GPT-5.1-Codex vs Inkling 2 Small
Inkling 2 Small leads GPT-5.1-Codex on coding, 48.9 to 15.3 on the Vibe Coding Index, and Inkling 2 Small costs 10.0x less per output token ($1.00 vs $10.00 per million). Updated November 14, 2026; 5 benchmarks have a result for both.
GPT-5.1-Codex or Inkling 2 Small: which to pick
Pick Inkling 2 Small for coding: it scores 48.9 on the Vibe Coding Index against 15.3 for GPT-5.1-Codex.
GPT-5.1-Codex is neither cheaper nor larger in context, and leads no benchmark both models were measured on.
- Shared results
- 5
- GPT-5.1-Codex only
- 20
- Inkling 2 Small only
- 46
- Like-for-like categories
- 3 of 9
Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
Inkling 2 Small
Inkling 2 Small scores 48.9 against 15.3.
2 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
No call
Only Inkling 2 Small has a AA Intelligence Index result, 30.6.
Directional only
Web design
Design Arena: websites
No call
Only GPT-5.1-Codex has a Design Arena: websites result, 1154.
Directional only
General
Vals Index
No call
Only Inkling 2 Small has a Vals Index result, 56.1%.
Directional only
Long documents
Listed context window
Inkling 2 Small
Inkling 2 Small takes 1.05M tokens against 400K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Inkling 2 Small
GPT-5.1-Codex $0.0063, Inkling 2 Small $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.1-Codex has the number, $0.892.
Directional only
At a glance
- Coding index
- GPT-5.1-Codex 15.3 from 2 benchmarks, Inkling 2 Small 48.9 from 3 benchmarks.
- Widest category
- Coding, 51.6 points apart on average over 3 shared benchmarks.
- Widest single gap
- Vibe Code Bench (Vals AI): GPT-5.1-Codex 13.1% against Inkling 2 Small 81.5%, 68.4 points apart on a 0 to 100 scale.
- Output price
- GPT-5.1-Codex $10.00 against Inkling 2 Small $1.00 per million output tokens, 10.0x apart.
- Context window
- GPT-5.1-Codex takes 400K tokens, Inkling 2 Small 1.05M.
Benchmark by benchmark
First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.
| Category | GPT-5.1-Codex | Bars | Inkling 2 Small | Ties |
|---|---|---|---|---|
| Coding | 0 | 3 | ||
| Reasoning | 0 | 1 | ||
| General | 0 | 1 | ||
| All shared boards | 0 | 5 |
CodingLike-for-likeSix of these boards feed the Vibe Coding Index03
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| SWE-bench Verified | 66.0% | Not measured | Only GPT-5.1-Codex measured |
| LMArena WebDev | 1338 | 1647 | Inkling 2 Small |
| LiveCodeBench (Vals AI) | 85.5% | Not measured | Only GPT-5.1-Codex measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 12.6% | Only Inkling 2 Small measured |
| Vibe Code Bench (Vals AI) | 13.1% | 81.5% | Inkling 2 Small |
| ProgramBench (Vals AI) | Not measured | 0.5% | Only Inkling 2 Small measured |
| SWE-bench Multimodal (Vals AI) | Not measured | 43.1% | Only Inkling 2 Small measured |
| CyberBench (Vals AI) | Not measured | 72.7% | Only Inkling 2 Small measured |
| LiveCodeBench (Artificial Analysis run) | 84.9% | Not measured | Only GPT-5.1-Codex measured |
| SciCode | Not measured | 52.3% | Only Inkling 2 Small measured |
| Terminal-Bench Hard (Artificial Analysis run) | 34.8% | Not measured | Only GPT-5.1-Codex measured |
| Terminal-Bench 4.0 (Artificial Analysis run) | Not measured | 13.1% | Only Inkling 2 Small measured |
| FrontierCode 2.0 | Not measured | 25.4% | Only Inkling 2 Small measured |
| Terminal-Bench | 57.8% | Not measured | Only GPT-5.1-Codex measured |
| ALE-Bench | 1244.9 | Not measured | Only GPT-5.1-Codex measured |
| LMArena Text: coding | Not measured | 1455 | Only Inkling 2 Small measured |
| LMArena Text: software and IT | Not measured | 1443 | Only Inkling 2 Small measured |
| LMArena WebDev: React | Not measured | 1660 | Only Inkling 2 Small measured |
| LMArena WebDev: HTML | 1346 | 1661 | Inkling 2 Small |
| SWE-Bench Pro V2 | Not measured | 97.7% | Only Inkling 2 Small measured |
| Terminal-Bench 2.0 | 57.8% | Not measured | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 31 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 30.6 | Only Inkling 2 Small measured |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index13 boards, none shared
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| Design Arena: agents building web apps | 994 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: agents building full-stack apps | 1086 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: agents building mobile apps | 1191 | Not measured | Only GPT-5.1-Codex measured |
| SREBench (Vals AI) | Not measured | 1.9% | Only Inkling 2 Small measured |
| Tax Agent Bench (Vals AI) | Not measured | 38.9% | Only Inkling 2 Small measured |
| Legal Research Bench (Vals AI) | Not measured | 46.6% | Only Inkling 2 Small measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 21.7% | Only Inkling 2 Small measured |
| BioMysteryBench (Vals AI) | Not measured | 70.0% | Only Inkling 2 Small measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 2.9% | Only Inkling 2 Small measured |
| Vals Science Index | Not measured | 32.7% | Only Inkling 2 Small measured |
| τ²-Bench Telecom | 83.0% | Not measured | Only GPT-5.1-Codex measured |
| APEX-Agents | Not measured | 46.8% | Only Inkling 2 Small measured |
| MCP Atlas | Not measured | 85.4% | Only Inkling 2 Small measured |
| Neither model has a result on the other 31 boards here | |||
ReasoningLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| MysteryMechanism (Vals AI) | Not measured | 25.2% | Only Inkling 2 Small measured |
| GPQA Diamond (Artificial Analysis run) | 86.0% | Not measured | Only GPT-5.1-Codex measured |
| Humanity's Last Exam (Artificial Analysis run) | 25.7% | 44.1% | Inkling 2 Small |
| HLE-Diamond (Artificial Analysis run) | Not measured | 28.7% | Only Inkling 2 Small measured |
| CritPt v2, hard subset (Artificial Analysis run) | Not measured | 35.0% | Only Inkling 2 Small measured |
| ARC-AGI | Not measured | 96.5% | Only Inkling 2 Small measured |
| ARC-AGI-2 | Not measured | 81.7% | Only Inkling 2 Small measured |
| LMArena Text: hard prompts | Not measured | 1421 | Only Inkling 2 Small measured |
| LMArena Text: expert | Not measured | 1478 | Only Inkling 2 Small measured |
| LMArena Text: hard prompts in English | Not measured | 1424 | Only Inkling 2 Small measured |
| Neither model has a result on the other 16 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| AIME 2025 (Artificial Analysis run) | 95.7% | Not measured | Only GPT-5.1-Codex measured |
| MathArena | Not measured | 42.4% | Only Inkling 2 Small measured |
| Neither model has a result on the other 12 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index4 boards, none shared
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| MMLU Pro (Artificial Analysis run) | 86.0% | Not measured | Only GPT-5.1-Codex measured |
| AA-Omniscience | Not measured | 16.1 | Only Inkling 2 Small measured |
| LMArena Text: science | Not measured | 1409 | Only Inkling 2 Small measured |
| LMArena Text: business and finance | Not measured | 1415 | Only Inkling 2 Small measured |
| Neither model has a result on the other 17 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index5 boards, none shared
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| Design Arena: websites | 1154 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: UI components | 1227 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: game dev | 1127 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: data viz | 1210 | Not measured | Only GPT-5.1-Codex measured |
| Design Arena: all code categories | 1142 | Not measured | Only GPT-5.1-Codex measured |
| Neither model has a result on the other 4 boards here | |||
GeneralLike-for-likePublic boards, shown as published, kept out of the index01
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| Vals Index | Not measured | 56.1% | Only Inkling 2 Small measured |
| SAGE (Vals AI) | Not measured | 88.6% | Only Inkling 2 Small measured |
| IFBench | 70.0% | Not measured | Only GPT-5.1-Codex measured |
| Long context reasoning (AA-LCR) | 69.3% | 83.3% | Inkling 2 Small |
| GDPval-AA | Not measured | 1630 | Only Inkling 2 Small measured |
| LMArena Text | Not measured | 1403 | Only Inkling 2 Small measured |
| LMArena Text: instruction following | Not measured | 1408 | Only Inkling 2 Small measured |
| LMArena Text: creative writing | Not measured | 1348 | Only Inkling 2 Small measured |
| LMArena Text: English | Not measured | 1418 | Only Inkling 2 Small measured |
| LMArena Text: non-English | Not measured | 1390 | Only Inkling 2 Small measured |
| LMArena Text: Russian | Not measured | 1377 | Only Inkling 2 Small measured |
| LMArena Text: multi-turn | Not measured | 1408 | Only Inkling 2 Small measured |
| LMArena Text: longer queries | Not measured | 1403 | Only Inkling 2 Small measured |
| LMArena Text: writing and language | Not measured | 1381 | Only Inkling 2 Small measured |
| LMArena Text: entertainment and media | Not measured | 1359 | Only Inkling 2 Small measured |
| Neither model has a result on the other 34 boards here | |||
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
| Benchmark | GPT-5.1-Codex | Inkling 2 Small | Leader |
|---|---|---|---|
| Neither model has a result on 5 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Inkling 2 Small costs less
Repository review
50K input + 3K output tokens
Inkling 2 Small costs less
Agent loop
200K input + 10K output tokens
Inkling 2 Small costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | OpenAI GPT-5.1-Codex | Thinking Machines Inkling 2 Small |
|---|---|---|
| Maker | OpenAI | Thinking Machines |
| Weights | No public weights listed | Open weights |
| Released | November 13, 2025 | November 9, 2026 |
| Context window | 400K | 1.05M |
| Input $/Mtok | $1.25 | $0.30 |
| Output $/Mtok | $10.00 | $1.00 |
| Coding index | 15.3 | 48.9 |
| Independent measurements behind it | 2 | 3 |
| Cost per solved task | $0.892 | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GPT-5.1-Codex better than Inkling 2 Small for coding?
Pick Inkling 2 Small for coding: it scores 48.9 on the Vibe Coding Index against 15.3 for GPT-5.1-Codex. GPT-5.1-Codex is neither cheaper nor larger in context, and leads no benchmark both models were measured on.
Which is cheaper, GPT-5.1-Codex or Inkling 2 Small?
GPT-5.1-Codex costs $1.25 per million input tokens and $10.00 per million output tokens; Inkling 2 Small costs $0.30 and $1.00. Cost per solved task is known for GPT-5.1-Codex only.
Which has the bigger context window, GPT-5.1-Codex or Inkling 2 Small?
Inkling 2 Small, with 1.05M tokens against 400K.
How many benchmarks is the GPT-5.1-Codex vs Inkling 2 Small comparison based on?
5 benchmarks have a result for both models as of November 14, 2026. GPT-5.1-Codex's coding index rests on 2 independent benchmarks and Inkling 2 Small's on 3. Where only one model has a result, the page says so instead of naming a winner.