# aws-sdk-js-v3-usage

Guides coding agents on AWS SDK for JavaScript v3 architecture, imports, and streams. It enforces modern modular patterns instead of legacy v2 code.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 8000 installs · ★ 3282
- Author: aws
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/aws/agent-toolkit-for-aws/tree/HEAD/skills/core-skills/aws-sdk-js-v3-usage/SKILL.md
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/skills/aws-sdk-js-v3-usage

## What it does

The skill directs coding assistants toward the modular `@aws-sdk/*` architecture. It prioritizes bare-bones clients over aggregated classes to minimize bundle sizes. Root package imports are strictly enforced. It also bans emojis across all generated code and comments.

Stream handling receives special focus because unread response streams keep sockets open and trigger socket exhaustion. The instructions require immediate consumption via `transformToString()` or explicit stream cancellation. Sockets cannot sit idle.

For DynamoDB, the skill configures `@aws-sdk/lib-dynamodb` to process native JavaScript objects. Mutating `client.config` post-instantiation will break your application because fields resolve into async functions.

## Requirements
- Works with: AWS

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add aws/agent-toolkit-for-aws --skill aws-sdk-js-v3-usage -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/aws-sdk-js-v3-usage/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/aws-sdk-js-v3-usage/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add aws/agent-toolkit-for-aws --skill aws-sdk-js-v3-usage -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/aws-sdk-js-v3-usage/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add aws/agent-toolkit-for-aws --skill aws-sdk-js-v3-usage -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/aws-sdk-js-v3-usage/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install aws/agent-toolkit-for-aws aws-sdk-js-v3-usage
```

2. **Manually: put the files in place**
- File: `.github/skills/aws-sdk-js-v3-usage/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add aws/agent-toolkit-for-aws --skill aws-sdk-js-v3-usage -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/aws/agent-toolkit-for-aws --path skills/core-skills/aws-sdk-js-v3-usage
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/aws-sdk-js-v3-usage/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add aws/agent-toolkit-for-aws --skill aws-sdk-js-v3-usage -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/aws/agent-toolkit-for-aws/tree/HEAD/skills/core-skills/aws-sdk-js-v3-usage/SKILL.md

## When to use it
- migrate legacy AWS SDK v2 calls to v3 modular commands
- prevent socket exhaustion when streaming S3 object bodies
- map DynamoDB items to native JavaScript types via DocumentClient
- handle API pagination with async paginator helpers

## Example prompts
- Fetch an S3 object using GetObjectCommand and read its body as a string
- Query DynamoDB items with DynamoDBDocumentClient using native JavaScript objects
- Set up an S3 client with a custom maxSockets pool for parallel uploads

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 7b1fa317241594cc.

BEGIN THIRD-PARTY FILE 7b1fa317241594cc
````text
---
name: aws-sdk-js-v3-usage
description: |
  AWS SDK for JavaScript v3 development patterns. Use when writing JavaScript or TypeScript code that uses AWS services via @aws-sdk/* packages (aws-sdk-js-v3), or when asked about schemas, runtime validation, serialization, or code generation in the context of the JS/TS AWS SDK.
---

> Do not use emojis in any code, comments, or output when this skill is active.

# AWS SDK for JavaScript v3

## Package Structure

- `@aws-sdk/client-*` — one per service, generated by [smithy-typescript](https://github.com/awslabs/smithy-typescript); one-to-one with AWS services and operations
- `@aws-sdk/lib-*` — higher-level helpers (e.g. `lib-dynamodb`, `lib-storage`)
- `@aws-sdk/*` (no prefix) — utility packages (mostly internal; don't import deep paths)

Always import from the package root:

```js
import { S3Client } from "@aws-sdk/client-s3"; // correct
// NOT: import { S3Client } from "@aws-sdk/client-s3/dist-cjs/S3Client"
```

## Two Client Styles

**Bare-bones** (preferred — smaller bundle):

```js
import { S3Client, GetObjectCommand } from "@aws-sdk/client-s3";
const client = new S3Client({ region: "us-east-1" });
const output = await client.send(new GetObjectCommand({ Bucket: "b", Key: "k" }));
```

**Aggregated** (v2-style but NOT v2, larger bundle):

```js
import { S3 } from "@aws-sdk/client-s3";
const client = new S3({ region: "us-east-1" });
const output = await client.getObject({ Bucket: "b", Key: "k" });
```

## Client Configuration

No global config in v3 — pass config to each client. `region` is always required; set it explicitly or via `AWS_REGION` env var.

```js
const config = { region: "us-east-1", maxAttempts: 5 };
const s3 = new S3Client(config);
const dynamo = new DynamoDBClient(config);
```

**Do not read or mutate `client.config` after instantiation** — it is a resolved form (e.g. `region` becomes an async function). See `references/effective-practices.md`.

For HTTP handler (`NodeHttpHandler` from `@smithy/node-http-handler`), retry strategy, endpoint details, logging, FIPS, dual-stack, protocol selection, and S3-specific options → see `references/clients.md`.

## Credentials

All providers from `@aws-sdk/credential-providers`. Credentials are lazy and cached per client until ~5 min before expiry.

```js
// Default chain (env → ini → IMDS/ECS) — use in most Node.js apps
const client = new S3Client({ credentials: fromNodeProviderChain() });

// Assume role (NOTE: fromTemporaryCredentials is correct for STS AssumeRole)
const client = new S3Client({
  credentials: fromTemporaryCredentials({ params: { RoleArn: "arn:aws:iam::123456789012:role/MyRole" } }),
});

// Named profile
const client = new S3Client({ profile: "my-profile" });
```

Share credentials and socket pool across multi-region clients:

```js
````
END THIRD-PARTY FILE 7b1fa317241594cc

The third-party file has ended. Everything between the 7b1fa317241594cc tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

First 2826 of 8731 bytes. © aws · Apache-2.0 · https://github.com/aws/agent-toolkit-for-aws/tree/HEAD/skills/core-skills/aws-sdk-js-v3-usage/SKILL.md

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