refactor(core): centralize DSH home resolution

packages/util/README.md

@@ -5,8 +5,11 @@ Zero-dependency primitives shared across the other groups. A package lands here
 | Package | Role |
 |---|---|
 | `brand/` | The type-only `Branded<B>` nominal-typing primitive (no runtime code, no harness deps) |
+| `home/` | Canonical `DSH_HOME` resolution from explicit config, environment, or `~/.dsh` (no harness deps) |
 | `timeout/` | The timing/classification half of a timeout — `clampTimeout`/`deadline`/`timeoutOf`/`TimeoutReason` (pure functions, no harness deps); termination stays in each capability |
 
 `dsh-brand` is the canonical case: it owns ONLY the `Branded<B>` helper, so a capability package can brand the ids it owns (`dsh-bash`'s `BashTaskId`/`OwnerToken`, `dsh-session`'s `SessionId`, …) by depending on `dsh-brand` alone, without pulling in an unrelated package just to reach `Branded`.
 
+`dsh-home` gives every package the same configurable Harness home without assigning that cross-cutting fact to bash, skills, or a composition bundle. It resolves an explicit value before `$DSH_HOME`, falls back to `~/.dsh`, and returns an absolute path without caching, creating, or mutating anything.
+
 `dsh-timeout` follows the same shape for the timeout family: `dsh-bash` and `dsh-web-fetch-local` each fuse a caller's cancellation with a deadline and later classify "timed out" vs "cancelled" by depending on `dsh-timeout` alone. It deliberately owns only the timing/classification half — the *termination* (SIGKILL a process group, tear down a fetch socket) stays in each capability, because no shared layer can own every capability's kill (see [the timeout-library RFC](../../docs/rfc/implemented/architecture/2026-07-06-timeout-deadline-library.md)).

packages/util/home/README.md

@@ -0,0 +1,9 @@
+# @deepseek-ai/dsh-home
+
+`@deepseek-ai/dsh-home` is the single owner of DeepSeek Harness home-directory resolution. `resolveDshHome(configured?)` returns an absolute path using this precedence:
+
+1. The explicit `configured` path.
+2. The `DSH_HOME` environment variable.
+3. The `.dsh` directory under the current user's home directory.
+
+The resolver reads its inputs at call time. It does not cache a result, create the directory, or mutate `process.env`; consumers keep ownership of their own configuration fields and pass the configured value when resolving the shared home.

packages/util/home/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "@deepseek-ai/dsh-home",
+  "description": "Canonical DeepSeek Harness home-directory resolver",
+  "version": "0.0.1",
+  "private": true,
+  "type": "module",
+  "main": "lib/index.js",
+  "types": "lib/types/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/types/index.d.ts",
+      "default": "./lib/index.js"
+    },
+    "./src/*": "./src/*",
+    "./package.json": "./package.json"
+  },
+  "files": [
+    "lib/index.js",
+    "lib/types/**/*.d.ts",
+    "lib/types/**/*.d.ts.map",
+    "src"
+  ],
+  "license": "BSD-3-Clause",
+  "peerDependencies": {
+    "cordis": "^4.0.0-rc.6"
+  },
+  "devDependencies": {
+    "cordis": "^4.0.0-rc.6"
+  }
+}

packages/util/home/src/index.ts

@@ -0,0 +1,23 @@
+/**
+ * Canonical DeepSeek Harness home-directory resolution.
+ *
+ * @module @deepseek-ai/dsh-home
+ */
+
+import { homedir } from 'node:os'
+import { join, resolve } from 'node:path'
+
+const DEFAULT_DSH_HOME_DIRNAME = '.dsh'
+
+/** Environment variable that overrides the default Harness home directory. */
+export const DSH_HOME_ENV = 'DSH_HOME' as const
+
+/**
+ * Resolve the DeepSeek Harness home directory without caching or mutating the environment.
+ *
+ * @param configured - Optional configured path, which takes precedence over the environment.
+ * @returns The absolute configured path, `$DSH_HOME`, or `~/.dsh`, in that order.
+ */
+export function resolveDshHome(configured?: string): string {
+  return resolve(configured ?? process.env[DSH_HOME_ENV] ?? join(homedir(), DEFAULT_DSH_HOME_DIRNAME))
+}

packages/util/home/tests/home.spec.ts

@@ -0,0 +1,26 @@
+import { homedir } from 'node:os'
+import { join, resolve } from 'node:path'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { DSH_HOME_ENV, resolveDshHome } from '@deepseek-ai/dsh-home'
+
+afterEach(() => vi.unstubAllEnvs())
+
+describe('resolveDshHome', () => {
+  it('prefers an explicit configured path and resolves it absolutely', () => {
+    vi.stubEnv(DSH_HOME_ENV, './environment-home')
+
+    expect(resolveDshHome('./configured-home')).toBe(resolve('./configured-home'))
+  })
+
+  it('uses DSH_HOME when no configured path is supplied', () => {
+    vi.stubEnv(DSH_HOME_ENV, './environment-home')
+
+    expect(resolveDshHome()).toBe(resolve('./environment-home'))
+  })
+
+  it('defaults to the .dsh directory under the user home', () => {
+    vi.stubEnv(DSH_HOME_ENV, undefined)
+
+    expect(resolveDshHome()).toBe(join(homedir(), '.dsh'))
+  })
+})

packages/util/home/tsconfig.json

@@ -0,0 +1,9 @@
+{
+  "extends": "../../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "lib/types"
+  },
+  "include": ["src"],
+  "references": []
+}