isolate-cli

isolate-cli is a skill for Claude Code, Codex from sergeyklay/.agents. It costs 208 tokens per session (3,747 once invoked), scanned A, original, Apache-2.0.

A guide for running a third-party command-line tool as an isolated subprocess. It checks what configuration, private input, files, and state the tool can access and whether anything remains afterward.

In plain words
What is it for?
It helps confine agent CLIs, linters, package managers, formatters, and similar tools when they handle private prompts, diffs, credentials, customer data, or sandbox policies.
Why use it?
External command-line tools may read global settings, write outside the project, or log private content without showing this in their exit status. This makes those boundaries testable.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents); mentions Gemini CLI.

Good fit It helps confine agent CLIs, linters, package managers, formatters, and similar tools when they handle private prompts, diffs, credentials, customer data, or sandbox policies.

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Install with agentmods
npx agentmods add skills/sergeyklay/.agents/isolate-cli
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.

Any agent
npx skills add sergeyklay/.agents --skill isolate-cli
Clone the repo
git clone --depth 1 https://github.com/sergeyklay/.agents

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 isolate-cli

README.md
[![agentmods](https://agentmods.dev/badge/skills/sergeyklay/.agents/isolate-cli/github.svg)](https://agentmods.dev/skills/sergeyklay/.agents/isolate-cli)
Your own site
<a href="https://agentmods.dev/skills/sergeyklay/.agents/isolate-cli"><img src="https://agentmods.dev/badge/skills/sergeyklay/.agents/isolate-cli/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for isolate-cli

Your own site · 80×15
<a href="https://agentmods.dev/skills/sergeyklay/.agents/isolate-cli"><img src="https://agentmods.dev/badge/skills/sergeyklay/.agents/isolate-cli.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 208 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,747 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 70
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
How audits are shown
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 5.1 $0.00208 $0.03747
Opus 5 $0.00104 $0.01873
Sonnet 5 $0.00042 $0.00749
Haiku 4.5 $0.00021 $0.00375

Measured today against content hash a81e8f67ba67, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

isolate-cli scanned grade A with 0 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 today.

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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/isolate-cli/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Confine an External CLI

A CLI invoked as a subprocess is not a function call. It reads the operator's global configuration, writes per-run state under the home directory keyed to the directory it ran in, and treats a config file it cannot compile as advice rather than as an instruction. None of those three shows up in an exit code: the private content piped in lands in a plaintext log outside the repository, the host accumulates state nobody audits, and the confinement believed to be in force is absent.

This skill is the mechanics of running such a tool and being able to say afterwards what it read, what it wrote, and what it left behind. Whether the run's result is evidence is a separate question and belongs to prove-checks.

Trigger

  • A script or skill invokes a third-party CLI as a subprocess: an agent CLI, a linter with a cache, a package manager, a formatter, anything with a state store outside the working directory.
  • A second tool or provider branch is added to a script that already does this.
  • The tool is handed a policy, deny-list, allow-list or sandbox configuration.
  • The content piped in is private: an unmerged diff, a prompt, a credential, customer data.
  • A measurement or benchmark series will invoke the tool repeatedly and the runs have to be comparable to each other.

Not this skill: reading the tool's behavior to answer a general question, which is research-it, or deciding whether the green that came out counts as proof, which is prove-checks.

Procedure

1. Read the state roots out of the installed artifact

The copy on disk is the one that runs. Release notes, the project README and the upstream default branch each describe a different one, and two versions of the same CLI commonly sit side by side under different runtime or package managers. Resolve and record the version and the real path before reading anything: command -v tool, then readlink -f on the result, then the package manifest or lockfile that installed it. This is research-it's source-priority rule narrowed to a single copy on disk (OPTIONAL when the question widens past this run into how the tool behaves in general).

Read the full file on GitHub · 132 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. today Changed a81e8f67ba67
  2. 3d ago Changed · +4 lines 925b94e9ea10
  3. 5d ago First seen · 128 lines · 208 tokens per session scan A ca7e597f7a7b

Subscribe to this mod's changes

isolate-cli is a skill published in the GitHub repository sergeyklay/.agents (5 stars, last pushed today), licensed Apache-2.0. It adds 208 tokens to every session and 3,747 once invoked, about $0.0010 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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