Gemini 3.1 Pro Preview Custom Tools vs GPT-4o Search Preview
Gemini 3.1 Pro Preview Custom Tools (2026) and GPT-4o Search Preview (2025) are compact production models from Google DeepMind and OpenAI. Gemini 3.1 Pro Preview Custom Tools ships a 1m-token context window, while GPT-4o Search Preview ships a 128k-token context window. On pricing, Gemini 3.1 Pro Preview Custom Tools costs $2/1M input tokens versus $2.50/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 3.1 Pro Preview Custom Tools fits 8x more tokens; pick it for long-context work and GPT-4o Search Preview for tighter calls.
Decision scorecard
Local evidence first| Signal | Gemini 3.1 Pro Preview Custom Tools | GPT-4o Search Preview |
|---|---|---|
| Best for | multimodal apps and long-context analysis | general production evaluation |
| Decision fit | RAG, Long context, and Vision | RAG, Long context, and Classification |
| Context window | 1m | 128k |
| Cheapest output | $12/1M tokens | $10/1M tokens |
| Provider routes | 1 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Gemini 3.1 Pro Preview Custom Tools has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemini 3.1 Pro Preview Custom Tools uniquely exposes Vision and Multimodal in local model data.
- Local decision data tags Gemini 3.1 Pro Preview Custom Tools for RAG, Long context, and Vision.
- GPT-4o Search Preview has the lower cheapest tracked output price at $10/1M tokens.
- Local decision data tags GPT-4o Search Preview for RAG, Long context, and Classification.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Gemini 3.1 Pro Preview Custom Tools
$4,600
Cheapest tracked route/tier: OpenRouter
GPT-4o Search Preview
$4,500
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $100. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- GPT-4o Search Preview is $2/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Gemini 3.1 Pro Preview Custom Tools is $2/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Gemini 3.1 Pro Preview Custom Tools adds Vision and Multimodal in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-01-01 | 2025-02-26 |
| Context window | 1m | 128k |
| Parameters | — | — |
| Architecture | decoder only | decoder only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | 2025-01 | 2023-10 |
Pricing and availability
| Pricing attribute | Gemini 3.1 Pro Preview Custom Tools | GPT-4o Search Preview |
|---|---|---|
| Input price | $2/1M tokens | $2.50/1M tokens |
| Output price | $12/1M tokens | $10/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 3.1 Pro Preview Custom Tools | GPT-4o Search Preview |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | No | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Gemini 3.1 Pro Preview Custom Tools and multimodal input: Gemini 3.1 Pro Preview Custom Tools. Both models share structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Gemini 3.1 Pro Preview Custom Tools lists $2/1M input and $12/1M output tokens on the cheapest tracked provider, while GPT-4o Search Preview lists $2.50/1M input and $10/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts GPT-4o Search Preview lower by about $0.25 per million blended tokens. Availability is 1 providers versus 1, so concentration risk also matters.
Choose Gemini 3.1 Pro Preview Custom Tools when long-context analysis, larger context windows, and lower input-token cost are central to the workload. Choose GPT-4o Search Preview when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions.
FAQ
Which has a larger context window, Gemini 3.1 Pro Preview Custom Tools or GPT-4o Search Preview?
Gemini 3.1 Pro Preview Custom Tools supports 1m tokens, while GPT-4o Search Preview supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Gemini 3.1 Pro Preview Custom Tools or GPT-4o Search Preview?
GPT-4o Search Preview is cheaper on tracked token pricing. Gemini 3.1 Pro Preview Custom Tools costs $2/1M input and $12/1M output tokens. GPT-4o Search Preview costs $2.50/1M input and $10/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Gemini 3.1 Pro Preview Custom Tools or GPT-4o Search Preview open source?
Gemini 3.1 Pro Preview Custom Tools is listed under Proprietary. GPT-4o Search Preview is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Gemini 3.1 Pro Preview Custom Tools or GPT-4o Search Preview?
Gemini 3.1 Pro Preview Custom Tools has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Gemini 3.1 Pro Preview Custom Tools or GPT-4o Search Preview?
Gemini 3.1 Pro Preview Custom Tools has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Gemini 3.1 Pro Preview Custom Tools and GPT-4o Search Preview?
Gemini 3.1 Pro Preview Custom Tools is available on OpenRouter. GPT-4o Search Preview is available on OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Continue comparing
Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.