FD linux-sysadmin
Linux 系统管理专家 — 覆盖用户权限、SSH、存储、网络、systemd、防火墙、 监控日志、备份恢复、证书TLS、Ansible、容器、IaC 十二大模块。 提供配置→验证→加固→监控→备份→自动化→故障排查→回滚完整闭环。 触发关键词:useradd/sudo/sshd_config/chmod/SELinux/fdisk/LVM/fstab/RAID/nmcli/iptables/firewalld/systemd/Prometheus/logrotate/rsync/borgbackup/certbot/OpenSSL/Ansible/Docker/Terraform。
As a process D 46/100 · Unfinished process — weak spots: result and completion, when it triggers, inputs and preconditions
What is at stake
The skill contains fragments that, in the wrong hands, cost money or data. Below: what the installer risks and what the author should do.
The skill contains commands that delete files, rewrite disks or execute code fetched from the network. The agent may run them without asking if it believes the instructions require it.
Replace destructive commands with safe equivalents that ask for confirmation, scope them to one folder, and stop piping curl into a shell: pin a version and a checksum.
Below is the worst case for this category. The finding here is medium: the guard saw a sign, not a proof.
The instructions or scripts send data out: environment variables, keys, file contents, chat history. You may never notice, because the agent performs the upload as "part of the task".
If the upload is not needed for the task, remove it: catalogs flag such skills and delist them. If it is needed, name the destination explicitly, say what leaves the machine, and give the user a switch.
How to improve
- Address the high-severity findings: each costs 18 safety points. If one is a false positive, add the rule id to guard.allow in spec.yaml.
- Say in the description WHEN to use the skill ("use when…", example requests): that is the agent's main cue.
- Your own cases (evals/evals.json, 4–6 real requests with expected answers): the full check would then run those instead of a model-drafted suite.
- A spec.yaml with trigger phrases and assertions — a behaviour contract for CI; `skilltest init` writes a template.
Guard findings · 40
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high Dangerous commands
cmd-persistencescripts/backup_manager.sh:187Persistence mechanism (cron / launchd / scheduled task / autorun registry)cron_backup=$(crontab -l 2>/dev/null | grep -i "backup\|borg\|restic\|rsync" | grep -v "^#")
Medium and low: 39
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medium Dangerous commands
cmd-disable-securityreferences/firewall_security.md:86Disables a security control (Defender, Gatekeeper, SIP, firewall, execution policy) (documentation of a security skill)iptables -F
security skill -
medium Dangerous commands
cmd-disable-securityreferences/firewall_security.md:269Disables a security control (Defender, Gatekeeper, SIP, firewall, execution policy) (documentation of a security skill)ufw disable
security skill -
medium Dangerous commands
cmd-persistencereferences/firewall_security.md:352Persistence mechanism (cron / launchd / scheduled task / autorun registry) (documentation of a security skill)chmod 600 /etc/crontab
security skill -
medium Exfiltration
exfil-read-secret-filesreferences/ssh_management.md:63Reads credential / secret files (documentation of a security skill)ssh-copy-id -i ~/.ssh/id_e…pub user@remote-host
security skill -
medium Dangerous commands
cmd-destructive-fs-scopedreferences/storage_filesystem.md:93Destructive command on a partition / current directory (normal in admin docs; verify the target) (documentation of a security skill)mkfs.ext4 /dev/vg_data/lv_data
security skill -
medium Dangerous commands
cmd-destructive-fs-scopedreferences/storage_filesystem.md:94Destructive command on a partition / current directory (normal in admin docs; verify the target) (documentation of a security skill)mkfs.xfs /dev/vg_data/lv_logs
security skill -
medium Dangerous commands
cmd-destructive-fs-scopedreferences/storage_filesystem.md:188Destructive command on a partition / current directory (normal in admin docs; verify the target) (documentation of a security skill)mkfs.ext4 /dev/sdb1
security skill -
medium Dangerous commands
cmd-destructive-fs-scopedreferences/storage_filesystem.md:192Destructive command on a partition / current directory (normal in admin docs; verify the target) (documentation of a security skill)mkfs.xfs /dev/sdb1
security skill -
medium Dangerous commands
cmd-destructive-fs-scopedreferences/storage_filesystem.md:196Destructive command on a partition / current directory (normal in admin docs; verify the target) (documentation of a security skill)mkfs.btrfs /dev/sdb1
security skill -
medium Dangerous commands
cmd-disable-securityreferences/user_permission.md:339Disables a security control (Defender, Gatekeeper, SIP, firewall, execution policy) (documentation of a security skill)setenforce 0 # 切换到 Permissive(不重启)
security skill -
low Dangerous commands
cmd-background-processreferences/backup_recovery.md:150Starts a background / autostarted process (documentation of a security skill)systemctl enable --now rsync
security skill -
low Dangerous commands
cmd-pipe-to-shellreferences/container_management.md:30Downloads and executes remote code from an unrecognised host (pipe to shell) (documentation of a security skill; the skill's own vendor host)curl -fsSL https://get.docker.com | bash
security skillvendor-host -
low Dangerous commands
cmd-background-processreferences/container_management.md:40Starts a background / autostarted process (documentation of a security skill)systemctl enable --now docker
security skill -
low Dangerous commands
cmd-background-processreferences/firewall_security.md:175Starts a background / autostarted process (documentation of a security skill)systemctl enable --now nftables
security skill -
low Dangerous commands
cmd-background-processreferences/firewall_security.md:451Starts a background / autostarted process (documentation of a security skill)systemctl enable --now fail2ban
security skill -
low Dangerous commands
cmd-shell-rcreferences/infrastructure_as_code.md:84Writes to a shell startup file (documentation of a security skill)echo 'export PATH="$HOME/.tfenv/bin:$PATH"' >> ~/.bashrc
security skill -
low Dangerous commands
cmd-background-processreferences/infrastructure_as_code.md:796Starts a background / autostarted process (documentation of a security skill)- systemctl enable --now docker
security skill -
low Dangerous commands
cmd-background-processreferences/infrastructure_as_code.md:797Starts a background / autostarted process (documentation of a security skill)- systemctl enable --now nginx
security skill -
low Dangerous commands
cmd-background-processreferences/infrastructure_as_code.md:817Starts a background / autostarted process (documentation of a security skill)systemctl enable --now node_exporter
security skill -
low Dangerous commands
cmd-background-processreferences/infrastructure_as_code.md:900Starts a background / autostarted process (documentation of a security skill)systemctl enable --now nginx
security skill -
low Dangerous commands
cmd-background-processreferences/monitoring_logging.md:53Starts a background / autostarted process (documentation of a security skill)systemctl enable --now sysstat
security skill -
low Dangerous commands
cmd-background-processreferences/monitoring_logging.md:138Starts a background / autostarted process (documentation of a security skill)systemctl enable --now node_exporter
security skill -
low Dangerous commands
cmd-background-processreferences/monitoring_logging.md:205Starts a background / autostarted process (documentation of a security skill)systemctl enable --now prometheus
security skill -
low Dangerous commands
cmd-background-processreferences/monitoring_logging.md:270Starts a background / autostarted process (documentation of a security skill)systemctl enable --now grafana-server
security skill -
low Dangerous commands
cmd-background-processreferences/monitoring_logging.md:491Starts a background / autostarted process (documentation of a security skill)systemctl enable --now elasticsearch
security skill -
low Dangerous commands
cmd-background-processreferences/quick_reference.md:64Starts a background / autostarted process (documentation table row; documentation of a security skill)| 开机自启 | `systemctl enable svc` | references/systemd_services.md |
tablesecurity skill -
low Dangerous commands
cmd-background-processreferences/quick_reference.md:67Starts a background / autostarted process (documentation table row; documentation of a security skill)| 定时任务 | `systemctl enable --now myapp.timer` | references/systemd_services.md |
tablesecurity skill -
low Dangerous commands
cmd-background-processreferences/quick_reference.md:238Starts a background / autostarted process (documentation of a security skill)systemctl enable --now myapp
security skill -
low Dangerous commands
cmd-background-processreferences/quick_reference.md:300Starts a background / autostarted process (documentation of a security skill)systemctl daemon-reload && systemctl enable --now node_exporter
security skill -
low Dangerous commands
cmd-background-processreferences/systemd_services.md:27Starts a background / autostarted process (documentation of a security skill)systemctl enable nginx
security skill -
low Dangerous commands
cmd-background-processreferences/systemd_services.md:29Starts a background / autostarted process (documentation of a security skill)systemctl enable --now nginx # 启用并立即启动
security skill -
low Dangerous commands
cmd-background-processreferences/systemd_services.md:219Starts a background / autostarted process (documentation of a security skill)systemctl enable --now backup.timer
security skill -
low Dangerous commands
cmd-cron-mentionscripts/backup_manager.sh:187Mentions editing / listing crontabcron_backup=$(crontab -l 2>/dev/null | grep -i "backup\|borg\|restic\|rsync" | grep -v "^#")
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low Dangerous commands
cmd-cron-mentionscripts/cert_check.sh:186Mentions editing / listing crontabelif crontab -l 2>/dev/null | grep -q certbot; then
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low Dangerous commands
cmd-cron-mentionscripts/system_audit.sh:186Mentions editing / listing crontab (documentation of a security skill)crontab -l 2>/dev/null || echo " 无 root crontab"
security skill -
low Dangerous commands
cmd-cron-mentionSKILL.md:178Mentions editing / listing crontab (documentation of a security skill)systemctl list-timers --all && crontab -l 2>/dev/null
security skill -
low Dangerous commands
cmd-privilegeSKILL.md:275Privilege escalation / world-writable permissions (negated — the text forbids it)- 不要用 `chmod 777` 解决权限问题
negated
A further 2 matches are quotations in this security skill's documentation and are not counted as findings.
Files scanned: 22. Evidence is masked. Grey chips explain why severity was lowered.
Against the Agent Skills spec
- warning
description-no-whendescription does not say WHEN to use the skill (no "use when")
Process rating: all ten parameters 46/100
- 0Result and completion. Does not say what the result is
- 0Inputs and preconditions. Does not say what the process needs to start
- 0Failures and branches. Linear process with no failure handling
- 0Progress reporting. Says nothing while it works
- 20When it triggers. No condition that starts the skill
- 60Tools and files. Uses tools (node) that frontmatter does not declare
- 100Steps. 32 steps
- 100Consistency. Name and required fields are in place
- 100Execution cost. Instruction body is 2753 tokens
- 100Running it twice. No mutating operations
- low 14 top-level sections: this looks like several domains in one skill
Everything here is measured from the skill text rather than judged by a model, so the numbers are checkable. A parameter weighs more when it is a more common reason for the process to stall.
Quality signals
- +5Description has no quoted example phrases that should trigger the skill
- +4Description does not say when NOT to use the skill (false activations)
- +3Output format is not stated: the model decides each time
- +1No license
- +2Single-language instructions
- +3Description length 295: enough signal without eating the budget
- +4Structure: 18 headings
- +3Step-by-step instructions: 32 items
- +4Has examples (5 code blocks)
- +4Reference files are cited in the instructions (13 of 13)
- +3All 7 scripts are documented
Quality base 70; lint remarks subtract, signals add up to 100. Result: 79.