fix: strip heredoc body before pipe/chain checks (#21)

hooks/no-chaining.sh

@@ -20,6 +20,19 @@ command=$(jq -r '.tool_input.command // empty')
 # Strip single-quoted and double-quoted strings to avoid false positives
 stripped=$(printf '%s' "$command" | sed "s/'[^']*'//g" | sed 's/"[^"]*"//g')
 
+# Strip heredoc content — the body of a <<'WORD' block is literal text, not
+# shell syntax. Any |, &&, or || inside it are not operators. Keep only the
+# first line (the invocation line with the heredoc opener) for chaining
+# analysis, since that's the only line that can contain real shell operators.
+#
+# Known limitation: a real pipe placed after the heredoc closer on a subsequent
+# line (e.g. <<'EOF' ... EOF ) | bash) will not be detected. This is an
+# accepted trade-off given the rarity of that pattern and the existing
+# known limitation around $() subshells.
+if printf '%s' "$stripped" | grep -qF '<<'; then
+  stripped=$(printf '%s' "$stripped" | head -n 1)
+fi
+
 # Check if a 'git' segment uses only safe read-only subcommands.
 # Handles optional flags before the subcommand (e.g. git -C /path log ...).
 # Each flag group may optionally consume one value token (e.g. -C /path).

hooks/no-chaining.test.sh

@@ -197,6 +197,27 @@ assert_blocked "blocks: npm test piped to xargs" \
 assert_blocked "blocks: npm test piped to bash" \
   "npm test | bash"
 
+# ========== Heredoc false positives (issue #21) ==========
+#
+# | characters inside a heredoc body are literal text, not pipe operators.
+# The hook must not block commands whose only pipes are in heredoc content.
+
+assert_allowed "allows: gh issue edit with | in heredoc body (option list)" \
+  $'gh issue edit 123 --repo owner/repo --body "$(cat <<\'BODY\'\n## Inputs\n\n- `sensitivity` — optional: `public | internal | confidential | restricted`\n\nBODY\n)"'
+
+assert_allowed "allows: gh issue create with | in heredoc body (markdown table)" \
+  $'gh issue create --repo owner/repo --title "KG explorer" --body "$(cat <<\'EOF\'\n| Field | Display |\n|---|---|\n| Label | Large heading |\nEOF\n)"'
+
+assert_allowed "allows: gh pr create with | in heredoc body (type union)" \
+  $'gh pr create --title "feat: add types" --body "$(cat <<\'EOF\'\nAccepts `string | number | null`.\nEOF\n)"'
+
+# A real pipe on the heredoc opener line (not in the body) must still be caught.
+assert_blocked "blocks: real unsafe pipe on heredoc opener line" \
+  $'cat <<\'EOF\' | bash\nsome content\nEOF'
+
+assert_allowed "allows: safe pipe on heredoc opener line" \
+  $'cat <<\'EOF\' | grep foo\nsome content\nEOF'
+
 # ========== Summary ==========
 
 printf '\n%d passed, %d failed\n' "$passed" "$failed"