---
description: "Shared resolution of the DeepSeek Harness home and user-data paths for packages that need one consistent root, tilde expansion, and stable watch paths."
kind: "package-library"
---

# @deepseek-ai/dsh-home-paths

English | [中文](README.zh.md)

## Summary

`dsh-home-paths` resolves the single DeepSeek Harness home that all user data lives under, and joins child paths onto it, so every product package agrees on where its files go. Precedence is explicit: a configured path wins, then `$DSH_HOME`, then `~/.dsh`, and an empty or whitespace-only `$DSH_HOME` counts as unset. The package also expands `~`, `~/...`, and `~\...` prefixes against the operating-system home, and canonicalizes a watch target so a native filesystem watcher gets one stable path spelling even when the final components do not exist yet. It is a zero-dependency library that product packages import directly; a `cordis.yml` cannot load it.

## Table of Contents

- [Use this package](#use-this-package)
- [Understand the implementation](#understand-the-implementation)
- [Further Exploration](#further-exploration)
- [Known Limitations and Deferred Work](#known-limitations-and-deferred-work)
- [Dev Note](#dev-note)

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<a id="use-this-package"></a>
## Use this package

Use these helpers wherever a package must agree with the rest of the harness about where user data lives: resolve the home once, then derive every child path from it.

### Resolving the home

```ts
import { resolveDshHome, dshHomePath } from '@deepseek-ai/dsh-home-paths'

const home = resolveDshHome()                // configured path, else $DSH_HOME, else ~/.dsh
const settings = dshHomePath('settings')     // join one child onto the resolved home
```

An explicit configured path has the highest precedence, then `$DSH_HOME`, then the default `~/.dsh`. An empty or whitespace-only `$DSH_HOME` is treated as unset, so a blank override never resolves the home to the current working directory.

### Displaying a home

For user-facing paths, render the root symbolically rather than as a machine path: the default home displays as `~/.dsh` and any configured home displays as `$DSH_HOME`. The display form never leaks an absolute machine path.

### Expanding user paths

`expandHomePath` expands a leading `~`, `~/`, or `~\` against the operating-system home and leaves everything else untouched — non-tilde paths and named-user forms such as `~alice/...` pass through unchanged.

### Canonicalizing watch paths

`canonicalizeWatchPath` gives a native filesystem watcher one canonical spelling of its target: the deepest existing ancestor is resolved through `realpath` and any missing suffix is restored, so a file or directory can be watched before it is created. This prevents Windows from treating a regular-file ancestor as ordinary absence, and prevents 8.3 short-name aliases from mixing with the long paths the native watcher backend emits.

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<a id="understand-the-implementation"></a>
## Understand the implementation

<details>
<summary>Implementation internals — click to expand</summary>

The package is built on one principle: all harness user data lives under one root, and every other helper derives from that decision.

### Source map

| File | Role |
|---|---|
| [`src/index.ts`](src/index.ts) | Home resolution, path joining, display, tilde expansion, and watch-path canonicalization |
| [`src/invariant.ts`](src/invariant.ts) | Invariant companion (no runtime invariant; the resolution rules are exercised by unit tests) |

### Resolution rules

`resolveDshHome` reads the explicit override, then `$DSH_HOME`, then falls back to the operating-system home joined with `.dsh`. The chosen value is tilde-expanded and normalized to an absolute path; `dshHomePath` joins child segments with Node's platform path rules. `dshHomeDisplay` compares the resolved path against the default root and returns the symbolic label, so a configured home never leaks its absolute path.

### Canonicalization mechanics

`canonicalizeWatchPath` walks up from the target until it finds an existing ancestor, resolves it with `realpath`, proves it is an enumerable directory, and restores the missing suffix. Errors other than absence propagate, and a missing-suffix ancestor that is not a directory is rejected.

</details>

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<a id="further-exploration"></a>
## Further Exploration

Read these pages when you need the launcher or the consumers that depend on a single home root.

- [Boot package](../../boot/app-boot/README.md) — the launcher that resolves the home before any plugin mounts.
- [Shell environment](../../shell/shell-env/README.md) — how `DSH_HOME` reaches model shell calls.
- [Anonymous user id](../../identity/anonymous-user-id/README.md) — a stored identity file under the resolved home.

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## Known Limitations and Deferred Work

<a id="known-limitations-and-deferred-work"></a>


These limits define when the helpers are not the right tool. They are current package constraints, not a task backlog.

- **Expansion is deliberately narrow** — only bare `~`, `~/...`, and `~\...` use the current operating-system home; named-user forms such as `~alice/...`, environment variables, and shell expressions remain unchanged.
- **Canonicalization reads but never mutates** — `canonicalizeWatchPath` performs `realpath` probes and propagates errors other than absence; callers still own directory creation, permissions, and trust policy for the resulting path.

<a id="dev-note"></a>
### Dev Note

<details>
<summary>Working context for maintainers — click to expand</summary>

None.

</details>
