The short version: nobody wins outright
"Coding" is not one skill. Which ruler you use flips the conclusion completely.
GPT-5.6's top tier is Sol. On the Claude side it is Fable 5. These two are the "expensive robot coworkers" people compare most.
The benchmarks, laid out
A few public leaderboards, straight numbers:
- Coding Agent Index v1.1: GPT-5.6 Sol 80, Claude Fable 5 77.2 — Sol slightly ahead
- SWE-Bench Pro (real GitHub issues): Claude Fable 5 80.0%, GPT-5.6 Sol 64.6% — Fable leads by 15 points
- Terminal-Bench 2.1 (CLI workflows): GPT-5.6 Sol 88.8%, Claude Fable 5 83.1% — Sol ahead
Same pair, two boards, two totally different stories. That is the whole point.
Coding: who is stronger
Sol wins on breadth: autonomous agent runs, terminal operations, cross-file edits — it flows better, and its output price is about half of Fable's (per million tokens $30 vs $50).
Fable wins on depth: real-repo pull requests, multi-file refactors, long-chain bugs. That 15-point SWE-Bench Pro gap is not something rounding erases. Anthropic's own customer signals agree — Cursor and GitHub both say it is steadier on long-horizon engineering.
Long-form and copywriting
This is where Claude has always led. Not because it writes prettier prose, but because it reads intent better: fewer corrective turns, sharper code review.
GPT-5.6 is not weak at long text, but if the output is meant for human eyes — proposals, reports, product copy — Claude's "human feel" runs deeper.
Pick based on the job (no hedging)
Running agents, terminal scripts, cost-sensitive → Sol. Half the price, wider surface.
Fixing real repos, writing long-form, quality over price → Fable. That 15-point gap saves an engineer two hours on exactly this kind of work.
One rule above all: benchmarks are a shortlist, not a marriage certificate. Run your own task once. It beats any leaderboard.
Related reads
For the full GPT-5.6 tier breakdown, and our Midjourney vs domestic image-tool comparison, ainspiro has separate deep dives.