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Claude 3.5 Sonnet input $3.00/1M ↓ -50%
GPT-4o input $2.50/1M
Gemini 1.5 Pro input $1.25/1M
Mistral Large input $2.00/1M ↓ -33%
DeepSeek V3 input $0.27/1M
synced 2026-04-05
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Function calling

Supports structured tool/function calling

What is function calling?

Function calling — also called tool use — lets the model invoke external functions during a conversation. Instead of generating text, the model outputs a structured call with parameters. Your code executes the function and returns the result. This is how AI applications interact with databases, APIs, and external services. Without function calling, a model can only talk. With it, it can act.

Why it matters

Without function calling, your AI application is a chatbot — it can talk but not act. With function calling, it becomes an agent that can query databases, call APIs, send emails, and trigger workflows. The model decides which tool to use and with what parameters. Your code executes it. This is the capability that separates conversational AI from production AI.

Where models stand

13 models with function calling enabled:

Data available for 13 of 271 tracked entities.

How sourc.dev tracks this

sourc.dev verifies function calling manually from official provider documentation, API responses, and published specifications. Every data point includes a source URL and verification date. When a value changes, the old value is preserved in the history table and the new value is recorded alongside it. Nothing is overwritten — the full timeline is always available.

Related
Frequently asked questions
FAQ How does sourc.dev measure function calling?

sourc.dev verifies this attribute manually from provider documentation. Every data point includes a source URL and verification date. Changes are recorded in the history table — nothing is overwritten.

FAQ How often is function calling updated?

This attribute is verified periodically against provider documentation. When sourc.dev detects a change, the new value is recorded alongside the old one with full provenance.

FAQ Why does function calling matter for developers?

Understanding function calling helps developers make informed decisions when choosing between models and providers. Rather than relying on marketing claims, sourc.dev provides verified, dated, source-linked data so the data decides.