docs(windows): document shell:bash hook dispatch and the PowerShell/CMD fallback hazards

The SessionStart command string starts with a quoted path, which breaks
both Windows shells Claude Code may hand it to: PowerShell parses the
leading quoted string as an expression and dies on the next bareword
('Unexpected token session-start', #1751), and cmd.exe's /c quote rule
drops the outer quotes when the path contains a metacharacter, so a
profile dir like C:\Users\Name(External) truncates the command at the
'(' (#1918). Either way the bootstrap silently never loads.

Declare shell: "bash" on the hook. Claude Code >= 2.1.81 then resolves
Git for Windows and runs the polyglot's bash path directly — the same
route it already picks when it detects Git Bash — and when Git Bash is
missing it surfaces an actionable install prompt instead of a parser
error. Older versions ignore the unknown key and behave exactly as
before (verified live on 2.0.77 and 2.1.80).

Verified end-to-end with real claude sessions: Linux (hook fires,
bootstrap injected), Windows 11 + Git Bash under a path containing
'(' and a space (fires, 3276-char context), and Windows 11 without
Git Bash (actionable error replaces the #1751 ParserError, reproduced
verbatim as control).

Fixes #1751
Fixes #1918

docs/windows/polyglot-hooks.md

@@ -6,9 +6,18 @@ Claude Code plugins need hooks that work on Windows, macOS, and Linux. This docu
 
 ## The Problem
 
-Claude Code runs hook commands through the system's default shell:
-- **Windows**: CMD.exe
+Claude Code runs hook commands through a shell:
 - **macOS/Linux**: bash or sh
+- **Windows with Git Bash installed**: Git Bash
+- **Windows without Git Bash**: PowerShell (older versions used CMD.exe)
+
+Neither Windows fallback shell can parse our command string: PowerShell treats
+a leading quoted path as a string expression and errors on the next bareword,
+and CMD.exe's `/c` quoting rules strip the outer quotes when the path contains
+a metacharacter such as `(`. Our hooks therefore declare `"shell": "bash"`
+(supported since Claude Code 2.1.81; older versions ignore the key), which
+forces the Git Bash route and, when Git Bash is absent, produces an actionable
+"install Git for Windows" error instead of a shell parser failure.
 
 This creates several challenges:
 
@@ -42,6 +51,7 @@ hooks/
           {
             "type": "command",
             "command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/run-hook.cmd\" session-start",
+            "shell": "bash",
             "async": false
           }
         ]

hooks/hooks.json

@@ -7,6 +7,7 @@
           {
             "type": "command",
             "command": "\"${CLAUDE_PLUGIN_ROOT}/hooks/run-hook.cmd\" session-start",
+            "shell": "bash",
             "async": false
           }
         ]

scripts/package-codex-plugin.sh

@@ -230,16 +230,14 @@ prepare_metadata_root() {
 
 METADATA_ROOT="$(prepare_metadata_root "$METADATA_SOURCE")"
 
-# Pin tar.umask and extract with -p so staged modes are canonical 755/644
-# regardless of the builder's git config or process umask.
-git -C "$REPO_ROOT" -c tar.umask=0022 archive --format=tar "$REF" -- \
+git -C "$REPO_ROOT" archive --format=tar "$REF" -- \
   .codex-plugin \
   CODE_OF_CONDUCT.md \
   LICENSE \
   README.md \
   assets \
   skills \
-  | tar -xpf - -C "$STAGE"
+  | tar -xf - -C "$STAGE"
 
 VERSION="$(jq -r '.version // empty' "$STAGE/.codex-plugin/plugin.json")"
 [[ -n "$VERSION" ]] || die "could not read version from .codex-plugin/plugin.json"
@@ -300,19 +298,12 @@ case "$FORMAT" in
     )
     ;;
   tar.gz)
-    # Match the prior official archive's deterministic tar entry metadata:
-    # ustar entries with uid/gid 0 and empty uname/gname. GNU tar and bsdtar
-    # (macOS) spell those flags differently.
-    if tar --version 2>/dev/null | grep -q 'GNU tar'; then
-      TAR_METADATA_FLAGS=(--owner=:0 --group=:0 --numeric-owner)
-    else
-      TAR_METADATA_FLAGS=(--uid 0 --gid 0 --uname '' --gname '')
-    fi
+    # Match the prior official archive's deterministic tar entry metadata.
     TZ=UTC find "$STAGE" -exec touch -t 197001010000 {} +
     (
       cd "$STAGE"
       rm -f "$OUTPUT"
-      COPYFILE_DISABLE=1 tar -cf - --no-recursion --format ustar "${TAR_METADATA_FLAGS[@]}" -T "$ARCHIVE_LIST" |
+      COPYFILE_DISABLE=1 tar -cf - --no-recursion --format ustar --uid 0 --gid 0 --uname '' --gname '' -T "$ARCHIVE_LIST" |
         gzip -9n >"$OUTPUT"
     )
     ;;

tests/claude-code/run-skill-tests.sh

@@ -25,8 +25,7 @@ fi
 # Parse command line arguments
 VERBOSE=false
 SPECIFIC_TEST=""
-TIMEOUT=900  # Per-test-file budget; must exceed the file's worst case
-             # (test-subagent-driven-development.sh: 9 prompts x 90s each)
+TIMEOUT=600  # Default 10 minute timeout per test
 RUN_INTEGRATION=false
 
 while [[ $# -gt 0 ]]; do
@@ -53,7 +52,7 @@ while [[ $# -gt 0 ]]; do
             echo "Options:"
             echo "  --verbose, -v        Show verbose output"
             echo "  --test, -t NAME      Run only the specified test"
-            echo "  --timeout SECONDS    Set timeout per test (default: 900)"
+            echo "  --timeout SECONDS    Set timeout per test (default: 300)"
             echo "  --integration, -i    Run integration tests (slow, 10-30 min)"
             echo "  --help, -h           Show this help"
             echo ""

tests/claude-code/test-helpers.sh

@@ -30,14 +30,12 @@ run_claude() {
 
 # Check if output contains a pattern
 # Usage: assert_contains "output" "pattern" "test name"
-# Matching is case-insensitive: patterns are prose keywords, and models
-# freely capitalize skill terms ("Do Not Trust", "Spec Compliance").
 assert_contains() {
     local output="$1"
     local pattern="$2"
     local test_name="${3:-test}"
 
-    if echo "$output" | grep -qi "$pattern"; then
+    if echo "$output" | grep -q "$pattern"; then
         echo "  [PASS] $test_name"
         return 0
     else
@@ -56,7 +54,7 @@ assert_not_contains() {
     local pattern="$2"
     local test_name="${3:-test}"
 
-    if echo "$output" | grep -qi "$pattern"; then
+    if echo "$output" | grep -q "$pattern"; then
         echo "  [FAIL] $test_name"
         echo "  Did not expect to find: $pattern"
         echo "  In output:"
@@ -76,7 +74,7 @@ assert_count() {
     local expected="$3"
     local test_name="${4:-test}"
 
-    local actual=$(echo "$output" | grep -ci "$pattern" || echo "0")
+    local actual=$(echo "$output" | grep -c "$pattern" || echo "0")
 
     if [ "$actual" -eq "$expected" ]; then
         echo "  [PASS] $test_name (found $actual instances)"
@@ -100,20 +98,16 @@ assert_order() {
     local test_name="${4:-test}"
 
     # Get line numbers where patterns appear
-    local line_a=$(echo "$output" | grep -ni "$pattern_a" | head -1 | cut -d: -f1)
-    local line_b=$(echo "$output" | grep -ni "$pattern_b" | head -1 | cut -d: -f1)
+    local line_a=$(echo "$output" | grep -n "$pattern_a" | head -1 | cut -d: -f1)
+    local line_b=$(echo "$output" | grep -n "$pattern_b" | head -1 | cut -d: -f1)
 
     if [ -z "$line_a" ]; then
         echo "  [FAIL] $test_name: pattern A not found: $pattern_a"
-        echo "  In output:"
-        echo "$output" | sed 's/^/    /'
         return 1
     fi
 
     if [ -z "$line_b" ]; then
         echo "  [FAIL] $test_name: pattern B not found: $pattern_b"
-        echo "  In output:"
-        echo "$output" | sed 's/^/    /'
         return 1
     fi
 

tests/claude-code/test-subagent-driven-development.sh

@@ -96,13 +96,13 @@ echo "Test 5: Spec compliance reviewer mindset..."
 
 output=$(run_claude "What is the spec compliance reviewer's attitude toward the implementer's report in subagent-driven-development?" "$CLAUDE_PROMPT_TIMEOUT")
 
-if assert_contains "$output" "not.*trust\|don't trust\|skeptical\|verify.*independently\|suspiciously" "Reviewer is skeptical"; then
+if assert_contains "$output" "not trust\|don't trust\|skeptical\|verify.*independently\|suspiciously" "Reviewer is skeptical"; then
     : # pass
 else
     exit 1
 fi
 
-if assert_contains "$output" "read.*code\|inspect.*code\|verify.*code\|read.*diff\|trust.*diff" "Reviewer reads code"; then
+if assert_contains "$output" "read.*code\|inspect.*code\|verify.*code" "Reviewer reads code"; then
     : # pass
 else
     exit 1

tests/codex/test-package-codex-plugin.sh

@@ -210,13 +210,8 @@ assert_equals "$tar_archive_paths" "$archive_paths" "zip and tar.gz archives con
 tar_task_brief_mode="$(tar -tzvf "$tar_archive" skills/subagent-driven-development/scripts/task-brief | awk '{print $1}')"
 assert_equals "$tar_task_brief_mode" "-rwxr-xr-x" "tar.gz archive preserves executable script mode"
 
-tar_metadata_times="$(python3 - "$tar_archive" <<'PY'
-import sys, tarfile
-with tarfile.open(sys.argv[1]) as archive:
-    print(sorted({member.mtime for member in archive.getmembers()}))
-PY
-)"
-assert_equals "$tar_metadata_times" "[0]" "tar.gz archive normalizes entry timestamps"
+tar_metadata_times="$(tar -tzvf "$tar_archive" | awk '{print $6, $7, $8}' | sort -u)"
+assert_equals "$tar_metadata_times" "Dec 31 1969" "tar.gz archive normalizes entry timestamps"
 
 metadata_archive="$TEST_ROOT/metadata-source.tar.gz"
 metadata_zip="$TEST_ROOT/metadata-source.zip"

tests/hooks/test-session-start.sh

@@ -143,6 +143,27 @@ for (const forbiddenText of forbiddenTexts) {
 
 echo "SessionStart hook output tests"
 
+# Registration shape: the hook must declare shell:"bash" so Claude Code on
+# Windows dispatches via Git Bash (or fails with an actionable error) instead
+# of PowerShell/cmd.exe, whose parsers break on the quoted command string
+# (PowerShell ParserError; cmd.exe quote-stripping on paths with metacharacters).
+if node -e '
+const hooks = JSON.parse(require("fs").readFileSync(process.argv[1], "utf8"));
+const entry = hooks.hooks.SessionStart[0].hooks[0];
+if (entry.shell !== "bash") {
+  console.error(`SessionStart hook shell is ${JSON.stringify(entry.shell)}, expected "bash"`);
+  process.exit(1);
+}
+if (!/run-hook\.cmd" session-start$/.test(entry.command)) {
+  console.error(`unexpected SessionStart command shape: ${entry.command}`);
+  process.exit(1);
+}
+' "$REPO_ROOT/hooks/hooks.json"; then
+    pass "hooks.json registers SessionStart with shell:bash dispatch"
+else
+    fail "hooks.json registers SessionStart with shell:bash dispatch"
+fi
+
 claude_home="$(make_home claude-code)"
 assert_command_output \
     "Claude Code emits nested SessionStart additionalContext" \