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October 27, 2026 / Issue 72 / 4 min read

OpenAI's new mid-tier model costs half as much and scores higher on agent tests. Rerun your model choices on cost per finished task, not price per token

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OpenAI released GPT-6.1 Terra(opens in a new tab) on October 26 at $1 per million input tokens and $5 per million output tokens, with cached input at $0.05. OpenAI says it beats the GPT-5.6 Terra model it replaces at half the price. It is live in the API as gpt-6.1-terra and in ChatGPT Work and Codex for Plus, Pro, Enterprise and Edu users.

The numbers that matter to a budget owner are per task, not per token. On OpenAI's Agents' Last Exam results, as reported by InfoWorld(opens in a new tab), Terra scored 60.0% at $1.01 per task. GPT-5.6 Terra scored 50.7% at $3.58, and OpenAI's own premium GPT-6.1 Sol scored 58.6% at $2.00. Claude Opus 5.5 still led at 63.2%, but at $8.82 per task. On the OSWorld computer use test, Claude Sonnet 5.5 led at 83.9% for $5.74, against Terra's 74.2% for $1.19. These are vendor-published benchmarks, so treat them as a shortlist, not a verdict.

The practical point: a model that costs about a quarter as much per benchmark task as the one it replaces changes which workloads pencil out. Agent pilots that were shelved because each run cost dollars may now cost cents. It also means a team that standardized on one premium model for everything is likely overpaying on routine work.

The counterweight comes from Greyhound Research's Sanchit Vir Gogia, quoted by InfoWorld(opens in a new tab): inference is only one line of agent cost. Review and integration still cost money, and in one illustrative coding workload, 5.4 extra seconds of human review erased the inference saving. A cheaper model that makes more mistakes your staff must catch is not cheaper.

So do not swap models on the price sheet alone. Pick three live workloads, run Terra beside your current model, and measure cost per finished, correct task, including review time. Keep model IDs pinned in code so a default change cannot move your bill.

Action items

OpenAI's GPT-6.1 Terra costs half as much as the model it replaces and scored higher on agent tests. Cost per finished task, not price per token, is now the number that decides which model to use.

For the CAIO

Rerun your model choices on three live workloads, count review time in the cost, and pin model IDs in code.

Researched and drafted by an automated workflow, then reviewed and edited by a human editor before publication. Every source is linked. See how we use AI here.

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