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Claude Opus 5

anthropic/claude-opus-5

anthropic

Newest Opus — step-change over Opus 4.8 for deep reasoning and agentic coding at the same price. 1M context, 128k output, adaptive thinking

Code Examples

from blockrun_llm import LLMClient

client = LLMClient()  # Uses BLOCKRUN_WALLET_KEY (never sent to server)
response = client.chat("anthropic/claude-opus-5", "Hello!")
import { LLMClient } from '@blockrun/llm';

const client = new LLMClient();  // Uses BLOCKRUN_WALLET_KEY (never sent to server)
const response = await client.chat('anthropic/claude-opus-5', 'Hello!');
curl -X POST https://blockrun.ai/api/v1/chat/completions \
  -H "Content-Type: application/json" \
  -H "PAYMENT-SIGNATURE: <payment_header>" \
  -d '{
    "model": "anthropic/claude-opus-5",
    "messages": [{"role": "user", "content": "Hello!"}],
    "max_tokens": 1024
  }'

Pricing

Input$5.00 / 1M tokens
Output$25.00 / 1M tokens
Context1M tokens
Max Output128K tokens

No markup on official Anthropic rates; $0.001 fee per call.

Payment

Network
Base
Currency
USDC
Protocol
x402

Pay per request with USDC on Base. No subscription required.

Try It

Send a message to try Claude Opus 5

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About Anthropic Claude Opus 5

Claude Opus 5 is a coding, reasoning and vision model from Anthropic with a 1M-token context window and up to 128K tokens of output per call. It is billed per token at the provider's list rate, with no markup on chat tokens. It is served through BlockRun's OpenAI-compatible API, so it can be called without an account, an API key, or a subscription.

What it costs

Claude Opus 5 is billed per token. The underlying rates are $5.00 per million input tokens and $25.00 per million output tokens with no platform margin on chat tokens; only a small per-transaction fee covering on-chain settlement is added on top, and the resulting price is quoted in the 402 before you pay. You are charged for the tokens a request actually consumes — there is no monthly commitment and no unused balance to forfeit. With a context window of 1,000,000 tokens and up to 128,000 tokens of output, a single call can carry a substantial working set.

Specifications

Context window
1,000,000 tokens
Maximum output
128,000 tokens
API compatibility
OpenAI-compatible
Payment
USDC via x402
Categories
chat, coding, reasoning, vision

Calling it from your code

Pass anthropic/claude-opus-5 as the model field. Because the endpoint mirrors the OpenAI chat completions schema, any existing OpenAI client works by changing the base URL — streaming, tool use, and multi-turn messages all behave the same way.

The first request returns a 402 carrying the exact price; a signed retry runs it, and client libraries fold the two into one call — how the payment works. See the documentation for request and response shapes, the LLM API page for every model on this endpoint, or browse the full catalog of 78 chat models to compare alternatives.

Related models

Every model on BlockRun is reached through the same endpoint and the same payment flow, so switching is a one-line change to the model field. These are the closest alternatives to Claude Opus 5: