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Azure Cosmos TS

MicrosoftOfficialCreated by Microsoft

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From the author

Azure Cosmos DB JavaScript/TypeScript SDK (@azure/cosmos) for data plane operations. Use for CRUD operations on documents, queries, bulk operations, and container management. Triggers: "Cosmos DB", "@azure/cosmos", "CosmosClient", "document CRUD", "NoSQL queries", "bulk operations", "partition key", "container.items".
— the description by Microsoft

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

The azure-cosmos-ts skill provides the interface for the @azure/cosmos SDK, enabling developers to interact with Azure Cosmos DB NoSQL data plane resources. It covers document CRUD operations, NoSQL query execution, bulk data processing, and container management within a TypeScript or JavaScript environment.

What it does

  • Performs CRUD operations on documents within Cosmos DB containers.
  • Executes NoSQL queries using parameterized query specifications.
  • Manages bulk operations for batch processing of data.
  • Handles container and database resource interactions.
  • Supports authentication via Microsoft Entra ID or account keys.
  • Implements optimistic concurrency control using ETags.

When to use it

  • When building applications that require data storage in Azure Cosmos DB.
  • When performing document-level operations in a Node.js environment.
  • When implementing batch data processing or bulk updates.
  • When needing to execute complex NoSQL queries with pagination.

Advantages

  • Provides native TypeScript support for type-safe database interactions.
  • Includes built-in support for bulk operation execution.
  • Supports secure authentication patterns using Azure Identity.
  • Offers structured error handling for common database response codes.

Usage examples

“How do I create a new document in my Cosmos DB container using the TypeScript SDK?”
The agent provides a code snippet using container.items.create, demonstrating how to define an interface for the document and pass it to the SDK method.
“Show me how to perform a parameterized query to find products by category.”
The agent generates a SqlQuerySpec object with the query string and parameters array, then demonstrates calling container.items.query with that specification.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/microsoft/azure-cosmos-ts/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip azure-cosmos-ts.zip -d .agents/skills

Documentation by Microsoft

@azure/cosmos (TypeScript/JavaScript)

Data plane SDK for Azure Cosmos DB NoSQL API operations — CRUD on documents, queries, bulk operations.

⚠️ Data vs Management Plane

  • This SDK (@azure/cosmos): CRUD operations on documents, queries, stored procedures

  • Management SDK (@azure/arm-cosmosdb): Create accounts, databases, containers via ARM

Installation

npm install @azure/cosmos @azure/identity

Current Version: 4.9.0
Node.js: >= 20.0.0

Environment Variables

COSMOS_ENDPOINT=https://<account>.documents.azure.com:443/
COSMOS_DATABASE=<database-name>
COSMOS_CONTAINER=<container-name>
# For key-based auth only (prefer AAD)
COSMOS_KEY=<account-key>
AZURE_TOKEN_CREDENTIALS=prod # Required only if DefaultAzureCredential is used in production

Authentication

import { CosmosClient } from "@azure/cosmos";
import { DefaultAzureCredential, ManagedIdentityCredential } from "@azure/identity";

// Local dev: DefaultAzureCredential. Production: set AZURE_TOKEN_CREDENTIALS=prod or AZURE_TOKEN_CREDENTIALS=<specific_credential>
const credential = new DefaultAzureCredential({requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"]});
// Or use a specific credential directly in production:
// See https://learn.microsoft.com/javascript/api/overview/azure/identity-readme?view=azure-node-latest#credential-classes
// const credential = new ManagedIdentityCredential();

const client = new CosmosClient({
  endpoint: process.env.COSMOS_ENDPOINT!,
  aadCredentials: credential,
});
Key-Based Authentication
import { CosmosClient } from "@azure/cosmos";

// Option 1: Endpoint + Key
const client = new CosmosClient({
  endpoint: process.env.COSMOS_ENDPOINT!,
  key: process.env.COSMOS_KEY!,
});

// Option 2: Connection String
const client = new CosmosClient(process.env.COSMOS_CONNECTION_STRING!);

Resource Hierarchy

CosmosClient
└── Database
    └── Container
        ├── Items (documents)
        ├── Scripts (stored procedures, triggers, UDFs)
        └── Conflicts

Core Operations

Database & Container Setup
const { database } = await client.databases.createIfNotExists({
  id: "my-database",
});

const { container } = await database.containers.createIfNotExists({
  id: "my-container",
  partitionKey: { paths: ["/partitionKey"] },
});
Create Document
interface Product {
  id: string;
  partitionKey: string;
  name: string;
  price: number;
}

const item: Product = {
  id: "product-1",
  partitionKey: "electronics",
  name: "Laptop",
  price: 999.99,
};

const { resource } = await container.items.create<Product>(item);
Read Document
const { resource } = await container
  .item("product-1", "electronics") // id, partitionKey
  .read<Product>();

if (resource) {
  console.log(resource.name);
}
Update Document (Replace)
const { resource: existing } = await container
  .item("product-1", "electronics")
  .read<Product>();

if (existing) {
  existing.price = 899.99;
  const { resource: updated } = await container
    .item("product-1", "electronics")
    .replace<Product>(existing);
}
Upsert Document
const item: Product = {
  id: "product-1",
  partitionKey: "electronics",
  name: "Laptop Pro",
  price: 1299.99,
};

const { resource } = await container.items.upsert<Product>(item);
Delete Document
await container.item("product-1", "electronics").delete();
Patch Document (Partial Update)
import { PatchOperation } from "@azure/cosmos";

const operations: PatchOperation[] = [
  { op: "replace", path: "/price", value: 799.99 },
  { op: "add", path: "/discount", value: true },
  { op: "remove", path: "/oldField" },
];

const { resource } = await container
  .item("product-1", "electronics")
  .patch<Product>(operations);

Queries

Simple Query
const { resources } = await container.items
  .query<Product>("SELECT * FROM c WHERE c.price < 1000")
  .fetchAll();
import { SqlQuerySpec } from "@azure/cosmos";

const querySpec: SqlQuerySpec = {
  query: "SELECT * FROM c WHERE c.partitionKey = @category AND c.price < @maxPrice",
  parameters: [
    { name: "@category", value: "electronics" },
    { name: "@maxPrice", value: 1000 },
  ],
};

const { resources } = await container.items
  .query<Product>(querySpec)
  .fetchAll();
Query with Pagination
const queryIterator = container.items.query<Product>(querySpec, {
  maxItemCount: 10, // Items per page
});

while (queryIterator.hasMoreResults()) {
  const { resources, continuationToken } = await queryIterator.fetchNext();
  console.log(`Page with ${resources?.length} items`);
  // Use continuationToken for next page if needed
}
Cross-Partition Query
const { resources } = await container.items
  .query<Product>(
    "SELECT * FROM c WHERE c.price > 500",
    { enableCrossPartitionQuery: true }
  )
  .fetchAll();

Bulk Operations

Execute Bulk Operations
import { BulkOperationType, OperationInput } from "@azure/cosmos";

const operations: OperationInput[] = [
  {
    operationType: BulkOperationType.Create,
    resourceBody: { id: "1", partitionKey: "cat-a", name: "Item 1" },
  },
  {
    operationType: BulkOperationType.Upsert,
    resourceBody: { id: "2", partitionKey: "cat-a", name: "Item 2" },
  },
  {
    operationType: BulkOperationType.Read,
    id: "3",
    partitionKey: "cat-b",
  },
  {
    operationType: BulkOperationType.Replace,
    id: "4",
    partitionKey: "cat-b",
    resourceBody: { id: "4", partitionKey: "cat-b", name: "Updated" },
  },
  {
    operationType: BulkOperationType.Delete,
    id: "5",
    partitionKey: "cat-c",
  },
  {
    operationType: BulkOperationType.Patch,
    id: "6",
    partitionKey: "cat-c",
    resourceBody: {
      operations: [{ op: "replace", path: "/name", value: "Patched" }],
    },
  },
];

const response = await container.items.executeBulkOperations(operations);

response.forEach((result, index) => {
  if (result.statusCode >= 200 && result.statusCode < 300) {
    console.log(`Operation ${index} succeeded`);
  } else {
    console.error(`Operation ${index} failed: ${result.statusCode}`);
  }
});

Partition Keys

Simple Partition Key
const { container } = await database.containers.createIfNotExists({
  id: "products",
  partitionKey: { paths: ["/category"] },
});
Hierarchical Partition Key (MultiHash)
import { PartitionKeyDefinitionVersion, PartitionKeyKind } from "@azure/cosmos";

const { container } = await database.containers.createIfNotExists({
  id: "orders",
  partitionKey: {
    paths: ["/tenantId", "/userId", "/sessionId"],
    version: PartitionKeyDefinitionVersion.V2,
    kind: PartitionKeyKind.MultiHash,
  },
});

// Operations require array of partition key values
const { resource } = await container.items.create({
  id: "order-1",
  tenantId: "tenant-a",
  userId: "user-123",
  sessionId: "session-xyz",
  total: 99.99,
});

// Read with hierarchical partition key
const { resource: order } = await container
  .item("order-1", ["tenant-a", "user-123", "session-xyz"])
  .read();

Error Handling

import { ErrorResponse } from "@azure/cosmos";

try {
  const { resource } = await container.item("missing", "pk").read();
} catch (error) {
  if (error instanceof ErrorResponse) {
    switch (error.code) {
      case 404:
        console.log("Document not found");
        break;
      case 409:
        console.log("Conflict - document already exists");
        break;
      case 412:
        console.log("Precondition failed (ETag mismatch)");
        break;
      case 429:
        console.log("Rate limited - retry after:", error.retryAfterInMs);
        break;
      default:
        console.error(`Cosmos error ${error.code}: ${error.message}`);
    }
  }
  throw error;
}

Optimistic Concurrency (ETags)

// Read with ETag
const { resource, etag } = await container
  .item("product-1", "electronics")
  .read<Product>();

if (resource && etag) {
  resource.price = 899.99;
  
  try {
    // Replace only if ETag matches
    await container.item("product-1", "electronics").replace(resource, {
      accessCondition: { type: "IfMatch", condition: etag },
    });
  } catch (error) {
    if (error instanceof ErrorResponse && error.code === 412) {
      console.log("Document was modified by another process");
    }
  }
}

TypeScript Types Reference

import {
  // Client & Resources
  CosmosClient,
  Database,
  Container,
  Item,
  Items,
  
  // Operations
  OperationInput,
  BulkOperationType,
  PatchOperation,
  
  // Queries
  SqlQuerySpec,
  SqlParameter,
  FeedOptions,
  
  // Partition Keys
  PartitionKeyDefinition,
  PartitionKeyDefinitionVersion,
  PartitionKeyKind,
  
  // Responses
  ItemResponse,
  FeedResponse,
  ResourceResponse,
  
  // Errors
  ErrorResponse,
} from "@azure/cosmos";

Best Practices

  1. Use Microsoft Entra Token Credential — Use DefaultAzureCredential for local development; use ManagedIdentityCredential or WorkloadIdentityCredential for production

  2. Always use parameterized queries — Prevents injection, improves plan caching

  3. Specify partition key — Avoid cross-partition queries when possible

  4. Use bulk operations — For multiple writes, use executeBulkOperations

  5. Handle 429 errors — Implement retry logic with exponential backoff

  6. Use ETags for concurrency — Prevent lost updates in concurrent scenarios

  7. Close client on shutdown — Call client.dispose() in cleanup

Common Patterns

Service Layer Pattern
export class ProductService {
  private container: Container;

  constructor(client: CosmosClient) {
    this.container = client
      .database(process.env.COSMOS_DATABASE!)
      .container(process.env.COSMOS_CONTAINER!);
  }

  async getById(id: string, category: string): Promise<Product | null> {
    try {
      const { resource } = await this.container
        .item(id, category)
        .read<Product>();
      return resource ?? null;
    } catch (error) {
      if (error instanceof ErrorResponse && error.code === 404) {
        return null;
      }
      throw error;
    }
  }

  async create(product: Omit<Product, "id">): Promise<Product> {
    const item = { ...product, id: crypto.randomUUID() };
    const { resource } = await this.container.items.create<Product>(item);
    return resource!;
  }

  async findByCategory(category: string): Promise<Product[]> {
    const querySpec: SqlQuerySpec = {
      query: "SELECT * FROM c WHERE c.partitionKey = @category",
      parameters: [{ name: "@category", value: category }],
    };
    const { resources } = await this.container.items
      .query<Product>(querySpec)
      .fetchAll();
    return resources;
  }
}
SDKPurposeInstall
@azure/cosmosData plane (this SDK)npm install @azure/cosmos
@azure/arm-cosmosdbManagement plane (ARM)npm install @azure/arm-cosmosdb
@azure/identityAuthenticationnpm install @azure/identity

Files

ATTRIBUTION.md

Attribution

This folder is an unmodified copy of the Agent Skill "azure-cosmos-ts", distributed by AutoGineer (https://autogineer.com/agent-skills).

The skill's own files are unmodified copies. AutoGineer is not affiliated with or endorsed by the author or the publisher.

Files added by AutoGineer

  • ATTRIBUTION.md: this file, written by AutoGineer

  • LICENSE: copied from LICENSE

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs Node.js

Security

No issues found by our static scan· No issues found

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by
Microsoft
Publisher
Microsoft (Official)
Source
microsoft/skills · .github/plugins/azure-sdk-typescript/skills/azure-cosmos-ts · commit 0696600
Licence
MIT License (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by Microsoft.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download azure-cosmos-ts.zip