Gemini 3.1 Pro Preview Custom Tools vs Mistral Magistral Small 2509
Gemini 3.1 Pro Preview Custom Tools (2026) and Mistral Magistral Small 2509 (2025) are general-purpose language models from Google DeepMind and MistralAI. Gemini 3.1 Pro Preview Custom Tools ships a 1m-token context window, while Mistral Magistral Small 2509 ships a not-yet-sourced context window. On pricing, Mistral Magistral Small 2509 costs $0.50/1M input tokens versus $2/1M 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.
Mistral Magistral Small 2509 is ~300% cheaper at $0.50/1M; pay for Gemini 3.1 Pro Preview Custom Tools only for vision-heavy evaluation.
Decision scorecard
Local evidence first| Signal | Gemini 3.1 Pro Preview Custom Tools | Mistral Magistral Small 2509 |
|---|---|---|
| Best for | multimodal apps and long-context analysis | provider-routed production |
| Decision fit | RAG, Long context, and Vision | General |
| Context window | 1m | — |
| Cheapest output | $12/1M tokens | $1.50/1M tokens |
| Provider routes | 1 tracked | 2 tracked |
| Shared benchmarks | 0 shared | 0 shared |
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, Multimodal, and Structured outputs in local model data.
- Local decision data tags Gemini 3.1 Pro Preview Custom Tools for RAG, Long context, and Vision.
- Mistral Magistral Small 2509 has the lower cheapest tracked output price at $1.50/1M tokens.
- Mistral Magistral Small 2509 has broader tracked provider coverage for fallback and route flexibility.
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
Mistral Magistral Small 2509
$775
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $3,825. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Gemini 3.1 Pro Preview Custom Tools and Mistral Magistral Small 2509; plan for SDK, billing, or endpoint changes.
- Mistral Magistral Small 2509 is $10.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Structured outputs before moving production traffic.
- No overlapping tracked provider route is sourced for Mistral Magistral Small 2509 and Gemini 3.1 Pro Preview Custom Tools; plan for SDK, billing, or endpoint changes.
- Gemini 3.1 Pro Preview Custom Tools is $10.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Gemini 3.1 Pro Preview Custom Tools adds Vision, Multimodal, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-01-01 | 2025-09-01 |
| Context window | 1m | — |
| Parameters | — | 24B |
| Architecture | Decoder Only | - |
| License | Proprietary | Apache 2.0OSI-approved |
| Openness | Proprietary | Open source |
| Weights | Not released | Unknown |
| Code | Unknown | Unknown |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | 2025-01 | - |
Pricing and availability
| Pricing attribute | Gemini 3.1 Pro Preview Custom Tools | Mistral Magistral Small 2509 |
|---|---|---|
| Input price | $2/1M tokens | $0.50/1M tokens |
| Output price | $12/1M tokens | $1.50/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 3.1 Pro Preview Custom Tools | Mistral Magistral Small 2509 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | No | No |
| JSON / Tool use | No | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
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Last reviewed: 2026-06-29. Data sourced from public model cards and provider documentation.