Anthropic Claude Model IDs

List of available model IDs for the Anthropic Claude API.

Last Updated: 2025-11-24

Model List

Claude 4.x (2025)

Model ID	Context	Max Output	Release	Features
`claude-opus-4-1-20250805`	200K	32K	2025-08	Most powerful. Complex reasoning & code generation
`claude-sonnet-4-5`	1M	64K	2025-09	Latest balanced model (recommended)
`claude-sonnet-4-20250514`	200K (1M beta)	64K	2025-05	Production recommended (date-fixed)
`claude-haiku-4-5-20251001`	200K	64K	2025-10	Fast & low-cost

Model Characteristics:

Opus: Highest performance, complex tasks (200K context)
Sonnet: Balanced, general-purpose (1M context)
Haiku: Fast & low-cost ($1/M input, $5/M output)

Basic Usage

from langchain_anthropic import ChatAnthropic

# Recommended: Latest Sonnet
llm = ChatAnthropic(model="claude-sonnet-4-5")

# Production: Date-fixed version
llm = ChatAnthropic(model="claude-sonnet-4-20250514")

# Fast & low-cost
llm = ChatAnthropic(model="claude-haiku-4-5-20251001")

# Highest performance
llm = ChatAnthropic(model="claude-opus-4-1-20250805")

Environment Variables

export ANTHROPIC_API_KEY="sk-ant-..."

Model Selection Guide

Use Case	Recommended Model
Cost-focused	`claude-haiku-4-5-20251001`
Balanced	`claude-sonnet-4-5`
Performance-focused	`claude-opus-4-1-20250805`
Production	`claude-sonnet-4-20250514` (date-fixed)

Claude Features

1. Large Context Window

Claude Sonnet 4.5 supports 1M tokens context window:

Model	Standard Context	Max Output	Notes
Sonnet 4.5	1M	64K	Latest version
Sonnet 4	200K (1M beta)	64K	1M available with beta header
Opus 4.1	200K	32K	High-performance version
Haiku 4.5	200K	64K	Fast version

# Using 1M context (Sonnet 4.5)
llm = ChatAnthropic(
    model="claude-sonnet-4-5",
    max_tokens=64000  # Max output: 64K
)

# Enable 1M context for Sonnet 4 (beta)
llm = ChatAnthropic(
    model="claude-sonnet-4-20250514",
    default_headers={"anthropic-beta": "max-tokens-3-5-sonnet-2024-07-15"}
)

2. Date-Fixed Versions

For production environments, date-fixed versions are recommended to prevent unexpected updates:

# ✅ Recommended (production)
llm = ChatAnthropic(model="claude-sonnet-4-20250514")

# ⚠️ Caution (development only)
llm = ChatAnthropic(model="claude-sonnet-4")

3. Tool Use (Function Calling)

Claude has powerful tool use capabilities (see Tool Use Guide for details).

4. Multi-Platform Support

Available on multiple cloud platforms (see Platform-Specific Guide for details):

Anthropic API (direct)
Google Vertex AI
AWS Bedrock
Azure AI (Microsoft Foundry)

Deprecated Models

Model	Deprecation Date	Migration Target
Claude 3 Opus	2025-07-21	`claude-opus-4-1-20250805`
Claude 3 Sonnet	2025-07-21	`claude-sonnet-4-5`
Claude 2.1	2025-07-21	`claude-sonnet-4-5`

Detailed Documentation

For advanced settings and parameters:

Claude Advanced Features - Parameter configuration, streaming, caching
Platform-Specific Guide - Usage on Vertex AI, AWS Bedrock, Azure AI
Tool Use Guide - Function Calling implementation

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