Long documents
Prompts that approach the documented context limit
GPT-5.6 Terra
GPT-5.6 Terra has the larger documented context window.
Confidence: documented
GPT-5.6 Terra vs o1
Updated September 24, 2026. Rank says GPT-5.6 Terra is ahead. Price, access, and your workload can each overturn that. Public scores include evidence status and uncertainty.
Both of these models will change. Get the price, version and retirement notices for the pair, each with its source. Follow model changes
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Decision reading
GPT-5.6 Terra has the higher public score, 72.58 versus 37.58, and the 90% score intervals do not overlap. 2 results are shared. Category rows resting on Estimated evidence or different benchmark sets are marked directional and do not name a winner.
- Shared results
- 2
- GPT-5.6 Terra only
- 30
- o1 only
- 2
- Like-for-like categories
- 1 / 8
Supported: GPT-5.6 Terra · Estimated: o1How the comparison works
Which one for your work
Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.
Chat turn cost
1K fresh input + 500 output tokens
GPT-5.6 Terra
GPT-5.6 Terra has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-rates
Show secondary and unsupported calls
Repository review cost
50K fresh input + 3K output tokens
GPT-5.6 Terra
GPT-5.6 Terra has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.
Confidence: listed-ratesCoding work
Code generation, repair, and software-engineering tasks
Not enough matched evidence
O1 is scored on Estimated evidence for coding, so the reading is directional rather than like-for-like.
Confidence: limitedAgentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
O1 is not ranked on the public lane for agentic, so no winner is named for agentic.
Confidence: limitedCache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Not enough matched evidence
The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. o1 does not fit this workload in one request. o1 has no published cached-input rate, so cached tokens use its listed input rate.
Confidence: rate-fallback
Which one for a specific job
Choose a job from the LLM Selector's task catalog to see the category row it rests on, under the same basis rules as the table below. A directional row stays directional; choosing a job never creates a winner.
The same task catalog as the LLM Selector. Each job names the evidence surface it rests on; nothing here adds a new score.
64.7GPT-5.6 Terra30.6o1
Directional only · BenchAlign v5.7
GPT-5.6 Terra scores higher, but at least one score rests on Estimated evidence or a different benchmark set. Directional only, no winner.
Coding scores combine specific tasks and setups. Match the editor, harness, and effort to your workflow.
Same basis rules as the category table below
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
30 GPT-5.6 Terra only
2 Shared
2 o1 only
2 categories rest on Estimated evidence or different evidence sets. Those rows remain visible for coverage context but do not name a winner.
Shape of the matched evidence
Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.
Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.
FrontierMath v2 (Tiers 1-3)Math
Normalized gap 75.6GPT-5.6 Terra:84.900%o1:9.310%GPQAKnowledge
Normalized gap 17.2GPT-5.6 Terra:92.9%o1:75.7%
Bars run 0–100 on each benchmark’s normalized display scale
Category results, on a stated basis
Each row shows the public-lane category score for both models: the BenchAlign v5.7 lane for agentic, coding, and knowledge, and the weighted public rows elsewhere, with the same rank each model page reports. A row is like-for-like only when both scores rest on Supported evidence or the same weighted set. Directional and not-comparable rows remain visible, but they never receive a winner.
Knowledge
Like-for-like- GPT-5.6 Terra
- 71.1
- Supported · #9/158
- o1
- 40.8
- Supported · #88/158
- Basis
- BenchAlign v5.7 lane · 8 vs 2 public rows
- Reading
- GPT-5.6 Terra leads
Coding
Directional only- GPT-5.6 Terra
- 64.7
- Supported · #8/135
- o1
- 30.6
- Estimated · #86/135
- Basis
- BenchAlign v5.7 lane · 8 vs 0 public rows
- Reading
- Directional only
Instruction following
Directional only- GPT-5.6 Terra
- 85.7
- #35/124
- o1
- 84.5
- #40/124
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Directional only
Agentic
Not comparable- GPT-5.6 Terra
- 59.5
- Supported · #18/105
- o1
- Not ranked
- Basis
- BenchAlign v5.7 lane · 9 vs 0 public rows
- Reading
- Not comparable
Reasoning
Not comparable- GPT-5.6 Terra
- 65.4
- #12/19
- o1
- 66.7
- Unranked · 2 rankable rows
- Basis
- Provisional lane · 2 vs 0 weighted rows
- Reading
- Not comparable
Multimodal
Not comparable- GPT-5.6 Terra
- 77.2
- #16/50
- o1
- Not ranked
- Basis
- Provisional lane · 1 vs 0 weighted rows
- Reading
- Not comparable
Multilingual
Not comparable- GPT-5.6 Terra
- Not ranked
- o1
- Not ranked
- Basis
- Provisional lane · 0 vs 0 weighted rows
- Reading
- Not comparable
Math
Not comparable- GPT-5.6 Terra
- 96.8
- Unranked · 3 rankable rows
- o1
- 32.5
- Unranked · 1 rankable row
- Basis
- Provisional lane · 2 vs 1 weighted rows
- Reading
- Not comparable
| Category | GPT-5.6 Terra | o1 | Basis | Reading |
|---|---|---|---|---|
| Knowledge | 71.1Supported · #9/158 | 40.8Supported · #88/158 | Like-for-likeBenchAlign v5.7 lane · 8 vs 2 public rows | GPT-5.6 Terra leads |
| Coding | 64.7Supported · #8/135 | 30.6Estimated · #86/135 | Directional onlyBenchAlign v5.7 lane · 8 vs 0 public rows | Directional only |
| Instruction following | 85.7#35/124 | 84.5#40/124 | Directional onlyProvisional lane · 0 vs 0 weighted rows | Directional only |
| Agentic | 59.5Supported · #18/105 | Not ranked | Not comparableBenchAlign v5.7 lane · 9 vs 0 public rows | Not comparable |
| Reasoning | 65.4#12/19 | 66.7Unranked · 2 rankable rows | Not comparableProvisional lane · 2 vs 0 weighted rows | Not comparable |
| Multimodal | 77.2#16/50 | Not ranked | Not comparableProvisional lane · 1 vs 0 weighted rows | Not comparable |
| Multilingual | Not ranked | Not ranked | Not comparableProvisional lane · 0 vs 0 weighted rows | Not comparable |
| Math | 96.8Unranked · 3 rankable rows | 32.5Unranked · 1 rankable row | Not comparableProvisional lane · 2 vs 1 weighted rows | Not comparable |
Ranks count the models scored in each category’s lane, so the agentic, coding, and knowledge denominators (BenchAlign v5.7) differ from the provisional-lane categories. Unranked scores sit on the provisional lane’s scale but never name a winner. Like-for-like rows within 0.5 points read as a practical tie.
Supported evidence per lane · bars run 0–100Methodology
What each workload costs
Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.
Chat turn
1K fresh input + 500 output tokens
- GPT-5.6 Terra
- $0.008
- Fits in one request
- o1
- $0.045
- Fits in one request
GPT-5.6 Terra has the lower modeled cost
Costs use the listed standard API rates.
Repository review
50K fresh input + 3K output tokens
- GPT-5.6 Terra
- $0.136
- Fits in one request
- o1
- $0.93
- Fits in one request
GPT-5.6 Terra has the lower modeled cost
Costs use the listed standard API rates.
Cache-heavy agent loop
200K cached + 20K fresh input + 10K output tokens
- GPT-5.6 Terra
- $0.2
- Fits in one request
- o1
- $3.90
- Does not fit in one request
- Cached input priced at the published list-input rate
o1 does not fit this workload in one request. o1 has no published cached-input rate, so cached tokens use its listed input rate.
Cached input falls back to the list input rate only where a cached rate is unpublished
Specification differences
Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.
SpecificationGPT-5.6 Terrao1
Context window
Maximum documented context; output-token limits may be lower.
GPT-5.6 Terra
1.05M
OpenAI model catalogo1
200K
API model ID
GPT-5.6 Terra
gpt-5.6-terra
OpenAI model catalogo1
Not sourced
Cached-input rate
A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.
GPT-5.6 Terra
$0.2 per 1M cached input tokens
OpenAI pricingo1
Not published
Documented inputs
GPT-5.6 Terra
text, image
OpenAI model catalogo1
Not sourced
Documented outputs
GPT-5.6 Terra
o1
Not sourced
Provider availability
GPT-5.6 Terra
Generally Available · OpenAI Responses API
OpenAI model catalogo1
Not sourced
Reasoning profile
GPT-5.6 Terra
Reasoning
o1
Reasoning
Weight access
GPT-5.6 Terra
Proprietary
o1
Proprietary
License
GPT-5.6 Terra
Proprietary
o1
Proprietary
Release date
GPT-5.6 Terra
2026-07-09
o1
2024-12-01
If you already use one of these models
- Deployment change
- Both entries list OpenAI as the provider. Confirm endpoint, model ID, limits, and feature support before switching.
- Quality signal
- GPT-5.6 Terra has the higher public score, 72.58 versus 37.58, and the 90% score intervals do not overlap.
- Workload cost
- Repository review: $0.136 vs $0.93. Cache-heavy agent loop: $0.2 vs $3.90.
- Context tradeoff
- GPT-5.6 Terra has the larger documented window (1.05M).
Run the same representative tasks against both endpoints before changing production traffic.
Questions
Which is better, GPT-5.6 Terra or o1?
GPT-5.6 Terra has the higher public score, 72.58 versus 37.58, and the 90% score intervals do not overlap. That is the clearest overall quality signal in the current public data.
Which is better for coding, GPT-5.6 Terra or o1?
GPT-5.6 Terra scores higher for coding on the public lane, 64.7 to 30.6. O1 is scored on Estimated evidence for coding, so the reading is directional rather than like-for-like. BenchLM does not name a winner for coding from a directional reading; read the shared benchmark rows directly and test the models on the same task set.
Which is better for agentic tasks, GPT-5.6 Terra or o1?
O1 is not ranked on the public lane for agentic tasks, so no winner is named for agentic tasks.
Which costs less, GPT-5.6 Terra or o1?
For the stated presets, chat costs $0.008 on GPT-5.6 Terra and $0.045 on o1; repository review costs $0.136 and $0.93; the cache-heavy agent loop costs $0.2 and $3.90. o1 does not fit this workload in one request. o1 has no published cached-input rate, so cached tokens use its listed input rate.
Which has the larger context window, GPT-5.6 Terra or o1?
GPT-5.6 Terra has the larger documented context window: 1.05M, compared with 200K.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence34 rows
Agentic
Terminal-Bench 3.0
GPT-5.6 Terra20.8%Sourceo1—Not directly comparable
Terminal-Bench 2.1
GPT-5.6 Terra87.4%Sourceo1—Not directly comparable
BrowseComp
GPT-5.6 Terra87.5%Sourceo1—Not directly comparable
OSWorld 2.0
GPT-5.6 Terra50.2%Sourceo1—Not directly comparable
CyberGym
GPT-5.6 Terra81.8%Sourceo1—Not directly comparable
ExploitGym
GPT-5.6 Terra23.2%Sourceo1—Not directly comparable
Toolathlon
GPT-5.6 Terra53.1%Sourceo1—Not directly comparable
Terminal-Bench 2.1 (Vals)
GPT-5.6 Terra77.5%Sourceo1—Not directly comparable
ApprenticeBench
GPT-5.6 Terra16%Sourceo1—Not directly comparable
Coding
SWE-bench Pro
GPT-5.6 Terra63.4%Sourceo1—Not directly comparable
Terminal-Bench 2.1
GPT-5.6 Terra87.4%Sourceo1—Not directly comparable
DeepSWE
GPT-5.6 Terra69.6%Sourceo1—Not directly comparable
FrontierCode 1.1 Extended
GPT-5.6 Terra55.8%Sourceo1—Not directly comparable
cursorBench32
GPT-5.6 Terra64.9%Sourceo1—Not directly comparable
VulcanBench v3
GPT-5.6 Terra87.0%Sourceo1—Not directly comparable
LiveCodeBench (Vals)
GPT-5.6 Terra85.9%Sourceo1—Not directly comparable
SWE-bench (Vals)
GPT-5.6 Terra95.4%Sourceo1—Not directly comparable
Reasoning
Multimodal
Knowledge
GPQA
GPT-5.6 Terra92.9%Sourceo175.7%SourceGPT-5.6 Terra leads this result
GPQA-D
GPT-5.6 Terra92.9%Sourceo1—Not directly comparable
HLE-Verified
GPT-5.6 Terra51.1%Sourceo1—Not directly comparable
LABBench2
GPT-5.6 Terra81.2%Sourceo1—Not directly comparable
HealthBench Professional
GPT-5.6 Terra57.7%Sourceo1—Not directly comparable
HealthBench Hard
GPT-5.6 Terra32.7%Sourceo1—Not directly comparable
GPQA Diamond (Vals)
GPT-5.6 Terra90.9%Sourceo1—Not directly comparable
MMLU-Pro (Vals)
GPT-5.6 Terra86.7%Sourceo1—Not directly comparable
MMLU
GPT-5.6 Terra—o191.8%SourceNot directly comparable
Instruction following
IFEval
GPT-5.6 Terra—o192.2%SourceNot directly comparable
Math
34 public results · 2 shared
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Last updated September 24, 2026