Tools, APIs & MCP Integrations
How agents connect to real-world systems
TL;DR
How agents connect to real-world systems
> Overview
This module focuses on the tool use layer: how agents call external APIs, execute functions, and interact with real systems through MCP. With RAG covered separately in Module 8, this module concentrates on the action side: agents that do things in the real world, not just retrieve information.
> Why This Matters for Your Product
This is where agents go from neat demo to real product. An agent that can look up customer data, create tickets, send emails, and update your CRM is transformative. But every tool is a potential security risk and failure point. The PM must decide which tools to expose, what permissions to grant, and how to handle failures gracefully.
> Interactive & tools
MCP architecture
MCP: Agent (client) → Protocol → Servers
Permissions
Permission matrix (example)
| Tool | Read | Write |
|---|---|---|
| CRM | ||
| Database |
Write = higher risk. Start read-only; add write with approval gates.
Related Engineering Patterns
These are the technical patterns your engineering team will implement. Understanding them helps you have better conversations.
Key Product Decisions
- [01]Which internal systems should the agent be able to access?
- [02]What data should agents read vs. write? What actions are irreversible?
- [03]What happens when an external tool fails mid-task?
- [04]Are you using MCP for standardized integrations or custom API wrappers?
Ask Your Engineering Team
- →What tools are we exposing and what permissions do they have?
- →How do we handle API failures or timeouts gracefully?
- →Are we using MCP or custom integrations for tool connections?
- →What is the latency cost of each tool call?
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