// Full configuration const client = new Anthropic({ apiKey: process.env.ANTHROPIC_API_KEY, // default: env var maxRetries: 3, // default: 2 timeout: 60_000, // default: 10 minutes baseURL: 'https://api.anthropic.com', // override for proxies defaultHeaders: { // custom headers 'claude-beta': 'prompt-caching-2024-07-31', }, });


### Step 2: Python

```python
import anthropic

# Sync client
client = anthropic.Anthropic()

# Async client
client = anthropic.AsyncAnthropic()

# Full configuration
client = anthropic.Anthropic(
    api_key=os.environ["ANTHROPIC_API_KEY"],
    max_retries=3,
    timeout=60.0,
    base_url="https://api.anthropic.com",
    default_headers={"claude-beta": "prompt-caching-2024-07-31"},
)

Output

Properly configured client with retries, timeouts, and custom headers
Type-safe error handling with specific exception classes
Streaming implementation using your preferred pattern
Prompt caching enabled for repeated system prompts (90% cost savings)
Batch processing configured for bulk operations (50% cost savings)

Error Handling

import Anthropic from '@claude-ai/sdk';

try {
  const message = await client.messages.create({ ... });
} catch (err) {
  if (err instanceof Anthropic.AuthenticationError) {
    // 401 — bad API key
  } else if (err instanceof Anthropic.RateLimitError) {
    // 429 — back off and retry
  } else if (err instanceof Anthropic.APIError) {
    // All other API errors
    console.error(err.status, err.error?.type, err.message);
  } else if (err instanceof Anthropic.APIConnectionError) {
    // Network failure — DNS, timeout, etc.
  }
}

try:
    message = client.messages.create(...)
except anthropic.AuthenticationError:
    ...  # 401
except anthropic.RateLimitError:
    ...  # 429
except anthropic.APIStatusError as e:
    print(e.status_code, e.message)
except anthropic.APIConnectionError:
    ...  # network failure

Streaming Patterns

Event-Based (TypeScript)

const stream = client.messages.stream({
  model: 'claude-sonnet-4-20250514',
  max_tokens: 2048,
  messages,
});

stream.on('text', (text) => process.stdout.write(text));
stream.on('error', (err) => console.error('Stream error:', err));
stream.on('end', () => console.log('\nDone'));

const finalMessage = await stream.finalMessage();

Async Iterator (TypeScript)

const stream = await client.messages.create({
  model: 'claude-sonnet-4-20250514',
  max_tokens: 2048,
  messages,
  stream: true,
});

for await (const event of stream) {
  if (event.type === 'content_block_delta') {
    process.stdout.write(event.delta.text || '');
  }
}

Context Manager (Python)

with client.messages.stream(
    model="claude-sonnet-4-20250514",
    max_tokens=2048,
    messages=messages,
) as stream:
    for text in stream.text_stream:
        print(text, end="", flush=True)

message = stream.get_final_message()

TypeScript Types

import Anthropic from '@claude-ai/sdk';

// Message types
type Message = Anthropic.Message;
type MessageParam = Anthropic.MessageParam;
type ContentBlock = Anthropic.ContentBlock;
type TextBlock = Anthropic.TextBlock;
type ToolUseBlock = Anthropic.ToolUseBlock;

// Tool types
type Tool = Anthropic.Tool;
type ToolResultBlockParam = Anthropic.ToolResultBlockParam;

// Request/response
type MessageCreateParams = Anthropic.MessageCreateParams;

Prompt Caching (Beta)

const message = await client.messages.create({
  model: 'claude-sonnet-4-20250514',
  max_tokens: 1024,
  system: [
    {
      type: 'text',
      text: longSystemPrompt, // 1024+ tokens to be cacheable
      cache_control: { type: 'ephemeral' },
    },
  ],
  messages: [{ role: 'user', content: userQuestion }],
}, {
  headers: { 'claude-beta': 'prompt-caching-2024-07-31' },
});
// Cache hit: 90% cheaper on input tokens
// message.usage.cache_creation_input_tokens / cache_read_input_tokens

Message Batches

// Submit up to 10,000 messages as a batch (50% cheaper, 24h SLA)
const batch = await client.messages.batches.create({
  requests: items.map((item, i) => ({
    custom_id: `item-${i}`,
    params: {
      model: 'claude-sonnet-4-20250514',
      max_tokens: 1024,
      messages: [{ role: 'user', content: item.prompt }],
    },
  })),
});

// Poll for completion
let status = await client.messages.batches.retrieve(batch.id);
while (status.processing_status !== 'ended') {
  await new Promise(r => setTimeout(r, 30000));
  status = await client.messages.batches.retrieve(batch.id);
}

Examples

See Client Configuration, Error Handling, Streaming Patterns, TypeScript Types, Prompt Caching, and Message Batches sections above for complete code examples.

Resources

TypeScript SDK
Python SDK
Prompt Caching
Message Batches

Next Steps

See clade-rate-limits for throughput optimization.

Prerequisites

Completed clade-install-auth
Familiarity with TypeScript generics or Python type hints
Understanding of async/await patterns

clade-sdk-patterns

Anthropic SDK Patterns

Overview

Client Configuration

Instructions

Step 1: TypeScript