Agents · best for
Best AI model for Function / Tool Calling (2026)
Reliable JSON tool-call generation. Ranked from 346 live models on the OpenRouter catalog, weighted for tool calling, structured output.
| # | Model | Score | In / 1M | Out / 1M | Context | |
|---|---|---|---|---|---|---|
| 1 | MoonshotAI: Kimi K2.6moonshotai/kimi-k2.6 | 120 | $0.80 | $3.50 | 262,144 | Try → |
| 2 | Google: Gemma 4 26B A4B (free)google/gemma-4-26b-a4b-it:free | 120 | Free | Free | 262,144 | Try → |
| 3 | Google: Gemma 4 26B A4B google/gemma-4-26b-a4b-it | 120 | $0.07 | $0.35 | 262,144 | Try → |
| 4 | Google: Gemma 4 31B (free)google/gemma-4-31b-it:free | 120 | Free | Free | 262,144 | Try → |
| 5 | Google: Gemma 4 31Bgoogle/gemma-4-31b-it | 120 | $0.13 | $0.38 | 262,144 | Try → |
| 6 | Qwen: Qwen3.6 Plusqwen/qwen3.6-plus | 120 | $0.33 | $1.95 | 1,000,000 | Try → |
| 7 | Z.ai: GLM 5V Turboz-ai/glm-5v-turbo | 120 | $1.20 | $4.00 | 202,752 | Try → |
| 8 | xAI: Grok 4.20x-ai/grok-4.20 | 120 | $2.00 | $6.00 | 2,000,000 | Try → |
| 9 | Xiaomi: MiMo-V2-Omnixiaomi/mimo-v2-omni | 120 | $0.40 | $2.00 | 262,144 | Try → |
| 10 | OpenAI: GPT-5.4 Nanoopenai/gpt-5.4-nano | 120 | $0.20 | $1.25 | 400,000 | Try → |
| 11 | OpenAI: GPT-5.4 Miniopenai/gpt-5.4-mini | 120 | $0.75 | $4.50 | 400,000 | Try → |
| 12 | Mistral: Mistral Small 4mistralai/mistral-small-2603 | 120 | $0.15 | $0.60 | 262,144 | Try → |
| 13 | ByteDance Seed: Seed-2.0-Litebytedance-seed/seed-2.0-lite | 120 | $0.25 | $2.00 | 262,144 | Try → |
| 14 | Qwen: Qwen3.5-9Bqwen/qwen3.5-9b | 120 | $0.10 | $0.15 | 262,144 | Try → |
| 15 | OpenAI: GPT-5.4openai/gpt-5.4 | 120 | $2.50 | $15.00 | 1,050,000 | Try → |
How we ranked these
For Function / Tool Calling, we weight models on tool calling, structured output. Higher means better. Scores combine OpenRouter's model metadata (context length, modality support, tool calling, structured output, reasoning capability) with public pricing. See full methodology →
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