing messages.
*/
type FsErrorCode =
| 'FS_NOT_FOUND'
| 'FS_NOT_DIRECTORY'
| 'FS_NOT_TEXT'
| 'FS_NOT_REGULAR_FILE'
| 'FS_TOO_LARGE'
| 'FS_PERMISSION_DENIED'
| 'FS_SANDBOX_DENIED'
| 'FS_IO_ERROR'
| 'FS_STALE_VERSION'
| 'FS_NOT_OBSERVED'
| 'FS_AMBIGUOUS_EDIT'
| 'FS_EDIT_NOT_FOUND'
| 'FS_ABORTED'目录列表使用 FS_NOT_DIRECTORY、FS_PERMISSION_DENIED 与 FS_IO_ERROR 区分已存在但并非目录的目标、被拒绝的列表操作和意外的后端 I/O 失败。FS_SANDBOX_DENIED 是强制执行沙箱的后端（dsh-fs-sandbox）所作的策略拒绝——模式边界拒绝了写入/编辑——与 FS_PERMISSION_DENIED（宿主内核拒绝）不同。FS_NOT_OBSERVED 表示策略插件没有此所有者的先前观测记录（或 createIfAbsent 遇到了现有文件）。FS_NOT_FOUND 也表示策略因确认缺失而拒绝 edit。FS_STALE_VERSION 表示后端版本不再与观测到的版本匹配（或提供方本身收到针对缺失目标的 edit）。新鲜度授权没有部分/完整之分，因此不存在 FS_PARTIAL_OBSERVATION。
文件 IO 不设超时
read/write/edit 不接受 timeoutMs，提供方约定也不设置截止时间——不同于 bash 与 web（它们消费 @deepseek-ai/dsh-timeout）以及 subprocess 支撑的 glob/grep（其声明的 timeoutMs 由 @deepseek-ai/dsh-tool-call-timeout-policy 强制执行）：那些是进程支撑的，截止时间可以真正终止工作。本地系统调用至多是尽力中止——超时无法迫使进行中的 fsync/rename 停下，因此这里的 timeoutMs 会成为 seam 无法强制执行的截止时间，而且恰好落在「显式优于隐式」禁止隐式默认值的位置。取消仍通过工具执行 signal 传播，在系统调用边界尽力中止。
服务与插件
FileSystem（ctx.fs，abstract）拥有提供方原语：resolve、processPath、fileUrl、contains、stat、lstat、readText、streamText、readBytes、listDir、writeText 与 editText。dsh-fs-observation-policy 不注册服务——它是一个通过 fs/* 事件门禁添加策略的插件：根据未见/缺失/存在状态对写入与编辑意图 waterfall 作出决策，并记录 FsObservation 值。执行器是 dsh-tool-fs：它通过 ctx.fs 读取/写入/编辑，分发 waterfall，并 emit 记录事件。下方生成的 ctx.fs 小节 展示确切的 ctx.fs 签名。
Cordis API
Generated from source by scripts/gen-cordis-catalog.ts (verified fresh by pnpm run verify-cordis-catalog in doc-sync; regenerate with pnpm run gen-cordis-catalog) — this section is byte-identical in both language sides of the page. Signature blocks use a ts cordis-catalog fence and keep the original source JSDoc; dispatch modes are defined in the primer, and the framework-inherited ctx API lives in cordis-api/inherited.md.
ctx.fs — FileSystem (abstract seam)
Abstract filesystem provider. Targets must preserve identity across aliases; reads expose regular UTF-8 text or typed errors, listings are stable and content-free, and mutations are atomic. Optional guards add stale protection without changing the unguarded provider contract.
/**
* Resolve a model/plugin-supplied path into a stable {@link FsTarget}. May perform I/O (a
* remote/sandboxed backend may need a round-trip to map a path to a stable identity), hence
* async even though the local backend only normalizes + realpaths.
*
* @param path - the path to resolve; relative paths resolve against `opts.cwd`.
* @param opts - optional cwd override and cancellation signal.
* @returns the stable target; the same file yields the same `targetKey`.
*/
abstract resolve(path: string, opts?: { cwd?: string; signal?: AbortSignal }): Promise<FsTarget>
/**
* Return the canonical absolute path a subprocess in this filesystem's
* execution world can open. The path is deliberately separate from
* {@link FsTarget.targetKey}: consumers may pass this value to another OS
* capability, but must continue treating the target key as opaque.
* @param target - the resolved target whose process path is required.
* @returns an absolute path in the backend's execution world.
*/
abstract processPath(target: FsTarget): string
/**
* Return the canonical `file:` URI for a target in this filesystem's
* execution world. Backends own URI encoding because the host platform may
* differ from the execution platform.
* @param target - the resolved target to encode.
* @returns the target's canonical file URI.
*/
abstract fileUrl(target: FsTarget): string
/**
* Test canonical containment without exposing or parsing backend target
* keys. Both targets must come from this provider.
* @param parent - canonical directory target.
* @param child - canonical candidate target.
* @returns true when `child` is `parent` or a descendant of it.
*/
abstract contains(parent: FsTarget, child: FsTarget): boolean
/**
* Return target metadata, or `undefined` when the target does not exist.
* @param target - the resolved target to stat.
* @param signal - aborts the metadata round-trip.
* @returns metadata only, never content; undefined for an absent target.
*/
abstract stat(target: FsTarget, signal?: AbortSignal): Promise<FsInfo | undefined>
/**
* Return path metadata without following the final path component when it is a
* symbolic link. This is intentionally path-shaped, not target-shaped:
* {@link resolve} follows symlinks to produce the stable identity used by
* normal reads/writes, while `lstat` lets a consumer reject the path itself
* before that follow happens.
*
* `opts.cwd` follows {@link resolve}'s cwd rules. `undefined` means the path is
* absent.
* @param path - the path to inspect; relative paths resolve against `opts.cwd`.
* @param opts - `cwd` overrides the backend's default base for relative paths.
* @param signal - aborts the metadata round-trip.
* @returns metadata only, never content; undefined for an absent path.
*/
abstract lstat(path: string, opts?: { cwd?: string }, signal?: AbortSignal): Promise<FsPathInfo | undefined>
/**
* Read the whole regular text file as a single decoded string.
* @param target - the resolved target to read.
* @param signal - aborts the read.
* @returns the full decoded UTF-8 content.
*/
abstract readText(target: FsTarget, signal?: AbortSignal): Promise<string>
/**
* Stream the whole regular text file as decoded text chunks (same text
* semantics as {@link readText}, for large files). The backend owns
* cross-chunk UTF-8 decoding and binary rejection so the policy layer never
* touches raw bytes.
* @param target - the resolved target to read.
* @param signal - aborts the stream, including between chunks.
* @returns the chunk iterable, decoded and validated like {@link readText}.
*/
abstract streamText(target: FsTarget, signal?: AbortSignal): Promise<AsyncIterable<string>>
/**
* Read the whole regular file as raw bytes with no decoding or binary
* rejection. The bound lives at this seam so a backend can never buffer an
* unbounded file: a target known or discovered to exceed `maxBytes` fails
* with `FS_TOO_LARGE` instead of returning a truncated result.
* @param target - the resolved target to read.
* @param signal - aborts the read.
* @param maxBytes - inclusive byte cap on the complete content.
* @returns the full raw content, at most `maxBytes` long.
*/
abstract readBytes(target: FsTarget, signal: AbortSignal | undefined, maxBytes: number): Promise<Uint8Array>
/**
* List direct children of a directory in stable name order. Returns resolved
* child targets plus cheap metadata only; never reads file contents.
* @param target - the resolved directory target.
* @param signal - aborts the listing.
* @returns one entry per direct child, in stable name order.
*/
abstract listDir(target: FsTarget, signal?: AbortSignal): Promise<FsDirEntry[]>
/**
* Atomically create or replace UTF-8 text. `expected` guards intent and
* staleness; omission allows unconditional overwrite.
* @param target - the resolved target to write.
* @param content - the full new file content.
* @param expected - the write intent guarding the write; omit for unconditional.
* @param signal - aborts before atomic publication takes effect.
* @param sandboxPolicy - the per-call mode and workspace root this write
* runs under; a sandboxing backend fences the write by it, the bare backend
* ignores it. Omit to leave the backend its own default.
* @returns the outcome, including the version the write produced.
*/
abstract writeText( target: FsTarget, content: string, expected?: FsWriteIntent, signal?: AbortSignal, sandboxPolicy?: SandboxExecutionPolicy, ): Promise<FsWriteOutcome>
/**
* Atomically edit literal text. When supplied, the version guard is checked
* before matching so stale content reports `FS_STALE_VERSION`; omission edits
* the current content without a freshness precondition.
* @param target - the resolved target to edit.
* @param edit - the literal search/replace request.
* @param expected - the version guard; omit for an unconditional edit.
* @param signal - aborts before atomic publication takes effect.
* @param sandboxPolicy - the per-call mode and workspace root this edit runs
* under; a sandboxing backend fences the edit by it, the bare backend
* ignores it. Omit to leave the backend its own default.
* @returns the outcome, including the version the edit produced.
*/
abstract editText( target: FsTarget, edit: FsEditRequest, expected?: { version: FsVersion }, signal?: AbortSignal, sandboxPolicy?: SandboxExecutionPolicy, ): Promise<FsEditOutcome>Types: SandboxExecutionPolicy
Source: packages/fs/fs/src/index.ts:86
fs/* events
fs/edit-intent — waterfall
Single-slot decision for the next FileSystem.editText. Calling next() yields an unconditional edit; the first returned guard wins.
/**
* Single-slot decision for the next {@link FileSystem.editText}. Calling
* `next()` yields an unconditional edit; the first returned guard wins.
* @param target - the resolved target about to be edited.
* @param actor - the opaque tool-execution context the decider keys off.
* @mode waterfall
*/
'fs/edit-intent'(target: FsTarget, actor: object | undefined, next: () => { version: FsVersion } | undefined | Promise<{ version: FsVersion } | undefined>): Promise<{ version: FsVersion } | undefined>Source: packages/fs/fs/src/index.ts:66
fs/observed — emit
Record an authoritative positive or negative observation. Listeners must be synchronous recorders: throws fail the tool call and returned promises are not awaited.
/**
* Record an authoritative positive or negative observation. Listeners must
* be synchronous recorders: throws fail the tool call and returned promises
* are not awaited.
* @param target - the target whose presence or absence was observed.
* @param observation - present with its version, or confirmed absent.
* @param actor - the observing tool-execution context; undefined records nothing useful.
* @mode emit
*/
'fs/observed'(target: FsTarget, observation: FsObservation, actor: object | undefined): voidSource: packages/fs/fs/src/index.ts:76
fs/write-intent — waterfall
Single-slot decision for the next FileSystem.writeText. Calling next() yields the bare provider's unconditional write; the first listener that returns an intent owns the decision rather than composing with peers.
/**
* Single-slot decision for the next {@link FileSystem.writeText}. Calling
* `next()` yields the bare provider's unconditional write; the first listener
* that returns an intent owns the decision rather than composing with peers.
* @param target - the resolved target about to be written.
* @param actor - the opaque tool-execution context the decider keys off.
* @mode waterfall
*/
'fs/write-intent'(target: FsTarget, actor: object | undefined, next: () => FsWriteIntent | undefined | Promise<FsWriteIntent | undefined>): Promise<FsWriteIntent | undefined>Source: packages/fs/fs/src/index.ts:58