GPT-5.6 Terra Pro

openai/gpt-5.6-terra-pro

GPT-5.6 Terra Pro on Sylphx Models · 1.05M of context. One Responses contract, with list prices published per million tokens.

Released: Jul 9, 2026 · 79 days old
Provider: OpenAI
Context: 1,050,000 tokens

Get an API key See a request sample Read the docs

Input $2.31 / MOutput $13.86 / MCached input $0.231 / MFull rate sheet

Context window1,050,000tokens per request

Max output128,000tokens per response

Input$2.31 / Mper million tokens

Output$13.86 / Mper million tokens

Cached input$0.231 / M90% off input

ReleasedJul 9, 202679 days old

Pricing

USD per million tokens

Input: $2.31
Output: $13.86
Cached input: $0.231

$5.20 for 750,000 input and 250,000 output tokens.

Assumption: one batch of 750,000 input plus 250,000 output tokens at the published list prices — recompute for your own mix. Blended $5.197 per million at a 3:1 mix.

Chat replies · 3:1 input:output: $5.197 / M
Long documents · 9:1 input:output: $3.465 / M
Heavy output · 1:1 input:output: $8.085 / M
Cache write: $5.775 / M
Currency and unit: USD / million tokens

Cached input reads cost 90% less than fresh input tokens.

Full rate sheet and billing rules.

Specification

Context window: 1,050,000 tokens
Max output: 128,000 tokens
Input modalities: Not published
Output modalities: Not published
Family: GPT Terra Pro
Version: v5.6
Provider: OpenAI
Released: Jul 9, 2026 · 79 days old
Model id: openai/gpt-5.6-terra-pro

Data posture

Standard

By default, prompts and outputs sent to this model are not used to train models. Training-discount lanes only with opt-in (x-sylphx-zdr: optional).

Training on what you send · default: No
Zero Data Retention · default: Yes
Training-discount lanes: Opt-in only · x-sylphx-zdr: optional

POST https://api.sylphx.ai/v1/responses

curl https://api.sylphx.ai/v1/responses \
  -H "Authorization: Bearer $SYLPHX_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5.6-terra-pro",
    "input": "Summarise this incident report in three bullets.",
    "stream": false
  }'

How to call it

Send the official Responses document to the base URL above with your Sylphx API key and this exact model id. Streaming arrives as ordered events with one terminal event.

Retries: send an Idempotency-Key and a retry replays the original response instead of billing twice.
Errors: typed envelopes tell you whether to retry, wait, or fix the request.
Keys: create and revoke Sylphx API keys in the Sylphx console.

Quickstart Responses API Errors and retries

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Independent evaluation

We do not publish benchmark scores for this model — we have not verified any. These external leaderboards run their own tests, so check them against your own workload.

Not our numbers

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