powershell-fix

A host-layer plugin for DeepSeek Harness (DSH) that detects and auto-fixes Windows PowerShell command syntax mistakes before they burn a tool-call round-trip — then executes the corrected command through the host shell seam, under the normal sandbox/approval policy.

AI agents (and humans) frequently paste bash-flavored commands into a Windows terminal. This plugin gives the agent one tool — powershell_fix — that checks, repairs, and runs such commands safely.

What it fixes

Line hygiene (the most frequent real-world breakage)

problem	fix
CRLF / stray \r from copy-paste	normalized to LF
pasted shell prompts (PS C:\> , C:\> , $ on every line)	stripped
trailing whitespace after a continuation char (invisible breakage)	removed
bash \ line continuation	PowerShell backtick
missing continuation before a -Parameter line	backtick inserted
dangling backtick before an empty line	removed
unbalanced quotes	warned (never blindly rewritten)

bash → PowerShell semantics

bash	PowerShell
export NAME=value	$env:NAME='value' (same-command $NAME refs rewritten to $env:NAME)
unset NAME	if (Test-Path Env:NAME) { Remove-Item Env:NAME } (guarded; inline-in-chain supported)
> /dev/null, 2> /dev/null, &> /dev/null	> $null, 2> $null, *> $null
a && b / `a
ls -la path	Get-ChildItem path -Force
rm -rf x	Remove-Item x -Recurse -Force
mkdir -p a/b/c	New-Item -ItemType Directory -Force …
touch f	timestamp update or New-Item -ItemType File
grep [-r] [-v] pat f…	Select-String (recursion via Get-ChildItem -Recurse)
which x / command -v x	(Get-Command x -ErrorAction SilentlyContinue).Source
head -n N f / tail -n N f / tail -f f	Get-Content -TotalCount N / -Tail N / -Wait
sed, awk, chmod, bare $PATH-style env refs	warned with PowerShell equivalents (never blindly rewritten)

Correct PowerShell passes through unchanged (no-op guarantee, covered by regression tests). The fixer is idempotent: fix(fix(x)) === fix(x).

Safety

• Execution goes through the host ctx.shell seam — the same sandbox, approval, and timeout policy as the built-in pwsh tool. This plugin adds no privilege.
• A built-in execution gate refuses to auto-execute semantically destructive commands even after fixing them: root-target recursive deletes (rm -rf /, Remove-Item C:\ -Recurse), Format-Volume, Clear-Disk, Set-ExecutionPolicy, del /s|/q, and environment/system persistence writes (setx, [Environment]::Set*, New-ItemProperty, Set-ItemProperty, reg add).
• execute: false (or autoExecute: false config) gives a dry-run: fix only, no execution.

Install (host layer — available to every session)

The package declares dsh.bundle.patch, so installing it into a profile adds it to the profile's layer stack automatically — no agent-preset line needed:

dsh plugin --profile web add file:/path/to/powershell-fix

Reconciling notices the dsh.bundle declaration and appends powershell-fix to dsh.profile.bundles; the bundled cordis.patch.yml inserts the plugin row at the host layer. Restart the harness, and every session on that profile gets:

• tool powershell_fix
• a system-prompt section teaching native PowerShell syntax and when to call the tool

Note: pnpm file: dependencies copy lib/*.js — after editing the source, delete node_modules/powershell-fix in the profile and re-run the add command ("Already up to date" is misleading).

Tool contract

// powershell_fix({ command, shell?, execute?, description? })
{
  "ok": true,
  "platform": "win32",
  "shell": "powershell51",          // auto-detected engine: pwsh | powershell51
  "original": "export A=1 && echo $A",
  "fixed": "$env:A='1'; if ($?) { echo $env:A }",
  "changed": true,
  "fixes": [{ "rule": "ENV_EXPORT", "notes": ["…"] }],
  "warnings": [{ "rule": "BARE_VAR", "note": "…" }],
  "execution": { "mode": "auto", "exitCode": 0, "stdout": "…", "stderr": "…" }
  // execution.mode: auto | dry-run | skipped-dangerous | aborted
}

Config (cordis row / dsh.bundle defaults): autoExecute (default true), timeoutMs (default 60000).

Development

Zero runtime dependencies (engine is pure JS); peer deps @deepseek-ai/dsh-tools and @deepseek-ai/schemastery resolve from the host.

node --test                          # unit tests (engine, 57 assertions)
node acceptance/mount_check.mjs <profile_web_dir>   # mount + live-path check
node acceptance/real_pwsh_e2e.mjs    # fixed commands executed by the real engine

中文说明

DSH host 层插件:在 Windows 终端上自动检测并修复 PowerShell 命令语法错误(bash 语法、续行符错误、粘贴带入的提示符与 CRLF),修复后经宿主 shell 缝隙执行——沙箱/审批策略与内置 pwsh 工具完全一致,危险命令只修复不执行。声明 dsh.bundle.patch,装入 profile 即对所有会话生效,无需改任何 preset。

License

MIT