Anthropic's most capable reasoning and agentic model, optimized for complex coding, enterprise workflows, and long-horizon tasks at half the cost of Fable 5.
curl https://api.venice.ai/api/v1/chat/completions \
-H "Authorization: Bearer $VENICE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-opus-5-5",
"messages": [{ "role": "user", "content": "Explain quantum tunneling simply." }]
}'Overview
Claude Opus 5.5 is Anthropic's flagship AI model for deep reasoning, agentic workflows, and professional coding. Released in July 2026, it delivers near-Fable 5 intelligence at half the price, with a 1M-token context window, vision, web search, and function calling — all while preserving privacy on Venice.
Running Claude Opus 5.5 on Venice ensures your prompts are never stored or profiled — anonymized processing means full sovereignty over your inputs. You get the same powerful, code-optimized model Anthropic offers, but without surveillance. This is permissionless access to a top-tier reasoning engine, with zero retention of your data.
Agent quickstart
The API is OpenAI-compatible: change the base URL and the model id and existing client code works unchanged.
curl https://api.venice.ai/api/v1/chat/completions \
-H "Authorization: Bearer $VENICE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-opus-5-5",
"stream": true,
"messages": [{ "role": "user", "content": "Draft the release note." }]
}'curl https://api.venice.ai/api/v1/chat/completions \
-H "Authorization: Bearer $VENICE_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "claude-opus-5-5",
"messages": [{ "role": "user", "content": "Find the rate limits." }],
"tools": [{
"type": "function",
"function": {
"name": "search_docs",
"description": "Search the API documentation.",
"parameters": {
"type": "object",
"properties": { "query": { "type": "string" } },
"required": ["query"]
}
}
}],
"tool_choice": "auto"
}'import os
from openai import OpenAI
client = OpenAI(
api_key=os.environ["VENICE_API_KEY"],
base_url="https://api.venice.ai/api/v1",
)
resp = client.chat.completions.create(
model="claude-opus-5-5",
messages=[{"role": "user", "content": "Build without permission."}],
)
print(resp.choices[0].message.content)Specifications
Assessment
Use cases
Prompting
Use explicit effort settings (high, xhigh, max) to control reasoning depth and cost.
Enable thinking mode selectively — it's on by default but can be disabled at effort high or below.
Leverage mid-conversation tool changes (beta) to adapt tools without losing cache.
Structure requests with JSON schema when you need predictable output formats.
Break long tasks into phases using clear separators — the model handles 1M-token context efficiently.
Include example inputs when using vision — clarity improves multimodal accuracy.
Alternatives
| Model | Best for | Context | Open weights | Price (Venice) |
|---|---|---|---|---|
| Claude Opus 5.5 | Deep reasoning, agentic coding | 1M tokens | No | $4.80 in · $24 out / 1M |
| Claude Fable 5.1 | Frontier intelligence | 1M tokens | No | $12 in · $60 out / 1M |
| Claude Sonnet 4.6 | Balanced production use | 1M tokens | No | $3.60 in · $18 out / 1M |
| DeepSeek V4.1 Flash | Cost-efficient reasoning | 1M tokens | Yes | $0.38 in · $1.50 out / 1M |
Choose Claude Opus 5.5 when you need the deepest reasoning and coding performance with full tooling — it's the smart balance between Fable 5's power and Sonnet's economy.
Pricing
Billed per token on Venice: $4.80 per 1M input tokens and $24 per 1M output tokens.
New Venice accounts include a free daily allowance and 500 welcome credits — no credit card required.
Getting a key
Create a key in API settings. Nothing else is required to start.
Export it as VENICE_API_KEY so the snippets above run unedited.
Point an existing OpenAI client at https://api.venice.ai/api/v1. The scheme is part of the value: an OpenAI client given a bare host does not resolve it.
Pass claude-opus-5-5 as the model and send the request.
FAQ
Claude Opus 5.5 is Anthropic's most capable AI model for complex reasoning, coding, and enterprise workflows. Released in July 2026, it features a 1M-token context window, vision, web search, and function calling, optimized for professional and agentic use cases.
On Venice, pricing is $4.80 per 1M input tokens and $24 per 1M output tokens. Cached input is significantly cheaper at $0.24 per 1M tokens, reducing costs for repeated access.
No. Claude Opus 5.5 is a proprietary model developed by Anthropic. It is not open source or freely available for self-hosting. You can use it via API on Venice with pay-per-use pricing.
Yes. It supports vision with multiple image inputs, enabling multimodal reasoning and analysis within its 1M-token context window.
Yes. It supports function calling, web search, and mid-conversation tool changes in beta, making it ideal for building dynamic AI agents and automation workflows.
Fable 5.1 is slightly more powerful, but Opus 5.5 delivers 99.5% of its performance at half the cost. For most professional and agentic tasks, Opus 5.5 offers the best value.
It has a 1,000K-token context window — among the largest available — allowing it to process entire codebases, long documents, and complex multimodal inputs in a single session.
One key, free to start, no credit card.