Claude

Claude 4.5 Family Technical Assessment (January 2026)

Claude operates as a conversational AI system built on proprietary large language model technology. The current production deployment consists of three Claude 4.5 models: Opus 4.5 (claude-opus-4-5-20251101), Sonnet 4.5 (claude-sonnet-4-5-20250929), and Haiku 4.5 (claude-haiku-4-5-20251001) with standard RESTful API access via POST /v1/messages 📑. All models support text and image inputs with text output, 200K context windows (1M beta for Sonnet 4.5), and 64K maximum output 📑. Internal training methodology, neural architecture specifications, and infrastructure implementation are not publicly disclosed 🌑.

Model Family Specifications

• Claude Opus 4.5: Flagship model positioned for complex coding, autonomous agents, and extended reasoning tasks. Pricing at $5 input/$25 output per million tokens—67% cheaper than predecessor Opus 4.1 ($15/$75) 📑. Unique effort parameter (low/medium/high) allows controllable reasoning depth trading latency for accuracy 📑. Benchmark Performance: 80.9% on SWE-bench Verified, positioning it as current leader in real-world software engineering tasks 📑.
• Claude Sonnet 4.5: Balanced model for production agents and coding workflows. Pricing at $3/$15 per million tokens 📑. Marketed as "best coding model in the world" for agentic tasks with 77.2% SWE-bench Verified score (200K context) 📑. Supports extended 1M context window via beta header context-1m-2025-08-07 📑. Operational Capacity: Anthropic reports 30+ hours of autonomous coding capability in internal testing 📑.
• Claude Haiku 4.5: Speed-optimized model delivering "near-frontier performance" at minimal latency. Pricing at $1/$5 per million tokens 📑. Classified under AI Safety Level 2 (ASL-2) versus ASL-3 for Opus and Sonnet models 📑.

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Developer Platform Capabilities

• Extended Thinking Mode: All Claude 4.5 models support optional extended reasoning by allocating additional tokens for pre-response processing 📑. Performance Impact: Affects prompt caching efficiency; thinking blocks from previous turns now preserved in context by default for Opus 4.5 📑.
• Memory Tool (Beta): API feature allowing persistent storage/retrieval beyond context window via memory_20250818 tool type 📑. Storage Backend: Project-scoped persistence infrastructure; specific database implementation not disclosed 🌑.
• Computer Use: Sonnet 4.5 and Opus 4.5 support screen interpretation and simulated keyboard/mouse input for autonomous computer navigation 📑. Opus 4.5 includes enhanced zoom tool for screen region inspection 📑.

Integration Architecture

• Multi-Platform Availability: Direct API, AWS Bedrock, Google Cloud Vertex AI, and Microsoft Azure AI Foundry 📑. Starting Claude 4.5, cloud platforms offer global endpoints (dynamic routing) and regional endpoints (geographic data routing with 10% premium) 📑.
• Tool Use Framework: Native support for web_search, code_execution, text_editor, computer_use, bash, and memory tools 📑. Execution Environment: Sandboxing mechanisms and security isolation for code execution not publicly detailed 🌑.

Claude Code Development Environment

• Version 2.x Features: Command-line and VS Code extension released with checkpoints (state save/rollback), native Git integration, and parallel sub-agents 📑.
• Model Context Protocol (MCP): Connector system for external data sources and tools 📑.

Evaluation Guidance

Technical teams should prioritize the following validation steps:

• Extended Thinking Cost: Benchmark the trade-off between "Thinking Tokens" consumption and code generation accuracy on SWE-bench tasks to calculate ROI 🧠.
• Computer Use Security: Audit the sandboxing environment when enabling "Computer Use" on Sonnet 4.5 to ensure the agent cannot access restricted filesystem areas 🌑.
• Migration Stability: Verify prompt consistency when migrating from Sonnet 3.5 to 4.5, specifically checking for regression in JSON schema adherence 📑.
• Azure Latency: Test regional endpoint latency on Azure AI Foundry compared to direct Anthropic API calls to determine the optimal deployment path 📑.