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Companion to 08. Tests whether a skill's own frontmatter hook can block its own load (it cannot — frontmatter hooks register AFTER load).
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Mac Cowork で、plugin-level SessionStart hook(host 側)から $CLAUDE_PLUGIN_DATA に書いた値が「別の chat session を跨いで」残るかを検証する probe。書き込み＆読み戻しは hook(persist.sh)側で行い、その結果は SessionStart の stdout として context に出る。この skill body は対比用に「VM Bash 側から DATA が見えるか／hook が書いたファイルを読めるか」を確認する。
Surfaces UPE_PROBE_* marker lines to test whether the plugin-level UserPromptExpansion hook fires on Cowork. Invoking this skill via slash is itself the trigger; compares against UserPromptSubmit and SessionStart controls.
Triggers the plugin-level PreToolUse hooks by running a sentinel bash command, to test (via session export) whether Cowork runs PreToolUse hook commands through cmd.exe or a POSIX shell, and whether the inline block pattern actually blocks the bash tool.
Surfaces the EXEC_* marker lines emitted by the plugin-level SessionStart hooks, which run hook commands in EXEC FORM (args present). Used to test whether exec form resolves ${CLAUDE_PLUGIN_ROOT} to a real path and exports it as an env var on Cowork, where shell form (§2.1/§2.2) failed both.
Shows what skill-body CLAUDE_PLUGIN_ROOT and friends substitute to on Mac Cowork, whether the VM Bash tool can use that path, and whether the Read tool can read a bundled file at that host path.
Proves whether a skill frontmatter PreToolUse Bash hook fires on Cowork by emitting only a block decision (no echo). A marked bash should be blocked even though no frontmatter stdout surfaces.
| name | 08b-self-block-attempt |
| description | Companion to 08. Tests whether a skill's own frontmatter hook can block its own load (it cannot — frontmatter hooks register AFTER load). |
| user-invocable | true |
| hooks | {"PreToolUse":[{"matcher":"Skill","hooks":[{"type":"command","command":"ver=\"${VERIFIER_VERSION_DIR:-v-unknown}\"; sid=\"${CLAUDE_SESSION_ID:-no-sid}\"; out_dir=\"$CLAUDE_PROJECT_DIR/findings/$ver/$sid\"; mkdir -p \"$out_dir\"; printf \"[08b-FM %s] tag=block-emitted reason=\\\"blocked by 08b-self-block-attempt\\\"\\n\" \"$(date -Iseconds)\" >> \"$out_dir/probe.log\"; printf '{\"decision\":\"block\",\"reason\":\"blocked by 08b-self-block-attempt (testing whether self-blocking works)\"}\\n'"}]}]} |
このスキルは自分自身（PreToolUse:Skill）を block しようとしますが、frontmatter hook は load 後にしか登録されないため、自身の最初の起動は block されません。
proj="${CLAUDE_PROJECT_DIR:-$PWD}"
ver="${VERIFIER_VERSION_DIR:-v-unknown}"
sid="${CLAUDE_SESSION_ID:-no-sid}"
out_dir="$proj/findings/$ver/$sid"
mkdir -p "$out_dir"
printf '[08b-BODY %s] tag=alive-check (this proves 08b loaded — frontmatter cannot block itself)\n' "$(date -Iseconds)" | tee -a "$out_dir/probe.log"
ユーザに「次のプロンプトで 08b-self-block-attempt skill をもう一度呼んでください と自然文で頼んでみてください」と依頼。
2 度目の呼び出しが block されることを確認（blocked by 08b-self-block-attempt が cli output に出る）。