Teams evaluating AI automation often conflate function calling (OpenAI, Anthropic, Google each have variants) with the Model Context Protocol. They overlap in purpose — letting models invoke external logic — but differ in scope and portability.
Function Calling: Provider-Specific
Function calling embeds tool definitions in the prompt or API request for a single model provider. You define JSON schemas, the model returns a structured call, and your application executes it.
This works well for bespoke apps where you control both the model and the executor. The downside: switching from GPT to Claude means rewriting tool wiring, auth, and execution paths.
MCP: A Shared Server Contract
MCP externalizes tools to an MCP server. Any compatible client discovers and calls those tools through a standard protocol. Your Meta Ads tools live on MCP360's server; Claude Desktop, Cursor, and ChatGPT connectors all speak the same interface.
That portability is the core trade-off. You invest in MCP server quality once; clients plug in without custom glue per provider.
Comparison at a Glance
| Dimension | Function calling | MCP |
|-----------|------------------|-----|
| Portability | Single provider | Multi-client |
| Tool hosting | Your app backend | MCP server (self or hosted) |
| Discovery | Per-request schemas | Connect-time catalog |
| Best for | Custom single-app agents | Shared business tool access |
When to Use Both
Many production setups use MCP for business systems (ads, CRM, ecommerce) and function calling for app-specific UI actions. MCP360 focuses on the former — maintained servers for Ad Platform MCP, CRM MCP, and 31 other categories.
Getting Started
Read the Model Context Protocol glossary, then follow MCP protocol explained for transport and tool details. Connect Claude in five minutes with our integration walkthrough.