E2B is open-source infrastructure that runs AI-generated code inside isolated cloud sandboxes. Developers use its JavaScript and Python SDKs to execute code and provide agents with computer-use tools.
Borrowing it
Nothing to install: this file belongs to e2b-dev/E2B. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/e2b-dev/E2B/main/CLAUDE.mdgit clone --depth 1 https://github.com/e2b-dev/E2BWrote 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.
[](https://agentmods.dev/instructions/e2b-dev/e2b/claude-md)<a href="https://agentmods.dev/instructions/e2b-dev/e2b/claude-md"><img src="https://agentmods.dev/badge/instructions/e2b-dev/e2b/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/e2b-dev/e2b/claude-md"><img src="https://agentmods.dev/badge/instructions/e2b-dev/e2b/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00375 | $0.00375 |
| Opus 5.5 | $0.00150 | $0.00150 |
| Sonnet 5.5 | $0.00075 | $0.00075 |
| Haiku 4.5 | $0.00038 | $0.00038 |
Grade A, and why
E2B CLAUDE.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 today.
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.
What it actually says
Use pnpm for node and uv for python to install and update dependencies.
Run pnpm run format, pnpm run lint and pnpm run typecheck before committing changes.
When modifying the SDK packages, ensure equivalent changes are applied to both JS as well as sync and async Python implementations.
Never edit the API, envd, or volume-content specs in spec/ by hand; they are synced with Copybara from e2b-dev/runtime and e2b-dev/belt at the commits pinned in spec/runtime-ref and spec/belt-ref (see copy.bara.sky and spec/README.md). To update the specs, bump the pins and re-run make codegen, which re-fetches them before generating.
Create or update tests covering affected codepaths and run them using pnpm run test.
Generate a changeset with pnpm changeset in the repository root when changing the public surface of packages/cli, packages/js-sdk, or packages/python-sdk; internal scripts, devtools, and tests don't need one.
Never use a major bump in a changeset unless a maintainer explicitly asks for a major release; breaking changes ship as minor and are called out in the changeset text.
When changing user-facing behavior of the SDKs or CLI, document it in e2b-dev/docs where applicable by updating or adding the relevant guide pages in a separate pull request there, and link it from the SDK pull request.
When creating a pull request, add usage examples for user-facing changes to the PR description.
When opening a new pull request, use the Linear MCP if available to link to related issues, or create a new issue from the PR description.
Keep PR descriptions up-to-date with changes.
Default credentials are stored in .env.local in the repository root or inside ~/.e2b/config.json.
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.
- today Changed · +2 lines · +85 tokens per session f8dab143ab1b
- 28d ago Changed · -1 lines · -14 tokens per session b5df5c979298
- 1mo ago Changed · -2 tokens per session e7c5afc35a8e
- 2mo ago First seen · 12 lines · 306 tokens per session scan A e90f4c942a65
E2B CLAUDE.md is an instructions file published in the GitHub repository e2b-dev/E2B (14,597 stars, last pushed today), licensed Apache-2.0. It adds 375 tokens to every session, about $0.0015 per session on Opus 5.5. 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.
Other instructions, from other repositories
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Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.