Union Alpha

Stealth model, operator anonymous. Union Alpha appeared on OpenCode on 2026-09-16 as a free one-week preview (“Union Alpha Free”, model id opencode-go/union-alpha) and the same day on OrcaRouter as a free OpenAI-compatible endpoint. OpenCode’s copy: built for agentic coding, supports images, no training on user data, capacity “5T tokens a day so far, potentially can go up”. Asked directly, the model answers that the maker is anonymous and it is a stealth model. No vendor, checkpoint, parameter count, or context window is published.

• The GLM hypothesis: community fingerprinting (run by Pliny the Liberator and others) found 21/21 image-bearing probes matching GLM-5.3 Flash prompt-token counts after a constant -17 offset, and gMASK / </think> markers adding +2 tokens in both Union and the GLM control. That is strong GLM-compatible tokenizer evidence, but the exact checkpoint and operator remain unconfirmed - GLM-5.4 is a plausible hypothesis, not an established identity. This card therefore carries no developer attribution.
• Measured performance: Artificial Analysis pegs it around 53% on Terminal-Bench v4.0 at an anticipated per-task cost near $2.50 - above GLM-5.3 (max) and level with GPT-6 Astra (high) on the same chart. If it holds up under replication, that is frontier-adjacent agentic coding at a flash-tier price.
• Availability: free during the launch window on both OpenCode and OrcaRouter (see the cloud-pricing table); a permanent price has not been announced.

Treat every number here as provisional until the operator identifies itself and third parties replicate the benchmarks.