Refactor server instructions to use strings.Builder pattern

internal/ghmcp/server.go

@@ -215,7 +215,7 @@ func NewMCPServer(cfg MCPServerConfig) (*mcp.Server, error) {
 		cfg.Translator,
 		github.FeatureFlags{
 			LockdownMode: cfg.LockdownMode,
-			InsiderMode: cfg.InsiderMode,
+			InsiderMode:  cfg.InsiderMode,
 		},
 		cfg.ContentWindowSize,
 		featureChecker,
@@ -235,7 +235,7 @@ func NewMCPServer(cfg MCPServerConfig) (*mcp.Server, error) {
 		WithToolsets(enabledToolsets).
 		WithTools(cfg.EnabledTools).
 		WithFeatureChecker(featureChecker)
-  
+
 	// Apply token scope filtering if scopes are known (for PAT filtering)
 	if cfg.TokenScopes != nil {
 		inventoryBuilder = inventoryBuilder.WithFilter(github.CreateToolScopeFilter(cfg.TokenScopes))

pkg/github/instructions.go

@@ -13,22 +13,10 @@ func GenerateInstructions(enabledToolsets []string) string {
 		return "" // Baseline mode
 	}
 
-	var instructions []string
-
-	// Core instruction - always included if context toolset enabled
-	if slices.Contains(enabledToolsets, "context") {
-		instructions = append(instructions, "Always call 'get_me' first to understand current user permissions and context.")
-	}
-
-	// Individual toolset instructions
-	for _, toolset := range enabledToolsets {
-		if inst := getToolsetInstructions(toolset, enabledToolsets); inst != "" {
-			instructions = append(instructions, inst)
-		}
-	}
+	var buf strings.Builder
 
 	// Base instruction with context management
-	baseInstruction := `The GitHub MCP Server provides tools to interact with GitHub platform.
+	buf.WriteString(`The GitHub MCP Server provides tools to interact with GitHub platform.
 
 Tool selection guidance:
 	1. Use 'list_*' tools for broad, simple retrieval and pagination of all items of a type (e.g., all issues, all PRs, all branches) with basic filtering.
@@ -39,37 +27,48 @@ Context management:
 	2. Use minimal_output parameter set to true if the full information is not needed to accomplish a task.
 
 Tool usage guidance:
-	1. For 'search_*' tools: Use separate 'sort' and 'order' parameters if available for sorting results - do not include 'sort:' syntax in query strings. Query strings should contain only search criteria (e.g., 'org:google language:python'), not sorting instructions.`
+	1. For 'search_*' tools: Use separate 'sort' and 'order' parameters if available for sorting results - do not include 'sort:' syntax in query strings. Query strings should contain only search criteria (e.g., 'org:google language:python'), not sorting instructions.`)
 
-	allInstructions := []string{baseInstruction}
-	allInstructions = append(allInstructions, instructions...)
+	// Core instruction - always included if context toolset enabled
+	if slices.Contains(enabledToolsets, "context") {
+		buf.WriteString(" Always call 'get_me' first to understand current user permissions and context.")
+	}
+
+	// Individual toolset instructions
+	for _, toolset := range enabledToolsets {
+		if inst := getToolsetInstructions(toolset, enabledToolsets); inst != "" {
+			buf.WriteString(" ")
+			buf.WriteString(inst)
+		}
+	}
 
-	return strings.Join(allInstructions, " ")
+	return buf.String()
 }
 
 // getToolsetInstructions returns specific instructions for individual toolsets
 func getToolsetInstructions(toolset string, enabledToolsets []string) string {
+	var buf strings.Builder
+
 	switch toolset {
 	case "pull_requests":
-		pullRequestInstructions := `## Pull Requests
+		buf.WriteString(`## Pull Requests
 
-PR review workflow: Always use 'pull_request_review_write' with method 'create' to create a pending review, then 'add_comment_to_pending_review' to add comments, and finally 'pull_request_review_write' with method 'submit_pending' to submit the review for complex reviews with line-specific comments.`
+PR review workflow: Always use 'pull_request_review_write' with method 'create' to create a pending review, then 'add_comment_to_pending_review' to add comments, and finally 'pull_request_review_write' with method 'submit_pending' to submit the review for complex reviews with line-specific comments.`)
 		if slices.Contains(enabledToolsets, "repos") {
-			pullRequestInstructions += `
+			buf.WriteString(`
 
-Before creating a pull request, search for pull request templates in the repository. Template files are called pull_request_template.md or they're located in '.github/PULL_REQUEST_TEMPLATE' directory. Use the template content to structure the PR description and then call create_pull_request tool.`
+Before creating a pull request, search for pull request templates in the repository. Template files are called pull_request_template.md or they're located in '.github/PULL_REQUEST_TEMPLATE' directory. Use the template content to structure the PR description and then call create_pull_request tool.`)
 		}
-		return pullRequestInstructions
 	case "issues":
-		return `## Issues
+		buf.WriteString(`## Issues
 
-Check 'list_issue_types' first for organizations to use proper issue types. Use 'search_issues' before creating new issues to avoid duplicates. Always set 'state_reason' when closing issues.`
+Check 'list_issue_types' first for organizations to use proper issue types. Use 'search_issues' before creating new issues to avoid duplicates. Always set 'state_reason' when closing issues.`)
 	case "discussions":
-		return `## Discussions
+		buf.WriteString(`## Discussions
 
-Use 'list_discussion_categories' to understand available categories before creating discussions. Filter by category for better organization.`
+Use 'list_discussion_categories' to understand available categories before creating discussions. Filter by category for better organization.`)
 	case "projects":
-		return `## Projects
+		buf.WriteString(`## Projects
 
 Workflow: 1) list_project_fields (get field IDs), 2) list_project_items (with pagination), 3) optional updates.
 
@@ -136,8 +135,10 @@ Common Qualifier Glossary (items):
 
 Never:
    - Infer field IDs; fetch via list_project_fields.
-   - Drop 'fields' param on subsequent pages if field values are needed.`
+   - Drop 'fields' param on subsequent pages if field values are needed.`)
 	default:
 		return ""
 	}
+
+	return buf.String()
 }