Anthropic · API

Claude Opus 5 API

Claude Opus 5 is the featured Opus route for complex coding agents, with 1M context, vision, and structured tool use.

Use 1M context with one OmniaKey API key.

Model ID: claude-opus-5
Context: 1M
Provider: Anthropic
Input · USD / 1M tokens: $1.4 USD; Official price $5 USD
Output · USD / 1M tokens: $7 USD; Official price $25 USD
Savings: 72%
Last verified: 2026-08-05

What this model is for

Claude Opus 5 sits above Sonnet 5 in the current Claude catalog on listed token price. It is the deliberate choice for work where a longer, more expensive attempt is preferable to repeated shallow retries: architectural changes, unfamiliar repositories, and reviews with a high cost of error.

The route accepts text and visual input, exposes structured tool use, and lists a 1M context window. Through OmniaKey, the same model ID works with the OpenAI-compatible endpoint shown below and with supported coding clients such as Claude Code, Cursor, Cline, and Aider.

Choose Opus 5 when ambiguity, architectural scope, or the cost of a wrong answer matters more than the lower token rate of Sonnet 5.

Best-fit coding workloads

Ambiguous refactors

Trace behavior across packages, identify hidden contracts, and plan changes before editing code.

Architecture and incident review

Use broad repository evidence when a missed dependency or incorrect conclusion is expensive.

Long-running tool agents

Combine search, tests, and structured tool calls in tasks that need sustained context.

Technical specification

Catalog facts and integration details verified for this route.

Model ID: claude-opus-5
Context: 1M
Inputs and tools: Vision · Tool use
API endpoint: /v1/chat/completions
Cache hit / 1M: $0.14 USD
Coding clients: Claude Code · Cursor · Cline · Aider

Limits to plan around

Opus 5 has a higher listed input and output rate than Sonnet 5, so routine edits and repetitive tasks can cost more without needing its positioning.
A 1M context limit is capacity, not a reason to send an entire repository unfiltered. Retrieval quality and client-side limits still shape usable context.
Model revisions can change output style and tool-call behavior. Test prompts, parsers, and approval boundaries before replacing a pinned production model.

Compare nearby models

Compare workload fit and current listed token rates before choosing a route.

Model	Best for	Context	Input	Output
Claude Opus 5This page claude-opus-5	Complex, ambiguous, or high-cost-of-error coding work where deeper analysis justifies the higher rate.	1M	$1.4 USD Official price $5 USD	$7 USD Official price $25 USD
Claude Sonnet 5 claude-sonnet-5	Daily implementation, tests, and repository maintenance when cost per iteration matters more.	1M	$0.84 USD Official price $3 USD	$4.2 USD Official price $15 USD
Claude Opus 4.8 claude-opus-4-8	Existing workflows pinned to the 4.8 model ID that need controlled migration testing.	1M	$1.4 USD Official price $5 USD	$7 USD Official price $25 USD

SDK quickstarts

Use one base URL and model ID from cURL, Python, or TypeScript.

Streaming chat completion

curl https://api.omniakey.com/v1/chat/completions \
  -H "Authorization: Bearer $OMNIAKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-5",
    "messages": [
      {"role": "user", "content": "Review this pull request"}
    ],
    "stream": true
  }'

Estimate token cost

Enter expected input and output tokens to compare current listed rates.

Input tokensOutput tokens

OmniaKey estimate: $0.28
Official-rate estimate: $1.00
Estimated savings: $0.72

Estimate covers input and output tokens only. Cache usage, retries, tools, and client-side token accounting can change the final charge.

Related coding guides

Deeper selection, setup, and troubleshooting guidance for this model family.

Claude Opus 5 vs GPT-5.6 Sol for Coding

Choose Opus 5 when ambiguous, long-horizon repository work rewards deeper investigation; choose GPT-5.6 Sol when you want the GPT-5.6 frontier model and its Responses-native tool stack.

Read guide

Claude Opus 5 review

Opus 5 is the best-value Claude for difficult, long-running agent work, but Sonnet 5 still wins on routine cost.

Read guide

Claude Code Pricing

Choose a subscription for a recurring allowance and hosted features, or API billing when you need metered usage, explicit model costs, and project-level spend control.

Read guide

Sources and verification

Model facts and links were checked on 2026-08-05. Provider documentation remains the authority for upstream behavior.

Frequently asked questions

How much does Claude Opus 5 cost on OmniaKey?

OmniaKey charges $1.4 USD per 1M input tokens and $7 USD per 1M output tokens, in USD. Official prices are $5 USD and $25 USD; you save 72%.

What is the context window for Claude Opus 5?

The listed context window is 1M. Actual usable limits can also depend on the client and upstream request format.

When is Claude Opus 5 worth using instead of Sonnet 5?

Use Opus 5 for ambiguous cross-system work, architectural decisions, difficult debugging, or reviews where a wrong answer is costly. Start routine implementation and repetitive maintenance on Sonnet 5, then escalate when the task stalls or needs broader reasoning.

Can I use Claude Opus 5 with Claude Code through OmniaKey?

Yes. The current catalog lists Claude Code compatibility. Configure the OmniaKey API base URL and key, then select the claude-opus-5 model ID where the client permits model selection.

What should I test before migrating to Claude Opus 5?

Replay representative prompts and tool workflows, then check output parsing, tool names and arguments, token usage, retry behavior, and human approval steps. Do not infer production compatibility from a single chat response.