diff --git a/plugins/issue-driven-dev/scripts/check-plugin-presence.sh b/plugins/issue-driven-dev/scripts/check-plugin-presence.sh
new file mode 100755
index 0000000..8c0686c
--- /dev/null
+++ b/plugins/issue-driven-dev/scripts/check-plugin-presence.sh
@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+# check-plugin-presence.sh — generic Claude Code plugin presence detector
+#
+# Usage:
+#   check-plugin-presence.sh <marketplace> <plugin-name>
+#
+# Examples:
+#   check-plugin-presence.sh claude-plugins-official ralph-loop
+#   check-plugin-presence.sh psychquant-claude-plugins che-word-mcp
+#
+# Used by:
+#   - idd-issue Step 1 Source Type Adapter (#27 fail-fast for .docx / Telegram / Mail / Notes)
+#   - scripts/check-ralph-loop.sh (wrapper for backward-compat from #28)
+#
+# Exit:
+#   0 — plugin installed (or IDD_SKIP_PLUGIN_CHECK=1)
+#   1 — plugin missing
+#   2 — usage error (wrong arg count)
+#
+# Detect path is hardcoded against Claude Code 2025-Q4 plugin cache schema.
+# When schema changes upstream, see #35 (path schema watch-list).
+
+set -u
+
+# Usage check
+if [ $# -ne 2 ]; then
+  cat >&2 <<EOF
+Usage: $(basename "$0") <marketplace> <plugin-name>
+
+Examples:
+  $(basename "$0") claude-plugins-official ralph-loop
+  $(basename "$0") psychquant-claude-plugins che-word-mcp
+EOF
+  exit 2
+fi
+
+MARKETPLACE="$1"
+PLUGIN="$2"
+
+# Escape hatch — let user bypass detect (#28 risk mitigation, #27 inheritance).
+# Print stderr warning so this leaves an audit trail.
+if [ "${IDD_SKIP_PLUGIN_CHECK:-}" = "1" ]; then
+  echo "⚠ IDD_SKIP_PLUGIN_CHECK=1 set — skipping ${MARKETPLACE}/${PLUGIN} detection (advanced override)" >&2
+  echo "  Caller will run as if ${PLUGIN} is installed." >&2
+  exit 0
+fi
+
+# Plugin cache layout (Claude Code 2025-Q4):
+#   ~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/.claude-plugin/plugin.json
+# Match any installed version under the plugin dir.
+#
+# Use bash array + nullglob (NOT unquoted `for f in $GLOB`) to handle HOME with
+# whitespace correctly (per #28 F3 verify finding).
+shopt -s nullglob
+files=( "${HOME}/.claude/plugins/cache/${MARKETPLACE}/${PLUGIN}"/*/.claude-plugin/plugin.json )
+shopt -u nullglob
+
+if (( ${#files[@]} > 0 )); then
+  exit 0
+fi
+
+cat >&2 <<EOF
+✗ ${PLUGIN} plugin not found.
+  Searched: ~/.claude/plugins/cache/${MARKETPLACE}/${PLUGIN}/*/.claude-plugin/plugin.json
+
+  Install:
+    claude plugin marketplace add <owner>/${MARKETPLACE}
+    claude plugin install ${PLUGIN}@${MARKETPLACE}
+
+  Or bypass this check (advanced): export IDD_SKIP_PLUGIN_CHECK=1
+EOF
+exit 1
diff --git a/plugins/issue-driven-dev/scripts/check-ralph-loop.sh b/plugins/issue-driven-dev/scripts/check-ralph-loop.sh
index 784a386..8497bbd 100755
--- a/plugins/issue-driven-dev/scripts/check-ralph-loop.sh
+++ b/plugins/issue-driven-dev/scripts/check-ralph-loop.sh
@@ -1,52 +1,22 @@
 #!/usr/bin/env bash
-# check-ralph-loop.sh — detect ralph-loop plugin presence
+# check-ralph-loop.sh — backward-compat wrapper around check-plugin-presence.sh
 #
-# Used by:
-#   - idd-verify --loop (Step 0a fail-fast)
-#   - idd-all Phase 0.6 (graceful degrade gate)
+# v2.54+ (#34 refactor): the actual detection logic moved to
+# scripts/check-plugin-presence.sh which accepts <marketplace> <plugin>.
+# This wrapper is preserved so #28's existing callers continue to work:
+#   - idd-verify --loop Step 0a fail-fast
+#   - idd-all Phase 0.6 graceful degrade gate
 #
-# Exit:
-#   0 — ralph-loop installed (or IDD_SKIP_RALPH_CHECK=1)
-#   1 — ralph-loop missing
+# Both `IDD_SKIP_RALPH_CHECK=1` and `IDD_SKIP_PLUGIN_CHECK=1` are honored
+# (legacy + new env var name).
 #
-# Detect path is hardcoded against Claude Code 2025-Q4 plugin cache schema.
-# When schema changes upstream, see #35 (path schema watch-list).
-# Source plugin lives at anthropics/claude-plugins-official.
+# Exit codes inherited from check-plugin-presence.sh:
+#   0 — installed
+#   1 — missing
 
-set -u
-
-# Escape hatch — let user bypass detect (#28 risk mitigation).
-# Print stderr warning so this leaves an audit trail (per F4 verify finding).
+# Honor legacy env var name from #28 v2.53.
 if [ "${IDD_SKIP_RALPH_CHECK:-}" = "1" ]; then
-  echo "⚠ IDD_SKIP_RALPH_CHECK=1 set — skipping ralph-loop detection (advanced override)" >&2
-  echo "  /idd-verify --loop and /idd-all (PR, unattended) will run as if ralph-loop is installed." >&2
-  exit 0
+  export IDD_SKIP_PLUGIN_CHECK=1
 fi
 
-# Plugin cache layout (Claude Code 2025-Q4):
-#   ~/.claude/plugins/cache/<marketplace>/<plugin>/<version>/.claude-plugin/plugin.json
-# Match any installed version under the plugin dir.
-#
-# F3 fix: use bash array + nullglob, NOT unquoted `for f in $GLOB`. The latter
-# word-splits when HOME contains whitespace (macOS display-name accounts,
-# iCloud Mobile Documents paths) → false-negative even when ralph-loop is
-# installed → silently breaks v2.40.0 backward-compat for /idd-all callers.
-shopt -s nullglob
-files=( "${HOME}/.claude/plugins/cache/claude-plugins-official/ralph-loop"/*/.claude-plugin/plugin.json )
-shopt -u nullglob
-
-if (( ${#files[@]} > 0 )); then
-  exit 0
-fi
-
-cat >&2 <<EOF
-✗ ralph-loop plugin not found.
-  Searched: ~/.claude/plugins/cache/claude-plugins-official/ralph-loop/*/.claude-plugin/plugin.json
-
-  Install:
-    claude plugin marketplace add anthropics/claude-plugins-official
-    claude plugin install ralph-loop@claude-plugins-official
-
-  Or bypass this check (advanced): export IDD_SKIP_RALPH_CHECK=1
-EOF
-exit 1
+exec "$(dirname "$0")/check-plugin-presence.sh" claude-plugins-official ralph-loop
diff --git a/plugins/issue-driven-dev/skills/idd-issue/SKILL.md b/plugins/issue-driven-dev/skills/idd-issue/SKILL.md
index 2a287fb..c58747e 100644
--- a/plugins/issue-driven-dev/skills/idd-issue/SKILL.md
+++ b/plugins/issue-driven-dev/skills/idd-issue/SKILL.md
@@ -276,6 +276,56 @@ UPSTREAM=$(echo "$REPO_JSON" | jq -r '.parent.nameWithOwner // empty')
 | 直接貼文字（無附件） | argument 直接帶文字 | n/a |
 | 混合（文字 + 圖片貼上） | argument 帶文字 + 使用者另外提供 path 清單 | 把使用者給的 path 全部納入 Step 4 上傳清單 |
 
+#### MCP plugin presence pre-flight (v2.54+, #27 fail-fast)
+
+當 source 是 `.docx` / Telegram / Apple Mail / Apple Notes(任一需要 MCP plugin 的類型),Step 1 一開始就 invoke `check-plugin-presence.sh` detect — 缺失則 **fail-fast abort** with structured error message (per #32 absorbed acceptance criteria)。
+
+```bash
+# Source-type → required plugin mapping
+case "$SOURCE_TYPE" in
+  docx|doc)
+    "$CLAUDE_PLUGIN_ROOT/scripts/check-plugin-presence.sh" psychquant-claude-plugins che-word-mcp || abort_source_unsupported "che-word-mcp" ".docx" "psychquant-claude-plugins" ;;
+  telegram)
+    "$CLAUDE_PLUGIN_ROOT/scripts/check-plugin-presence.sh" psychquant-claude-plugins che-telegram-mcp || abort_source_unsupported "che-telegram-mcp" "Telegram chat" "psychquant-claude-plugins" ;;
+  apple-mail)
+    "$CLAUDE_PLUGIN_ROOT/scripts/check-plugin-presence.sh" psychquant-claude-plugins che-apple-mail-mcp || abort_source_unsupported "che-apple-mail-mcp" "Apple Mail" "psychquant-claude-plugins" ;;
+  apple-notes)
+    "$CLAUDE_PLUGIN_ROOT/scripts/check-plugin-presence.sh" psychquant-claude-plugins che-apple-notes-mcp || abort_source_unsupported "che-apple-notes-mcp" "Apple Notes" "psychquant-claude-plugins" ;;
+  text|md|mixed)
+    : ;; # no plugin needed for raw text / markdown / pasted text+paths
+esac
+```
+
+`abort_source_unsupported` 印出 structured error message(format spec from #32 absorbed acceptance criteria):
+
+```
+✗ Source detected as <SOURCE_DESC> but `<PLUGIN>` MCP plugin is not installed.
+
+該 source type 需要對應 MCP plugin 才能讀取文字 + 抽圖。
+
+Options:
+  1) Install plugin (recommended):
+     claude plugin marketplace add PsychQuant/<MARKETPLACE>
+     claude plugin install <PLUGIN>@<MARKETPLACE>
+     # 不知道 marketplace? 跑: claude plugin marketplace list
+     # 詳見: plugins/issue-driven-dev/README.md#optional-per-source-type
+
+  2) Convert to another supported format:
+     - Save as `.md` or `.txt` then paste content directly
+     - Or screenshot then attach as image (如果 主要內容是 figures)
+
+  3) Manual fallback (not recommended for archives):
+     paste relevant text into prompt directly
+
+Aborting /idd-issue. Run again after installing or converting.
+```
+
+**Why fail-fast not silent fallback** (per #27 + #32 absorbed):
+- Silent fallback (e.g. "讓使用者手動處理") 讓使用者誤以為 IDD **不支援**該格式,而非少裝 plugin
+- Explicit error + 3 options 把責任 explicit 還給使用者,各 source-type 統一格式建立 mental model
+
+**Bypass**: `IDD_SKIP_PLUGIN_CHECK=1` env var 跳過 detect(同 #34 generic helper escape hatch)。
+
 #### Telegram source 專屬流程（最常見且最容易漏的）
 
 當原始描述中含 `chat_id` / Telegram URL / `@username` 引用時，**強制**走以下流程，不問：