Add Octicon icons to MCP tools #1603

SamMorrowDrums · 2025-12-13T23:22:06Z

Summary

This PR adds Octicon icons to all MCP tools, using the new Icons field 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

Upgrade MCP Go SDK from v1.1.0 to v1.2.0-pre.1 (adds Icons field on Tool struct)
Update NewServer() to use new Capabilities API instead of deprecated HasTools/HasResources/HasPrompts fields

Icon Infrastructure (pkg/toolsets/server_tool.go)

Add Icon field to ToolsetMetadata for storing Octicon name
Add OcticonURL(name, size) helper to generate CDN URLs for Octicon SVGs
Add Icons() method on ToolsetMetadata that returns []mcp.Icon (16x16 and 24x24 sizes)
Update RegisterFunc() to automatically apply icons from toolset metadata when registering tools

Icon Assignments (pkg/github/tools.go)

All 22 toolset metadata constants now have appropriate Octicon icons:

repos → repo, issues → issue-opened, pull_requests → git-pull-request
actions → play, code_security → codescan, dependabot → dependabot
notifications → bell, discussions → comment-discussion
And more...

The chosen icons:

Why the Refactor Makes This Easier

Before refactor: Would need to call SetIcons() on every toolset creation in DefaultToolsetGroup(), or modify each individual tool definition.

After refactor: Simply add Icon field to ToolsetMetadata in one place, and icons are automatically applied to all tools via RegisterFunc(). The self-describing nature of ServerTool with embedded ToolsetMetadata enables this clean architecture.

Testing

All existing tests pass
Icons are served from GitHub's Octicon CDN at raw.githubusercontent.com/primer/octicons/main/icons/

Migrate search.go tools (SearchRepositories, SearchCode, SearchUsers, SearchOrgs) to use the new NewTool helper and ToolDependencies pattern. - Functions now take only TranslationHelperFunc and return ServerTool - Handler generation uses ToolDependencies for typed access to clients - Update tools.go call sites to remove getClient parameter - Update tests to use new Handler(deps) pattern This demonstrates the migration pattern for additional tool files. Co-authored-by: Adam Holt <oholt@github.com>

Convert GetMe, GetTeams, and GetTeamMembers to use the new typed dependency injection pattern: - Functions now take only translations helper, return toolsets.ServerTool - Handler is generated lazily via deps.GetClient/deps.GetGQLClient - Tests updated to use serverTool.Handler(deps) pattern - Fixed error return pattern to return nil for Go error (via result.IsError) Co-authored-by: Adam Holt <oholt@github.com>

Convert all gist tools (ListGists, GetGist, CreateGist, UpdateGist) to use the new NewTool helper with ToolDependencies injection. - Remove getClient parameter from function signatures - Use deps.GetClient(ctx) inside handlers - Standardize error handling with utils.NewToolResultErrorFromErr() - Update all tests to use serverTool.Handler(deps) pattern Co-authored-by: Adam Holt <oholt@github.com>

Convert all notification tools to use the new NewTool helper with ToolDependencies injection. Co-authored-by: Adam Holt <oholt@github.com>

…encies Convert all 18 tool functions in repositories.go to use the new NewTool helper pattern with typed ToolDependencies, isolating type assertions to a single location and improving code maintainability. Functions converted: - GetCommit, ListCommits, ListBranches - CreateOrUpdateFile, CreateRepository, GetFileContents - ForkRepository, DeleteFile, CreateBranch, PushFiles - ListTags, GetTag, ListReleases, GetLatestRelease, GetReleaseByTag - ListStarredRepositories, StarRepository, UnstarRepository This is part of a stacked PR series to systematically migrate all tool files to the new pattern. Co-authored-by: Adam Holt <oholt@github.com>

Convert all 8 tool functions in issues.go to use the new NewTool helper pattern which standardizes dependency injection: - IssueRead: GetClient, GetGQLClient, RepoAccessCache, Flags - ListIssueTypes: GetClient - AddIssueComment: GetClient - SubIssueWrite: GetClient - SearchIssues: GetClient - IssueWrite: GetClient, GetGQLClient - ListIssues: GetGQLClient - AssignCopilotToIssue: GetGQLClient Updated tools.go to use direct function calls instead of NewServerToolLegacy wrappers. Updated all tests in issues_test.go to use the new ToolDependencies pattern and Handler() method. Co-authored-by: Adam Holt <oholt@github.com>

Convert all 10 pull request tool functions to use the NewTool pattern with ToolDependencies injection: - PullRequestRead - CreatePullRequest - UpdatePullRequest - ListPullRequests - MergePullRequest - SearchPullRequests - UpdatePullRequestBranch - PullRequestReviewWrite - AddCommentToPendingReview - RequestCopilotReview Update tools.go to use direct function calls (removing NewServerToolLegacy wrappers) for PR functions. Update all tests in pullrequests_test.go to use the new handler pattern with deps and 2-value return. Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

Convert all 14 tool functions in actions.go to use the NewTool pattern with ToolDependencies for dependency injection. This is part of a broader effort to standardize the tool implementation pattern across the codebase. Changes: - ListWorkflows, ListWorkflowRuns, RunWorkflow, GetWorkflowRun - GetWorkflowRunLogs, ListWorkflowJobs, GetJobLogs - RerunWorkflowRun, RerunFailedJobs, CancelWorkflowRun - ListWorkflowRunArtifacts, DownloadWorkflowRunArtifact - DeleteWorkflowRunLogs, GetWorkflowRunUsage The new pattern: - Takes only translations.TranslationHelperFunc as parameter - Returns toolsets.ServerTool with Tool and Handler - Handler receives ToolDependencies for client access - Enables better testability and consistent interface Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

…t to NewTool pattern Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

Convert 4 functions from NewServerToolLegacy wrapper to NewTool: - ListGlobalSecurityAdvisories - GetGlobalSecurityAdvisory - ListRepositorySecurityAdvisories - ListOrgRepositorySecurityAdvisories Update tools.go toolset registration and tests. Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

This PR converts projects.go, labels.go, and dynamic_tools.go from the legacy NewServerToolLegacy wrapper pattern to the new NewTool pattern with proper ToolDependencies. Changes: - projects.go: Convert all 9 project functions to use NewTool with ToolHandlerFor[map[string]any, any] and 3-return-value handlers - projects_test.go: Update tests to use new serverTool.Handler(deps) pattern - labels.go: Convert GetLabel, ListLabels, and LabelWrite to NewTool pattern - labels_test.go: Update tests to use new pattern - dynamic_tools.go: Refactor functions to return ServerTool directly (using NewServerToolLegacy internally since they have special dependencies) - tools.go: Remove NewServerToolLegacy wrappers for dynamic tools registration Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

Add CLI flag and config support for feature flags in the local server: - Add --features flag to main.go (StringSlice, comma-separated) - Add EnabledFeatures field to StdioServerConfig and MCPServerConfig - Create createFeatureChecker() that builds a set from enabled features - Wire WithFeatureChecker() into the toolset group filter chain This enables tools/resources/prompts that have FeatureFlagEnable set to a flag name that is passed via --features. The checker uses a simple set membership test for O(1) lookup. Usage: github-mcp-server stdio --features=my_feature,another_feature GITHUB_FEATURES=my_feature github-mcp-server stdio

This commit adds comprehensive validation tests to ensure all MCP items have required metadata: - TestAllToolsHaveRequiredMetadata: Validates Toolset.ID and Annotations - TestAllToolsHaveValidToolsetID: Ensures toolsets are in AvailableToolsets() - TestAllResourcesHaveRequiredMetadata: Validates resource metadata - TestAllPromptsHaveRequiredMetadata: Validates prompt metadata - TestToolReadOnlyHintConsistency: Validates IsReadOnly() matches annotation - TestNoDuplicate*Names: Ensures unique names across tools/resources/prompts - TestAllToolsHaveHandlerFunc: Ensures all tools have handlers - TestDefaultToolsetsAreValid: Validates default toolset IDs - TestToolsetMetadataConsistency: Ensures consistent descriptions per toolset Also fixes a bug discovered by these tests: ToolsetMetadataGit was defined but not added to AvailableToolsets(), causing get_repository_tree to have an invalid toolset ID.

When no toolsets are specified and dynamic mode is disabled, the server should use the default toolsets. The bug was introduced when adding dynamic toolsets support: 1. CleanToolsets(nil) was converting nil to empty slice 2. Empty slice passed to WithToolsets means 'no toolsets' 3. This resulted in zero tools being registered Fix: Preserve nil for non-dynamic mode (nil = use defaults in WithToolsets) and only set empty slice when dynamic mode is enabled without explicit toolsets.

Copilot

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.go with 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

pkg/toolsets/server_tool.go

bretthowell714-source

Thank you

- Rename AddDeprecatedToolAliases to WithDeprecatedToolAliases for immutable filter chain consistency (returns new ToolsetGroup) - Remove unused mockGetRawClient from generate_docs.go (use nil instead) - Remove legacy ServerTool functions (NewServerToolLegacy and NewServerToolFromHandlerLegacy) - no usages - Add panic in Handler()/RegisterFunc() when HandlerFunc is nil - Add HasHandler() method for checking if tool has a handler - Add tests for HasHandler and nil handler panic behavior - Update all tests to use new WithDeprecatedToolAliases pattern

…lsetGroup This change applies the same HandlerFunc pattern used by tools to resources, allowing NewToolsetGroup to be fully stateless (only requiring translations). Key changes: - Add ResourceHandlerFunc type to toolsets package - Update ServerResourceTemplate to use HandlerFunc instead of direct Handler - Add HasHandler() and Handler(deps) methods to ServerResourceTemplate - Update RegisterResourceTemplates to take deps parameter - Refactor repository resource definitions to use HandlerFunc pattern - Make AllResources(t) stateless (only takes translations) - Make NewToolsetGroup(t) stateless (only takes translations) - Update generate_docs.go - no longer needs mock clients - Update tests to use new patterns This resolves the concern about mixed concerns in doc generation - the toolset metadata and resource templates can now be created without any runtime dependencies, while handlers are generated on-demand when deps are provided during registration.

- Replace slice joining with strings.Builder for all doc generation - Iterate AllTools() directly instead of ToolsetIDs()/ToolsForToolset() - Removes need for special 'dynamic' toolset handling (no tools = no output) - Context toolset still explicitly handled for custom description - Consistent pattern across generateToolsetsDoc, generateToolsDoc, generateRemoteToolsetsDoc, and generateDeprecatedAliasesTable

- Add AvailableToolsets() method that returns toolsets with actual tools - Support variadic exclude parameter for filtering out specific toolsets - Simplifies doc generation by removing manual skip logic - Naturally excludes empty toolsets (like 'dynamic') without special cases

- Runs on pull requests to main - Compares PR branch against merge-base with origin/main - Outputs full conformance report to GitHub Actions Job Summary - Uploads detailed report as artifact for deeper investigation - Does not fail the build on differences (may be intentional)

Address review feedback to use maps for collections. Added lookup maps (toolsByName, resourcesByURI, promptsByName) while keeping slices for ordered iteration. This provides O(1) lookup for: - FindToolByName - filterToolsByName (used by ForMCPRequest) - filterResourcesByURI - filterPromptsByName Maps are built once during Build() and shared in ForMCPRequest copies.

Add toolsetIDSet (map[ToolsetID]bool) to Registry for O(1) HasToolset lookups. Previously HasToolset iterated through all tools, resourceTemplates, and prompts to check if any belonged to the given toolset. Now it's a simple map lookup. The set is populated during the single-pass processToolsets() call, which already collected all valid toolset IDs. This adds zero new iteration - just returns the existing validIDs map. processToolsets now returns 6 values: - enabledToolsets, unrecognized, toolsetIDs, toolsetIDSet, defaultToolsetIDs, descriptions

FindToolByName() is only called once per request at most (to find toolset ID for dynamic enablement). The SDK handles tool dispatch after registration. A simple linear scan over ~90 tools is trivially fast and avoids: - sync.Once complexity - Map allocation - Premature optimization for non-existent 'repeated lookups' The pre-computed maps we keep (toolsetIDSet, etc.) are justified because they're used for filtering logic that runs on every request.

- 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

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.

SamMorrowDrums and others added 16 commits December 13, 2025 12:47

refactor(notifications): migrate notifications.go to NewTool pattern

34cf61e

Convert all notification tools to use the new NewTool helper with ToolDependencies injection. Co-authored-by: Adam Holt <oholt@github.com>

refactor(git): migrate GetRepositoryTree to NewTool pattern

d29e73b

refactor(security): migrate code_scanning, secret_scanning, dependabo…

24b9cbb

…t to NewTool pattern Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

refactor(discussions): migrate to NewTool pattern

d8a485e

Co-authored-by: Adam Holt <omgitsads@users.noreply.github.com>

SamMorrowDrums requested a review from a team as a code owner December 13, 2025 23:22

Copilot AI review requested due to automatic review settings December 13, 2025 23:22

Copilot started reviewing on behalf of SamMorrowDrums December 13, 2025 23:22 View session

Copilot AI reviewed Dec 13, 2025

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bretthowell714-source approved these changes Dec 14, 2025

View reviewed changes

SamMorrowDrums added 6 commits December 14, 2025 12:43

refactor: simplify ForMCPRequest switch cases

b13d9fe

refactor(generate_docs): hoist success logging to generateAllDocs

2142b02

SamMorrowDrums force-pushed the SamMorrowDrums/server-tool-refactor-toolsets branch 2 times, most recently from f6fca35 to 3b4eb63 Compare December 14, 2025 23:38

SamMorrowDrums added 10 commits December 15, 2025 22:32

Update third-party licenses for SDK upgrade

ed0f2d0

Add GitHub mark icon to server metadata

7230856

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.

SamMorrowDrums force-pushed the SamMorrowDrums/add-icons-to-tools branch from 813b441 to 29583e1 Compare December 15, 2025 22:42

SamMorrowDrums changed the base branch from SamMorrowDrums/server-tool-refactor-toolsets to SamMorrowDrums/registry-builder-pattern December 15, 2025 22:42

SamMorrowDrums added 5 commits December 15, 2025 23:48

Add mark-github icon for server metadata

73a8772

Base automatically changed from SamMorrowDrums/registry-builder-pattern to SamMorrowDrums/server-tool-refactor-toolsets December 16, 2025 18:53

Base automatically changed from SamMorrowDrums/server-tool-refactor-toolsets to SamMorrowDrums/server-tool-refactor-projects December 16, 2025 19:01

Base automatically changed from SamMorrowDrums/server-tool-refactor-projects to SamMorrowDrums/server-tool-refactor-security-advisories December 16, 2025 19:02

Base automatically changed from SamMorrowDrums/server-tool-refactor-security-advisories to SamMorrowDrums/server-tool-refactor-discussions December 16, 2025 19:02

Base automatically changed from SamMorrowDrums/server-tool-refactor-discussions to SamMorrowDrums/server-tool-refactor-code-scanning December 16, 2025 19:02

Base automatically changed from SamMorrowDrums/server-tool-refactor-code-scanning to SamMorrowDrums/server-tool-refactor-git December 16, 2025 19:02

Base automatically changed from SamMorrowDrums/server-tool-refactor-git to SamMorrowDrums/server-tool-refactor-actions December 16, 2025 19:03

Base automatically changed from SamMorrowDrums/server-tool-refactor-actions to SamMorrowDrums/server-tool-refactor-pullrequests December 16, 2025 19:03

Base automatically changed from SamMorrowDrums/server-tool-refactor-pullrequests to SamMorrowDrums/server-tool-refactor-issues December 16, 2025 19:36

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SamMorrowDrums force-pushed the SamMorrowDrums/server-tool-refactor-notifications branch from 33662a0 to daee6b8 Compare December 16, 2025 20:44

Base automatically changed from SamMorrowDrums/server-tool-refactor-notifications to SamMorrowDrums/server-tool-refactor December 16, 2025 20:53

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Add Octicon icons to MCP tools #1603

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SamMorrowDrums commented Dec 13, 2025 •

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Summary

Changes

SDK Upgrade

Icon Infrastructure (pkg/toolsets/server_tool.go)

Icon Assignments (pkg/github/tools.go)

The chosen icons:

Why the Refactor Makes This Easier

Testing

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Pull request overview

Key Changes

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SamMorrowDrums commented Dec 13, 2025 •

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