sandboxd AGENTS.md

sandboxd AGENTS.md is an instructions file for Codex, OpenCode from tastyeffectco/sandboxd. It costs 2,187 tokens per session, scanned B, original, MIT.

Instructions for sandboxd, a service that uses Docker to create isolated Linux development containers with preview URLs for running dev servers.

In plain words
What is it for?
Use it to install sandboxd, create and manage development sandboxes, expose previews, keep workspaces persistent, and troubleshoot basic setup.
Why use it?
It explains the setup, operation, and removal steps in one place, so users do not need to work out how the container service fits together.

Instructions file for CodexOpenCode

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/tastyeffectco/sandboxd/agents-md
Clone the repo
git clone --depth 1 https://github.com/tastyeffectco/sandboxd

Made for: Codex, OpenCode.

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 sandboxd AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/tastyeffectco/sandboxd/agents-md.svg)](https://agentmods.dev/instructions/tastyeffectco/sandboxd/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/tastyeffectco/sandboxd/agents-md"><img src="https://agentmods.dev/badge/instructions/tastyeffectco/sandboxd/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 2,187 This file is loaded in full into every session.
When invoked 2,187 The same file — it is already loaded in full.
Security scan B 2 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 $0.02187 $0.02187
Opus 5 $0.01094 $0.01094
Sonnet 5 $0.00437 $0.00437
Haiku 4.5 $0.00219 $0.00219

Measured 3d ago against content hash 703cbef8add8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade B, and why

sandboxd AGENTS.md scanned grade B with 2 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 3d 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.

Sends data to an external URLmediumData exfiltration

A POST to an outside endpoint may be telemetry or may be exfiltration; either way the mod talks to somewhere, and you should know where.

curl -s -XPOST $API/v1/agents/anthropic/api-key -d '{"api_key":"sk-ant-..."}'

Makes network callslowCapability

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

curl -s http://127.0.0.1:9090/healthz # -> ok
AGENTS.md · 158 lines

How it starts

The opening of the file, as written. The whole thing — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.

AGENTS.md — operating sandboxd

A complete, self-contained runbook for an AI agent (or a human) to install, run, use, and remove sandboxd with no outside knowledge. Commands are copy-pasteable. Human-readable docs: README.md, ARCHITECTURE.md.

What this is

A single-host service that creates isolated Linux dev containers ("sandboxes"), each with an HTTP/HTTPS preview URL for a dev server running inside it. It runs entirely on Docker: a Go control plane (sandboxd) + Traefik, both in containers; each sandbox is a sibling container. Sandboxes stop when idle and wake on the next request. Workspaces persist on disk.

Prerequisites

  • Linux host with Docker Engine + the Compose plugin (docker compose).
  • Ability to run Docker (either your user is in the docker group, or you have sudo; the scripts auto-detect and use sudo if needed).
  • Assumes a standard Docker daemon. (If the daemon uses userns-remap, the shipped --userns=host defaults keep it working — see ARCHITECTURE.md.)

Install

git clone https://github.com/tastyeffectco/sandboxd.git
cd sandboxd
./install.sh

install.sh is idempotent. It: checks Docker, copies .env.example.env, builds the base image (sandboxd-base:0.3.0) and the control plane, creates the data dir, and runs docker compose up -d. The base-image build takes a few minutes the first time, then caches.

Configuration lives in .env (all keys documented in .env.example). The two you may change before installing:

  • HTTP_PORT (default 80) — set to e.g. 8088 if port 80 is taken; preview URLs then include it.
  • SANDBOXD_API_BIND (default 127.0.0.1:9090) — where the API is published.

Verify it's up:

curl -s http://127.0.0.1:9090/healthz   # -> ok
curl -s http://127.0.0.1:9090/readyz    # -> ready

Core API

Base URL = http://${SANDBOXD_API_BIND} (default http://127.0.0.1:9090). Auth is off by default (local). If you set SANDBOXD_API_AUTH_DISABLED=false

  • SANDBOXD_API_TOKENS=name:secret, add -H "Authorization: Bearer secret".

Read the full file on GitHub · 158 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. 3d ago First seen · 158 lines · 2,187 tokens per session scan B 703cbef8add8

Subscribe to this mod's changes

sandboxd AGENTS.md is an instructions file published in the GitHub repository tastyeffectco/sandboxd (925 stars, last pushed 5d ago), licensed MIT. It adds 2,187 tokens to every session, about $0.0109 per session on Opus 5. A static security scan graded it B with 2 findings (sends data to an external url, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.