Pricing, context window, capabilities, and release date — pulled from each provider's public docs. Both are available via the same AIgateway OpenAI-compatible endpoint; flip the model string to switch.
Both models stream in parallel through your own AIgateway key. Tokens, latency, and cost update as they arrive.
| Claude Opus 5.5 anthropic/claude-opus-5.5 | GPT-5.6 Terra openai/gpt-5.6-terra | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Family | Claude 4 | GPT-5 |
| Modality | text | text |
| Context window | 1,000,000 tok | 1,050,000 tok |
| Max output | 128,000 tok | 128,000 tok |
| Released | 2026-09-23 | 2026-07-10 |
| Input price | $4.00 /1M | $2.00 /1M |
| Output price | $20.00 /1M | $12.00 /1M |
| Cache read | — | — |
| Tools | yes | yes |
| Streaming | yes | yes |
| Vision | yes | yes |
| JSON mode | yes | yes |
| Reasoning | yes | yes |
| Prompt caching | — | — |
Claude Opus 5.5 is Anthropic's model for long-running agentic coding and knowledge work. It combines a one million token context window with adaptive thinking that is always on, a 128K token maximum output, and a medium default effort level.
GPT-5.6 Terra is an OpenAI GPT-5.6 model that balances intelligence and cost, using the Responses API for reasoning and stateful context management.
# pip install aigateway-py openai
# aigateway-py: sub-accounts, evals, replays, jobs, webhook verify.
# openai SDK: chat/embeddings/images/audio — drop-in compat per our SDK's own guidance.
from openai import OpenAI
client = OpenAI(
base_url="https://api.aigateway.sh/v1",
api_key="sk-aig-...",
)
# Try Claude Opus 5.5
client.chat.completions.create(
model="anthropic/claude-opus-5.5",
messages=[{"role":"user","content":"hello"}],
)
# Try GPT-5.6 Terra — same client, same key
client.chat.completions.create(
model="openai/gpt-5.6-terra",
messages=[{"role":"user","content":"hello"}],
)