200k Context Window
Ingest 500-page archives with near-perfect retrieval accuracy for massive repository analysis.
claude-opus-4-5-20251101 / web-search
Claude 4.5 Opus is Anthropic's pinnacle for logic-heavy tasks. Use Claude 4.5 Opus code to refactor microservices, analyze 200k context codebases, or execute agentic loops with the new dynamic web search tool.
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API
Web Search
curl --request POST "https://gptproto.com/v1/messages" \
--header "Authorization: Bearer $GPTPROTO_API_KEY" \
--header "Content-Type: application/json" \
--header "anthropic-version: 2023-06-01" \
--data '{
"model": "claude-opus-4-5-20251101",
"max_tokens": 1024,
"messages": [
{
"role": "user",
"content": "What'\''s the weather in NYC?"
}
],
"tools": [
{
"type": "web_search_20250305",
"name": "web_search",
"max_uses": 5
}
]
}'Key Features of Claude 4.5 Opus
A breakdown of the advanced capabilities found in Claude 4.5 Opus code for professional users.
Dynamic Web Search
Claude filters web results via code execution to provide accurate, real-time cited answers.
System 2 Reasoning
Designed for PhD-level research and logic puzzles, outperforming GPT-5 in internal benchmarks.
Agentic Tool Use
Optimized for autonomous loops with a 25% reduction in hallucinated tool parameters for RPA.
Build with claude opus 4.5 20251101 in Minutes
Follow these simple steps to set up your account, get credits, and start sending API requests to claude opus 4.5 20251101 via GPT Proto.
Sign up
Create your free GPT Proto account to begin. You can set up an organization for your team at any time.
Top up
Your balance can be used across all models on the platform, including claude opus 4.5 20251101, giving you the flexibility to experiment and scale as needed.
Generate your API key
In your dashboard, create an API key — you'll need it to authenticate when making requests to claude opus 4.5 20251101.
Make your first API call
Use your API key with our sample code to send a request to claude opus 4.5 20251101 via GPT Proto and see instant AI-powered results.
Claude 4.5 Opus FAQ
What makes Claude 4.5 Opus code better for logic?
Claude 4.5 Opus uses advanced 'System 2' thinking, achieving a 91.2% on MMLU benchmarks. This makes the model uniquely suited for multi-layered logic puzzles and PhD-level research queries. Compared to earlier models, Claude maintains strict adherence to complex system prompts over long conversations, ensuring that technical synthesis remains accurate even as context grows toward the 200,000 token limit.
How does Claude 4.5 Opus handle massive codebases?
With a 200k context window and 99.9% retrieval accuracy, Claude can ingest mid-sized repositories or 500-page archives. Developers use Claude 4.5 Opus code to find contradictory clauses in legal sets or identify architectural bottlenecks across dozens of files. This massive repository analysis capability ensures that the model provides context-aware refactoring and logic verification that smaller models simply cannot match.
What is dynamic filtering in Claude 4.5 Opus search?
The web_search_20260209 tool version allows Claude to write and execute code to post-process search results. Instead of loading full HTML, Claude filters data before it hits the context window. This reduces token consumption while improving accuracy for technical documentation searches and citation verification. It is specifically designed to keep your Claude 4.5 Opus instances updated with real-time web content without degrading performance.
Is Claude 4.5 Opus pricing competitive on GPTProto?
Yes. Input is $15.00 and output is $75.00 per 1M tokens. By using GPTProto, you access Tier 4 rate limits immediately, avoiding the $5,000 monthly spend requirement usually needed for the native Anthropic API. We also offer a 90% discount on cache hits ($1.50/1M tokens) and a 50% discount for batch processing, making high-volume Claude 4.5 Opus code execution more economical for enterprise-grade deployments.
Does Claude 4.5 Opus support multimodal inputs?
Claude 4.5 Opus natively processes images, PDFs, and documents. It can reason across text and visual diagrams within a technical blueprint or financial chart. This allows for the synthesis of complex data types in a single conversation turn. Whether you are extracting specs from high-res diagrams or analyzing handwritten notes, Claude 4.5 Opus provides high-fidelity multimodal intelligence that outperforms GPT-4o in standard MMMU benchmarks.
When should I use Claude 4.5 Opus instead of Sonnet?
Use Claude 4.5 Opus for deep technical synthesis, architectural planning, and high-order reasoning where precision is paramount. While Claude 4.5 Sonnet offers a better speed-to-intelligence ratio for general tasks, Opus is the 'heavy' model designed for tasks that require balancing many competing variables. If your project involves complex financial modeling or full-stack engineering refactors, Claude 4.5 Opus is the superior choice.
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