Update GitHub MCP Server to v0.19.0 and add "default" toolset support

[Copilot]

Overview

This PR updates the GitHub MCP Server from v0.18.0 to v0.19.0 and adds support for the new "default" toolset feature introduced in the upstream release. This enhancement simplifies workflow configuration by allowing users to specify toolset: [default] instead of explicitly listing individual toolsets.

Changes

1. Version Update (v0.18.0 → v0.19.0)

Updated the default GitHub MCP Server Docker image version across the codebase:

• pkg/constants/constants.go: Updated DefaultGitHubMCPServerVersion constant
• Updated 6 test files to reflect the new version in assertions
• All 66 workflows now compile with ghcr.io/github/github-mcp-server:v0.19.0

2. "default" Toolset Support

Added support for the new "default" toolset keyword introduced in GitHub MCP Server v0.19.0 PR #1229:

Schema Update:

"enum": [
  "all",
  "default",  // ← New
  "context",
  "repos",
  // ...
]

Usage Examples:

# Simple usage - equivalent to: context, repos, issues, pull_requests, users
tools:
  github:
    toolset: [default]

# Combine with additional toolsets
tools:
  github:
    toolset: [default, discussions]

3. Documentation

Updated three documentation files with comprehensive guidance:

• .github/instructions/github-agentic-workflows.instructions.md
• pkg/cli/templates/instructions.md
• .github/instructions/github-mcp-server.instructions.md

Each file now explains:

• What toolsets are available (including "default")
• That "default" is shorthand for: context, repos, issues, pull_requests, users
• Example usage patterns for both simple and combined configurations

4. Testing

Added comprehensive test coverage for the "default" toolset:

• TestGetGitHubToolsets: Validates toolset parsing
• TestClaudeEngineGitHubToolsetsRendering: Verifies Claude engine output
• TestCopilotEngineGitHubToolsetsRendering: Verifies Copilot engine output
• TestCodexEngineGitHubToolsetsRendering: Verifies Codex engine output

All tests verify that:

• Single "default" toolset generates GITHUB_TOOLSETS=default
• Combined toolsets generate correctly (e.g., GITHUB_TOOLSETS=default,discussions)

Benefits

1. Simplified Configuration: Users can write toolset: [default] instead of listing 5 separate toolsets
2. Easier Extension: Combining defaults with additional toolsets is cleaner: [default, discussions] vs [context, repos, issues, pull_requests, users, discussions]
3. Backward Compatible: Existing workflows continue to work without changes
4. Future-Proof: Leverages native support in GitHub MCP Server v0.19.0

Validation

• ✅ All Go unit tests pass
• ✅ All 66 workflows compile successfully with new version
• ✅ Manual testing confirms correct environment variable generation
• ✅ Schema validation passes

Related

• Resolves the issue opened by the CLI Version Checker workflow
• Implements recommendation from @pelikhan to add "default" toolset support
• Aligns with GitHub MCP Server v0.19.0 release

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[ca] Update GitHub MCP Server to v0.19.0</issue_title>
<issue_description># Update GitHub MCP Server to v0.19.0

Version Summary

• Previous: v0.18.0 → New: v0.19.0
• Release Date: October 20, 2025 (released today)
• Interval: 10 days between releases (v0.18.0 released October 10, 2025)

Release Information

• GitHub Release: https://github.com/github/github-mcp-server/releases/tag/v0.19.0
• Changelog: github/github-mcp-server@v0.18.0...v0.19.0

Breaking Changes

None

New Features

1. Default Toolset Configuration Enhancement

• Added support for "default" toolset string in configuration
• Simplifies configuration by allowing "default" instead of explicitly naming toolsets
• Examples:
  • Use "default" instead of "context,repos,issues,pull_requests,users"
  • Use "default,discussions" instead of "context,repos,issues,pull_requests,users,discussions"
• Reference: PR #1229

2. Improved Error Handling

• Unknown toolsets can now be ignored gracefully
• Reference: PR #1202

Tool Consolidation

Pull Request Review Tools Consolidation

The following pull request review tools have been consolidated into a single pull_request_review_write tool:

• create_and_submit_pull_request_review (removed)
• create_pending_pull_request_review (removed)
• submit_pending_pull_request_review (removed)
• delete_pending_pull_request_review (removed)

New tool: pull_request_review_write with method parameter:

• create - Create a new review
• submit_pending - Submit a pending review
• delete_pending - Delete a pending review

This follows the pattern established in v0.18.0 where pull request read tools were consolidated.

Reference: PR #1192

Bug Fixes

• Fixed subdomain isolation URL parsing
  • Reference: PR #1218
• Fixed environment variable mapping for read-only mode
  • Reference: PR #1067

Documentation Updates

• Restructured README for better GHES/GHEC visibility
  • Reference: PR #1210
• Updated README for remote-only tools
  • Reference: PR #1227
• Added Gemini CLI additional options documentation
  • Reference: PR #1223
• Documented new "GitHub Support Docs Search" tool
  • Reference: PR #1225

Infrastructure

• Simplified Registry release pipeline
  • Reference: PR #1204
• Added Gemini CLI extension
  • Reference: PR #1232

Impact Assessment

• Risk Level: Low
• Affected Features:
  • GitHub MCP Server Docker image version in workflows
  • Pull request review workflow consolidation may require workflow adjustments if using the removed tools
• Migration Required: No
  • The update only changes the default Docker image version
  • Tool consolidation is transparent to gh-aw users unless workflows explicitly use the removed tools
  • For more details on toolsets: 🚀 Improving GitHub MCP Server Performance and Resource Consumption: Introducing default toolsets github/github-mcp-server#1182

Changes Made

✅ Updated pkg/constants/constants.go from v0.18.0 to v0.19.0
✅ Ran make recompile successfully
✅ All 39 workflow files compiled without errors

Other CLI Versions Checked

• Claude Code: 2.0.22 (up to date)
• Copilot CLI: 0.0.346 (up to date)
• Codex: 0.47.0 (up to date)

Next Steps

1. Review this issue for accuracy
2. Test workflows to ensure compatibility
3. Monitor for any issues with the new GitHub MCP Server version

---

This issue was automatically created by the CLI Version Checker workflow

AI generated by CLI Version Checker</issue_description>

Comments on the Issue (you are @copilot in this section)

@pelikhan @copilot implement recommendation and add "default" toolset to list of toolsets. Update default list of allowed tools for local and remote servers.

Fixes #2034

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[github-actions]

Agentic Changeset Generator triggered by this pull request.

[joe10832]

@copilot