Refactor: Extract duplicate GitHub MCP remote config rendering into shared helper

[Copilot]

Problem

The GitHub MCP remote configuration rendering logic was duplicated between claude_engine.go and copilot_engine.go, creating a maintenance burden and increasing the risk of divergent behavior. Both engines built the same header map and YAML block with only minor differences (token format, tools field, and env section), requiring any future updates to be applied in two places.

Duplicate locations:

• pkg/workflow/claude_engine.go:652-681 (30 lines)
• pkg/workflow/copilot_engine.go:402-444 (43 lines)

Solution

Extracted the common GitHub MCP remote configuration rendering logic into a new shared helper function RenderGitHubMCPRemoteConfig() in engine_shared_helpers.go. This follows the existing pattern established by RenderGitHubMCPDockerConfig() for local mode rendering.

New Shared Helper

The RenderGitHubMCPRemoteConfig() function accepts a GitHubMCPRemoteOptions struct that allows engines to specify their variations:

type GitHubMCPRemoteOptions struct {
    ReadOnly           bool     // Enable read-only mode
    Toolsets           string   // GitHub toolsets to enable
    AuthorizationValue string   // Authorization header value
    IncludeToolsField  bool     // Whether to include tools field
    AllowedTools       []string // Allowed tools list
    IncludeEnvSection  bool     // Whether to include env section
}

Claude usage (no tools, no env):

RenderGitHubMCPRemoteConfig(yaml, GitHubMCPRemoteOptions{
    ReadOnly:           readOnly,
    Toolsets:           toolsets,
    AuthorizationValue: fmt.Sprintf("Bearer %s", effectiveToken),
    IncludeToolsField:  false,
    IncludeEnvSection:  false,
})

Copilot usage (with tools and env):

RenderGitHubMCPRemoteConfig(yaml, GitHubMCPRemoteOptions{
    ReadOnly:           readOnly,
    Toolsets:           toolsets,
    AuthorizationValue: "Bearer \\${GITHUB_PERSONAL_ACCESS_TOKEN}",
    IncludeToolsField:  true,
    AllowedTools:       allowedTools,
    IncludeEnvSection:  true,
})

Changes

• pkg/workflow/engine_shared_helpers.go (+79 lines): Added shared helper function and options struct
• pkg/workflow/claude_engine.go (-22 lines net): Refactored to use shared helper
• pkg/workflow/copilot_engine.go (-44 lines net): Refactored to use shared helper
• pkg/workflow/github_remote_config_test.go (+240 lines): Comprehensive test coverage

Total duplicate code eliminated: 73 lines

Testing

Added comprehensive unit tests covering:

• Claude-style configuration (without tools or env sections)
• Copilot-style configuration (with tools and env sections)
• Read-only mode with X-MCP-Readonly header
• Wildcard tools (["*"])
• Specific allowed tools list
• Header alphabetical ordering
• Tools array comma formatting

All existing tests pass:

• ✅ 240+ unit tests
• ✅ GitHub remote mode integration tests (Claude, Copilot, Codex)
• ✅ All 67 workflow files compile successfully
• ✅ Generated YAML output unchanged

Benefits

1. Single source of truth - Remote config logic now exists in one location
2. Easier maintenance - Future updates only need to be applied once
3. Reduced risk - Eliminates possibility of divergent behavior between engines
4. Better testability - Shared helper can be tested independently
5. Consistent behavior - Both engines use identical rendering logic
6. Follows patterns - Matches existing RenderGitHubMCPDockerConfig approach

This refactoring maintains 100% backward compatibility with zero breaking changes while significantly improving code quality and maintainability.

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Fixes #[issue number] (duplicate code detected in commit 82e9c3e)

Original prompt

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This section details on the original issue you should resolve

<issue_title>[duplicate-code] 🔍 Duplicate Code Detected: GitHub MCP Remote Config Rendering</issue_title>
<issue_description># 🔍 Duplicate Code Detected: GitHub MCP Remote Config Rendering

Analysis of commit 82e9c3e

Assignee: @copilot

Summary

The GitHub MCP remote configuration block is duplicated between the Claude and Copilot engine renderers. Both functions build the same header map and YAML block with only minor token differences, making future fixes error-prone.

Duplication Details

Pattern: Repeated GitHub MCP remote header rendering logic

• Severity: Medium
• Occurrences: 2
• Locations:
  • pkg/workflow/claude_engine.go:652
  • pkg/workflow/copilot_engine.go:402
• Code Sample:

  // Remote mode - use hosted GitHub MCP server
  yaml.WriteString("                \"type\": \"http\",\n")
  yaml.WriteString("                \"url\": \"(redacted)",\n")
  yaml.WriteString("                \"headers\": {\n")
  
  headers := make(map[string]string)
  headers["Authorization"] = fmt.Sprintf("Bearer %s", effectiveToken)
  
  if readOnly {
      headers["X-MCP-Readonly"] = "true"
  }
  
  if toolsets != "" {
      headers["X-MCP-Toolsets"] = toolsets
  }
  
  writeHeadersToYAML(yaml, headers, "                  ")
  yaml.WriteString("                }\n")

Impact Analysis

• Maintainability: Two nearly identical blocks must be kept in sync; fixes to headers or indentation must be applied twice.
• Bug Risk: Minor differences (e.g., Authorization value) already exist, increasing the chance of inconsistent behavior across engines.
• Code Bloat: Adds ~15 repeated lines that could live in a single helper.

Refactoring Recommendations

1. Extract Common Helper

   • Lift the shared remote-rendering logic into a function (e.g. renderGitHubMCPRemoteConfig) that accepts token formatting callbacks.
   • Estimated effort: 1-2 hours.
   • Benefits: Single source of truth, easier updates.

2. Parameterize Authorization Value

   • Pass the differing Authorization string as a parameter so both engines can reuse the helper.
   • Benefits: Eliminates divergence and clarifies intentional differences.

Implementation Checklist

• Review duplication findings
• Prioritize refactoring tasks
• Create refactoring plan
• Implement changes
• Update tests
• Verify no functionality broken

Analysis Metadata

• Analyzed Files: 2
• Detection Method: Serena semantic code analysis
• Commit: 82e9c3e
• Analysis Date: 2025-10-23

AI generated by Duplicate Code Detector</issue_description>

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

Fixes #2246

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