The Poets & CodersStrict ZDR Verified

Anthropic

Nuanced writing, heavy coding, strategy & empathy.

Laboratory Overview

Anthropic is an AI safety and research lab dedicated to building reliable, beneficial, and steerable AI systems. Creators of Claude Opus 5, Sonnet 5, and Haiku, Anthropic excels at deep contextual synthesis, nuanced prose, and autonomous coding.

Core Research Focus:Nuanced writingheavy codingempathyfinancial/legal reasoninglow hallucinationtransparent inspectable deliberationmeta-cognitive multi-agent coordination.

Privacy & Zero Data Retention

Strict Zero Data Retention (ZDR): Requests are processed ephemerally in RAM. No user data, prompts, or completions are stored, indexed, or used for model training.

No user telemetry sent to Anthropic

Anthropic Foundation Models (12)

Available under ARMES unified subscription without separate API keys or billing agreements.

Tier:

Dense autoregressive decoder-only transformer with grouped-query attention and adaptive, always-on extended thinking; 1M-token context; native image input

Ultra

Opus 5.5

Claude Opus 5.5 (anthropic/claude-opus-5.5) is Anthropic's September 22, 2026 flagship Opus-class reasoning model, succeeding Claude Opus 5 with a 1M-token context window, native image input, adaptive always-on extended thinking, and $4/$20 per million input/output tokens. It leads the frontier on agentic coding, terminal/computer-use, knowledge-work Elo (GDPval-AA v2.1: 1846), and long-horizon tool-use evals, at a reported ~97 tokens/sec on Benchmark Heaven telemetry.

AA Intelligence Index:57.6

1M ctx

$4.00 / $20.00 /MTok

Intelligence Dossier Try in Chat

Sparse Mixture-of-Experts (MoE) Multimodal Transformer

MoEUltra

Opus 5

Anthropic's flagship 1M-context frontier multimodal foundation model, engineered for deep reasoning, autonomous coding agents, and complex long-horizon system execution.

AA Intelligence Index:50.8

1M ctx

$5.00 / $25.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Ultra

Opus 4.8

Anthropic's most capable model (released May 28, 2026; knowledge cutoff Jan 2026).

Terminal-Bench 2.1:84.6%

1M ctx

$5.00 / $25.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Ultra

Opus 4.7

Successor to Opus 4.6 at the same price (released Apr 16, 2026).

SWE-bench Verified:83.5%

1M ctx

$5.00 / $25.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Ultra

Opus 4.6

Creative writing, complex UI/UX coding, architectural decisions, production debugging, strategic advising, deep conceptual reasoning, emotional support

SWE-bench:80.8%

200K+ ctx

$5.00 / $25.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Ultra

Opus 4.5

Premium creative and analytical work

AA Intelligence Index:29.1

200K ctx

$5.00 / $25.00 /MTok

Intelligence Dossier Try in Chat

Dense Autoregressive Decoder-Only Transformer (undisclosed parameters; always-on adaptive thinking)

Pro

Sonnet 5.5

Claude Sonnet 5.5 (anthropic/claude-sonnet-5.5) is Anthropic's Sonnet-class workhorse released September 28, 2026 — a 1M-token-context, image-capable, always-thinking autoregressive model priced at $2/$10 per 1M input/output tokens. It succeeds Sonnet 5 as a direct upgrade, delivering a step-change in agentic coding (Terminal-Bench 4.0 70.6% vs Sonnet 5's 10.3%) and computer use (OSWorld 2.1 80.1%) while running at ~140 tps.

Terminal-Bench 4.0:70.6%

1M ctx

$2.00 / $10.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Pro

Sonnet 5

Anthropic's most agentic Sonnet yet (released Jun 30, 2026; knowledge cutoff Jan 2026).

SWE-bench Pro:53.8%

1M ctx

$2.20 / $11.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Pro

Sonnet 4.6

Coding, debugging, knowledge work, financial/legal reasoning, business writing, translation, data analysis, research.

SWE-bench:80.2%

200K+ ctx

$3.00 / $15.00 /MTok

Intelligence Dossier Try in Chat

Dense Transformer

Pro

Sonnet 4.5

Strong all-around coding and analysis

AA Intelligence Index:20.7

200K+ ctx

$3.00 / $15.00 /MTok

Intelligence Dossier Try in Chat

Dense Autoregressive Transformer (Claude 5.5 family; adaptive test-time reasoning tokens)

Free

Haiku 5.5

Claude Haiku 5.5 is Anthropic's fastest, most capable small model (released Oct 7, 2026), a dense autoregressive transformer with adaptive adjustable-effort thinking, a 1M-token context window, and vision input. Priced at $0.10/$0.50 per 1M input/output tokens, it delivers ~237 tps and strong agentic/coding gains over Haiku 4.5.

AA Intelligence Index:43.4

1M ctx

$0.11 / $0.55 /MTok

Intelligence Dossier Try in Chat

Dense Multimodal Transformer

Pro

Haiku 4.5

Anthropic's high-speed, frontier-class efficient model delivering 73.3% SWE-bench Verified coding performance at $1/$5 per million tokens with extended thinking capabilities.

SWE-bench Verified:73.3%

200K ctx

$1.00 / $5.00 /MTok

Intelligence Dossier Try in Chat

Explore Other AI Labs on ARMES

Compare models across the 26+ leading laboratories unified in your workspace.