Claude Opus 5 vs union-alpha
Wins 3 of 4 areas
Coding · Reasoning · Following instructions
Wins 0 of 4 areas
—
Claude Opus 5 is the stronger all-rounder.
Scores updated · 7 tests both models report · How we compare
Where each one wins
Tests won in each of the four areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
Reasoning, math and following instructions rest on a single test each.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Opus 5 pulls ahead
- Fixes real GitHub issues, working as an agentLiveBench · Agentic Coding+10.5points ahead
- Fresh logic puzzles that change regularlyLiveBench · Reasoning+10.4points ahead
- Follows detailed instructions exactlyLiveBench · Instruction Following+4.3points ahead
Where union-alpha pulls ahead
No clear win on a test scored out of 100.
Every test, side by side
All 7 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Opus 5
- LiveBench · Agentic CodingClaude Opus 5 by 10.565.254.7+10.5
- LiveBench · Codingtie81.582.2tie
Following instructionsClaude Opus 5
- LiveBench · Instruction FollowingClaude Opus 5 by 4.363.859.5+4.3
Other results2 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- livebench_languageClaude Opus 5 by 2.888.785.9+2.8
- livebench_data_analysistie74.574.6tie
Questions people ask
Which is better, Claude Opus 5 or union-alpha?
Claude Opus 5 wins three of the four areas where both have results: coding, reasoning and following instructions. union-alpha wins none. They are level on math.
Which is better for coding?
Claude Opus 5. It wins 1 of the 2 coding tests both models report; union-alpha wins none, and 1 is a tie.
How do you compare the two?
We use the 7 benchmark tests both models have published scores on. The verdict counts the 5 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 2 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.