Toolsets and Icons

This document explains how to work with toolsets and icons in the GitHub MCP Server.

Toolset Overview

Toolsets are logical groupings of related tools. Each toolset has metadata defined in pkg/github/tools.go:

ToolsetMetadataRepos = inventory.ToolsetMetadata{
    ID:          "repos",
    Description: "GitHub Repository related tools",
    Default:     true,
    Icon:        "repo",
}

Toolset Fields

Adding Icons to Toolsets

Icons help users quickly identify toolsets in MCP-compatible clients. We use Primer Octicons for all icons.

Step 1: Choose an Octicon

Browse the Octicon gallery and select an appropriate icon. Use the base name without size suffix (e.g., repo not repo-16).

Step 2: Add Icon to Required Icons List

Icons are defined in pkg/octicons/required_icons.txt, which is the single source of truth for which icons should be embedded:

# Required icons for the GitHub MCP Server
# Add new icons below (one per line)
repo
issue-opened
git-pull-request
your-new-icon  # Add your icon here

Step 3: Fetch the Icon Files

Run the fetch-icons script to download and convert the icon:

# Fetch a specific icon
script/fetch-icons your-new-icon

# Or fetch all required icons
script/fetch-icons

This script:

• Downloads the 24px SVG from Primer Octicons
• Converts to PNG with light theme (dark icons for light backgrounds)
• Converts to PNG with dark theme (white icons for dark backgrounds)
• Saves both variants to pkg/octicons/icons/

Requirements: The script requires rsvg-convert:

• Ubuntu/Debian: sudo apt-get install librsvg2-bin
• macOS: brew install librsvg

Step 4: Update the Toolset Metadata

Add or update the Icon field in the toolset definition:

// In pkg/github/tools.go
ToolsetMetadataRepos = inventory.ToolsetMetadata{
    ID:          "repos",
    Description: "GitHub Repository related tools",
    Default:     true,
    Icon:        "repo",  // Add this line
}

Step 5: Regenerate Documentation

Run the documentation generator to update all markdown files:

go run ./cmd/github-mcp-server generate-docs

This updates icons in:

• README.md - Toolsets table and tool section headers
• docs/remote-server.md - Remote toolsets table

Remote-Only Toolsets

Some toolsets are only available in the remote GitHub MCP Server (hosted at api.githubcopilot.com). These are defined in pkg/github/tools.go with their icons, but are not registered with the local server:

// Remote-only toolsets
ToolsetMetadataCopilot = inventory.ToolsetMetadata{
    ID:          "copilot",
    Description: "Copilot related tools",
    Icon:        "copilot",
}

The RemoteOnlyToolsets() function returns the list of these toolsets for documentation generation.

To add a new remote-only toolset:

1. Add the metadata definition in pkg/github/tools.go
2. Add it to the slice returned by RemoteOnlyToolsets()
3. Regenerate documentation

Tool Icon Inheritance

Individual tools inherit icons from their parent toolset. When a tool is registered with a toolset, its icons are automatically set:

// In pkg/inventory/server_tool.go
toolCopy.Icons = tool.Toolset.Icons()

This means you only need to set the icon once on the toolset, and all tools in that toolset will display the same icon.

How Icons Work in MCP

The MCP protocol supports tool icons via the icons field. We provide icons in two formats:

1. Data URIs - Base64-encoded PNG images embedded in the tool definition
2. Light/Dark variants - Both theme variants are provided for proper display

The octicons.Icons() function generates the MCP-compatible icon objects:

// Returns []mcp.Icon with both light and dark variants
icons := octicons.Icons("repo")

Existing Toolset Icons

Troubleshooting

Icons not appearing in documentation

1. Ensure PNG files exist in pkg/octicons/icons/ with -light.png and -dark.png suffixes
2. Run go run ./cmd/github-mcp-server generate-docs to regenerate
3. Check that the Icon field is set on the toolset metadata

Icons not appearing in MCP clients

1. Verify the client supports MCP tool icons
2. Check that the octicons package is properly generating base64 data URIs
3. Ensure the icon name matches a file in pkg/octicons/icons/

CI Validation

The following tests run in CI to catch icon issues early:

pkg/octicons.TestEmbeddedIconsExist

Verifies that all icons listed in pkg/octicons/required_icons.txt have corresponding PNG files embedded.

pkg/github.TestAllToolsetIconsExist

Verifies that all toolset Icon fields reference icons that are properly embedded.

pkg/github.TestToolsetMetadataHasIcons

Ensures all toolsets have an Icon field set.

If any of these tests fail:

1. Add the missing icon to pkg/octicons/required_icons.txt
2. Run script/fetch-icons to download the icon
3. Commit the new icon files