diff --git a/README.ja.md b/README.ja.md
index 05e8470..9ac4633 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -82,7 +82,7 @@ exstruct input.xlsx -o out.json --pretty   # 整形 JSON をファイルへ
 exstruct input.xlsx --format yaml          # YAML（pyyaml が必要）
 exstruct input.xlsx --format toon          # TOON（python-toon が必要）
 exstruct input.xlsx --sheets-dir sheets/   # シートごとに分割出力
-exstruct input.xlsx --auto-page-breaks-dir auto_areas/  # COM 限定（利用可能な環境のみ表示）
+exstruct input.xlsx --auto-page-breaks-dir auto_areas/  # 常時表示。実行には standard/verbose + Excel COM が必要
 exstruct input.xlsx --alpha-col           # 列キーを A, B, ..., AA 形式で出力
 exstruct input.xlsx --include-backend-metadata  # shape/chart の backend metadata を含める
 exstruct input.xlsx --mode light           # セル＋テーブル候補のみ
@@ -90,8 +90,8 @@ exstruct input.xlsx --mode libreoffice     # COM なしで図形/コネクタ/
 exstruct input.xlsx --pdf --image          # PDF と PNG（Excel COM 必須）
 ```
 
-自動改ページ範囲の書き出しは API/CLI 両方に対応（Excel/COM が必要）し、CLI は利用可能な環境でのみ `--auto-page-breaks-dir` を表示します。
-`mode=libreoffice` では `--pdf` / `--image` / `--auto-page-breaks-dir` を早期エラーにし、これらの機能は `standard` または `verbose` + Excel COM を前提にします。
+自動改ページ範囲の書き出しは API/CLI 両方に対応（Excel/COM が必要）し、CLI では `--auto-page-breaks-dir` を常時表示したうえで実行時に検証します。
+`mode=libreoffice` では `--pdf` / `--image` / `--auto-page-breaks-dir` を早期エラーにし、`mode=light` でも `--auto-page-breaks-dir` を拒否します。これらの機能は `standard` または `verbose` + Excel COM を前提にします。
 CLI の既定では列キーは従来どおり 0 始まりの数値文字列（`"0"`, `"1"`, ...）です。Excel 形式（`"A"`, `"B"`, ...）が必要な場合は `--alpha-col` を指定してください。
 CLI の既定では shape/chart の `provenance` / `approximation_level` / `confidence` も出力しません。必要な場合は `--include-backend-metadata` を指定してください。
 注意: MCP の `exstruct_extract` は `options.alpha_col=true` が既定で、CLI の既定（`false`）とは異なります。
diff --git a/README.md b/README.md
index a59b358..885605a 100644
--- a/README.md
+++ b/README.md
@@ -93,7 +93,7 @@ exstruct input.xlsx -o out.json --pretty   # write pretty JSON to a file
 exstruct input.xlsx --format yaml          # YAML (requires pyyaml)
 exstruct input.xlsx --format toon          # TOON (requires python-toon)
 exstruct input.xlsx --sheets-dir sheets/   # write one file per sheet
-exstruct input.xlsx --auto-page-breaks-dir auto_areas/  # COM only; shown only when available
+exstruct input.xlsx --auto-page-breaks-dir auto_areas/  # always shown; execution requires standard/verbose + Excel COM
 exstruct input.xlsx --alpha-col            # output column keys as A, B, ..., AA
 exstruct input.xlsx --include-backend-metadata  # include shape/chart backend metadata
 exstruct input.xlsx --mode light           # cells + table candidates only
@@ -101,8 +101,8 @@ exstruct input.xlsx --mode libreoffice     # best-effort extraction of shapes/co
 exstruct input.xlsx --pdf --image          # PDF and PNGs (Excel COM required)
 ```
 
-Auto page-break export is available from both the API and the CLI when Excel/COM is available. The CLI exposes `--auto-page-breaks-dir` only in COM-capable environments.
-`mode=libreoffice` rejects `--pdf`, `--image`, and `--auto-page-breaks-dir` early. Use `standard` or `verbose` with Excel COM for those features.
+Auto page-break export is available from both the API and the CLI when Excel/COM is available. The CLI always exposes `--auto-page-breaks-dir`, but validates it at execution time.
+`mode=libreoffice` rejects `--pdf`, `--image`, and `--auto-page-breaks-dir` early, and `mode=light` also rejects `--auto-page-breaks-dir`. Use `standard` or `verbose` with Excel COM for those features.
 By default, the CLI keeps legacy 0-based numeric string column keys (`"0"`, `"1"`, ...). Use `--alpha-col` when you need Excel-style keys (`"A"`, `"B"`, ...).
 By default, serialized shape/chart output omits backend metadata (`provenance`, `approximation_level`, `confidence`) to reduce token usage. Use `--include-backend-metadata` or the corresponding Python/MCP option when you need it.
 Note: MCP `exstruct_extract` defaults to `options.alpha_col=true`, which differs from the CLI default (`false`).
diff --git a/dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md b/dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md
new file mode 100644
index 0000000..60a1f0e
--- /dev/null
+++ b/dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md
@@ -0,0 +1,75 @@
+# ADR-0008: Extraction CLI Runtime Capability Validation
+
+## Status
+
+`accepted`
+
+## Background
+
+The extraction CLI currently probes Excel COM availability while building its
+argument parser so that `--auto-page-breaks-dir` is shown only on COM-capable
+hosts. On Windows this probe may instantiate `xlwings.App()` and launch Excel
+even for lightweight commands such as `exstruct --help`.
+
+This behavior creates two policy problems that are likely to recur:
+
+- parser construction performs host-dependent side effects and adds startup
+  latency before the user has requested any COM-only behavior
+- help output changes by host capability even though the CLI syntax itself is
+  stable across hosts
+
+ExStruct already treats extraction-mode validation as part of the product
+contract in ADR-0001, and treats rich-backend fallback as a runtime concern in
+ADR-0002. We need a CLI-facing policy for how capability-gated extraction flags
+should be exposed and validated without reintroducing startup probes.
+
+## Decision
+
+- Extraction CLI parser construction must remain side-effect-free and must not
+  probe COM or launch Excel.
+- Capability-gated extraction flags may remain visible in help output when
+  their syntax is stable across hosts and their requirements can be validated at
+  execution time.
+- `--auto-page-breaks-dir` is always exposed in extraction CLI help.
+- `--auto-page-breaks-dir` is validated only when the user requests it:
+  - `mode="libreoffice"` keeps the existing invalid-combination validation
+  - `mode="light"` is rejected explicitly because auto page-break export
+    requires COM-backed `standard` or `verbose`
+  - `mode="standard"` / `mode="verbose"` require Excel COM and fail with an
+    explicit runtime error when COM is unavailable
+- Ordinary extraction without requested COM-only side outputs keeps the existing
+  fallback policy from ADR-0002.
+
+## Consequences
+
+- `exstruct --help` and parser construction become faster and stop triggering
+  Excel startup side effects.
+- CLI help becomes consistent across hosts because it documents syntax instead
+  of reflecting a startup-time environment probe.
+- Users on unsupported hosts may still see `--auto-page-breaks-dir`, but they
+  now receive an actionable runtime error instead of hidden syntax or silent
+  export skipping.
+- Future extraction CLI features that are host-capability-gated should prefer
+  execution-time validation over parser-time probing unless the syntax itself is
+  host-specific.
+
+## Rationale
+
+- Tests:
+  - `tests/cli/test_cli.py`
+- Code:
+  - `src/exstruct/cli/main.py`
+  - `src/exstruct/cli/availability.py`
+- Related specs:
+  - `docs/cli.md`
+  - `README.md`
+  - `README.ja.md`
+  - `dev-docs/specs/excel-extraction.md`
+
+## Supersedes
+
+- None
+
+## Superseded by
+
+- None
diff --git a/dev-docs/adr/README.md b/dev-docs/adr/README.md
index 07d34ff..77a7ac4 100644
--- a/dev-docs/adr/README.md
+++ b/dev-docs/adr/README.md
@@ -42,3 +42,4 @@ ADRs record what was decided, under which constraints, and which trade-offs were
 | `ADR-0005` | PathPolicy Safety Boundary | `accepted` | `safety` |
 | `ADR-0006` | Public Edit API and Host-Owned Safety Boundary | `accepted` | `editing` |
 | `ADR-0007` | Editing CLI as Public Operational Interface | `accepted` | `editing` |
+| `ADR-0008` | Extraction CLI Runtime Capability Validation | `accepted` | `cli` |
diff --git a/dev-docs/adr/decision-map.md b/dev-docs/adr/decision-map.md
index a0e3b46..2620cc7 100644
--- a/dev-docs/adr/decision-map.md
+++ b/dev-docs/adr/decision-map.md
@@ -6,6 +6,7 @@ This document is a human-readable map for navigating ADRs by domain.
 
 - `ADR-0001` Extraction Mode Responsibility Boundaries (`accepted`)
 - `ADR-0002` Rich Backend Fallback Policy (`accepted`)
+- `ADR-0008` Extraction CLI Runtime Capability Validation (`accepted`)
 
 ## mode
 
@@ -33,6 +34,7 @@ This document is a human-readable map for navigating ADRs by domain.
 - `ADR-0003` Output Serialization Omission Policy (`accepted`)
 - `ADR-0004` Patch Backend Selection Policy (`accepted`)
 - `ADR-0007` Editing CLI as Public Operational Interface (`accepted`)
+- `ADR-0008` Extraction CLI Runtime Capability Validation (`accepted`)
 
 ## mcp
 
@@ -57,6 +59,7 @@ This document is a human-readable map for navigating ADRs by domain.
 ## cli
 
 - `ADR-0007` Editing CLI as Public Operational Interface (`accepted`)
+- `ADR-0008` Extraction CLI Runtime Capability Validation (`accepted`)
 
 ## Supersession Relationships
 
diff --git a/dev-docs/adr/index.yaml b/dev-docs/adr/index.yaml
index 15089ad..e2fcd6b 100644
--- a/dev-docs/adr/index.yaml
+++ b/dev-docs/adr/index.yaml
@@ -102,3 +102,19 @@ adrs:
       - docs/api.md
       - README.md
       - README.ja.md
+  - id: ADR-0008
+    title: Extraction CLI Runtime Capability Validation
+    status: accepted
+    path: dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md
+    primary_domain: cli
+    domains:
+      - cli
+      - extraction
+      - compatibility
+    supersedes: []
+    superseded_by: []
+    related_specs:
+      - docs/cli.md
+      - README.md
+      - README.ja.md
+      - dev-docs/specs/excel-extraction.md
diff --git a/dev-docs/specs/excel-extraction.md b/dev-docs/specs/excel-extraction.md
index 18d6e70..4cf454d 100644
--- a/dev-docs/specs/excel-extraction.md
+++ b/dev-docs/specs/excel-extraction.md
@@ -56,6 +56,7 @@ What is extracted:
 
 - print_areas are retrieved via pre-com (openpyxl); COM only supplements missing parts
 - auto_page_breaks are retrieved via COM only
+- The extraction CLI always exposes auto page-break export syntax and validates the required mode/runtime at execution time instead of probing COM during parser construction
 
 ## Colors Map
 
diff --git a/docs/cli.md b/docs/cli.md
index 687e650..8309870 100644
--- a/docs/cli.md
+++ b/docs/cli.md
@@ -120,6 +120,7 @@ empty workbook.
 | `--include-backend-metadata` | Include shape/chart backend metadata (`provenance`, `approximation_level`, `confidence`) in structured output. |
 | `--sheets-dir DIR` | Write one file per sheet (format follows `--format`). |
 | `--print-areas-dir DIR` | Write one file per print area (format follows `--format`). |
+| `--auto-page-breaks-dir DIR` | Write one file per auto page-break area. The flag is always shown in help, but execution requires `--mode standard` or `--mode verbose` with Excel COM. |
 
 ## Common workflows
 
@@ -157,6 +158,8 @@ exstruct sample.xlsx --pdf --image --dpi 144 -o out.json
   are usually the better fit.
 - On non-COM environments, prefer `--mode libreoffice` for best-effort rich extraction on `.xlsx/.xlsm`, or `--mode light` for minimal extraction.
 - `--mode libreoffice` is best-effort, not a strict subset of COM output. It does not render PDFs/PNGs and does not compute auto page-break areas in v1.
+- `--auto-page-breaks-dir` is always shown in help output and is validated at execution time.
 - `--mode libreoffice` combined with `--pdf`, `--image`, or `--auto-page-breaks-dir` fails early with a configuration error instead of silently ignoring the option.
+- `--mode light` also rejects `--auto-page-breaks-dir`; use `--mode standard` or `--mode verbose` with Excel COM for auto page-break export.
 - `--sheets-dir` and `--print-areas-dir` accept existing or new directories (created if missing).
 - `--alpha-col` switches row column keys from legacy numeric strings (`"0"`, `"1"`, ...) to Excel-style keys (`"A"`, `"B"`, ...). CLI default is disabled for backward compatibility.
diff --git a/src/exstruct/cli/availability.py b/src/exstruct/cli/availability.py
index fc4c6b7..0e7ec78 100644
--- a/src/exstruct/cli/availability.py
+++ b/src/exstruct/cli/availability.py
@@ -22,7 +22,7 @@ class ComAvailability(BaseModel):
 
 
 def get_com_availability() -> ComAvailability:
-    """Detect whether Excel COM is available for CLI features.
+    """Detect whether Excel COM is available for runtime CLI features.
 
     Returns:
         ComAvailability describing whether COM features can be used.
diff --git a/src/exstruct/cli/main.py b/src/exstruct/cli/main.py
index c3d66d3..5d9a25f 100644
--- a/src/exstruct/cli/main.py
+++ b/src/exstruct/cli/main.py
@@ -7,8 +7,9 @@
 import sys
 
 from exstruct import process_excel
-from exstruct.cli.availability import ComAvailability, get_com_availability
+from exstruct.cli.availability import get_com_availability
 from exstruct.cli.edit import is_edit_subcommand, run_edit_cli
+from exstruct.constraints import validate_libreoffice_process_request
 
 
 def _ensure_utf8_stdout() -> None:
@@ -29,33 +30,21 @@ def _ensure_utf8_stdout() -> None:
         return
 
 
-def _add_auto_page_breaks_argument(
-    parser: argparse.ArgumentParser, availability: ComAvailability
-) -> None:
-    """Add auto page-break export option when COM is available."""
-    if not availability.available:
-        return
+def _add_auto_page_breaks_argument(parser: argparse.ArgumentParser) -> None:
+    """Add the auto page-break export option to the extraction CLI."""
     parser.add_argument(
         "--auto-page-breaks-dir",
         type=Path,
         help=(
             "Optional directory to write one file per auto page-break area "
-            "(Excel COM only; not supported in libreoffice mode)."
+            "(format follows --format; requires --mode standard or "
+            "--mode verbose with Excel COM)."
         ),
     )
 
 
-def build_parser(
-    availability: ComAvailability | None = None,
-) -> argparse.ArgumentParser:
-    """Build the CLI argument parser.
-
-    Args:
-        availability: Optional COM availability for tests or overrides.
-
-    Returns:
-        Configured argument parser.
-    """
+def build_parser() -> argparse.ArgumentParser:
+    """Build the CLI argument parser."""
     parser = argparse.ArgumentParser(
         description="CLI for ExStruct extraction.",
         epilog=(
@@ -130,10 +119,7 @@ def build_parser(
         type=Path,
         help="Optional directory to write one file per print area (format follows --format).",
     )
-    resolved_availability = (
-        availability if availability is not None else get_com_availability()
-    )
-    _add_auto_page_breaks_argument(parser, resolved_availability)
+    _add_auto_page_breaks_argument(parser)
     parser.add_argument(
         "--alpha-col",
         action="store_true",
@@ -150,6 +136,36 @@ def build_parser(
     return parser
 
 
+def _validate_auto_page_breaks_request(args: argparse.Namespace) -> None:
+    """Validate runtime requirements for auto page-break export."""
+    auto_page_breaks_dir = getattr(args, "auto_page_breaks_dir", None)
+    if auto_page_breaks_dir is None:
+        return
+
+    message = (
+        "--auto-page-breaks-dir requires --mode standard or --mode verbose "
+        "with Excel COM."
+    )
+    if args.mode == "libreoffice":
+        validate_libreoffice_process_request(
+            args.input,
+            mode=args.mode,
+            include_auto_page_breaks=True,
+            pdf=args.pdf,
+            image=args.image,
+        )
+        return
+    if args.mode == "light":
+        raise RuntimeError(message)
+
+    availability = get_com_availability()
+    if availability.available:
+        return
+
+    reason = f" Reason: {availability.reason}" if availability.reason else ""
+    raise RuntimeError(f"{message}{reason}")
+
+
 def main(argv: list[str] | None = None) -> int:
     """Run the CLI entrypoint.
 
@@ -173,6 +189,7 @@ def main(argv: list[str] | None = None) -> int:
         return 0
 
     try:
+        _validate_auto_page_breaks_request(args)
         process_excel(
             file_path=input_path,
             output_path=args.output,
diff --git a/tasks/feature_spec.md b/tasks/feature_spec.md
index fe3d38b..f4bb9dc 100644
--- a/tasks/feature_spec.md
+++ b/tasks/feature_spec.md
@@ -42,3 +42,128 @@
 
 - `not-needed`
 - rationale: this was release preparation and task-log retention cleanup. The policy decisions already live in `ADR-0006`, `ADR-0007`, and the editing specs.
+
+## 2026-03-20 issue #107 extraction CLI startup optimization
+
+### Goal
+
+- Stop probing Excel COM availability while building the extraction CLI parser.
+- Keep `--auto-page-breaks-dir` visible in help output on every host.
+- Validate `--auto-page-breaks-dir` only when the user actually requests it at execution time.
+- Return an explicit CLI error when auto page-break export is requested from an unsupported mode or unsupported runtime.
+
+### Public contract
+
+- `build_parser()` and `exstruct --help` must not call the COM availability probe.
+- `--auto-page-breaks-dir` is always listed in extraction CLI help output.
+- `--auto-page-breaks-dir` runtime behavior:
+  - `mode="libreoffice"` keeps the existing `ConfigError` path and combined-error precedence.
+  - `mode="light"` is rejected explicitly by the CLI with a message that auto page-break export requires `standard` or `verbose` with Excel COM.
+  - `mode="standard"` / `mode="verbose"` trigger COM availability probing only when the flag is present.
+  - When COM is unavailable, the CLI exits non-zero and prints an actionable message that names the flag and includes the availability reason when present.
+- Existing `--pdf` / `--image` runtime behavior is unchanged in this task.
+
+### Permanent destinations
+
+- `dev-docs/adr/`
+  - `ADR-0008` records the extraction CLI policy change: runtime capability validation instead of parser-time environment probing.
+- `docs/`
+  - `docs/cli.md` becomes the canonical public CLI contract for always-visible `--auto-page-breaks-dir` and runtime validation wording.
+- `README.md` and `README.ja.md`
+  - Update quick-start examples and current-behavior prose so they no longer claim the flag is hidden on unsupported hosts.
+- `dev-docs/specs/`
+  - `dev-docs/specs/excel-extraction.md` should keep the internal guarantee that auto page-break extraction is COM-only and tied to runtime validation.
+- `tasks/feature_spec.md` and `tasks/todo.md`
+  - Retain only the temporary working record, verification, and migration notes for this issue.
+
+### Constraints
+
+- Do not broaden the task into a Python API or MCP contract change.
+- Do not rewrite historical release notes that describe the old behavior at the time they shipped.
+- Preserve existing file-not-found behavior and existing `libreoffice` combined-error precedence.
+
+### Verification plan
+
+- `tests/cli/test_cli.py`
+  - Help output always includes `--auto-page-breaks-dir`.
+  - Parser/help generation does not call `get_com_availability()`.
+  - `mode="light"` + `--auto-page-breaks-dir` fails with a clear runtime error.
+  - `mode="standard"` / `mode="verbose"` + `--auto-page-breaks-dir` + unavailable COM fails with a clear runtime error.
+  - Existing `libreoffice` rejection tests still pass.
+- Targeted pytest for the CLI extraction test module.
+- `uv run task build-docs`
+- `uv run task precommit-run`
+
+### ADR verdict
+
+- `required`
+- rationale: this changes the public extraction CLI contract for help visibility and execution-time validation of a COM-only flag, and it sets a reusable policy for future capability-gated CLI features.
+
+## 2026-03-20 issue #107 review follow-up: libreoffice auto page-break fast-fail
+
+### Goal
+
+- Align `mode="libreoffice"` handling for `--auto-page-breaks-dir` with the new CLI-side fast-fail policy.
+- Preserve the existing LibreOffice single-error and combined-error precedence from the shared validator.
+- Prove that the CLI rejects the invalid request before `process_excel()` runs.
+
+### Public contract
+
+- `--mode libreoffice --auto-page-breaks-dir ...` fails in the CLI layer without calling `process_excel()`.
+- When `--pdf` or `--image` is also present, the CLI keeps the existing combined LibreOffice error message precedence.
+- This follow-up does not change the already documented `standard` / `verbose` COM-runtime validation policy.
+
+### Permanent destinations
+
+- No new permanent destination is required beyond the documents already updated for issue `#107`.
+- The durable contract remains in `docs/cli.md`, `README.md`, `README.ja.md`, `dev-docs/specs/excel-extraction.md`, and `dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md`.
+
+### Constraints
+
+- Reuse the existing LibreOffice validator instead of duplicating message composition in the CLI.
+- Keep parser/help no-probe behavior unchanged.
+
+### Verification plan
+
+- `tests/cli/test_cli.py`
+  - `mode="libreoffice"` + `--auto-page-breaks-dir` rejects before `process_excel()`.
+  - `mode="libreoffice"` + rendering + `--auto-page-breaks-dir` keeps the combined error and also rejects before `process_excel()`.
+- Targeted pytest for `tests/cli/test_cli.py`.
+
+### ADR verdict
+
+- `not-needed`
+- rationale: this is a corrective follow-up that aligns implementation with the already-recorded `ADR-0008` policy rather than creating a new architectural decision.
+
+## 2026-03-20 issue #107 review follow-up: wording and help-text clarity
+
+### Goal
+
+- Resolve the PR review wording nits in tracked documentation.
+- Make the extraction CLI help text for `--auto-page-breaks-dir` match the runtime contract already documented elsewhere.
+
+### Public contract
+
+- The help text for `--auto-page-breaks-dir` states that it writes one file per auto page-break area, follows `--format`, and requires `--mode standard` or `--mode verbose` with Excel COM.
+- This follow-up does not change runtime behavior; it only tightens wording and help-text clarity.
+
+### Permanent destinations
+
+- No new permanent destination is required.
+- The durable wording lives in `src/exstruct/cli/main.py`, `dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md`, and the existing issue `#107` task notes.
+
+### Constraints
+
+- Keep the change limited to wording/help-text clarity; do not change runtime validation or expand scope beyond the reviewed lines.
+
+### Verification plan
+
+- `tests/cli/test_cli.py`
+  - Help output still includes `--auto-page-breaks-dir`.
+  - Help output includes the clarified runtime-contract wording.
+- `uv run pytest tests/cli/test_cli.py -q`
+
+### ADR verdict
+
+- `not-needed`
+- rationale: this is a wording-only follow-up under the existing `ADR-0008` decision.
diff --git a/tasks/todo.md b/tasks/todo.md
index a1fb48d..32ed7d7 100644
--- a/tasks/todo.md
+++ b/tasks/todo.md
@@ -26,3 +26,95 @@
   - `rg -n "0\.7\.0|v0\.7\.0" pyproject.toml uv.lock CHANGELOG.md mkdocs.yml docs/release-notes/v0.7.0.md`
   - `rg -n "^## " tasks/feature_spec.md tasks/todo.md`
   - `git diff --check -- CHANGELOG.md docs/release-notes/v0.7.0.md mkdocs.yml pyproject.toml uv.lock tasks/feature_spec.md tasks/todo.md dev-docs/architecture/overview.md`
+
+## 2026-03-20 issue #107 extraction CLI startup optimization
+
+### Planning
+
+- [x] Confirm issue `#107` details with `gh issue view 107`.
+- [x] Read current extraction CLI code, related docs/specs, and relevant tests.
+- [x] Classify ADR need for the public CLI contract change.
+- [x] Add the issue `#107` working spec to `tasks/feature_spec.md`.
+- [x] Add or update the ADR for extraction CLI runtime capability validation.
+- [x] Refactor extraction CLI parser construction so it never probes COM availability.
+- [x] Always register `--auto-page-breaks-dir` in extraction CLI help.
+- [x] Add runtime validation for `--auto-page-breaks-dir` covering `light` mode and unavailable COM on `standard` / `verbose`.
+- [x] Keep existing `libreoffice` rejection and combined-error precedence intact.
+- [x] Update extraction CLI tests for no-probe help and runtime validation.
+- [x] Update current user docs and internal specs for the new CLI contract.
+- [x] Run targeted pytest for extraction CLI coverage.
+- [x] Run `uv run task build-docs`.
+- [x] Run `uv run task precommit-run`.
+- [x] Review task/spec retention and record permanent destinations in the Review section.
+
+### Review
+
+- Extraction CLI parser construction is now side-effect free: `build_parser()` always registers `--auto-page-breaks-dir`, and COM probing happens only when that flag is requested at runtime from a supported mode.
+- `mode="light"` now fails explicitly for `--auto-page-breaks-dir`, while `mode="libreoffice"` keeps the existing core validation and combined-error precedence.
+- Permanent destinations:
+  - `dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md` records the policy change and why parser-time probing is forbidden.
+  - `docs/cli.md`, `README.md`, and `README.ja.md` now describe the always-visible flag and execution-time validation contract.
+  - `dev-docs/specs/excel-extraction.md` now records the internal guarantee that the extraction CLI validates auto page-break export at runtime instead of parser construction.
+- ADR checks:
+  - `adr-linter`: no high/medium/low findings for `ADR-0008`.
+  - `adr-reviewer`: `ready`, no findings.
+  - `adr-reconciler`: no policy drift, no stale references, two low-evidence findings addressed by adding `verbose` and `main(["--help"])` regression tests.
+  - `adr-indexer`: index artifacts were synchronized manually from the ADR source text (`README.md`, `index.yaml`, `decision-map.md`).
+- Verification:
+  - `gh issue view 107 --json number,title,body,labels,assignees,state,url`
+  - `uv run pytest tests/cli/test_cli.py tests/cli/test_edit_cli.py -q`
+  - `uv run task build-docs`
+  - `uv run task precommit-run`
+  - `git diff --check`
+
+## 2026-03-20 issue #107 review follow-up: libreoffice auto page-break fast-fail
+
+### Planning
+
+- [x] Re-read the CLI review comment and compare it with `src/exstruct/cli/main.py` and the shared LibreOffice validator.
+- [x] Update `tasks/feature_spec.md` with the follow-up contract and verification scope.
+- [x] Make the CLI reject `--mode libreoffice --auto-page-breaks-dir` before `process_excel()`.
+- [x] Preserve the existing combined LibreOffice error precedence when rendering flags are also present.
+- [x] Add regression tests that prove the CLI rejects these requests before `process_excel()` runs.
+- [x] Run targeted pytest for `tests/cli/test_cli.py`.
+- [x] Update this Review section with the final validation result and retention decision.
+
+### Review
+
+- The review finding was valid: `_validate_auto_page_breaks_request()` treated `mode="light"` as a CLI-side fast-fail but let `mode="libreoffice"` fall through to the engine layer, which made responsibility and failure timing inconsistent.
+- `src/exstruct/cli/main.py` now reuses `validate_libreoffice_process_request(...)` for `--auto-page-breaks-dir` in `mode="libreoffice"`, so the CLI rejects invalid requests before `process_excel()` while preserving the existing single-error and combined-error message precedence.
+- `tests/cli/test_cli.py` now proves both `libreoffice + --auto-page-breaks-dir` and `libreoffice + --pdf + --auto-page-breaks-dir` fail before `process_excel()` runs, and that these paths do not probe COM availability.
+- Retention decision:
+  - No new permanent document was needed. This follow-up only brought the implementation back into alignment with the policy already recorded in `ADR-0008`, `docs/cli.md`, `README.md`, `README.ja.md`, and `dev-docs/specs/excel-extraction.md`.
+  - The temporary working notes for this follow-up can stay limited to this section in `tasks/feature_spec.md` and `tasks/todo.md`.
+- Verification:
+  - `uv run pytest tests/cli/test_cli.py -q`
+  - `uv run task precommit-run`
+  - `git diff --check`
+
+## 2026-03-20 issue #107 review follow-up: wording and help-text clarity
+
+### Planning
+
+- [x] Retrieve the PR review comments with `gh` and classify which findings are substantive.
+- [x] Confirm the wording nits in `tasks/todo.md` and `dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md`.
+- [x] Clarify the `--auto-page-breaks-dir` help text in `src/exstruct/cli/main.py` so it matches the runtime contract.
+- [x] Update CLI help tests for the clarified wording.
+- [x] Run targeted pytest for `tests/cli/test_cli.py`.
+- [x] Run `uv run task precommit-run`.
+- [x] Record the review outcome and retention decision here.
+
+### Review
+
+- The explicit PR review findings were valid but minor: `tasks/todo.md` and `dev-docs/adr/ADR-0008-extraction-cli-runtime-capability-validation.md` each had a hyphenation nit (`low-evidence`, `side-effect-free`).
+- A separate suppressed Copilot note about `--auto-page-breaks-dir` help text was also substantively valid: the old string mentioned only LibreOffice rejection and omitted that output files follow `--format`, while the actual runtime contract also rejects `light` and requires `standard`/`verbose` with Excel COM.
+- `src/exstruct/cli/main.py` now states the fuller contract in the argument help text, and `tests/cli/test_cli.py` now checks for the clarified help wording without depending on exact `argparse` line wrapping.
+- Retention decision:
+  - No new ADR or spec migration was needed. The durable contract remains in `ADR-0008`, `docs/cli.md`, and the README files; this follow-up only aligns wording and help text with that existing policy.
+  - The temporary working record can stay limited to this section in `tasks/feature_spec.md` and `tasks/todo.md`.
+- Verification:
+  - `gh pr view 111 --json number,title,reviewDecision,reviews,comments,files,url`
+  - `gh api repos/harumiWeb/exstruct/pulls/111/comments`
+  - `uv run pytest tests/cli/test_cli.py -q`
+  - `uv run task precommit-run`
+  - `git diff --check`
diff --git a/tests/cli/test_cli.py b/tests/cli/test_cli.py
index d35eb1d..786a1e6 100644
--- a/tests/cli/test_cli.py
+++ b/tests/cli/test_cli.py
@@ -372,12 +372,17 @@ def test_cli_libreoffice_rejects_auto_page_breaks_dir(
 ) -> None:
     """Verify that the CLI rejects auto page-break export in LibreOffice mode."""
 
+    def _raise_process_excel(*_args: object, **_kwargs: object) -> None:
+        raise AssertionError("process_excel should not run for CLI-side rejection")
+
+    def _raise_com_probe() -> ComAvailability:
+        raise AssertionError("LibreOffice validation should not probe COM")
+
+    monkeypatch.setattr("exstruct.cli.main.process_excel", _raise_process_excel)
+    monkeypatch.setattr("exstruct.cli.main.get_com_availability", _raise_com_probe)
+
     xlsx = _prepare_sample_excel(tmp_path)
     auto_dir = tmp_path / "auto"
-    monkeypatch.setattr(
-        "exstruct.cli.main.get_com_availability",
-        lambda: ComAvailability(available=True, reason=None),
-    )
 
     result = _run_cli(
         [
@@ -399,12 +404,17 @@ def test_cli_libreoffice_rejects_rendering_and_auto_page_breaks(
 ) -> None:
     """Verify that the CLI LibreOffice rejects rendering and auto page breaks."""
 
+    def _raise_process_excel(*_args: object, **_kwargs: object) -> None:
+        raise AssertionError("process_excel should not run for CLI-side rejection")
+
+    def _raise_com_probe() -> ComAvailability:
+        raise AssertionError("LibreOffice validation should not probe COM")
+
+    monkeypatch.setattr("exstruct.cli.main.process_excel", _raise_process_excel)
+    monkeypatch.setattr("exstruct.cli.main.get_com_availability", _raise_com_probe)
+
     xlsx = _prepare_sample_excel(tmp_path)
     auto_dir = tmp_path / "auto"
-    monkeypatch.setattr(
-        "exstruct.cli.main.get_com_availability",
-        lambda: ComAvailability(available=True, reason=None),
-    )
 
     result = _run_cli(
         [
@@ -425,20 +435,109 @@ def test_cli_libreoffice_rejects_rendering_and_auto_page_breaks(
     )
 
 
-def test_cli_parser_includes_auto_page_breaks_option() -> None:
-    """Ensure the auto page-breaks option is registered when COM is available."""
-    availability = ComAvailability(available=True, reason=None)
-    parser = build_parser(availability=availability)
+def test_cli_parser_always_includes_auto_page_breaks_option() -> None:
+    """Ensure the auto page-breaks option is always registered with clear help."""
+    parser = build_parser()
     help_text = parser.format_help()
     assert "--auto-page-breaks-dir" in help_text
+    assert "format follows --format" in help_text
+    assert "requires --mode" in help_text
+    assert "standard or --mode verbose with Excel COM" in help_text
+
 
+def test_cli_parser_help_does_not_probe_com_availability(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Ensure help generation never triggers COM availability probing."""
+
+    def _raise() -> ComAvailability:
+        raise AssertionError("get_com_availability should not run during help setup")
 
-def test_cli_parser_excludes_auto_page_breaks_option() -> None:
-    """Ensure the auto page-breaks option is hidden when COM is unavailable."""
-    availability = ComAvailability(available=False, reason="disabled")
-    parser = build_parser(availability=availability)
+    monkeypatch.setattr("exstruct.cli.main.get_com_availability", _raise)
+
+    parser = build_parser()
     help_text = parser.format_help()
-    assert "--auto-page-breaks-dir" not in help_text
+    assert "--auto-page-breaks-dir" in help_text
+
+
+def test_cli_main_help_does_not_probe_com_availability(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Ensure the main help entrypoint never triggers COM availability probing."""
+
+    def _raise() -> ComAvailability:
+        raise AssertionError("get_com_availability should not run during --help")
+
+    monkeypatch.setattr("exstruct.cli.main.get_com_availability", _raise)
+
+    stdout_buffer = io.StringIO()
+    with redirect_stdout(stdout_buffer), pytest.raises(SystemExit) as exc_info:
+        cli_main(["--help"])
+
+    assert exc_info.value.code == 0
+    assert "--auto-page-breaks-dir" in stdout_buffer.getvalue()
+
+
+def test_cli_auto_page_breaks_rejects_light_mode(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    """Verify that light mode rejects auto page-break export explicitly."""
+
+    def _raise() -> ComAvailability:
+        raise AssertionError("light mode validation should not probe COM")
+
+    monkeypatch.setattr("exstruct.cli.main.get_com_availability", _raise)
+
+    xlsx = _prepare_sample_excel(tmp_path)
+    auto_dir = tmp_path / "auto"
+    result = _run_cli(
+        [
+            str(xlsx),
+            "--mode",
+            "light",
+            "--auto-page-breaks-dir",
+            str(auto_dir),
+        ]
+    )
+
+    assert result.returncode == 1
+    combined_output = _stdout_text(result) + _stderr_text(result)
+    assert (
+        "--auto-page-breaks-dir requires --mode standard or --mode verbose "
+        "with Excel COM."
+    ) in combined_output
+
+
+@pytest.mark.parametrize("mode", ["standard", "verbose"])  # type: ignore[misc]
+def test_cli_auto_page_breaks_requires_com_at_runtime(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch, mode: str
+) -> None:
+    """Verify that auto page-break export fails clearly when COM is unavailable."""
+
+    xlsx = _prepare_sample_excel(tmp_path)
+    auto_dir = tmp_path / "auto"
+    monkeypatch.setattr(
+        "exstruct.cli.main.get_com_availability",
+        lambda: ComAvailability(available=False, reason="Non-Windows platform."),
+    )
+
+    result = _run_cli(
+        [
+            str(xlsx),
+            "--mode",
+            mode,
+            "--auto-page-breaks-dir",
+            str(auto_dir),
+        ]
+    )
+
+    assert result.returncode == 1
+    combined_output = _stdout_text(result) + _stderr_text(result)
+    assert (
+        "--auto-page-breaks-dir requires --mode standard or --mode verbose "
+        "with Excel COM."
+    ) in combined_output
+    assert "Reason: Non-Windows platform." in combined_output
 
 
 def test_CLI_stdout_is_utf8_with_cp932_env(tmp_path: Path) -> None:
diff --git a/tests/cli/test_edit_cli.py b/tests/cli/test_edit_cli.py
index 078b4f6..1fed5fc 100644
--- a/tests/cli/test_edit_cli.py
+++ b/tests/cli/test_edit_cli.py
@@ -9,7 +9,6 @@
 from pydantic import BaseModel
 import pytest
 
-from exstruct.cli.availability import ComAvailability
 import exstruct.cli.edit as edit_cli_module
 from exstruct.cli.edit import is_edit_subcommand
 import exstruct.cli.main as cli_main_module
@@ -429,9 +428,7 @@ def _raise_os_error(_request: object) -> object:
 
 
 def test_extraction_help_mentions_editing_commands() -> None:
-    help_text = build_parser(
-        availability=ComAvailability(available=False, reason="test")
-    ).format_help()
+    help_text = build_parser().format_help()
 
     assert "Editing commands:" in help_text
     assert "exstruct patch --input book.xlsx --ops ops.json" in help_text