Icons

Add visual icons to your servers, tools, resources, and prompts

New in version 2.13.0

Icons provide visual representations for your MCP servers and components, helping client applications present better user interfaces. When displayed in MCP clients, icons help users quickly identify and navigate your server’s capabilities.

Icon Format

Icons use the standard MCP Icon type from the MCP protocol specification. Each icon specifies:

• src: URL or data URI pointing to the icon image
• mimeType (optional): MIME type of the image (e.g., “image/png”, “image/svg+xml”)
• sizes (optional): Array of size descriptors (e.g., [“48x48”], [“any”])

from mcp.types import Icon

icon = Icon(
    src="https://example.com/icon.png",
    mimeType="image/png",
    sizes=["48x48"]
)

Server Icons

Add icons and a website URL to your server for display in client applications:

from fastmcp import FastMCP
from mcp.types import Icon

mcp = FastMCP(
    name="WeatherService",
    website_url="https://weather.example.com",
    icons=[
        Icon(
            src="https://weather.example.com/icon-48.png",
            mimeType="image/png",
            sizes=["48x48"]
        ),
        Icon(
            src="https://weather.example.com/icon-96.png",
            mimeType="image/png",
            sizes=["96x96"]
        ),
    ]
)

Server icons appear in MCP client interfaces to help users identify your server among others they may have installed.

Component Icons

Icons can be added to individual tools, resources, resource templates, and prompts:

Tool Icons

from mcp.types import Icon

@mcp.tool(
    icons=[Icon(src="https://example.com/calculator-icon.png")]
)
def calculate_sum(a: int, b: int) -> int:
    """Add two numbers together."""
    return a + b

Resource Icons

@mcp.resource(
    "config://settings",
    icons=[Icon(src="https://example.com/config-icon.png")]
)
def get_settings() -> dict:
    """Retrieve application settings."""
    return {"theme": "dark", "language": "en"}

Resource Template Icons

@mcp.resource(
    "user://{user_id}/profile",
    icons=[Icon(src="https://example.com/user-icon.png")]
)
def get_user_profile(user_id: str) -> dict:
    """Get a user's profile."""
    return {"id": user_id, "name": f"User {user_id}"}

Prompt Icons

@mcp.prompt(
    icons=[Icon(src="https://example.com/prompt-icon.png")]
)
def analyze_code(code: str):
    """Create a prompt for code analysis."""
    return f"Please analyze this code:\n\n{code}"

Using Data URIs

For small icons or when you want to embed the icon directly, use data URIs:

from mcp.types import Icon
from fastmcp.utilities.types import Image

# SVG icon as data URI
svg_icon = Icon(
    src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIyNCIgaGVpZ2h0PSIyNCI+PHBhdGggZD0iTTEyIDJDNi40OCAyIDIgNi40OCAyIDEyczQuNDggMTAgMTAgMTAgMTAtNC40OCAxMC0xMFMxNy41MiAyIDEyIDJ6Ii8+PC9zdmc+",
    mimeType="image/svg+xml"
)

@mcp.tool(icons=[svg_icon])
def my_tool() -> str:
    """A tool with an embedded SVG icon."""
    return "result"

# Generating a data URI from a local image file.
img = Image(path="./assets/brand/favicon.png")
icon = Icon(src=img.to_data_uri())

@mcp.tool(icons=[icon])
def file_icon_tool() -> str:
    """A tool with an icon generated from a local file."""
    return "result"