Add Octicon icons to MCP tools #1603
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Pull request overview
This PR adds Octicon icons to all MCP tools by upgrading the MCP Go SDK from v1.1.0 to v1.2.0-pre.1 and implementing icon infrastructure that automatically applies icons based on toolset metadata.
Key Changes
- Upgraded MCP Go SDK to v1.2.0-pre.1 to enable Icons field support
- Added icon infrastructure in
pkg/toolsets/server_tool.gowith automatic icon application during tool registration - Assigned appropriate Octicon icons to all 22 toolset metadata constants
Reviewed changes
Copilot reviewed 4 out of 5 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| go.mod | Upgraded modelcontextprotocol/go-sdk from v1.1.0 to v1.2.0-pre.1 |
| go.sum | Updated checksums for SDK upgrade and new golang-jwt/jwt/v5 dependency |
| pkg/github/server.go | Migrated from deprecated HasTools/HasResources/HasPrompts to new Capabilities API structure |
| pkg/toolsets/server_tool.go | Added Icon field to ToolsetMetadata, OcticonURL helper, Icons() method, and automatic icon application in RegisterFunc |
| pkg/github/tools.go | Assigned Octicon icon names to all 22 toolset metadata constants |
bretthowell714-source
approved these changes
Dec 14, 2025
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- Upgrade MCP Go SDK from v1.1.0 to v1.2.0-pre.1 for Icon support - Add Icon field to ToolsetMetadata for Octicon name assignment - Add OcticonURL() helper to generate CDN URLs for Octicon SVGs - Add Icons() method on ToolsetMetadata to generate MCP Icon objects - Apply icons automatically in RegisterFunc when tool is registered - Add icons to all 22 toolset metadata constants with appropriate Octicons - Update server.go to use new Capabilities API (fixes deprecation warnings) This demonstrates how the toolsets refactor makes adding new features simpler: icons are defined once in ToolsetMetadata and automatically applied to all tools in that toolset during registration.
- Replace runtime size validation with compile-time enum type (Size with SizeSM=16, SizeLG=24) - Fix RegisterFunc mutation by making shallow copy of tool before modifying Icons - Add comprehensive tests for octicons package (URL, Icons, Size constants) - Add toolsets tests for ToolsetMetadata.Icons(), RegisterFunc mutation prevention, and existing icon preservation - Improve icon choices for better visual semantics: - actions: play → workflow (more specific to GitHub Actions) - secret_protection: key → shield-lock (better represents protection) - gists: code → logo-gist (dedicated gist icon exists)
Add the mark-github octicon to the server's Implementation struct so that MCP clients can display the GitHub logo for this server. The icon is provided in both 16x16 and 24x24 SVG sizes.
- Remove duplicate old toolsets functions (AvailableToolsets, GetValidToolsetIDs, GetDefaultToolsetIDs) - Use Registry.AvailableToolsets() and Registry.HasToolset() instead - Replace stubTranslator with translations.NullTranslationHelper - Use new SDK Capabilities struct instead of deprecated HasTools/HasResources/HasPrompts - Add icon-related tests to registry_test.go
- Embed SVG icons using go:embed for offline use and faster loading - Convert icons to base64 data URIs at runtime - Fall back to CDN URL for non-embedded icons - Add test to verify all toolset icons are properly embedded - 44 SVG files (22 icons × 2 sizes) totaling ~27KB
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MCP clients don't support SVG data URIs, so convert all embedded icons to PNG format using rsvg-convert. Changes: - Convert all 44 SVG icons to PNG format - Add 8 new icons: copilot, git-merge, repo-forked, star-fill - Update octicons.go to use PNG MIME type - Add script/fetch-icons for easy icon management - Update tests and toolsnaps for PNG format
- Switch from size-based (16/24px) to theme-based (light/dark) icons - Use only 16x16 icons for smaller bundle size - Generate white (inverted) icons for dark theme backgrounds - Add icons to resources and prompts (auto-applied from toolset metadata) - Add 'file' icon for repository content resources - Update fetch-icons script to generate both theme variants
- Switch from 16px to 24px icons for better visibility - Use SVG fill attribute (#24292f for light, #ffffff for dark) instead of ImageMagick color inversion for cleaner theme variants - Remove ImageMagick dependency from fetch-icons script
- repository_content: repo icon - repository_content_branch: git-branch icon - repository_content_commit: git-commit icon (new) - repository_content_tag: tag icon - repository_content_pr: git-pull-request icon Resources now have explicit icons set rather than relying on toolset fallback.
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Summary
This PR adds Octicon icons to all MCP tools, using the new
Iconsfield added in MCP Go SDK v1.2.0-pre.1.Stacked on #1602 (toolsets refactor) - demonstrates how the refactored architecture makes adding new cross-cutting features simpler.
Changes
SDK Upgrade
Iconsfield on Tool struct)NewServer()to use newCapabilitiesAPI instead of deprecatedHasTools/HasResources/HasPromptsfieldsIcon Infrastructure (pkg/toolsets/server_tool.go)
Iconfield toToolsetMetadatafor storing Octicon nameOcticonURL(name, size)helper to generate CDN URLs for Octicon SVGsIcons()method onToolsetMetadatathat returns[]mcp.Icon(16x16 and 24x24 sizes)RegisterFunc()to automatically apply icons from toolset metadata when registering toolsIcon Assignments (pkg/github/tools.go)
All 22 toolset metadata constants now have appropriate Octicon icons:
repos→repo,issues→issue-opened,pull_requests→git-pull-requestactions→play,code_security→codescan,dependabot→dependabotnotifications→bell,discussions→comment-discussionThe chosen icons:
Why the Refactor Makes This Easier
Before refactor: Would need to call
SetIcons()on every toolset creation inDefaultToolsetGroup(), or modify each individual tool definition.After refactor: Simply add
Iconfield toToolsetMetadatain one place, and icons are automatically applied to all tools viaRegisterFunc(). The self-describing nature ofServerToolwith embeddedToolsetMetadataenables this clean architecture.Testing
raw.githubusercontent.com/primer/octicons/main/icons/Related