AI Agentic Persistence
Specifically tuned for long-horizon tasks where the model must iterate autonomously to overcome environment limitations or script errors.
claude-opus-5 / file-analysis
The AI Opus 5 API is a high-reasoning model featuring a 1M token context window and native visual PDF analysis. Built by Anthropic for complex autonomous agents, it offers frontier-tier intelligence at standard Opus pricing via GPTProto.com.
$ 4
$ 5
file
$ 20
$ 25
text
AI Opus 5 API Standout Features
Discover the core technical capabilities that make the AI Opus 5 API the leader in reasoning-heavy agentic workflows.
Visual PDF AI Analysis
Native multimodal support allows the model to see charts, diagrams, and tables within PDFs, providing deeper document understanding than text alone.
Prompt Caching API
Save 90% on input costs for repeated long-context queries with a minimum cache size of just 512 tokens, making agents faster and cheaper.
1M Token AI Context
Process massive datasets with nearly perfect recall. This huge context window eliminates the need for complex RAG in many document synthesis tasks.
How to Get a claude-opus-5 API Key
Getting a claude-opus-5 API key takes four steps and a few minutes. Create a free GPTProto account, add credits, generate your key, and make your first call — at $4 / $20 it's a cheaper claude-opus-5 API key than going direct, and one key works across every model on the platform. Full claude-opus-5 Documentation is in the docs.
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-5, 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-5.
Make your first API call
Use your API key with our sample code to send a request to claude-opus-5 via GPT Proto and see instant AI-powered results.
AI Opus 5 API: Frequently Asked Questions
Find answers to common questions about the AI Opus 5 API, including technical specs, token pricing, and agentic capabilities for enterprise deployments at scale.
How does the AI Opus 5 API handle reasoning latency?
Without thinking mode enabled, the AI Opus 5 API latency matches the previous generation. When internal reasoning is active, time-to-first-token averages 2 to 4 seconds. This delay allows the model to perform test-time compute scaling, which significantly improves logic and reduces errors in complex coding or mathematical tasks. For users requiring sub-second response times, we recommend utilizing Fast Mode or our Auto-Fallback routing.
Is data from the AI Opus 5 API used for training?
No. When you access the AI Opus 5 API through GPTProto.com, your data is protected by enterprise-grade privacy standards. Anthropic does not use data sent via the API for training their models by default. This ensures that your proprietary codebases, financial documents, and sensitive customer information remain confidential and secure throughout the inference process, satisfying strict corporate compliance requirements.
What are the PDF processing limits for this AI model?
The AI Opus 5 API supports standard PDFs up to 32MB and 600 pages. For requests where the context window is under 1M tokens, the page limit is 100. Because this AI model uses vision capabilities to analyze documents, each page is processed as both text and image. For very dense documents with complex tables or small fonts, we suggest splitting the PDF into sections or using the Files API to avoid exceeding request size limits.
How does the AI Opus 5 API pricing compare to Fable?
The AI Opus 5 API offers frontier-level reasoning at exactly half the cost of Claude Fable 5. Input tokens are priced at $5.00 per 1M, and output tokens are $25.00 per 1M. This allows developers to build high-intelligence agents without the premium costs associated with standard frontier-tier models. Additionally, GPTProto users benefit from a 90% discount on prompt caching hits, significantly lowering costs for repeated long-context queries.
Does the AI Opus 5 API support tool use changes?
Yes, the AI Opus 5 API supports mid-conversation tool dynamic changes. Using the specific 2026-07-01 header, you can modify tool definitions between conversation turns without losing your prompt cache. This is ideal for multi-step agents that need to adapt their available functions based on the current state of a workflow, such as moving from data extraction tools to database write tools within a single long-running session.
Can the AI Opus 5 API analyze charts in PDFs?
Absolutely. Unlike basic text extraction models, the AI Opus 5 API features native multimodal vision. It converts PDF pages into images to understand visual layouts, charts, graphs, and diagrams. This makes it an ideal tool for financial analysis or visual engineering tasks where the meaning of the document is tied to its visual representation. To ensure full visual understanding, ensure your request is sent to the visual analysis endpoint.