Skip to content

Anthropic Claude

What it is

Anthropic is an AI safety and research company that produces the Claude family of LLMs, known for strong reasoning, coding performance, and large context windows.

What problem it solves

Offers a high-performance alternative to OpenAI with a focus on "Constitutional AI" (safety) and exceptional performance in coding, long-form document analysis, and complex reasoning tasks.

Where it fits in the stack

LLM / Reasoning Engine / Provider. Often used as the primary engine for coding agents due to its high accuracy in code generation and refactoring.

Typical use cases

  • Pair Programming: Sonnet is typically the default Claude lane for tools like Aider.
  • Complex Analysis: Summarizing long technical documentation or legal files.
  • Strict Adherence: Workflows requiring close following of complex formatting rules.

Getting started

Install the SDK: 

pip install anthropic

Basic API call (Python): 

import anthropic

client = anthropic.Anthropic()

message = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[
        {"role": "user", "content": "Hello, Claude"}
    ]
)
print(message.content)

Strengths

  • Coding Excellence: Sonnet is widely regarded as one of the strongest daily-driver models for software engineering.
  • Safety Focus: Built with Constitutional AI principles for better alignment and safety.
  • Large Context: Ability to handle up to 200k+ tokens (and expanding).
  • Low Hallucination: Generally exhibits high factual accuracy and honesty.
  • Pricing Tiers: Offers a competitive range from the low-cost Haiku (high speed, low cost) to the flagship Sonnet (balanced performance/cost) and Opus (most capable/expensive).

Model routing

Haiku

  • Use for: fast classification, extraction, rewriting, and cheap high-volume tasks
  • Default? No
  • Comment: use when throughput matters more than deep reasoning

Sonnet

  • Use for: default coding, planning, document reasoning, and most daily serious work
  • Default? Yes
  • Comment: best Claude default for mixed quality/cost work

Opus

  • Use for: premium escalation on hard synthesis, difficult reasoning, or high-stakes final passes
  • Default? No
  • Comment: use only after Sonnet fails or when the answer quality matters enough to justify the premium

See the central routing guide: Model Routing Guide

Limitations

  • Cloud Dependency: Requires external API access (proprietary, closed-source).
  • Rate Limits: Can be stricter than OpenAI on lower usage tiers.
  • Cost: High-end models like Opus are significantly more expensive than smaller models.

When to use it

  • For software development tasks where Sonnet is the right default
  • When safety and alignment are critical priorities for your application.
  • For analyzing very long documents or entire codebases in a single context.
  • When you want a three-tier routing strategy: Haiku for cheap work, Sonnet for defaults, Opus for escalation

When not to use it

  • When a local/offline solution is required for privacy or cost.
  • If you need native image generation (DALL-E style) in the same API call.

Licensing and cost

  • Open Source: No (Proprietary)
  • Cost: Paid (Usage-based pricing; free tier available via console for testing)
  • Self-hostable: No (Cloud service)

Sources / References

Contribution Metadata

  • Last reviewed: 2026-03-15
  • Confidence: high