What changed
xAI released Grok 4.6 on 12 August 2026. It builds on Grok 4.5 with a particular focus on long-running agents, and on staying with complex tasks across many steps, from researching a topic to working across a codebase 1. Artificial Analysis published its own measurements the same day: Grok 4.6 debuts on AA-Briefcase, its private benchmark of long-horizon agentic knowledge work tasks, with an Elo of 1577, which puts it at Fable 5-tier and behind the Claude Opus 5 family 2.
Turns are the cost you actually pay
Read the second half of that measurement before the first. Artificial Analysis reports the following average run profile 2:
| Average run profile | Grok 4.6 | Claude Opus 5 (max) |
|---|---|---|
| Turns to resolve a task | ~53 | ~103 |
| Input tokens | ~0.5B | ~2.0B |
Artificial Analysis draws the economic conclusion itself: long-horizon work accumulates context fast, so reaching a comparable answer in half the turns and a quarter of the input tokens is an advantage that outruns the per-token price 2. I would push it further. A turn is not only tokens. It is a round-trip that can time out, hit a rate limit, or return a malformed tool call, so a loop needing twice as many fails more often for reasons unrelated to reasoning quality. That is the axis a single score hides.
Impact on your team
Treat this as a placement decision. Grok 4.6 sits behind the Claude Opus 5 family on quality and resolves tasks in roughly half the turns 2, so I would put it inside the long loop, where every extra round-trip is paid in context and wall-clock, and keep the higher tier at the boundary to frame the run and read what comes back. I would not move a production loop on these numbers today: the figure that would justify the move is the one Artificial Analysis pins least, with no benchmark named on the run profile and a comparator configuration you may not be running. Watch for a run profile published against a named benchmark, with a comparator matching what you ship. That is the sentence that turns this into a migration.