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When using the Streamable HTTP transport, MCP servers often need access to the underlying HTTP request context. The HttpContext provides request metadata including headers, user identity, route data, and more.

​
Basic Setup

To access HttpContext in your MCP server tools or handlers:
1

Register IHttpContextAccessor

Add the IHttpContextAccessor service to your application (typically in Program.cs):
~/workspace/source/docs/concepts/httpcontext/samples/Program.cs
builder.Services.AddHttpContextAccessor();
2

Inject in your tool class

Accept IHttpContextAccessor in your tool class constructor:
[McpServerToolType]
public class MyTools(IHttpContextAccessor httpContextAccessor)
{
    private readonly IHttpContextAccessor _httpContextAccessor = httpContextAccessor;
}
3

Access the current context

Use the HttpContext property to get the current request context:
var context = _httpContextAccessor.HttpContext;
if (context != null)
{
    // Access request information
}

​
Complete Example

Here’s a complete example that retrieves HTTP headers from the current request:
~/workspace/source/docs/concepts/httpcontext/samples/Tools/ContextTools.cs
using ModelContextProtocol.Server;
using System.ComponentModel;

namespace HttpContext.Tools;

public class ContextTools(IHttpContextAccessor httpContextAccessor)
{
    [McpServerTool(UseStructuredContent = true)]
    [Description("Retrieves the HTTP headers from the current request and returns them as a JSON object.")]
    public object GetHttpHeaders()
    {
        var context = httpContextAccessor.HttpContext;
        if (context == null)
        {
            return "No HTTP context available";
        }

        var headers = new Dictionary<string, string>();
        foreach (var header in context.Request.Headers)
        {
            headers[header.Key] = string.Join(", ", header.Value.ToArray());
        }

        return headers;
    }
}

​
Common Use Cases

​
Accessing Request Headers

Retrieve specific headers from the current request: 
[McpServerTool]
[Description("Gets the user agent from the request")]
public string GetUserAgent(IHttpContextAccessor httpContextAccessor)
{
    var context = httpContextAccessor.HttpContext;
    if (context == null) return "No context available";

    var userAgent = context.Request.Headers["User-Agent"].FirstOrDefault();
    return userAgent ?? "No User-Agent header found";
}

​
Accessing User Identity

Retrieve authenticated user information: 
[McpServerToolType]
public class UserTools(IHttpContextAccessor httpContextAccessor)
{
    [McpServerTool]
    [Description("Gets the current authenticated user name")]
    public string GetCurrentUser()
    {
        var context = httpContextAccessor.HttpContext;
        if (context?.User?.Identity?.IsAuthenticated == true)
        {
            return context.User.Identity.Name ?? "Unknown user";
        }
        return "Not authenticated";
    }

    [McpServerTool]
    [Description("Gets all user claims")]
    public Dictionary<string, string> GetUserClaims()
    {
        var context = httpContextAccessor.HttpContext;
        if (context?.User == null) return new();

        var claims = new Dictionary<string, string>();
        foreach (var claim in context.User.Claims)
        {
            claims[claim.Type] = claim.Value;
        }
        return claims;
    }
}

​
Accessing Request Path and Query

Retrieve URL information: 
[McpServerTool]
[Description("Gets request path and query string information")]
public object GetRequestInfo(IHttpContextAccessor httpContextAccessor)
{
    var context = httpContextAccessor.HttpContext;
    if (context == null) return "No context available";

    return new
    {
        Path = context.Request.Path.Value,
        QueryString = context.Request.QueryString.Value,
        Method = context.Request.Method,
        Scheme = context.Request.Scheme,
        Host = context.Request.Host.Value
    };
}

​
Accessing Remote IP Address

Get the client’s IP address: 
[McpServerTool]
[Description("Gets the client IP address")]
public string GetClientIp(IHttpContextAccessor httpContextAccessor)
{
    var context = httpContextAccessor.HttpContext;
    if (context == null) return "No context available";

    var remoteIp = context.Connection.RemoteIpAddress;
    return remoteIp?.ToString() ?? "Unknown";
}

​
Custom Response Headers

Add custom headers to the response: 
[McpServerTool]
[Description("Performs an operation and sets custom response headers")]
public string ProcessWithCustomHeaders(IHttpContextAccessor httpContextAccessor)
{
    var context = httpContextAccessor.HttpContext;
    if (context != null)
    {
        context.Response.Headers.Add("X-Custom-Header", "CustomValue");
        context.Response.Headers.Add("X-Processing-Time", DateTime.UtcNow.ToString("o"));
    }

    return "Processing complete with custom headers";
}

​
Advanced Scenarios

​
Per-Request Services

Access services scoped to the current HTTP request: 
[McpServerToolType]
public class AdvancedTools(IHttpContextAccessor httpContextAccessor)
{
    [McpServerTool]
    [Description("Uses request-scoped services")]
    public string UseRequestScopedService()
    {
        var context = httpContextAccessor.HttpContext;
        if (context == null) return "No context available";

        // Access request-scoped services
        var scopedService = context.RequestServices.GetService<IMyScopedService>();
        return scopedService?.DoWork() ?? "Service not available";
    }
}

​
Session Data

Access HTTP session data: 
[McpServerTool]
[Description("Gets a value from session")]
public string GetSessionValue(string key, IHttpContextAccessor httpContextAccessor)
{
    var context = httpContextAccessor.HttpContext;
    if (context?.Session == null) return "Session not available";

    var value = context.Session.GetString(key);
    return value ?? $"No value found for key: {key}";
}

[McpServerTool]
[Description("Sets a value in session")]
public string SetSessionValue(string key, string value, IHttpContextAccessor httpContextAccessor)
{
    var context = httpContextAccessor.HttpContext;
    if (context?.Session == null) return "Session not available";

    context.Session.SetString(key, value);
    return $"Session value set: {key} = {value}";
}

​
Request Body Access

Accessing the request body through HttpContext in MCP tools is not recommended because the MCP framework already reads the body to deserialize the JSON-RPC request. Use tool parameters instead.

​
Best Practices

The HttpContext may be null in certain scenarios (testing, background tasks):
var context = httpContextAccessor.HttpContext;
if (context == null)
{
    return "No HTTP context available";
}
Inject IHttpContextAccessor via constructor rather than using static access:
// ✅ Good: Constructor injection
public class MyTools(IHttpContextAccessor httpContextAccessor)

// ❌ Bad: Static or service locator patterns
Don’t store HttpContext in fields or properties - always get it from the accessor when needed:
// ✅ Good: Get context when needed
var context = _httpContextAccessor.HttpContext;

// ❌ Bad: Store in field
private readonly HttpContext _context;
Code that relies on HttpContext won’t work with non-HTTP transports (stdio, SSE). Consider making HTTP-specific features optional:
var context = httpContextAccessor.HttpContext;
if (context != null)
{
    // HTTP-specific logic
}
else
{
    // Fallback for non-HTTP transports
}
IHttpContextAccessor uses AsyncLocal<T> internally to provide the current context. This is thread-safe and works correctly with async/await.

​
API Reference

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