GPT-5.6 Terra

openai/gpt-5.6-terra

balances intelligence and cost.

cmd --model gpt-5.6-terra
Intelligence index
56.6
Output speed
120.5 tok/s
Input
$2 /M
Output
$12 /M
Cache read
$0.20 /M
Agent-loop cost
$0.74 /M in
Context window
1.05M tokens
Released
July 9, 2026
Modalities

vs. the lineup

GPT-5.6 Terra beside its stablemates and nearest rivals. The ◆ marks the best value in each column across every row shown.

pin a rival:
ModelIntelligenceCodingSpeedInput $/MOutput $/MBlended $/MContext
GPT-5.6 Sol60.977.464.7$5$30$11.251.05M
GPT-5.6 Terra56.676.7120.5$2$12$4.501.05M
GPT-5.556.374.9$5$30$11.25200K
GPT-5.453.171.1$2.50$15$5.63400K
GPT-5.6 Luna52.371.4159.5$0.20$1.20$0.451.05M
GPT-5.3 Codex45.5118.6$2$8$3.50400K
DeepSeek V4 Pro (latest)pinned45.359.463.3$0.43$0.87$0.541M
DeepSeek V4 Flash (latest)pinned5269.1115.9$0.14$0.28$0.181M

coding performance

The Intelligence Index and its sub-scores, ranked against every scored model in the catalog. A metric that has not been measured for GPT-5.6 Terra has been left empty.

Coding Index
76.7
#3 of 40 scored
Terminal-Bench
88
#3 of 40 scored
Intelligence Index
56.6
#8 of 46 scored
Long-context reasoning
79.7
reasoning across a long context
SciCode
53.9
scientific coding
GPQA Diamond
92.5
graduate-level QA

price bands

GPT-5.6 Terra is not billed at one flat rate — the price changes with how much context a request carries. The header quotes the standard band; here is every band.

BandContextInput $/MOutput $/MCache read $/M
Standard≤ 272K$2.00$12.00$0.20
Long context> 272K$4.00$18.00$0.40

usage calculator

How far a month of credits goes on GPT-5.6 Terra.

GPT-5.6 Terra runs on Pro and up — from $20/mo.
Input tokensfresh prompt
800
Output tokensmodel reply
180
Cache read tokensre-read context
50K
cost / request $0.014 · in $2 · out $12 · cache $0.20 per M
fresh input 12%output 16%cache reads 73%
Requests / 30 days
1.5K
$20 credits ÷ $0.014 per request
~291 quick fixes~58 bug fixes~10 feature PRs

what real work costs

Real coding tasks priced end to end on GPT-5.6 Terra, from a quick lookup to a full-repo agent run.

One agent task
$0.26
180K in at 75% cache hit, 12K out
What you pay
$1.36 /M
all-in across every token that task touched
Sticker input
$2 /M
cache reads bill at $0.20 /M instead
TaskTokens in · outGPT-5.6 TerraMuse Spark 1.2Claude Haiku 4.5
Quick lookup / one-liner8K · 1K$0.02$0.0063$0.0065
Review a 500-line PR60K · 4K$0.09$0.05$0.04
Fix a bug (agent loop)180K · 12K$0.26$0.13$0.12
Refactor a module320K · 20K$0.47$0.23$0.21
Full-repo agent run900K · 45K$1.08$0.54$0.49

frequently asked

What is GPT-5.6 Terra best for?+
GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier. It is suited for everyday coding, reasoning, and agentic tasks where capability and cost need to be balanced, offering strong performance at roughly half the cost of Sol.
How much does GPT-5.6 Terra cost?+
$2/M input and $12/M output, cache reads $0.20/M. In an agent loop most input is cache-read, so the effective input rate is about $0.74/M.
Which plan do I need?+
Available on Pro and above.
How do I switch to it?+
Run cmd --model gpt-5.6-terra, or type /model in a session and pick it. You can switch mid-session without losing context.

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Benchmarks from Artificial Analysis (v4.1)commandcode.ai/models/gpt-5-6-terra