---
id: "stealth/union-alpha"
also: ["stealth/union-alpha"]
card_usd_per_m: "0.0 in, 0.0 out, at stealth"
context: 262144
max_output: 131072
input: ["text", "image"]
output: ["text"]
released: "2026-09-16"
params: ["max_tokens", "response_format", "temperature", "tool_choice", "tools", "top_p"]
endpoints: 1
gateways: "openrouter (1)"
no_training: 1
trains: 0
retains_prompts: 1
---
# Union Alpha

Union Alpha is a multimodal model built for research, coding, and agentic workflows, while delivering frontier-level performance across a broad range of general-purpose tasks. Union Alpha is a stealth model....