Technical articles on AI agents, Azure, .NET, architecture, and EV charging systems from Sydney.

Tag: AI Agents

MCP Transport Types Explained: stdio vs Streamable HTTP vs SSE in C#

Nobody tells you this when you start building MCP servers, but picking the wrong MCP transport is the kind of mistake that doesn’t hurt immediately. It hurts three months later when you’re trying to deploy to Azure and realise your architecture assumes a single process on a single machine. I’ve been there. This post is what I wish I’d read before that happened.

The MCP C# SDK gives you four transport options: stdio, Streamable HTTP, SSE, and in-memory. They all carry the same JSON-RPC 2.0 messages between your AI client and your server — the difference is in where your server lives, how connections are managed, and what happens under production load. I’ll walk through each one honestly, with working C# code and the stuff the official docs gloss over.

If you haven’t read my post on what MCP servers actually are, start there first — this one assumes you already know the basics.

What Is an MCP Transport, Exactly?

The simplest way I can put it: the MCP transport is the pipe that carries messages between the AI model and your server. The protocol itself — tool calls, capability manifests, responses — is identical regardless of which transport you use. What changes is the physical channel those messages travel through.

Think of it like this. The conversation between you and a colleague is the same whether you’re in the same room, on a video call, or texting. The transport just determines who can initiate, how fast messages arrive, and what happens when the connection drops.

The Four Transports at a Glance

Before I go into detail on each one, here’s the map. I’ll refer back to this table throughout.

Transport Direction Sessions Scales horizontally? Best for
stdio Bidirectional Implicit — one per process N/A Local tools, Claude Desktop, IDE integrations
Streamable HTTP (stateless) Request-response None ✅ No constraints Production APIs, Azure Container Apps
Streamable HTTP (stateful) Bidirectional Mcp-Session-Id header ⚠️ Needs sticky sessions Long-running agents, server push notifications
SSE (legacy) Server→client stream + POST Query string session ID ⚠️ Needs sticky sessions Legacy client compatibility only
In-memory Bidirectional Implicit — one per pipe N/A Unit tests, same-process embedding

1. stdio — Start Here, Always

stdio is the one that surprised me the most when I first encountered MCP. The client literally launches your server as a child process and the two talk through stdin and stdout. No HTTP, no ports, no certificates. Your server is just a program reading from one pipe and writing to another.

This is how Claude Desktop connects to local MCP servers. You add your server to claude_desktop_config.json, Claude spawns the process, and from that point on the two are talking JSON-RPC over standard I/O. It’s almost offensively simple for something that enables quite sophisticated agent behaviour.

What I like about it

  • It just works, everywhere. No networking, no firewall rules, no TLS ceremony. If you can run the binary, you have a working MCP server. I’ve got stdio servers running in environments where I’m not allowed to open any network ports.
  • Bidirectional by default. The server can push notifications back to the client at any time — stdin/stdout flow control gives you natural backpressure with zero configuration.
  • Clean isolation. Each client connection gets its own process. If the server crashes, the client knows immediately and only that session is affected. Nothing shared, nothing leaked.
  • Easiest to debug. You can literally run the server in a terminal and type JSON at it. I’ve done this more times than I’d like to admit.

What to watch out for

  • Local only. The server has to live on the same machine as the client. This rules it out for any cloud or API-style deployment.
  • One client per process. Not a problem for dev tools, but if you’re imagining dozens of agents sharing one server instance — that’s not stdio’s job.
  • Secret leakage is a real risk. This one caught me off guard. By default, your child process inherits every environment variable from the parent — which means GITHUB_TOKEN, OPENAI_API_KEY, AWS_SECRET_ACCESS_KEY, all of it flows straight to your server (or a third-party server you’re connecting to). The fix is one option, but you have to know to set it.

Server — the code is three lines

var builder = Host.CreateApplicationBuilder(args);

builder.Services.AddMcpServer()
    .WithStdioServerTransport()
    .WithTools<MyTools>();

// stdout belongs to the protocol — logs must go to stderr
builder.Logging.AddConsole(options =>
{
    options.LogToStandardErrorThreshold = LogLevel.Trace;
});

await builder.Build().RunAsync();

Client

var transport = new StdioClientTransport(new StdioClientTransportOptions
{
    Command = "dotnet",
    Arguments = ["run", "--project", "MyMcpServer"],
    ShutdownTimeout = TimeSpan.FromSeconds(10)
});

await using var client = await McpClient.CreateAsync(transport);

The environment variable thing — actually fix this

Don’t skip this, especially if you’re connecting to any third-party MCP server. The safe pattern is to start from the SDK’s curated allowlist and add only what your specific server needs:

// GetDefaultEnvironmentVariables() gives you PATH, HOME, and standard
// system dirs — nothing sensitive
var env = StdioClientTransportOptions.GetDefaultEnvironmentVariables();
env["MY_SERVER_API_KEY"] = apiKey; // add only what's needed

var transport = new StdioClientTransport(new StdioClientTransportOptions
{
    Command = "my-mcp-server",
    InheritEnvironmentVariables = false, // <-- this is the important bit
    EnvironmentVariables = env,
});

If you’re writing the server yourself and you know exactly what it needs, this feels like overkill. If you’re connecting to someone else’s server — treat it like any other third-party code and don’t hand it your credentials by default.

2. Streamable HTTP — What You Want in Production

Once your MCP server needs to live somewhere other than the developer’s laptop, Streamable HTTP is the answer. It’s the transport I reach for on every Azure deployment, and the one the SDK team clearly considers the future of the protocol.

Here’s how it works: the client sends an HTTP POST. The server holds that POST response body open as an SSE stream and writes the JSON-RPC response through it — along with any intermediate messages like progress updates. So you get the reliability and auth ecosystem of HTTP, with real-time streaming baked in. Clever.

It comes in two flavours and the choice matters a lot for your deployment architecture.

Stateless mode — what I use by default

Every request is independent. No session tracking. No in-memory state between calls. This is gloriously simple to operate — deploy three instances behind Azure Front Door and every request can land on any instance. No sticky session configuration, no session replication, no “which node has this user’s state” debugging at 2am.

The trade-off: the server can’t send unsolicited messages to the client. If your tools are pure request-response — client asks, server answers — stateless is perfect and I’d argue it’s the right default for most tool-use scenarios.

Stateful mode — when you need server push

If your server needs to push notifications mid-conversation — progress updates on a long-running job, real-time alerts, streaming intermediate results — you need stateful mode. The server issues an Mcp-Session-Id header after the first request and tracks per-session state in memory. Clients can also open long-lived GET requests to receive unsolicited notifications.

The cost is operational: you need session affinity at your load balancer. On Azure Container Apps this means pinning the session to a specific replica. Not complicated, but it’s a constraint you need to plan for.

Server code

dotnet add package ModelContextProtocol.AspNetCore

Stateless (the default I recommend):

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddMcpServer()
    .WithHttpTransport(options =>
    {
        options.Stateless = true;
    })
    .WithTools<MyTools>();

var app = builder.Build();
app.MapMcp(); // registers POST /mcp and GET /mcp
app.Run();

Stateful (when you need server push):

builder.Services.AddMcpServer()
    .WithHttpTransport(options =>
    {
        options.Stateless = false;
    })
    .WithTools<MyTools>();

Client

// AutoDetect tries Streamable HTTP first, falls back to SSE if needed
var transport = new HttpClientTransport(new HttpClientTransportOptions
{
    Endpoint = new Uri("https://my-mcp-server.example.com/mcp")
    // TransportMode defaults to AutoDetect
});

await using var client = await McpClient.CreateAsync(transport);

Session resumption — more useful than it sounds

In stateful mode, if the connection drops mid-conversation, you don’t have to start from scratch. Store the session ID and server info after connecting, then resume:

// Save these after first connection
string savedSessionId = client.SessionId;
McpServerCapabilities savedCaps = client.ServerCapabilities;
McpImplementation savedServerInfo = client.ServerInfo;

// On reconnect
var transport = new HttpClientTransport(new HttpClientTransportOptions
{
    Endpoint = new Uri("https://my-mcp-server.example.com/mcp"),
    KnownSessionId = savedSessionId
});

await using var client = await McpClient.ResumeSessionAsync(transport, new ResumeClientSessionOptions
{
    ServerCapabilities = savedCaps,
    ServerInfo = savedServerInfo
});

For long-running agent workflows — the kind where the model is orchestrating a multi-step task over several minutes — this is the difference between a graceful reconnect and a broken session that kills the job.

If you have browser clients (CORS)

Most MCP clients aren’t browsers, but if yours is, you’ll need CORS. One thing worth emphasising: CORS is not a substitute for host name validation — you need both. The CORS config tells browsers which origins are allowed; host name validation protects against DNS rebinding attacks from non-browser clients.

var allowedOrigins = builder.Configuration
    .GetSection("Mcp:AllowedOrigins")
    .Get<string[]>() ?? ["http://localhost:5173"];

builder.Services.AddCors(options =>
{
    options.AddPolicy("McpBrowserClient", policy =>
    {
        policy.WithOrigins(allowedOrigins)
            .WithMethods("POST", "GET", "DELETE")
            .WithHeaders("Content-Type", "Authorization",
                         "MCP-Protocol-Version", "Mcp-Session-Id")
            .WithExposedHeaders("Mcp-Session-Id");
    });
});

app.UseCors();
app.MapMcp("/mcp").RequireCors("McpBrowserClient");

3. SSE — Use It Only If You Have To

I’ll be straight with you: I wouldn’t choose SSE for anything new. The SDK marks EnableLegacySse as obsolete with diagnostic MCP9004, and that label exists for a reason.

SSE splits communication across two endpoints: your server streams to the client over a /sse connection, and the client sends messages back via HTTP POST to a /message endpoint. It was the original remote transport before Streamable HTTP arrived, and it has a structural flaw that’s hard to work around: the POST endpoint returns HTTP 202 before your handler even runs, which means there’s no backpressure. Under load, requests pile up and you can’t signal to the client that the server is overwhelmed.

The only reason to use SSE today is compatibility. Some older MCP clients — early Claude Desktop builds, some third-party tools — only speak SSE. If you need to support them alongside newer clients, run SSE alongside Streamable HTTP and let clients self-select.

Client

var transport = new HttpClientTransport(new HttpClientTransportOptions
{
    Endpoint = new Uri("https://my-mcp-server.example.com/sse"),
    TransportMode = HttpTransportMode.Sse,
    MaxReconnectionAttempts = 5,
    DefaultReconnectionInterval = TimeSpan.FromSeconds(1)
});

Server — note the pragma

builder.Services.AddMcpServer()
    .WithHttpTransport(options =>
    {
        options.Stateless = false; // SSE requires stateful mode

#pragma warning disable MCP9004
        options.EnableLegacySse = true;
#pragma warning restore MCP9004
    })
    .WithTools<MyTools>();

The fact that you need a pragma suppression to enable it should tell you everything about the SDK team’s intentions here.

4. In-Memory — Your Testing Best Friend

This one doesn’t get talked about enough. The in-memory transport connects a client and server using System.IO.Pipelines inside the same process — no network, no serialisation overhead, no infrastructure. For unit and integration tests it’s genuinely great.

What I like about it: your tests exercise the real MCP protocol, not mocks. Tool registration, schema generation, capability negotiation — all of it runs for real, just without a network between the two sides. I caught a schema mismatch bug in a tool’s [Description] attribute using an in-memory test that I’d completely missed in manual testing.

using System.IO.Pipelines;
using ModelContextProtocol.Client;
using ModelContextProtocol.Protocol;
using ModelContextProtocol.Server;

Pipe clientToServer = new(), serverToClient = new();

await using var server = McpServer.Create(
    new StreamServerTransport(
        clientToServer.Reader.AsStream(),
        serverToClient.Writer.AsStream()),
    new McpServerOptions
    {
        ToolCollection =
        [
            McpServerTool.Create(
                (string message) => $"Echo: {message}",
                new() { Name = "echo" })
        ]
    });

_ = server.RunAsync();

await using var client = await McpClient.CreateAsync(
    new StreamClientTransport(
        clientToServer.Writer.AsStream(),
        serverToClient.Reader.AsStream()));

var tools = await client.ListToolsAsync();
var echo = tools.First(t => t.Name == "echo");
Console.WriteLine(await echo.InvokeAsync(new() { ["arg"] = "Hello, MCP!" }));
// Output: Echo: Hello, MCP!

One limitation worth knowing: in-memory tests won’t catch network-specific failure modes — timeouts, dropped connections, serialisation edge cases from real socket buffers. Use in-memory for protocol correctness tests, and add a handful of real HTTP integration tests for your production transport paths.

Which MCP Transport Should You Use?

Here’s the decision in plain terms. I’ve seen people overthink this — pick the one that fits your deployment and move on.

Your situation Use this
Connecting to Claude Desktop, VS Code, or any local AI client stdio
Remote server on Azure / AWS, tools are pure request-response Streamable HTTP — stateless
Remote server, needs server push or long-running job tracking Streamable HTTP — stateful
Supporting a legacy client that only speaks SSE SSE (but plan to migrate)
Writing unit or integration tests In-memory
Not sure — want the client to handle it automatically HttpTransportMode.AutoDetect on the client

One More Thing: Enterprise SSO with the ID-JAG Flow

If you’re deploying an MCP server inside a corporate environment with Okta or Entra ID, you’ll likely hit the question of how agents authenticate without requiring users to log in every time. The SDK has a built-in solution for this: the Identity Assertion Grant flow.

In short: it exchanges an OIDC ID token from your identity provider for an MCP access token via a two-step RFC-standard token exchange. Your agent stays authenticated, the access token is cached until expiry, and you call InvalidateCache() if you get a 401 and need to refresh.

using ModelContextProtocol.Authentication;

var provider = new IdentityAssertionGrantProvider(
    new IdentityAssertionGrantProviderOptions
    {
        ClientId = "mcp-client-id",
        IdpTokenEndpoint = "https://company.okta.com/oauth2/token",
        IdpClientId = "idp-client-id",
        // This callback retrieves the current user's ID token from your SSO client
        IdTokenCallback = (context, cancellationToken) =>
            mySsoClient.GetIdTokenAsync(cancellationToken)
    },
    new HttpClient());

var tokens = await provider.GetAccessTokenAsync(
    resourceUrl: new Uri("https://mcp-server.example.com"),
    authorizationServerUrl: new Uri("https://auth.mcp-server.example.com"),
    cancellationToken: ct);

// On 401: provider.InvalidateCache() forces a fresh exchange next call

I’ll cover enterprise auth in more depth in a dedicated post — there’s enough there to warrant its own treatment, especially for Azure-hosted scenarios with Entra ID.

Frequently Asked Questions

What is the default MCP transport in the C# SDK?

There isn’t one — you choose explicitly when configuring the server. The most common starting points are WithStdioServerTransport() for local tools and WithHttpTransport() from ModelContextProtocol.AspNetCore for anything deployed remotely.

Can I switch transports without rewriting my tools?

Yes, completely. The transport is configured in Program.cs; your [McpServerTool] methods don’t know or care which transport is active. I’ve migrated projects from stdio to Streamable HTTP in under 10 minutes — it’s genuinely just a config change.

What is the difference between stateless and stateful Streamable HTTP?

Stateless means each HTTP POST is a standalone request — no session, no shared state, infinitely scalable. Stateful means the server issues an Mcp-Session-Id and tracks per-session state in memory, which enables server-to-client push notifications and session resumption but requires sticky sessions at your load balancer.

Is SSE still supported in the MCP C# SDK?

Yes, but it’s marked obsolete (diagnostic MCP9004). The SDK team recommends Streamable HTTP for all new work. SSE is there for backwards compatibility with older clients and will likely be removed in a future major version.

What transport does Claude Desktop use?

stdio. Claude Desktop launches your server as a child process using the command defined in claude_desktop_config.json and communicates over stdin/stdout. This is why local MCP servers for Claude are so simple to set up — no networking involved at all.

Can I run stdio and Streamable HTTP on the same server?

Not in a single AddMcpServer() setup, but the practical pattern is to put your tool logic in a shared class library and have two thin host projects — one with stdio for local dev tooling, one with Streamable HTTP for production. The tool code is identical; only the entry point differs.


Transport decisions look simple on paper and get complicated fast when you’re deploying to Azure with sticky session requirements and corporate SSO in the way. If you’re navigating that and want a second opinion, find me on LinkedIn — I’m in Sydney and happy to talk it through.

This is part of my MCP server series: What Are MCP Servers? · Real-World MCP Case Study · Production MCP Deployment on Azure.

What Are MCP Servers? A Complete Guide for AI Engineers

If you’re building AI agents that need to interact with real systems — databases, APIs, internal tools — you’ve probably run into the same wall I did. I’m talking about the mess of hardcoded JSON schemas in system prompts, brittle API wrappers, and production incidents that happen when the LLM invents a parameter name that doesn’t exist. An MCP server (Model Context Protocol server) is the structured solution to that problem, and as an AI engineer working in Sydney, it’s now a core part of how I build agent systems.

Let me walk you through what MCP servers are, why they matter, and how to build one in C# using the official SDK — with real, working code.

The Problem an MCP Server Solves

When you build an AI agent that needs to do things — query a database, call an API, read a file — you have to teach the model what tools exist, what they accept, and what they return. The old approach was: write it into the system prompt and pray.

The problem is that system prompts don’t have a schema. If your tool expects a date in ISO 8601 format and the model sends "tomorrow", your app crashes. If you rename a parameter, you need to update prompts scattered across multiple deployments. There’s no contract between the AI and your code.

MCP fixes this by defining a standard protocol — a contract — between AI models (clients) and the external capabilities they need (servers). An MCP server advertises what tools it offers, what inputs each tool expects, and what it returns. The model calls tools through MCP the same way a browser calls APIs through HTTP: with a defined interface that both sides agree on in advance.

This isn’t just theoretical tidiness. It’s what makes AI agents maintainable in production.

How an MCP Server Works

Think of MCP like a USB-C standard for AI tools. Before USB-C, every device had its own charger. After, one cable works everywhere. MCP does the same thing for AI capabilities.

Here’s the flow when an AI agent uses an MCP tool:

  1. The agent (MCP client) connects to your MCP server at startup.
  2. The server sends a capabilities manifest — a list of tools it provides, with their names, descriptions, and input schemas.
  3. The agent’s host (Claude, ChatGPT, your own orchestrator) reads this manifest and makes the tools available to the model.
  4. When the model decides to call a tool, it sends a structured request through the client.
  5. Your server executes the tool and returns a structured response.
  6. The model reads the result and continues reasoning.

The beauty of step 2 is that the model now has a machine-readable description of your tools — not a paragraph of English in a system prompt, but a typed schema. Fewer hallucinations. Cleaner architecture. Tools you can version and test independently.

The Three Things an MCP Server Can Expose

MCP servers can expose three types of capabilities:

Tools — Functions the model can call. Think of these as your API endpoints. A tool takes typed inputs and returns a result. This is what most people think of when they hear “MCP server.”

Resources — Read-only data the model can access. Like files, database records, or live feeds. The model can browse available resources and read their contents.

Prompts — Reusable prompt templates the model can invoke. Useful for standardising how certain tasks are framed across your application.

For most enterprise use cases, you’ll mostly be building Tools. Resources matter when you want the model to explore data rather than query it directly. Prompts are useful in multi-agent workflows.

Architecture Overview

Before we touch code, here’s how the pieces connect. The diagram shows the three zones: the AI client (Claude Desktop or your app), the MCP server (our C# application), and the backend systems it talks to. Use the zoom controls inside the diagram to explore it in detail.

MCP Server architecture: AI client → JSON-RPC protocol → C# server → backend systems. Pan and zoom inside the diagram, or open full-screen in draw.io ↗

Building a Real MCP Server in C#

Enough theory. Let me show you how this looks in code using the official MCP C# SDK (ModelContextProtocol), which Microsoft co-maintains with Anthropic. This is production-ready code — not a toy example.

Step 1: Install the packages

dotnet add package ModelContextProtocol
dotnet add package Microsoft.Extensions.Hosting

This gives you the full MCP server runtime with the .NET generic host, dependency injection, and logging baked in.

Step 2: Project structure

MyMcpServer/
├── Program.cs
├── Tools/
│   └── ProductTools.cs
└── MyMcpServer.csproj

Step 3: Wire up the host in Program.cs

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using MyMcpServer.Tools;

var builder = Host.CreateApplicationBuilder(args);

builder.Services.AddMcpServer()
    .WithStdioServerTransport()   // Claude Desktop and most MCP clients use stdio
    .WithTools<ProductTools>();   // Register your tool class

// Log to stderr — stdout must stay clean for the MCP protocol
builder.Logging.AddConsole(options =>
{
    options.LogToStandardErrorThreshold = LogLevel.Trace;
});

// Your tools get full DI — inject anything here
builder.Services.AddSingleton<IProductRepository, SqlProductRepository>();

await builder.Build().RunAsync();

Three things worth noting. First, AddMcpServer() wires up the entire MCP runtime — you write zero protocol handling. Second, WithStdioServerTransport() is for local Claude Desktop use; for Azure deployments you swap it for the ModelContextProtocol.AspNetCore HTTP transport. Third, your tool classes get full dependency injection — inject your database, HTTP clients, loggers, anything.

Step 4: Define your tools with attributes

using ModelContextProtocol;
using ModelContextProtocol.Server;
using System.ComponentModel;

namespace MyMcpServer.Tools;

[McpServerToolType]
public sealed class ProductTools
{
    private readonly IProductRepository _repo;

    public ProductTools(IProductRepository repo)
    {
        _repo = repo;
    }

    [McpServerTool, Description("Search for products by name or SKU. Returns matching products with current stock levels.")]
    public async Task<string> SearchProducts(
        [Description("The product name or SKU to search for.")] string query,
        [Description("Maximum number of results to return. Defaults to 10.")] int limit = 10)
    {
        var results = await _repo.SearchAsync(query, limit);

        if (!results.Any())
            return $"No products found matching '{query}'.";

        return string.Join("\n---\n", results.Select(p =>
            $"SKU: {p.Sku}\nName: {p.Name}\nStock: {p.StockLevel}\nPrice: {p.Price:C}"));
    }

    [McpServerTool, Description("Get detailed information about a specific product by its SKU.")]
    public async Task<string> GetProductDetails(
        [Description("The product SKU (e.g. PROD-12345).")] string sku)
    {
        var product = await _repo.GetBySkuAsync(sku);

        if (product is null)
            return $"No product found with SKU '{sku}'.";

        return $"""
            SKU: {product.Sku}
            Name: {product.Name}
            Description: {product.Description}
            Stock Level: {product.StockLevel} units
            Price: {product.Price:C}
            Category: {product.Category}
            Last Updated: {product.UpdatedAt:yyyy-MM-dd HH:mm} UTC
            """;
    }
}

The [McpServerTool] attribute registers the method as an MCP tool. The [Description] attributes on both the method and its parameters become the typed schema that the AI model reads — this replaces the fragile English paragraphs in your system prompt. If the description is precise, the model uses the tool correctly. If the parameter description specifies the expected format, the model sends the right format. Every time.

What the AI Model Actually Sees

When Claude or any MCP client connects to this server, it automatically receives a capabilities manifest generated from your C# code:

{
  "tools": [
    {
      "name": "SearchProducts",
      "description": "Search for products by name or SKU. Returns matching products with current stock levels.",
      "inputSchema": {
        "type": "object",
        "properties": {
          "query": {
            "type": "string",
            "description": "The product name or SKU to search for."
          },
          "limit": {
            "type": "integer",
            "description": "Maximum number of results to return. Defaults to 10.",
            "default": 10
          }
        },
        "required": ["query"]
      }
    }
  ]
}

The SDK generates this JSON schema from your C# method signatures automatically. No manual schema writing. No JSON maintenance. Rename a parameter in C#, the schema updates. Add a new tool method, it appears in the manifest. This is the developer experience that was missing before MCP.

Running It Locally with Claude Desktop

To test your MCP server with Claude Desktop, add it to your claude_desktop_config.json:

{
  "mcpServers": {
    "product-server": {
      "command": "dotnet",
      "args": ["run", "--project", "/path/to/MyMcpServer"]
    }
  }
}

Restart Claude Desktop, open a conversation, and ask: “What products do we have in the PROD-1 range?” Claude will automatically call SearchProducts, read the result, and answer from real data — not a hallucination.

That moment when you see the AI reach into your actual database and return a real answer is quietly satisfying in a way that’s hard to describe until you’ve experienced it.

When Should You Build an MCP Server?

Build one when:

  • You want the same capabilities available to multiple AI clients (Claude, Copilot, your internal tools) without duplicating integration code.
  • You’re building an AI agent that needs to interact with internal systems — databases, ERPs, CRMs — that aren’t publicly accessible.
  • You want to give your tools a proper versioned schema rather than relying on natural language in prompts.
  • You’re building a multi-agent system and need a reliable way for agents to share capabilities.

Don’t bother when you’re prototyping with a single model and a single capability. Use function calling directly. MCP pays off when you’re thinking about the long run — multiple clients, multiple tools, real maintainability.

The Bigger Picture

MCP is becoming the USB-C of AI tooling. Claude supports it natively. GitHub Copilot is adding support. OpenAI’s agent framework is converging on it. If you’re building AI systems that need to interact with the real world, this is the protocol worth learning now.

More importantly for us as engineers: it gives us a way to reason about AI tool integrations the same way we reason about APIs. Contract-first, typed, testable, versioned. That’s the kind of discipline that makes enterprise AI systems actually work in production.

I’ve been working with MCP servers on Azure-hosted agent systems, and the difference in maintainability compared to prompt-embedded tool descriptions is night and day. If you’re building anything beyond a demo, start here.


Working on an AI integration project in Sydney and want to talk through the architecture? Connect with me on LinkedIn — I’m always up for a conversation about what’s actually working in production.

Next up: How I Built an MCP Server for Enterprise Data — a Real-World Case Study, where I go deeper on authentication, error handling, and deploying to Azure Container Apps.

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