For coding agents, GPT-5.6 Terra costs 5.1x as much as Devstral 2 per request ($0.052 vs $0.010 on our measured traffic), because GPT-5.6 Terra lists at $2 input, $0.20 cached input and $12 output per million tokens against $0.40, $0.04 and $2 for Devstral 2, and GPT-5.6 Terra charges more for prompts over 272K tokens.
Run GPT-5.6 Terra in your agent from $19/month
See plans| Cost at list price | Devstral 2 | GPT-5.6 Terra |
|---|---|---|
| Prompt under 100K tokens50% of requests, 87% of input cached | $0.0062 | $0.032 |
| Prompt of 100K to 272K39% of requests, 88% of input cached | $0.015 | $0.078 |
| Prompt over 272K tokens11% of requests, 86% of input cached | n/a | n/a |
| Average request | $0.010 | $0.052 |
| 100 requests | $1.01 | $5.19 |
| Median session16 requests; a session ends after 10 idle minutes | $0.12 | $0.63 |
| A month of regular usemedian of 20 users active on 5+ days | $12.73 | $65.30 |
Each logged request priced at the vendor’s list rates for its own token counts, including cache reads and any higher rate for long prompts. Average output: 698 tokens per request. Both models are priced on the requests up to 262K tokens that fit in both context windows; band shares above describe all requests.
| Artificial Analysis | Devstral 2 | GPT-5.6 Terra |
|---|---|---|
| Intelligence Index10 evaluations, 0 to 100 | 9 | 42 |
| Terminal-Bench 4.0agentic coding in a terminal | 0.0% | 35.4% |
| Output speedmedian | n/a | 135 tokens/s |
| Time to first answer tokenincludes thinking time | n/a | 2.2 min |
Source: Artificial Analysis (artificialanalysis.ai). Measured variants: Devstral 2; GPT-5.6 Terra (Max), speed on OpenAI. Fetched October 13, 2026. Artificial Analysis runs Terminal-Bench 4.0 in its own setup, so its scores differ from the tbench.ai leaderboard.
Devstral 2's 262K window cannot take 12% of coding-agent requests, so the comparison uses only requests both can take. GPT-5.6 Terra scores clearly higher on the benchmarks above, so it may finish hard tasks in fewer steps.
Pick a winner in each dimension. You can change your vote any time.
Correctness and depth of what it produces
Tool calls, instruction-following, and multi-step tasks
Tokens per second and time-to-first-token
How much capability you get per dollar
Consistent results: fewer refusals, loops and format breaks
Setting it up? GPT-5.6 Terra: model ID, providers and agent config
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