Add support for disabling instructions via environment variable

Author: olaservo

pkg/github/instructions.go

@@ -1,9 +1,17 @@
 package github
 
-import "strings"
+import (
+	"os"
+	"strings"
+)
 
 // GenerateInstructions creates server instructions based on enabled toolsets
 func GenerateInstructions(enabledToolsets []string) string {
+	// For testing - add a flag to disable instructions
+	if os.Getenv("DISABLE_INSTRUCTIONS") == "true" {
+		return "" // Baseline mode
+	}
+	
 	var instructions []string
 
 	// Core instruction - always included if context toolset enabled

pkg/github/instructions_test.go

@@ -1,6 +1,7 @@
 package github
 
 import (
+	"os"
 	"strings"
 	"testing"
 )
@@ -104,6 +105,79 @@ func TestGenerateInstructions(t *testing.T) {
 	}
 }
 
+func TestGenerateInstructionsWithDisableFlag(t *testing.T) {
+	tests := []struct {
+		name              string
+		disableEnvValue   string
+		enabledToolsets   []string
+		expectedEmpty     bool
+		expectedContains  []string
+	}{
+		{
+			name:            "DISABLE_INSTRUCTIONS=true returns empty",
+			disableEnvValue: "true",
+			enabledToolsets: []string{"context", "issues", "pull_requests"},
+			expectedEmpty:   true,
+		},
+		{
+			name:            "DISABLE_INSTRUCTIONS=false returns normal instructions",
+			disableEnvValue: "false",
+			enabledToolsets: []string{"context"},
+			expectedEmpty:   false,
+			expectedContains: []string{
+				"GitHub MCP Server provides GitHub API tools",
+				"Always call 'get_me' first",
+			},
+		},
+		{
+			name:            "DISABLE_INSTRUCTIONS unset returns normal instructions",
+			disableEnvValue: "",
+			enabledToolsets: []string{"issues"},
+			expectedEmpty:   false,
+			expectedContains: []string{
+				"GitHub MCP Server provides GitHub API tools",
+				"search_issues",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Save original env value
+			originalValue := os.Getenv("DISABLE_INSTRUCTIONS")
+			defer func() {
+				if originalValue == "" {
+					os.Unsetenv("DISABLE_INSTRUCTIONS")
+				} else {
+					os.Setenv("DISABLE_INSTRUCTIONS", originalValue)
+				}
+			}()
+
+			// Set test env value
+			if tt.disableEnvValue == "" {
+				os.Unsetenv("DISABLE_INSTRUCTIONS")
+			} else {
+				os.Setenv("DISABLE_INSTRUCTIONS", tt.disableEnvValue)
+			}
+
+			result := GenerateInstructions(tt.enabledToolsets)
+
+			if tt.expectedEmpty {
+				if result != "" {
+					t.Errorf("Expected empty instructions but got: %s", result)
+				}
+				return
+			}
+
+			for _, expectedContent := range tt.expectedContains {
+				if !strings.Contains(result, expectedContent) {
+					t.Errorf("Expected instructions to contain '%s', but got: %s", expectedContent, result)
+				}
+			}
+		})
+	}
+}
+
 func TestGetToolsetInstructions(t *testing.T) {
 	tests := []struct {
 		toolset  string