Claude Opus 5 vs GPT-5.6 Sol: Two Flagships, Different Jobs (2026 Pricing)
Opus 5 at $4.5/$22.5, GPT-5.6 Sol at $3.6/$18 — Sol is 20% cheaper. But their strengths differ: cross-file code reasoning versus multi-step agentic planning.
The gap between flagships is smaller than you think
On most single-shot tasks you will struggle to rank two current flagships — the difference emerges **in long chains**: over 20-50 consecutive steps, small deviations compound. That is why 'run it once and see' rarely settles anything, while running one complete real workflow does. If your usage is single-turn Q&A, take the cheaper one.
A cost reality check
Flagship output prices 5× input, and agent work is output-heavy and turn-heavy. An unguarded agent loop can burn tens of dollars in minutes. Three guardrails: ① a hard step cap; ② tiering — flagship plans, cheap tier executes; ③ a small-sample dry run before production. These save far more than picking the cheaper of two flagships.
How to run a comparison that means something
Do not benchmark on poems or riddles — that measures nothing you care about. **Take your single most typical, most time-consuming real task** and run it three times on each model with identical prompts. Record: ① first-attempt success rate; ② rounds of correction needed; ③ total tokens consumed. Those three numbers map directly to your actual cost. Total outlay: $2-5.
How to call them
base_url https://cocodot.co/api/ai/v1; model `claude-opus-5` (code mco-7) or `gpt-5.6-sol` (code mog-8-s). Claude Code users can set ANTHROPIC_BASE_URL=https://cocodot.co/api/ai and pick the model via ANTHROPIC_MODEL. Flagships require a small top-up (trial credit covers budget tiers only).
Two flagships (cocodot pricing, USD per M tokens)
| Claude Opus 5 | GPT-5.6 Sol | |
|---|---|---|
| Input / Output | $4.5 / $22.5 | $3.6 / $18 |
| List price | $5 / $25 | $4 / $20 |
| Blended (3:1) | ~$9 | ~$7.2 |
| Positioning | cross-file code, long-chain consistency | multi-step logic, agentic reasoning |