OpenSandbox AGENTS.md

OpenSandbox AGENTS.md is an instructions file for Codex, OpenCode from opensandbox-group/OpenSandbox. It costs 1,693 tokens per session, scanned A, original, Apache-2.0.

Repository instructions that tell a coding agent how the OpenSandbox monorepo is organised and which guidance applies to each area. A monorepo is one repository containing several related projects.

In plain words
What is it for?
Finding the right code, documentation, tests, and instructions when working on OpenSandbox server code, SDKs, Kubernetes components, command-line tools, or other areas.
Why use it?
They reduce the risk of the agent working in the wrong part of the repository or missing rules for a specific directory.

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/opensandbox-group/opensandbox/agents-md
Clone the repo
git clone --depth 1 https://github.com/opensandbox-group/OpenSandbox

Made for: Codex, OpenCode.

Per session 1,693 This file is loaded in full into every session.
When invoked 1,693 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 $0.01693 $0.01693
Opus 5 $0.00847 $0.00847
Sonnet 5 $0.00339 $0.00339
Haiku 4.5 $0.00169 $0.00169

Measured 3d ago against content hash ef18bc5d12dc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

OpenSandbox AGENTS.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 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.

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.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenSandbox AGENTS

Use this file as the root router for the monorepo. Prefer the nearest AGENTS.md in the directory tree for task-specific instructions.

Repository Map

  • server/: FastAPI lifecycle control plane, Docker/Kubernetes runtime integration, snapshot metadata, and server tests
  • components/execd/: in-sandbox execution daemon
  • components/egress/: per-sandbox network egress policy sidecar
  • components/ingress/: ingress gateway and endpoint routing
  • components/internal/: shared Go helpers used by runtime components
  • sdks/: sandbox, code-interpreter, and MCP SDKs plus generated clients
  • specs/: public OpenAPI contracts and examples
  • kubernetes/: Kubernetes operator, CRDs, task-executor, Helm charts, and Kind e2e tests
  • cli/: osb command-line client and bundled CLI skills
  • tests/: cross-language end-to-end SDK tests
  • docs/, examples/, sandboxes/, oseps/: documentation, samples, images/environments, and proposals

Routing

  • For server/**, or lifecycle server behavior, sandbox creation flow, or user-visible server config, read server/AGENTS.md.
  • For sdks/**, or SDK generation, handwritten adapters, or cross-language SDK alignment, read sdks/AGENTS.md.
  • For specs/**, or API contract, schema, or example changes, read specs/AGENTS.md.
  • For kubernetes/**, or CRDs, controller behavior, task execution, Helm/Kustomize deployment, pool scheduling, pause/resume snapshots, or Kind e2e tests, read kubernetes/AGENTS.md.
  • For cross-cutting changes spanning spec, server, and SDKs, start with specs/AGENTS.md and then read affected consumer guides.
  • For runtime component changes under components/**, read the nearest README.md or DEVELOPMENT.md; keep component APIs aligned with specs/ and SDK consumers.
  • For CLI changes under cli/**, read cli/README.md and verify command help/output behavior alongside unit tests.
  • For cross-language e2e tests under tests/**, read the language-local README and keep test assumptions aligned with current server and SDK behavior.
  • For areas without a local AGENTS.md, use the nearest README.md, DEVELOPMENT.md, and CI workflow as the next source of truth.

Read the full file on GitHub · 123 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 · 123 lines · 1,693 tokens per session scan A ef18bc5d12dc

Subscribe to this mod's changes

OpenSandbox AGENTS.md is an instructions file published in the GitHub repository opensandbox-group/OpenSandbox (14,896 stars, last pushed 2d ago), licensed Apache-2.0. It adds 1,693 tokens to every session, about $0.0085 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.