Protocol & architecture
Hosts, transports (e.g. stdio, streamable HTTP), capability discovery, and how JSON-RPC-style messaging maps to MCP method names in current spec revisions.
· Independent guide — always verify against the official MCP specification.
Model Context Protocol
What is MCP?
MCP stands for the Model Context Protocol—an open protocol (documented as a specification) for how applications that host large language models (LLMs) discover and interact with external context: tools (actions), resources (readable data), and structured prompts. Instead of every editor, IDE, or agent inventing its own plugin wire format, MCP defines a shared client–server protocol so the same integration logic can be reused across compliant hosts. For vocabulary only, open the compact MCP glossary.
Key takeaways
- MCP means Model Context Protocol—an open way for LLM hosts to talk to MCP servers that expose tools, resources, and prompts.
- It is a protocol layer, not a single vendor product: many IDEs and assistants can implement a host; many communities ship servers.
- Security does not come “for free”: a malicious server can act like privileged code—see the FAQ on safety.
- Normative behavior (methods, transports, versioning) lives on modelcontextprotocol.io; this site summarizes for discovery.
MCP vs one-off “AI plugins”
Search traffic often compares MCP to ad-hoc extensions. MCP’s leverage is interoperability: one server implementation can attach to many hosts, and hosts can swap integrations without rewriting proprietary wire formats for each pair.
| Topic | Bespoke per-product plugins | Model Context Protocol |
|---|---|---|
| Discovery | Custom manifest per vendor | Shared capability negotiation in the spec |
| Primitives | Varies widely (no common names) | Tools, resources, prompts (standardized concepts) |
| Transports | Often undocumented or product-specific | Documented patterns (e.g. stdio, HTTP streaming in spec revisions) |
| Audience | Single app ecosystem | Cross-editor / cross-agent reuse when hosts comply |
Why MCP exists
LLM applications routinely need grounded answers, side effects (file edits, tickets, queries), and retrieval from proprietary systems. Historically those capabilities were bolted on with bespoke APIs per product. MCP standardizes the shape of those conversations—capabilities negotiation, message framing, and error semantics—while leaving business logic inside each server implementation.
This site is an independent educational summary. It does not replace the specification, does not endorse any particular vendor implementation, and does not constitute security or legal advice. When integrating MCP, treat every server as privileged code with access to credentials and user data available to the host process.
From the same editorial network, 25web.tech gathers practical notes on web engineering and getting sites live, while whatisanapp.org answers the parallel question “what is an app?” in a similar explainer tone—helpful when you are drawing lines between assistants, hosts, and conventional applications.
Explore further
FAQ
MCP vs REST APIs, safety boundaries, Cursor/IDE integration at a high level, and common misconceptions.
Glossary
Short definitions: MCP host, MCP server, tools, resources, prompts, transports, JSON-RPC framing—built for snippets and long-tail queries.
Resources
Official documentation, specification source, and related reading for implementers.