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Model Comparison

GPT-5.1-Codex vs Hy-MT2-1.8BWhich Is Better in 2026?

OpenAI: GPT-5.1-Codex logoOpenAI•Tencent: Hy-MT2-1.8B logoTencent

GPT-5.1-Codex vs Hy-MT2-1.8B: which should you choose in 2026?

GPT-5.1-Codex (by OpenAI) and Hy-MT2-1.8B (by Tencent) are compared below. Here is how they stack up on benchmarks, price, and capabilities, and which one to pick in 2026.

There are not enough shared, protocol-compatible benchmark results to declare a performance leader.

Hy-MT2-1.8B is about 44.5× cheaper on a blended 3:1 input/output basis ($0.07725 vs $3.44 per 1M tokens).

GPT-5.1-Codex has the larger context window (400,000 tokens vs 8,192 tokens).

Choose GPT-5.1-Codex if…

  • • you work with longer documents, transcripts, or codebases
  • • you need a model with explicit reasoning support
  • • you need image inputs

Choose Hy-MT2-1.8B if…

  • • lower blended API cost matters for your workload

The benchmark count includes only results measured with a matching benchmark version and protocol. Arena scores are shown separately. Missing, preliminary, and incompatible data is not treated as a controlled win. Published point-score comparisons are labeled separately when protocol details are incomplete. For text-output models, the verdict also compares token pricing and context windows.

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Performance benchmarks

Every value links to its source. A dash means that no reviewed result is available for that exact model and protocol.

GPT-5.1-Codex and Hy-MT2-1.8B benchmark results
BenchmarkGPT-5.1-CodexHy-MT2-1.8B
AutomationBench-AA

A 657-task benchmark of multi-step work across simulated SaaS applications in six business domains. The Artificial Analysis protocol reports a guardrail-aware score and is distinct from both the public Zapier split and the unrelated dynamic AutoBench framework.

Guardrail-aware score

——
BrowseComp

A benchmark of difficult, verifiable information-seeking questions designed to measure an agent's ability to locate hard-to-find facts through web browsing.

Accuracy

——
OSWorld-Verified

A verified computer-use benchmark in which multimodal agents operate desktop applications and are graded from the resulting environment state.

Mean task reward

——
SWE-Bench Verified

A human-validated subset of real GitHub issues used to measure whether a coding agent can produce repository patches that resolve the associated tests.

Resolved

66.0%
SWE-bench
—
Terminal-Bench 2.1

Version 2.1 of the benchmark for completing realistic tasks in terminal environments. Harness, resource limits, and attempt count are part of the protocol.

Mean task success

——
AutoBench

A dynamic LLM evaluation framework in which models generate questions, answer them, and participate in reciprocal peer assessment. AutoBench is distinct from Zapier's AutomationBench.

Weighted peer-assessment score

——
GPQA Diamond

The highest-quality subset of Graduate-Level Google-Proof Q&A, designed to test expert-level scientific reasoning in biology, physics, and chemistry.

Accuracy

——
Humanity's Last Exam

A 2,500-question expert-level benchmark spanning dozens of academic fields. Tool-assisted and no-tools results are separate protocols and must not be merged.

Accuracy

——
Arena preference scores
Arena (Code/WebDev)

Human preference score for code and web development

1336 ±12
—

Benchmark sources

Reviewed evidence last updated 2026-08-09. Arena data last refreshed Aug 25, 2026.

Pricing, capabilities, and model facts

GPT-5.1-Codex and Hy-MT2-1.8B model facts
FeatureGPT-5.1-CodexHy-MT2-1.8B
Context & model facts
DeveloperOpenAITencent
API providerOpenAITencent
Input context400,000 tokens8,192 tokens
Maximum output128,000 tokens4,096 tokens
Released——
Added to WritingmateNov 13, 2025Aug 20, 2026
LicenseNot availableNot available
Knowledge cutoff——
Capabilities
InputsText, ImageText
OutputsTextText
Provider endpoint accepts tool parametersYesNo
ReasoningYesNo
VisionYesNo
Image GenerationNoNo
Video GenerationNoNo
API pricing
Input (per 1M tokens)$1.25$0.044
Output (per 1M tokens)$10.00$0.177
Blended 3:1 input/output$3.44$0.07725
API performance
p95 latencyNot measuredNot measured
Output throughputNot measuredNot measured
Writingmate shows API performance only when both models have enough observations from the same measurement window, prompt profile, and provider. Third-party latency values are not copied into this table.

Data sources

  • Writingmate model catalog (pricing, limits, and availability)

Catalog data last updated Aug 20, 2026.

Why Pay for Multiple Subscriptions?

Comparing GPT-5.1-Codex from OpenAI with Hy-MT2-1.8B from Tencent? Instead of managing separate API keys and subscriptions, get both with Writingmate.

Subscription-plan access for GPT-5.1-Codex and Hy-MT2-1.8B
PlanPriceGPT-5.1-CodexHy-MT2-1.8BAI ImagesAI Video
Writingmate Pro
Most popular
$20/moIncludedIncludedNano Banana Pro, FLUX.2, DALL-E & moreSora 2, VEO 3.1
Writingmate Ultimate
Power users
$60/moIncludedIncludedNano Banana Pro, FLUX.2, DALL-E & moreSora 2, VEO 3.1
View Plans & Pricing

GPT-5.1-Codex vs Hy-MT2-1.8B FAQ

Which is better, GPT-5.1-Codex or Hy-MT2-1.8B?

There are not enough shared, protocol-compatible benchmark results to declare a performance leader. Hy-MT2-1.8B is about 44.5× cheaper on a blended 3:1 input/output basis ($0.07725 vs $3.44 per 1M tokens). GPT-5.1-Codex has the larger context window (400,000 tokens vs 8,192 tokens).

Which model is cheaper to use through an API?

Hy-MT2-1.8B is about 44.5× cheaper on a blended 3:1 input/output basis ($0.07725 vs $3.44 per 1M tokens).

Which model supports more context?

GPT-5.1-Codex has the larger context window (400,000 tokens vs 8,192 tokens).

Can I switch between GPT-5.1-Codex and Hy-MT2-1.8B?

Yes. Use the model selector on this page to open any current Writingmate model comparison. You can also run the same prompt with both models in Writingmate.