fix(hooks): rewrite patch_settings_cl_v2_simple.ps1 to avoid argv-dup bug

- Use PATH-resolved `bash` as first token instead of quoted `.exe` path
  so Claude Code v2.1.116 argv duplication does not feed a binary to
  bash as its $0 (repro: exit 126 "cannot execute binary file").
- Point the command at `observe-wrapper.sh` and pass distinct `pre` /
  `post` positional arguments so PreToolUse and PostToolUse are
  registered as separate entries.
- Normalize the wrapper path to forward slashes before embedding in the
  hook command to avoid MSYS backslash surprises.
- Write UTF-8 (no BOM) with CRLF normalized to LF so downstream JSON
  parsers never see mixed line endings.
- Preserve existing hooks (legacy `observe.sh`, third-party entries)
  by appending only when the canonical command string is not already
  registered. Re-runs are idempotent ([SKIP] both phases).
- Keep the script compatible with Windows PowerShell 5.1: fall back to
  a manual PSCustomObject → Hashtable conversion when
  `ConvertFrom-Json -AsHashtable` is unavailable, and materialize hook
  arrays as `System.Collections.ArrayList` so single-element arrays
  survive PS 5.1 `ConvertTo-Json` serialization.

Companion to PR #1524 (settings.local.json shape fix) and PR #1540
(install_hook_wrapper.ps1 argv-dup fix).

docs/fixes/PATCH-SETTINGS-SIMPLE-FIX-20260422.md

@@ -0,0 +1,78 @@
+# patch_settings_cl_v2_simple.ps1 argv-dup bug workaround (2026-04-22)
+
+## Summary
+
+`docs/fixes/patch_settings_cl_v2_simple.ps1` is the minimal PowerShell
+helper that patches `~/.claude/settings.local.json` so the observer hook
+points at `observe-wrapper.sh`. It is the "simple" counterpart of
+`docs/fixes/install_hook_wrapper.ps1` (PR #1540): it never copies the
+wrapper script, it only rewrites the settings file.
+
+The previous version of this helper registered the raw `observe.sh` path
+as the hook command, shared a single command string across `PreToolUse`
+and `PostToolUse`, and relied on `ConvertTo-Json` defaults that can emit
+CRLF line endings. Under Claude Code v2.1.116 the first argv token is
+duplicated, so the wrapper needs to be invoked with a specific shape and
+the two hook phases need distinct entries.
+
+## What the fix does
+
+- First token is the PATH-resolved `bash` (no quoted `.exe` path), so the
+  argv-dup bug no longer passes a binary as a script. Matches PR #1524 and
+  PR #1540.
+- The wrapper path is normalized to forward slashes before it is embedded
+  in the hook command, avoiding MSYS backslash handling surprises.
+- `PreToolUse` and `PostToolUse` receive distinct commands with explicit
+  `pre` / `post` positional arguments.
+- The settings file is written UTF-8 (no BOM) with CRLF normalized to LF
+  so downstream JSON parsers never see mixed line endings.
+- Existing hooks (including legacy `observe.sh` entries and unrelated
+  third-party hooks) are preserved — the script only appends the new
+  wrapper entries when they are not already registered.
+- Idempotent on re-runs: a second invocation recognizes the canonical
+  command strings and logs `[SKIP]` instead of duplicating entries.
+
+## Resulting command shape
+
+```
+bash "C:/Users/<you>/.claude/skills/continuous-learning/hooks/observe-wrapper.sh" pre
+bash "C:/Users/<you>/.claude/skills/continuous-learning/hooks/observe-wrapper.sh" post
+```
+
+## Usage
+
+```powershell
+pwsh -File docs/fixes/patch_settings_cl_v2_simple.ps1
+# Windows PowerShell 5.1 is also supported:
+powershell -NoProfile -ExecutionPolicy Bypass -File docs/fixes/patch_settings_cl_v2_simple.ps1
+```
+
+The script backs up the existing settings file to
+`settings.local.json.bak-<timestamp>` before writing.
+
+## PowerShell 5.1 compatibility
+
+`ConvertFrom-Json -AsHashtable` is PowerShell 7+ only. The script tries
+`-AsHashtable` first and falls back to a manual `PSCustomObject` →
+`Hashtable` conversion on Windows PowerShell 5.1. Both hook buckets
+(`PreToolUse`, `PostToolUse`) and their inner `hooks` arrays are
+materialized as `System.Collections.ArrayList` before serialization, so
+PS 5.1's `ConvertTo-Json` cannot collapse single-element arrays into bare
+objects.
+
+## Verified cases (dry-run)
+
+1. Fresh install — no existing settings → creates canonical file.
+2. Idempotent re-run — existing canonical file → `[SKIP]` both phases,
+   file contents unchanged apart from the pre-write backup.
+3. Legacy `observe.sh` present → preserves the legacy entries and
+   appends the new `observe-wrapper.sh` entries alongside them.
+
+All three cases produce LF-only output and match the shape registered by
+PR #1524's manual fix to `settings.local.json`.
+
+## Related
+
+- PR #1524 — settings.local.json shape fix (same argv-dup root cause)
+- PR #1539 — locale-independent `detect-project.sh`
+- PR #1540 — `install_hook_wrapper.ps1` argv-dup fix (companion script)

docs/fixes/patch_settings_cl_v2_simple.ps1

@@ -0,0 +1,187 @@
+# Simple patcher for settings.local.json - CL v2 hooks (argv-dup safe)
+#
+# No Japanese literals - keeps the file ASCII-only so PowerShell parses it
+# regardless of the active code page.
+#
+# argv-dup bug workaround (Claude Code v2.1.116):
+#   - Use PATH-resolved `bash` (no quoted .exe) as the first argv token.
+#   - Point the hook at observe-wrapper.sh (not observe.sh).
+#   - Pass `pre` / `post` as explicit positional arguments so PreToolUse and
+#     PostToolUse are registered as distinct commands.
+#   - Normalize the wrapper path to forward slashes to keep MSYS/Git Bash
+#     happy and write the JSON with LF endings only.
+#
+# References:
+#   - PR #1524 (settings.local.json argv-dup fix)
+#   - PR #1540 (install_hook_wrapper.ps1 argv-dup fix)
+$ErrorActionPreference = "Stop"
+
+$SettingsPath = "$env:USERPROFILE\.claude\settings.local.json"
+$WrapperDst   = "$env:USERPROFILE\.claude\skills\continuous-learning\hooks\observe-wrapper.sh"
+$BashExe      = "bash"
+
+# Normalize wrapper path to forward slashes and build distinct pre/post
+# commands. Quoting keeps spaces in the path safe.
+$wrapperPath = $WrapperDst -replace '\\','/'
+$preCmd  = $BashExe + ' "' + $wrapperPath + '" pre'
+$postCmd = $BashExe + ' "' + $wrapperPath + '" post'
+
+Write-Host "=== CL v2 Simple Patcher (argv-dup safe) ===" -ForegroundColor Cyan
+Write-Host "Target      : $SettingsPath"
+Write-Host "Wrapper     : $wrapperPath"
+Write-Host "Pre command : $preCmd"
+Write-Host "Post command: $postCmd"
+
+# Ensure parent dir exists
+$parent = Split-Path $SettingsPath
+if (-not (Test-Path $parent)) {
+    New-Item -ItemType Directory -Path $parent -Force | Out-Null
+}
+
+function New-HookEntry {
+    param([string]$Command)
+    # Inner `hooks` uses ArrayList so a single-element list does not get
+    # collapsed into an object when PS 5.1 ConvertTo-Json serializes the
+    # enclosing Hashtable.
+    $inner = [System.Collections.ArrayList]::new()
+    $null = $inner.Add(@{ type = "command"; command = $Command })
+    return @{
+        matcher = "*"
+        hooks   = $inner
+    }
+}
+
+# Convert a PSCustomObject tree (as returned by ConvertFrom-Json on PS 5.1)
+# into nested Hashtables/Arrays so the merge logic below works uniformly.
+# PS 7+ gets the same shape via `ConvertFrom-Json -AsHashtable` directly.
+function ConvertTo-HashtableRecursive {
+    param($InputObject)
+    if ($null -eq $InputObject) { return $null }
+    if ($InputObject -is [System.Collections.IDictionary]) {
+        $result = @{}
+        foreach ($key in $InputObject.Keys) {
+            $result[$key] = ConvertTo-HashtableRecursive -InputObject $InputObject[$key]
+        }
+        return $result
+    }
+    if ($InputObject -is [System.Management.Automation.PSCustomObject]) {
+        $result = @{}
+        foreach ($prop in $InputObject.PSObject.Properties) {
+            $result[$prop.Name] = ConvertTo-HashtableRecursive -InputObject $prop.Value
+        }
+        return $result
+    }
+    if ($InputObject -is [System.Collections.IList] -or $InputObject -is [System.Array]) {
+        # Use ArrayList so PS 5.1 ConvertTo-Json preserves single-element
+        # arrays instead of collapsing them into objects. Plain Object[]
+        # suffers from that collapse when embedded in a Hashtable value.
+        $result = [System.Collections.ArrayList]::new()
+        foreach ($item in $InputObject) {
+            $null = $result.Add((ConvertTo-HashtableRecursive -InputObject $item))
+        }
+        return ,$result
+    }
+    return $InputObject
+}
+
+function Read-SettingsAsHashtable {
+    param([string]$Path)
+    $raw = Get-Content -Raw -Path $Path -Encoding UTF8
+    if ([string]::IsNullOrWhiteSpace($raw)) { return @{} }
+    # Prefer `-AsHashtable` (PS 7+); fall back to manual conversion on PS 5.1
+    # where that parameter does not exist.
+    try {
+        return ($raw | ConvertFrom-Json -AsHashtable)
+    } catch {
+        $obj = $raw | ConvertFrom-Json
+        return (ConvertTo-HashtableRecursive -InputObject $obj)
+    }
+}
+
+$preEntry  = New-HookEntry -Command $preCmd
+$postEntry = New-HookEntry -Command $postCmd
+
+if (Test-Path $SettingsPath) {
+    $backup = "$SettingsPath.bak-$(Get-Date -Format 'yyyyMMdd-HHmmss')"
+    Copy-Item $SettingsPath $backup -Force
+    Write-Host "[BACKUP] $backup" -ForegroundColor Yellow
+
+    try {
+        $existing = Read-SettingsAsHashtable -Path $SettingsPath
+    } catch {
+        Write-Host "[WARN] Failed to parse existing JSON, will overwrite (backup preserved)" -ForegroundColor Yellow
+        $existing = @{}
+    }
+    if ($null -eq $existing) { $existing = @{} }
+
+    if (-not $existing.ContainsKey("hooks")) {
+        $existing["hooks"] = @{}
+    }
+    # Normalize the two hook buckets into ArrayList so both existing and newly
+    # added entries survive PS 5.1 ConvertTo-Json array collapsing.
+    foreach ($key in @("PreToolUse", "PostToolUse")) {
+        if (-not $existing.hooks.ContainsKey($key)) {
+            $existing.hooks[$key] = [System.Collections.ArrayList]::new()
+        } elseif (-not ($existing.hooks[$key] -is [System.Collections.ArrayList])) {
+            $list = [System.Collections.ArrayList]::new()
+            foreach ($item in @($existing.hooks[$key])) { $null = $list.Add($item) }
+            $existing.hooks[$key] = $list
+        }
+        # Each entry's inner `hooks` array needs the same treatment so legacy
+        # single-element arrays do not serialize as bare objects.
+        foreach ($entry in $existing.hooks[$key]) {
+            if ($entry -is [System.Collections.IDictionary] -and $entry.ContainsKey("hooks") -and
+                -not ($entry["hooks"] -is [System.Collections.ArrayList])) {
+                $innerList = [System.Collections.ArrayList]::new()
+                foreach ($item in @($entry["hooks"])) { $null = $innerList.Add($item) }
+                $entry["hooks"] = $innerList
+            }
+        }
+    }
+
+    # Duplicate check uses the exact command string so legacy observe.sh
+    # entries are left in place unless re-run manually removes them.
+    $hasPre = $false
+    foreach ($e in $existing.hooks.PreToolUse) {
+        foreach ($h in @($e.hooks)) { if ($h.command -eq $preCmd) { $hasPre = $true } }
+    }
+    $hasPost = $false
+    foreach ($e in $existing.hooks.PostToolUse) {
+        foreach ($h in @($e.hooks)) { if ($h.command -eq $postCmd) { $hasPost = $true } }
+    }
+
+    if (-not $hasPre) {
+        $null = $existing.hooks.PreToolUse.Add($preEntry)
+        Write-Host "[ADD] PreToolUse" -ForegroundColor Green
+    } else {
+        Write-Host "[SKIP] PreToolUse already registered" -ForegroundColor Gray
+    }
+    if (-not $hasPost) {
+        $null = $existing.hooks.PostToolUse.Add($postEntry)
+        Write-Host "[ADD] PostToolUse" -ForegroundColor Green
+    } else {
+        Write-Host "[SKIP] PostToolUse already registered" -ForegroundColor Gray
+    }
+
+    $json = $existing | ConvertTo-Json -Depth 20
+} else {
+    Write-Host "[CREATE] new settings.local.json" -ForegroundColor Green
+    $newSettings = @{
+        hooks = @{
+            PreToolUse  = @($preEntry)
+            PostToolUse = @($postEntry)
+        }
+    }
+    $json = $newSettings | ConvertTo-Json -Depth 20
+}
+
+# Write UTF-8 no BOM and normalize CRLF -> LF so hook parsers never see
+# mixed line endings.
+$jsonLf = $json -replace "`r`n","`n"
+$utf8 = [System.Text.UTF8Encoding]::new($false)
+[System.IO.File]::WriteAllText($SettingsPath, $jsonLf, $utf8)
+
+Write-Host ""
+Write-Host "=== Patch SUCCESS ===" -ForegroundColor Green
+Write-Host ""
+Get-Content -Path $SettingsPath -Encoding UTF8