cursor

Safety rules for containerized development with Cursor. They require all file, code, and shell work to run inside managed environments.

In plain words
What is it for?
Use them when creating or editing code in a container, and to tell users how to view the environment log or check out the resulting work.
Why use it?
They keep changes isolated and prevent direct operations from damaging the local project or its Git data.

Cursor rule

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/dagger/container-use/cursor
Clone the repo
git clone --depth 1 https://github.com/dagger/container-use
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 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 $0.00130 $0.00130
Opus 5 $0.00065 $0.00065
Sonnet 5 $0.00026 $0.00026
Haiku 4.5 $0.00013 $0.00013

Measured 2d ago against content hash 1bc07942263f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cursor 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 2d 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.

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

Copies of this mod

2 near-identical copies found in the catalogue:

rules/cursor.mdc · 12 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. 2d ago First seen · 12 lines · 130 tokens per session scan A 1bc07942263f

Subscribe to this mod's changes

cursor is a cursor rule published in the GitHub repository dagger/container-use (4,027 stars, last pushed 15d ago), licensed Apache-2.0. 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. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.