Stage 05 of 11 · MCP & Integrations · 3 min · Reviewed Aug 2026
MCP and Integrations: Servers, Clients, and Third-Party Tools
MCP (open, 2024; widely adopted through 2025–2026) standardizes how hosts talk to servers that expose tools, resources, and prompts. You still own auth, scopes, and what the agent is allowed to call. This is integration engineering, not a magic bus.
- MCP
- Servers
- Clients
- Third-party tools
What you learn
How to connect agents to external capabilities through a protocol instead of a pile of one-off plugins.
Why MCP exists
Every product used to invent its own plugin format: ChatGPT actions, custom GPTs, vendor “tools” with unique JSON. MCP gives a common client/server contract so a Git server, a Slack server, a Postgres server, and a browser server can all speak the same language to Cursor, Claude, or your own host.
You still write the server. You still define scopes. The protocol removes glue, not responsibility.
Servers, tools, resources, prompts
An MCP server exposes tools (actions), resources (readable URIs — files, tickets, schemas), and optionally prompts (reusable instruction packs). A host/client connects, lists capabilities, and lets the model call tools or read resources under policy.
Resources are underrated: they are how you give an agent a file without pasting it into the system prompt. Tools are for mutation and queries. Do not implement “read the repo” as a 12-argument tool if a resource URI will do.
{
"mcpServers": {
"repo": {
"command": "npx",
"args": ["-y", "@example/mcp-git"],
"env": { "GIT_DIR": "/work/app/.git" }
}
}
}Visual
MCP Server Anatomy
An MCP server exposes three capability types to a host/client: tools (actions the model can invoke), resources (readable URIs like files and schemas), and prompts (reusable instruction packs). The host connects, lists capabilities, and enforces policy.
Clients and hosts
The host is the app the human uses (IDE, desktop agent, your web worker). It owns UX, secrets, and which servers are enabled. The client library speaks . The model never sees the raw socket — it sees tool schemas the host registered.