container-use

Rules for using isolated development environments called containers, which package code and tools separately from the main system. All file, code, and shell work must happen inside those environments.

In plain words
What is it for?
Use it when editing files, running commands, or working with code in a container; view results with container-use log and retrieve them with container-use checkout.
Why use it?
It keeps development changes isolated and makes the resulting work accessible through the container-use workflow.

Cursor rule for Cursor

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 rules/usrrname/cursorrules/container-use
Clone the repo
git clone --depth 1 https://github.com/usrrname/cursorrules

Made for: Cursor.

Per session 130 This file is loaded in full into every session.
When invoked 130 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00130 $0.00130
Opus 5 $0.00065 $0.00065
Sonnet 5 $0.00026 $0.00026
Haiku 4.5 $0.00013 $0.00013

Measured yesterday against content hash d23d49721a4d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

container-use 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 yesterday.

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.

Origin

This is a copy

100% identical to cursor — 1 line differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.cursor/rules/mcp/container-use.mdc · 11 lines

What it actually says

ALWAYS use ONLY Environments for ANY and ALL file, code, or shell operations—NO EXCEPTIONS—even for simple or generic requests.

DO NOT install or use the git cli with the environment_run_cmd tool. All environment tools will handle git operations for you. Changing ".git" yourself will compromise the integrity of your environment.

You MUST inform the user how to view your work using container-use log <env_id> and container-use checkout <env_id>. Failure to do this will make your work inaccessible to others.

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. yesterday First seen · 11 lines · 130 tokens per session scan A d23d49721a4d

Subscribe to this mod's changes

container-use is a cursor rule published in the GitHub repository usrrname/cursorrules (10 stars, last pushed 4mo ago), licensed ISC. It adds 130 tokens to every session, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to cursor, differing in 1 line, and is treated as a copy.