GPT-5.6 Luna vs Inkling 2 Small

GPT-5.6 Luna leads Inkling 2 Small on coding, 55.3 to 48.9 on the Vibe Coding Index, and Inkling 2 Small costs 1.2x less per output token ($1.00 vs $1.20 per million). Updated November 14, 2026; 44 benchmarks have a result for both.

Replace GPT-5.6 Luna Replace Inkling 2 Small

GPT-5.6 LunaOpenAI

Coding: 55.3
Overall: 57.1
Output $/M: $1.20

T Inkling 2 SmallThinking Machines

Coding: 48.9
Overall: 56.9
Output $/M: $1.00

vs boards won of 44 shared

GPT-5.6 Luna or Inkling 2 Small: which to pick

Pick GPT-5.6 Luna for coding: it scores 55.3 on the Vibe Coding Index against 48.9 for Inkling 2 Small.

Pick Inkling 2 Small for output tokens 1.2x cheaper ($1.00 vs $1.20 per million) and work measured by LMArena WebDev or Terminal-Bench 4 (Vals AI), where it leads.

Model AGPT-5.6 LunaOpenAI55.3/1005 independent benchmarks$0.04 per solved task Model BInkling 2 SmallThinking Machines48.9/1003 independent benchmarksNo cost per solved task

44817

Shared results: 44
GPT-5.6 Luna only: 81
Inkling 2 Small only: 7
Like-for-like categories: 6 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
GPT-5.6 Luna
GPT-5.6 Luna scores 55.3 against 48.9.
5 and 3 benchmarks behind the scores
Intelligence
AA Intelligence Index
Inkling 2 Small
Inkling 2 Small leads, 30.6 against 23.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only GPT-5.6 Luna has a AA Agentic Index result, 42.1.
Directional only
Reasoning
GPQA Diamond
No call
Only GPT-5.6 Luna has a GPQA Diamond result, 91.7%.
Directional only
Knowledge
MMLU Pro
No call
Only GPT-5.6 Luna has a MMLU Pro result, 86.0%.
Directional only
Web design
Design Arena: websites
No call
Only GPT-5.6 Luna has a Design Arena: websites result, 1248.
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
GPT-5.6 Luna
GPT-5.6 Luna takes 1.05M tokens against 1.05M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
No call
GPT-5.6 Luna $0.0008, Inkling 2 Small $0.0008 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only GPT-5.6 Luna has the number, $0.04.
Directional only

At a glance

Coding index: GPT-5.6 Luna 55.3 from 5 benchmarks, Inkling 2 Small 48.9 from 3 benchmarks.
Widest category: Knowledge, 8.2 points apart on average over 3 shared benchmarks.
Widest single gap: ARC-AGI-2: GPT-5.6 Luna 59.5% against Inkling 2 Small 81.7%, 22.1 points apart on a 0 to 100 scale.
Output price: GPT-5.6 Luna $1.20 against Inkling 2 Small $1.00 per million output tokens, 1.2x apart.
Context window: GPT-5.6 Luna takes 1.05M 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.

Boards won, where both have a result
Category	GPT-5.6 Luna	Inkling 2 Small
Coding	4	8
Intelligence	0	1
Agentic work	0	7
Reasoning	2	7
Knowledge	2	1
General	11	1
All shared boards	19	25

CodingLike-for-likeSix of these boards feed the Vibe Coding Index48

Coding benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
LMArena WebDev	1519	1647	Inkling 2 Small
AA Coding Index	71.4	Not measured	Only GPT-5.6 Luna measured
SWE-bench Verified (Vals AI)	93.0%	Not measured	Only GPT-5.6 Luna measured
Terminal-Bench 4 (Vals AI)	11.6%	12.6%	Inkling 2 Small
Vibe Code Bench (Vals AI)	77.1%	81.5%	Inkling 2 Small
Code migration (Vals AI)	44.5%	Not measured	Only GPT-5.6 Luna measured
ProgramBench (Vals AI)	0.0%	0.5%	Inkling 2 Small
IOI (Vals AI)	61.8%	Not measured	Only GPT-5.6 Luna measured
Terminal-Bench 2.1 (Vals AI)	79.0%	Not measured	Only GPT-5.6 Luna measured
SWE-bench Multimodal (Vals AI)	Not measured	43.1%	Only Inkling 2 Small measured
Vibe Code Bench 1-100 (Vals AI)	22.6%	Not measured	Only GPT-5.6 Luna measured
SkillsBench (Vals AI)	60.5%	Not measured	Only GPT-5.6 Luna measured
CyberBench (Vals AI)	73.6%	72.7%	GPT-5.6 Luna
SciCode	53.6%	52.3%	GPT-5.6 Luna
Terminal-Bench 4.0 (Artificial Analysis run)	11.6%	13.1%	Inkling 2 Small
FrontierCode 2.0	17.6%	25.4%	Inkling 2 Small
FrontierCode	39.8%	Not measured	Only GPT-5.6 Luna measured
WeirdML	60.9%	Not measured	Only GPT-5.6 Luna measured
MirrorCode	21.1%	Not measured	Only GPT-5.6 Luna measured
ALE-Bench	1667.4	Not measured	Only GPT-5.6 Luna measured
LMArena Text: coding	1467	1455	GPT-5.6 Luna
LMArena Text: software and IT	1464	1443	GPT-5.6 Luna
LMArena WebDev: React	1508	1660	Inkling 2 Small
LMArena WebDev: HTML	1522	1661	Inkling 2 Small
LMArena WebDev: from an image	1517	Not measured	Only GPT-5.6 Luna measured
SciCode	6.2%	Not measured	Only GPT-5.6 Luna measured
SWE-Bench Pro V2	Not measured	97.7%	Only Inkling 2 Small measured
GameBench 2	54.0	Not measured	Only GPT-5.6 Luna measured
Terminal-Bench 2.1	75.7%	Not measured	Only GPT-5.6 Luna measured
Terminal-Bench 3.0	14.3%	Not measured	Only GPT-5.6 Luna measured
Terminal-Bench 4.0	17.3%	Not measured	Only GPT-5.6 Luna measured
CursorBench 4.0	35.9%	Not measured	Only GPT-5.6 Luna measured
Neither model has a result on the other 20 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index01

Intelligence benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
AA Intelligence Index	23.8	30.6	Inkling 2 Small
Epoch Capabilities Index	156.7	Not measured	Only GPT-5.6 Luna measured

Agentic workLike-for-likePublic boards, shown as published, kept out of the index07

Agentic work benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
AA Agentic Index	42.1	Not measured	Only GPT-5.6 Luna measured
SREBench (Vals AI)	1.5%	1.9%	Inkling 2 Small
Finance Agent (Vals AI)	55.0%	Not measured	Only GPT-5.6 Luna measured
Tax Agent Bench (Vals AI)	24.8%	38.9%	Inkling 2 Small
Legal Research Bench (Vals AI)	36.5%	46.6%	Inkling 2 Small
Harvey's Legal Agent Benchmark (Vals AI)	Not measured	21.7%	Only Inkling 2 Small measured
Excel Modeling Benchmark (Vals AI)	67.1%	Not measured	Only GPT-5.6 Luna measured
BioMysteryBench (Vals AI)	61.5%	70.0%	Inkling 2 Small
Terminal-Bench-Science (Vals AI)	0.0%	2.9%	Inkling 2 Small
Vals Science Index	25.3%	32.7%	Inkling 2 Small
APEX-Agents	43.0%	46.8%	Inkling 2 Small
BALROG	45.6%	Not measured	Only GPT-5.6 Luna measured
Vending-Bench 2	$4,095	Not measured	Only GPT-5.6 Luna measured
MCP Atlas	Not measured	85.4%	Only Inkling 2 Small measured
Neither model has a result on the other 30 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index27

Reasoning benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
GPQA Diamond	91.7%	Not measured	Only GPT-5.6 Luna measured
MysteryMechanism (Vals AI)	14.4%	25.2%	Inkling 2 Small
MMMU Pro (Vals AI)	85.0%	Not measured	Only GPT-5.6 Luna measured
GPQA Diamond (Artificial Analysis run)	91.1%	Not measured	Only GPT-5.6 Luna measured
Humanity's Last Exam (Artificial Analysis run)	39.5%	44.1%	Inkling 2 Small
HLE-Diamond (Artificial Analysis run)	20.9%	28.7%	Inkling 2 Small
CritPt v2, hard subset (Artificial Analysis run)	30.5%	35.0%	Inkling 2 Small
GPQA Diamond (Epoch AI run)	91.6%	Not measured	Only GPT-5.6 Luna measured
ARC-AGI	88.0%	96.5%	Inkling 2 Small
ARC-AGI-2	59.5%	81.7%	Inkling 2 Small
SimpleBench	46.8%	Not measured	Only GPT-5.6 Luna measured
Chess puzzles	43.0%	Not measured	Only GPT-5.6 Luna measured
Mystery game puzzles	21.0%	Not measured	Only GPT-5.6 Luna measured
LMArena Text: hard prompts	1452	1421	GPT-5.6 Luna
LMArena Text: expert	1477	1478	Inkling 2 Small
LMArena Text: hard prompts in English	1460	1424	GPT-5.6 Luna
LMArena Vision: diagrams	1271	Not measured	Only GPT-5.6 Luna measured
LMArena Vision: homework	1281	Not measured	Only GPT-5.6 Luna measured
Kagi LLM Benchmark	49.1%	Not measured	Only GPT-5.6 Luna measured
GoBench	1091	Not measured	Only GPT-5.6 Luna measured
Neither model has a result on the other 6 boards here

MathDirectional onlyPublic boards, shown as published, kept out of the index7 boards, none shared

Math benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
OTIS Mock AIME	98.3%	Not measured	Only GPT-5.6 Luna measured
FrontierMath, tiers 1 to 3	82.1%	Not measured	Only GPT-5.6 Luna measured
FrontierMath, tier 4	61.0%	Not measured	Only GPT-5.6 Luna measured
ProofBench	60.0%	Not measured	Only GPT-5.6 Luna measured
LMArena Text: math	1457	Not measured	Only GPT-5.6 Luna measured
LMArena Text: mathematical work	1467	Not measured	Only GPT-5.6 Luna measured
MathArena	Not measured	42.4%	Only Inkling 2 Small measured
Neither model has a result on the other 7 boards here

KnowledgeLike-for-likePublic boards, shown as published, kept out of the index21

Knowledge benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
MMLU Pro	86.0%	Not measured	Only GPT-5.6 Luna measured
LegalBench (Vals AI)	84.0%	Not measured	Only GPT-5.6 Luna measured
CorpFin (Vals AI)	64.2%	Not measured	Only GPT-5.6 Luna measured
TaxEval (Vals AI)	76.2%	Not measured	Only GPT-5.6 Luna measured
MortgageTax (Vals AI)	67.3%	Not measured	Only GPT-5.6 Luna measured
MedCode (Vals AI)	42.4%	Not measured	Only GPT-5.6 Luna measured
AA-Omniscience	-17.1	16.1	Inkling 2 Small
SimpleQA Verified	41.0%	Not measured	Only GPT-5.6 Luna measured
LMArena Text: science	1434	1409	GPT-5.6 Luna
LMArena Text: medicine and healthcare	1399	Not measured	Only GPT-5.6 Luna measured
LMArena Text: legal and government	1444	Not measured	Only GPT-5.6 Luna measured
LMArena Text: business and finance	1439	1415	GPT-5.6 Luna
FACTS Benchmark Suite	56.9%	Not measured	Only GPT-5.6 Luna measured
Neither model has a result on the other 8 boards here

Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards, none shared

Web design benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
Design Arena: websites	1248	Not measured	Only GPT-5.6 Luna measured
Design Arena: UI components	1241	Not measured	Only GPT-5.6 Luna measured
Design Arena: game dev	1190	Not measured	Only GPT-5.6 Luna measured
Design Arena: data viz	1203	Not measured	Only GPT-5.6 Luna measured
Design Arena: 3D	1099	Not measured	Only GPT-5.6 Luna measured
Design Arena: all code categories	1221	Not measured	Only GPT-5.6 Luna measured
Design Arena: SVG	1185	Not measured	Only GPT-5.6 Luna measured
Design Arena: ASCII art	1142	Not measured	Only GPT-5.6 Luna measured
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index111

General benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	Inkling 2 Small	Leader
Vals Index	Not measured	56.1%	Only Inkling 2 Small measured
Public Benefits Bench (Vals AI)	61.2%	Not measured	Only GPT-5.6 Luna measured
SAGE (Vals AI)	Not measured	88.6%	Only Inkling 2 Small measured
MedScribe (Vals AI)	84.4%	Not measured	Only GPT-5.6 Luna measured
Vals Multimodal Index	69.1%	Not measured	Only GPT-5.6 Luna measured
Long context reasoning (AA-LCR)	83.7%	83.3%	GPT-5.6 Luna
GDPval-AA	1470	1630	Inkling 2 Small
DTBench	89.1%	Not measured	Only GPT-5.6 Luna measured
LMCA	48.5%	Not measured	Only GPT-5.6 Luna measured
Surface Evolver Bench	61.9%	Not measured	Only GPT-5.6 Luna measured
Furniture assembly	42.5%	Not measured	Only GPT-5.6 Luna measured
LMArena Text	1431	1403	GPT-5.6 Luna
LMArena Text: instruction following	1437	1408	GPT-5.6 Luna
LMArena Text: creative writing	1396	1348	GPT-5.6 Luna
LMArena Vision	1256	Not measured	Only GPT-5.6 Luna measured
LMArena Text: English	1442	1418	GPT-5.6 Luna
LMArena Text: non-English	1417	1390	GPT-5.6 Luna
LMArena Text: Chinese	1472	Not measured	Only GPT-5.6 Luna measured
LMArena Text: German	1456	Not measured	Only GPT-5.6 Luna measured
LMArena Text: Japanese	1416	Not measured	Only GPT-5.6 Luna measured
LMArena Text: Korean	1408	Not measured	Only GPT-5.6 Luna measured
LMArena Text: French	1454	Not measured	Only GPT-5.6 Luna measured
LMArena Text: Spanish	1448	Not measured	Only GPT-5.6 Luna measured
LMArena Text: Russian	1426	1377	GPT-5.6 Luna
LMArena Text: Polish	1403	Not measured	Only GPT-5.6 Luna measured
LMArena Text: multi-turn	1434	1408	GPT-5.6 Luna
LMArena Text: longer queries	1436	1403	GPT-5.6 Luna
LMArena Text: writing and language	1418	1381	GPT-5.6 Luna
LMArena Text: entertainment and media	1401	1359	GPT-5.6 Luna
LMArena Vision: English	1260	Not measured	Only GPT-5.6 Luna measured
LMArena Vision: Chinese	1301	Not measured	Only GPT-5.6 Luna measured
LMArena Vision: reading text	1263	Not measured	Only GPT-5.6 Luna measured
LMArena Vision: humor	1192	Not measured	Only GPT-5.6 Luna measured
LMArena Vision: creative writing	1256	Not measured	Only GPT-5.6 Luna measured
LMArena Document	1454	Not measured	Only GPT-5.6 Luna measured
EQ-Bench 4	1146	Not measured	Only GPT-5.6 Luna measured
Neither model has a result on the other 13 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for GPT-5.6 Luna and Inkling 2 Small
Benchmark	GPT-5.6 Luna	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

GPT-5.6 Luna$0.0008Fits in one request

Inkling 2 Small$0.0008Fits in one request

Same cost

Repository review

50K input + 3K output tokens

GPT-5.6 Luna$0.014Fits in one request

Inkling 2 Small$0.018Fits in one request

GPT-5.6 Luna costs less

Agent loop

200K input + 10K output tokens

GPT-5.6 Luna$0.052Fits in one request

Inkling 2 Small$0.070Fits in one request

GPT-5.6 Luna 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.

Specifications of GPT-5.6 Luna and Inkling 2 Small
Specification	OpenAI GPT-5.6 Luna	Thinking Machines Inkling 2 Small
Maker	OpenAI	Thinking Machines
Weights	No public weights listed	Open weights
Released	July 9, 2026	November 9, 2026
Context window	1.05M	1.05M
Input $/Mtok	$0.20	$0.30
Output $/Mtok	$1.20	$1.00
Coding index	55.3	48.9
Independent measurements behind it	5	3
Cost per solved task	$0.04	Not computable
Source	OpenRouter listing	OpenRouter listing

Questions

Is GPT-5.6 Luna better than Inkling 2 Small for coding?

Pick GPT-5.6 Luna for coding: it scores 55.3 on the Vibe Coding Index against 48.9 for Inkling 2 Small. Pick Inkling 2 Small for output tokens 1.2x cheaper ($1.00 vs $1.20 per million) and work measured by LMArena WebDev or Terminal-Bench 4 (Vals AI), where it leads.

Which is cheaper, GPT-5.6 Luna or Inkling 2 Small?

GPT-5.6 Luna costs $0.20 per million input tokens and $1.20 per million output tokens; Inkling 2 Small costs $0.30 and $1.00. Cost per solved task is known for GPT-5.6 Luna only.

Which has the bigger context window, GPT-5.6 Luna or Inkling 2 Small?

GPT-5.6 Luna, with 1.05M tokens against 1.05M.

How many benchmarks is the GPT-5.6 Luna vs Inkling 2 Small comparison based on?

44 benchmarks have a result for both models as of November 14, 2026. GPT-5.6 Luna's coding index rests on 5 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.

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GPT-5.6 Luna or Inkling 2 Small: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Reasoning

Knowledge

Web design

General

Long documents

Everyday cost

Cost per solved task