agentmods.dev

arcbox copilot-instructions.md

Project instructions for ArcBox, a Rust-based tool that runs containers and virtual machines on macOS and Linux.

In plain words
What is it for?
Use them when changing ArcBox's command-line tool, runtime, networking, virtual-machine layers, guest components, or Docker-compatible interface.
Why use it?
They give a coding agent the project's architecture, platform differences, communication methods, and required development practices.

Instructions file for GitHub Copilot

996 4d ago A scan 1,576 tokens original Apache-2.0
View the source file arcboxlabs/arcbox
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 instructions/arcboxlabs/arcbox/copilot-instructions
Clone the repo
git clone --depth 1 https://github.com/arcboxlabs/arcbox

Made for: GitHub Copilot.

Per session 1,576 This file is loaded in full into every session.
When invoked 1,576 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 $0.01576 $0.01576
Opus 5 $0.00788 $0.00788
Sonnet 5 $0.00315 $0.00315
Haiku 4.5 $0.00158 $0.00158

Measured 2d ago against content hash e26f712aad53, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

arcbox copilot-instructions.md 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.

.github/copilot-instructions.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ArcBox AI Agent Instructions

ArcBox is a pure-Rust, high-performance container and VM runtime targeting macOS (primary) and Linux, aiming to surpass OrbStack's performance metrics.

Architecture Overview

Three-tier structure:

  • Core layer (common/, virt/, rpc/, runtime/, app/): MIT/Apache-2.0 licensed foundation
  • Pro layer (pro/): BSL-1.1 licensed enhanced features (smart caching, snapshots, advanced networking)
  • Guest components (guest/arcbox-agent): Runs inside VMs, cross-compiled to Linux ARM64/x86_64

Key layers (bottom-up):

abctl (CLI)
    ↓ gRPC over Unix socket
arcbox-daemon
    ↓
arcbox-core (Runtime)
    ↓
arcbox-fs / arcbox-net / arcbox-container
    ↓
arcbox-virtio (VirtIO devices) -> arcbox-vmm (VM monitor)
    ↓
arcbox-hypervisor / arcbox-vz (platform virtualization)

Communication: Host <-> Guest via vsock and ArcBox protocol crates (arcbox-protocol, arcbox-grpc, arcbox-transport). Docker API compatibility is provided by arcbox-docker (Axum REST server + guest dockerd proxy).

Critical Platform Differences

macOS specifics:

  • Uses Apple's Virtualization.framework (not KVM)
  • All VM-related binaries require code signing: 
    codesign --entitlements bundle/arcbox.entitlements --force -s - arcbox-daemon
    Required for: examples, tests touching hypervisor. See arcbox.entitlements
  • mode_t types (e.g., libc::S_IFMT) are u16 (Linux: u32). Use u32::from() for cross-platform compatibility
  • No fallocate - use ftruncate instead
  • xattr APIs have different argument order than Linux

Development Workflows

Building:

cargo build -p <crate>           # Dev build specific crate
cargo build --release            # Full optimized build

Testing:

cargo test -p <crate>
cargo test -- --nocapture        # Show test output
cargo test -- --ignored          # Run privileged tests (require VM access)

Guest agent cross-compilation:

Read the full file on GitHub · 173 lines

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 · 173 lines · 1,576 tokens per session scan A e26f712aad53

Subscribe to this mod's changes

arcbox copilot-instructions.md is an instructions file published in the GitHub repository arcboxlabs/arcbox (996 stars, last pushed 4d ago), licensed Apache-2.0. It adds 1,576 tokens to every session, about $0.0079 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.

DevOps and cloudLanguagesPlanningai-agentscomputer-usecontainersdockerfirecrackermicrovm
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