GPT-6.1 Terra halves GPT-5.6 Terra prices with same context window

OpenAI's GPT-6.1 Terra costs $1 per million input tokens versus $2 for GPT-5.6 Terra, and $5 versus $12 for output. Both keep a 1,050,000-token context window and 128,000-token output limit, but tool calls now require the Responses API.

• Input $1 vs $2, output $5 vs $12 per million tokens
• Context window of 1,050,000 tokens and 128,000 output tokens unchanged
• In Codex tests GPT-6.1 Terra passed 9 of 9 tasks, GPT-5.6 passed 8 and 6 of 9
• Tool-calling requests must move from Chat Completions to Responses API