# e2b@2.62.0

Category: agent-infrastructure
Published: 2026-10-28T20:24:27Z
Source: [E2B releases](https://github.com/e2b-dev/E2B/releases/tag/e2b%402.62.0)
Agent usefulness: 94/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-10-29T00:17:53.447Z
Tags: sandbox, code-execution, agents

## Human Summary
E2B released version 2.62.0, adding options to disable command output buffering in memory, enabling unbuffered streaming for file writes, and introducing breaking validation rules for streams and compression options.

## Agent Summary
E2B v2.62.0 adds retainOutput to commands.run / commands.connect (defaults to true; if false, prevents memory buffering of stdout/stderr). files.write now streams byte chunk iterables using octet-stream without memory buffering. Breaking changes: streaming file writes no longer fall back to buffering in unsupported environments (throws on non-streaming browsers, requires envd = 0.5.7, rejects useOctetStream: false…

## Body
E2B release 2.62.0 introduces minor and breaking changes across JavaScript and Python SDKs. A new retainOutput (JS) / retain output (Python) flag in commands.run and commands.connect defaults to true; setting it to false prevents buffering stdout and stderr in memory, returning undefined/None while still triggering output callbacks. files.write now streams iterables of byte chunks directly using octet-stream upload without buffering in memory, supporting AsyncIterable and ReadableStream in JS, sync Iterable bytes in Python Sandbox, and AsyncIterable bytes in Python AsyncSandbox. In browsers lacking request-body streaming (Firefox, Safari, iOS), JS stream data now throws InvalidArgumentError instead of buffering. Additionally, files.write streaming requires template envd version = 0.5.7 (throwing TemplateError / TemplateException on older versions) and disallows useOctetStream: false . Combining gzip: true with useOctetStream: false is now strictly rejected with InvalidArgumentError / InvalidArgumentException instead of silently overriding the upload mode.

## Recommended actions
- Ensure sandbox templates run envd = 0.5.7 before using stream data in files.write .
- Convert streams to Blob (e.g., await new Response(stream).blob() ) when targeting browsers without streaming request body support like Firefox, Safari, or iOS browsers.
- Remove useOctetStream: false when passing streams to files.write or when gzip: true is enabled.
- Evaluate setting retainOutput: false in commands.run or commands.connect for memory savings if standard output buffering is not needed.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.