# azure-cosmos-java

A skill that tells your agent how to use the Azure Cosmos DB Java SDK: clients, queries, partition keys and error handling.

- skill · `type=skill` · Claude Code, GitHub Copilot · ★ 3149
- Author: Microsoft
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/microsoft/skills/tree/HEAD/.github/plugins/azure-sdk-java/skills/azure-cosmos-java/SKILL.md
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/skills/azure-cosmos-java

## What it does

The skill covers the `azure-cosmos` client library for the NoSQL API. It walks through `CosmosClient` and `CosmosAsyncClient`, the `CosmosDatabase` and `CosmosContainer` hierarchy, creating a database and container, CRUD calls and `queryItems`. Code samples are Java, and reference tables list the consistency levels from Strong down to Eventual along with what each client class is for.

You need `COSMOS_ENDPOINT` and `COSMOS_KEY` in your environment, and the dependency comes in through Maven — either `com.azure:azure-cosmos` directly or the `azure-sdk-bom`. No key means no client, so sort out account access before asking the agent to write anything.

Error handling gets its own section. A 409 status means the item is already there, 429 means you hit the request limit, and the response carries `getRetryAfterDuration()`. The skill also pushes you to build one client and keep it for the whole app, and to switch on direct mode when latency matters in production.

## Requirements
- Works with: Azure

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add microsoft/skills --skill azure-cosmos-java -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/azure-cosmos-java/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/azure-cosmos-java/

### Codex

**Manually: put the files in place**
- File: `.agents/skills/azure-cosmos-java/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

**Manually: put the files in place**
- File: `.cursor/skills/azure-cosmos-java/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install microsoft/skills azure-cosmos-java
```

2. **Manually: put the files in place**
- File: `.github/skills/azure-cosmos-java/SKILL.md`

### Gemini CLI

**Platform CLI**
```bash
gemini skills install https://github.com/microsoft/skills --path .github/plugins/azure-sdk-java/skills/azure-cosmos-java
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/azure-cosmos-java/SKILL.md` — The legacy .windsurf/skills/ path still works

### 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/microsoft/skills/tree/HEAD/.github/plugins/azure-sdk-java/skills/azure-cosmos-java/SKILL.md

## When to use it
- create a database and container in Cosmos DB from Java
- move blocking calls to `CosmosAsyncClient` with chained `flatMap`
- catch a 429 and retry after the given delay
- pick a partition key that spreads data and requests
- read the RU cost of an operation from `getRequestCharge`

## Example prompts
- Write a Java `CosmosClient` for Cosmos DB, reading the endpoint and key from environment variables
- Build async CRUD for the `myContainer` container with partition key `/partitionKey`
- Add `CosmosException` handling for status codes 409 and 429

## Source text · SKILL.md · MIT

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: 15f2a15f1f15d974.

BEGIN THIRD-PARTY FILE 15f2a15f1f15d974
````text
---
name: azure-cosmos-java
description: |
  Azure Cosmos DB SDK for Java. NoSQL database operations with global distribution, multi-model support, and reactive patterns.
  Triggers: "CosmosClient java", "CosmosAsyncClient", "cosmos database java", "cosmosdb java", "document database java".
license: MIT
metadata:
  author: Microsoft
  version: "1.0.0"
  package: azure-cosmos
---

# Azure Cosmos DB SDK for Java

Client library for Azure Cosmos DB NoSQL API with global distribution and reactive patterns.

## Installation

```xml
<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-cosmos</artifactId>
    <version>LATEST</version>
</dependency>
```

Or use Azure SDK BOM:

```xml
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.azure</groupId>
            <artifactId>azure-sdk-bom</artifactId>
            <version>{bom_version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

<dependencies>
    <dependency>
        <groupId>com.azure</groupId>
        <artifactId>azure-cosmos</artifactId>
    </dependency>
</dependencies>
```

## Environment Variables

```bash
COSMOS_ENDPOINT=https://<account>.documents.azure.com:443/
COSMOS_KEY=<your-primary-key>
```

## Authentication

### Key-based Authentication

```java
import com.azure.cosmos.CosmosClient;
import com.azure.cosmos.CosmosClientBuilder;

CosmosClient client = new CosmosClientBuilder()
    .endpoint(System.getenv("COSMOS_ENDPOINT"))
    .key(System.getenv("COSMOS_KEY"))
    .buildClient();
```

### Async Client

```java
import com.azure.cosmos.CosmosAsyncClient;

CosmosAsyncClient asyncClient = new CosmosClientBuilder()
    .endpoint(serviceEndpoint)
    .key(key)
    .buildAsyncClient();
```

### With Customizations

```java
import com.azure.cosmos.ConsistencyLevel;
import java.util.Arrays;

CosmosClient client = new CosmosClientBuilder()
    .endpoint(serviceEndpoint)
    .key(key)
    .directMode(directConnectionConfig, gatewayConnectionConfig)
    .consistencyLevel(ConsistencyLevel.SESSION)
    .connectionSharingAcrossClientsEnabled(true)
    .contentResponseOnWriteEnabled(true)
    .userAgentSuffix("my-application")
    .preferredRegions(Arrays.asList("West US", "East US"))
    .buildClient();
```

## Client Hierarchy

| Class | Purpose |
|-------|---------|
| `CosmosClient` / `CosmosAsyncClient` | Account-level operations |
| `CosmosDatabase` / `CosmosAsyncDatabase` | Database operations |
| `CosmosContainer` / `CosmosAsyncContainer` | Container/item operations |

## Core Workflow

### Create Database

```java
// Sync
client.createDatabaseIfNotExists("myDatabase")
    .map(response -> client.getDatabase(response.getProperties().getId()));

// Async with chaining
asyncClient.createDatabaseIfNotExists("myDatabase")
    .map(response -> asyncClient.getDatabase(response.getProperties().getId()))
    .subscribe(database -> System.out.println("Created: " + database.getId()));
```

### Create Container

```java
asyncClient.createDatabaseIfNotExists("myDatabase")
````
END THIRD-PARTY FILE 15f2a15f1f15d974

The third-party file has ended. Everything between the 15f2a15f1f15d974 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 3107 of 7499 bytes. © Microsoft · MIT · https://github.com/microsoft/skills/tree/HEAD/.github/plugins/azure-sdk-java/skills/azure-cosmos-java/SKILL.md

_Part of the page did not fit — see the HTML version._

---
NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md