ModelFoldclaude-opus-5
Claude Opus 5 is Anthropic’s thoughtful and proactive model, bringing near-Fable 5 intelligence to end-to-end coding, complex reasoning, visual analysis, and long-horizon enterprise work.
Pricing: Input 500 credits / 1M tokens (≈ $2.50), Output 2500 credits / 1M tokens (≈ $12.50).
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Claude Opus 5 API for Thoughtful and Proactive Agentic Work
Access Claude Opus 5 API on ModelFold to build intelligent systems that can reason, code, analyze visual content, use tools, verify results, and carry demanding software, research, and enterprise tasks from initial planning to final delivery.
Claude Opus 5 Brings Fable 5 Intelligence into Everyday Work
Claude Opus 5 is Anthropic’s advanced model for demanding reasoning, agentic coding, and enterprise knowledge work. Drawing on the frontier intelligence represented by Claude Fable 5, it brings thoughtful and proactive execution to frequent production workloads. Claude Opus 5 can plan, implement, verify, and refine complex tasks from start to finish, supporting end-to-end software development, precise code review, root-cause bug analysis, scientific research, visual document understanding, and complex office deliverables. Now available through ModelFold, Claude Opus 5 API allows developers to adjust reasoning effort according to different requirements for intelligence, latency, and token consumption. Lower effort levels remain effective for faster everyday workloads, while higher settings provide additional depth for difficult coding, problem-solving, and long-horizon agentic tasks. It also supports long-context processing, adaptive thinking, vision input, file analysis, prompt caching, and tool-assisted execution. Refer to the latest Claude Opus 5 API documentation on ModelFold for current parameters, context limits, supported tools, beta features, and request formats.
What Claude Opus 5 Improves Beyond Claude Opus 4.8
Thoughtful and Proactive Execution with Claude Opus 5 API
Claude Opus 5 API takes a more active role in moving complex assignments toward completion. It can plan the required steps, use available tools, inspect intermediate results, recover from unsuccessful approaches, and continue refining its work without waiting for repeated instructions. This stronger follow-through is particularly valuable for long-horizon coding, research, automation, and enterprise tasks that cannot be completed reliably in a single response.
More Performance per Task from Anthropic Claude Opus 5 API
Efficiency improves across agentic coding, computer use, multidisciplinary reasoning, and business automation. Anthropic reports that Claude Opus 5 can outperform competing models at a similar or lower cost per task, while flexible effort settings let developers allocate fewer tokens to routine workloads and reserve deeper reasoning for more difficult assignments. Supported effort levels, thinking behavior, pricing, and request parameters should be confirmed in the latest Claude Opus 5 API documentation on ModelFold.
Novel Problem-Solving through Claude 5 Opus API
Unfamiliar problems benefit from stronger abstraction, experimentation, and adaptive reasoning. On ARC-AGI 3, Claude Opus 5 achieved a score three times higher than the next-best evaluated model, reflecting its ability to infer hidden rules and develop solutions without relying only on familiar patterns. Claude 5 Opus API is therefore suited to analytical tasks where the initial information is incomplete, ambiguous, or unlike standard training examples.
End-to-End Coding and Bug Finding in Claude Opus 5 API
Software engineering improvements extend from implementation to verification. Claude Opus 5 API can complete multi-file features, conduct repository-wide refactors, review code with high precision and recall, identify underlying causes instead of surface symptoms, and find edge cases that simpler patches may overlook. It also performs strongly on major coding evaluations, including Frontier-Bench, CursorBench, and the Artificial Analysis Coding Agent Index. Once you've evaluated Claude Opus 5 on these end-to-end engineering tasks, run the same multi-file features and repository-wide refactors through the Grok 4.6 API to compare their coding intelligence on identical workloads.
Long-Context, Visual, and Office Work with Opus 5 API
Large repositories, lengthy documents, charts, diagrams, technical drawings, spreadsheets, and presentation materials can be processed within connected workflows. Opus 5 API maintains reasoning, instruction following, and tool use across a one-million-token context window while supporting visual analysis, multi-sheet workbook creation, structured slide decks, scientific research, and coordinated subagent execution. Check the latest API documentation for current context limits, output limits, supported file formats, vision inputs, and tool availability.
More Aligned Agentic Behavior from Anthropic Claude Opus 5 API
Anthropic’s automated behavioral audit identifies Claude Opus 5 as its most aligned model to date. It recorded the lowest overall rate of misaligned behavior among the evaluated recent Claude models, alongside stronger adherence to Claude’s Constitution and lower rates of deceptive or reckless actions. These improvements provide a more controlled foundation for applications that allow an AI system to use tools, modify files, or carry out multi-step decisions.
Stronger Cybersecurity Assistance with Defined Safeguards
Cybersecurity performance improves over Claude Opus 4.8, particularly when identifying vulnerabilities in source code and helping developers understand or remediate software weaknesses. However, Claude Opus 5 remains substantially behind Mythos 5 at developing exploits, and its safeguards restrict higher-risk activities such as exploit generation, penetration testing, and binary-based vulnerability scanning. Availability of fallback behavior, security classifiers, and related beta functions depends on the integration, so consult the latest Claude Opus 5 API documentation on ModelFold for current implementation details.
Claude Opus 5 vs Claude Fable 5, Opus 4.8, and GPT-5.6 Sol Across Major Benchmarks
Claude Opus 5 demonstrates broad performance gains across terminal coding, knowledge work, novel problem-solving, agentic search, computer use, business automation, and biological reasoning. It records the leading result on several major evaluations, including Frontier-Bench v0.1, GDPval-AA v2, ARC-AGI 3, BrowseComp, OSWorld 2.0, and AutomationBench. Claude Fable 5 remains narrowly ahead on selected multidisciplinary, coding, legal, and health evaluations, while GPT-5.6 Sol leads DeepSWE v1.1 and stays closely matched on agentic search.
| Evaluation Area | Benchmark | Claude Opus 5 | Claude Fable 5 | Claude Opus 4.8 | GPT-5.6 Sol |
|---|---|---|---|---|---|
| Agentic Terminal Coding | Frontier-Bench v0.1 | 43.3% | 33.7% | 21.1% | 34.4% |
| Knowledge Work | GDPval-AA v2 | 1861 | 1747 | 1593 | 1736 |
| Novel Problem-Solving | ARC-AGI 3 | 30.2% | — | 1.5% | 7.8% |
| Agentic Search | BrowseComp | 90.8% | 87.4% | 84.3% | 90.4% |
| Multidisciplinary Reasoning | Humanity’s Last Exam, No Tools | 56.3% | 56.5% | 49.8% | — |
| Multidisciplinary Reasoning | Humanity’s Last Exam, With Tools | 64.7% | 63.9% | 57.9% | — |
| Computer Use | OSWorld 2.0 | 70.6% | 66.1% | 55.7% | 62.6% |
| Agentic Coding | DeepSWE v1.1 | 68.8% | 69.7% | 59.0% | 72.7% |
| Agentic Coding | FrontierCode v1.1, Main | 53.4% | 53.5% | 46.5% | 47.5% |
| Business Workflows | AutomationBench | 26.0% | 17.4% | 17.0% | 18.1% |
| Legal | Legal Agent Benchmark, Held-Out | 11.7% | 13.3% | 10.4% | 2.5% |
| Health | HealthBench Professional | 59.8% | 66.0%† | 57.4% | 60.5% |
| Biology | BioMysteryBench, Hard | 49.4% | 46.5% | 42.4% | — |
| Biology | BioMysteryBench, Human-Solved | 90.1% | 89.0%† | 88.5% | — |
Bring Claude Opus 5 API into Your Application in Three Steps
Get started with our product in just a few simple steps...
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1. Create an Account and Get Your Claude Opus 5 API Key
Sign up for ModelFold or log in to your existing account, then generate an API key from the account dashboard. Keep the credential on a secure backend and never expose it in frontend code, public repositories, or shared files.
- 2
2. Select Anthropic Claude Opus 5 API and Prepare Your Request
Choose Claude Opus 5 from the available model list and structure the request with clear instructions, relevant context, expected output, and task boundaries. For complex coding or agentic work, include the complete specification, acceptance criteria, required files, and desired response format from the beginning.
- ✓
3. Test and Integrate Claude 5 Opus API
Send a representative test request, review the output quality, and adjust supported settings to balance reasoning depth, latency, and token usage. Once the results are consistent, connect the request to your application and add error handling, response validation, retries, and usage monitoring. Refer to the latest Claude Opus 5 API documentation on ModelFold for current model identifiers, endpoints, parameters, context limits, function schemas, tool-calling behavior, file requirements, and beta features.
Where Claude Opus 5 API Fits into Complex Real-World Work
End-to-End Software Engineering with Claude Opus 5 API
Development teams can use Claude Opus 5 API to explore unfamiliar repositories, implement multi-file features, refactor connected components, write tests, resolve integration failures, and validate the completed change. Stronger follow-through helps reduce unfinished stubs, superficial fixes, and repeated prompting across longer software tasks.
Code Review and Bug Investigation through Anthropic Claude Opus 5 API
Pull requests and large codebases can be examined for functional defects, hidden edge cases, architectural weaknesses, and incorrect assumptions. Anthropic Claude Opus 5 API can trace an issue beyond its visible symptom, investigate the underlying cause, and suggest corrections that account for related files, dependencies, and expected system behavior.
Research and Professional Analysis with Claude 5 Opus API
Reports, financial materials, scientific papers, policies, and extensive document collections can be evaluated as part of one connected assignment. Claude 5 Opus API can compare evidence, identify inconsistencies, develop structured conclusions, and transform the analysis into reports, recommendations, spreadsheets, or other decision-ready deliverables.
Long-Horizon Automation and Visual Work using Opus 5 API
Multi-stage applications can use Opus 5 API to interpret charts, PDFs, diagrams, screenshots, and technical references while coordinating research, tool use, content creation, and verification over extended tasks. It is also suited to workflows involving structured presentations, formula-driven spreadsheets, frontend visual replication, and parallel subagents working on independent parts of a larger objective.
Why Choose ModelFold for Claude Opus 5 API Access
One OpenAI-Compatible Endpoint
Send model claude-opus-5 to POST https://ai.modelfold.online/v1/chat/completions with Authorization: Bearer YOUR_API_KEY and an OpenAI-style messages array. Any HTTP client or OpenAI-compatible SDK works. Input and output token pricing is shown in the pricing section above.
Simple Request and Response Format
Each request carries the model id, your messages and an optional max_tokens. The response returns the assistant message in choices[0].message.content together with token usage and the credits charged, so cost tracking needs no extra calls.
Try Thinking Mode in the Playground
The Playground on this page lets you switch thinking on for Claude Opus 5 and compare answers before you integrate. It is billed per token from your wallet, exactly like the API.
Other Claude Models on the Same Endpoint
Claude Opus 5.5, Claude Opus 4.8 and Claude Sonnet 5.5 use the same /v1/chat/completions endpoint with their own model ids, and GET https://ai.modelfold.online/v1/models lists every model id your key can use.
FAQs About Claude Opus 5 API
What Is Claude Opus 5?⌄
Claude Opus 5 is Anthropic’s advanced model for demanding reasoning, agentic coding, and professional knowledge work. It is designed to carry complex assignments from initial planning through execution, verification, and final delivery, with particular strengths in end-to-end software engineering, code review, bug finding, visual analysis, scientific research, office deliverables, and long-horizon agentic tasks.
Is Claude Opus 5 API Available on ModelFold?⌄
Yes. Claude Opus 5 API is now available on ModelFold for developers building software products, coding assistants, research tools, internal business systems, and automated workflows. After creating an account and generating an API key, developers can select the supported Claude Opus 5 model and follow the current documentation to prepare and send requests.
How Does Claude Opus 5 Improve on Claude Opus 4.8?⌄
Claude Opus 5 brings significant gains in end-to-end coding, code review, root-cause bug analysis, novel problem-solving, computer use, business automation, scientific reasoning, and proactive task completion. It also performs more efficiently across different reasoning effort levels, allowing many workloads to achieve stronger results without automatically using the highest token and latency settings.
How Is Claude Opus 5 Different from Claude Fable 5?⌄
Claude Opus 5 is positioned as a thoughtful and proactive model that approaches the frontier intelligence of Claude Fable 5 while remaining practical for frequent production workloads.
What Can Anthropic Claude Opus 5 API Be Used For?⌄
Anthropic Claude Opus 5 API can support multi-file feature development, large codebase refactoring, pull request review, bug investigation, deep research, document analysis, spreadsheet creation, presentation development, visual interface replication, scientific reasoning, computer-use agents, and coordinated subagent workflows. It is particularly useful when an application must connect planning, execution, validation, and final delivery within one extended task.
How Much Context Does Claude Opus 5 Support?⌄
Claude Opus 5 supports a one-million-token context window as its default and maximum context capacity. This allows it to work across large repositories, extensive document collections, long conversations, and multi-stage agentic sessions while maintaining instructions and relevant context. Current output limits, file sizes, supported formats, and context-handling requirements should be confirmed in the latest Claude Opus 5 API documentation on ModelFold.
Does Claude Opus 5 API Support Function Calling, Tools, and Adjustable Reasoning?⌄
Claude Opus 5 supports tool use, prompt caching, adaptive thinking, and configurable effort levels for balancing reasoning depth, latency, and token usage. Anthropic has also introduced features such as mid-conversation tool changes and automatic fallbacks in beta. Available function schemas, effort values, thinking controls, tool types, fallback behavior, and beta capabilities may vary by integration, so refer to the latest Claude Opus 5 API documentation on ModelFold for current implementation details.
How Does Claude Opus 5 API Pricing Work on ModelFold?⌄
Claude Opus 5 API pricing on ModelFold is based on the platform’s current usage rates, generally including the input and output tokens consumed by each request. Total cost can vary according to prompt length, generated output, reasoning effort, context usage, retries, and tool-assisted execution. Review the latest ModelFold pricing information and Claude Opus 5 API documentation before estimating development or production expenses.
| Input | 500 credits 1M tokens≈ $2.50 |
| Output | 2500 credits 1M tokens≈ $12.50 |
Billed per token: input and output are priced separately, and thinking tokens count as output. The Playground charges exactly the same way.
Read API docs →curl https://ai.modelfold.online/v1/chat/completions \
-H "Authorization: Bearer $MODELFOLD_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"claude-opus-5","messages":[{"role":"user","content":"Hello"}]}'