Claude Opus 5.5
Claude Opus 5.5 (upstream claude-opus-5-5), Anthropic's model for long-running agentic coding and knowledge work: 1M-token context, 128K max output, text and image input. Adaptive thinking is always on, with depth set by effort (default medium), and forced tool use is not supported.
anthropic/claude-opus-5.5
Capabilities
Claude Opus 5.5 is a language model served through the Pika developer API. Send it a list of chat messages and it streams back a text reply, using the Anthropic Messages API shape.
Authentication
api key header
The Pika API uses API keys to authenticate requests. Send your key in the X-API-Key header. Your API key is a secret. Don't expose it in browsers or other client-side code. Instead, call the API from your server. The signed-in playground uses a portal session and never sends your API key.
header
X-API-Key: YOUR_API_KEY
Endpoint
synchronous · chat completions
POSThttps://api.dev.pika.art/anthropic/v1/messages
Request
POST /anthropic/v1/messages
Request
curl -X POST https://api.dev.pika.art/anthropic/v1/messages \-H "X-API-Key: YOUR_API_KEY" \-H "anthropic-version: 2023-06-01" \-H "Content-Type: application/json" \-d '{"model": "anthropic/claude-opus-5.5","max_tokens": 1024,"messages": [{ "role": "user", "content": "Hello, who are you?" }]}'
Pass anthropic/claude-opus-5.5 as the model and a messages array of { role, content } turns. Set stream: true to receive tokens incrementally over server-sent events.
The Python and TypeScript examples use the official Anthropic SDK with its base URL pointed at https://api.dev.pika.art/anthropic — no Pika-specific SDK is needed. Keep your Pika API key and existing Anthropic code works without a rewrite.
Errors
shared across calls
Errors use conventional HTTP status codes with a JSON body of the shape {"message": "..."}. A missing or invalid key returns 401.