feat: add PRU-aware budget config with Copilot plan presets

cmd/nightshift/commands/doctor.go

@@ -246,7 +246,7 @@ func checkProviders(cfg *config.Config, add func(string, checkStatus, string)) (
 			add("copilot.data_path", statusOK, path)
 		}
 		copilotProvider = providers.NewCopilotWithPath(path)
-		monthlyLimit := int64(cfg.GetProviderBudget("copilot"))
+		monthlyLimit := cfg.GetCopilotMonthlyLimit()
 		if pct, err := copilotProvider.GetUsedPercent(mode, monthlyLimit); err != nil {
 			add("copilot.usage", statusFail, err.Error())
 		} else {

internal/budget/budget.go

@@ -312,10 +312,8 @@ func (m *Manager) GetUsedPercent(provider string) (float64, error) {
 		if m.copilot == nil {
 			return 0, fmt.Errorf("copilot provider not configured")
 		}
-		// Copilot uses monthly request limits, not weekly token budgets
-		// Convert weekly budget to monthly limit for consistency
-		// Note: This is a simplification; actual monthly limits should be configured separately
-		monthlyLimit := weeklyBudget * 4 // Approximate: 4 weeks per month
+		// Use config-driven monthly limit (plan preset, explicit, or fallback)
+		monthlyLimit := m.cfg.GetCopilotMonthlyLimit()
 		return m.copilot.GetUsedPercent(mode, monthlyLimit)
 
 	default:

internal/config/config.go

@@ -76,6 +76,17 @@ type ProviderConfig struct {
 	DangerouslySkipPermissions bool `mapstructure:"dangerously_skip_permissions"`
 	// DangerouslyBypassApprovalsAndSandbox tells the CLI to bypass approvals and sandboxing.
 	DangerouslyBypassApprovalsAndSandbox bool `mapstructure:"dangerously_bypass_approvals_and_sandbox"`
+
+	// MonthlyLimit sets the monthly premium request (PRU) limit for Copilot.
+	// If zero, falls back to CopilotPlan preset or weeklyTokens * 4.
+	// Only meaningful for the copilot provider.
+	MonthlyLimit int64 `mapstructure:"monthly_limit"`
+
+	// CopilotPlan sets the GitHub Copilot plan for automatic PRU limit detection.
+	// Valid values: "free" (50), "pro" (300), "pro_plus" (1500),
+	// "business" (300), "enterprise" (1000).
+	// If empty, uses MonthlyLimit or falls back to weeklyTokens * 4.
+	CopilotPlan string `mapstructure:"copilot_plan"`
 }
 
 // ProjectConfig defines a project to manage.
@@ -498,6 +509,34 @@ func (c *Config) GetProviderBudget(provider string) int {
 	return c.Budget.WeeklyTokens
 }
 
+// CopilotPlanLimits maps Copilot plan names to monthly PRU limits.
+var CopilotPlanLimits = map[string]int64{
+	"free":       50,
+	"pro":        300,
+	"pro_plus":   1500,
+	"business":   300,
+	"enterprise": 1000,
+}
+
+// GetCopilotMonthlyLimit returns the monthly PRU limit for the Copilot provider.
+// Resolution order: MonthlyLimit field > CopilotPlan preset > weeklyTokens * 4 fallback.
+func (c *Config) GetCopilotMonthlyLimit() int64 {
+	// Explicit monthly limit takes priority
+	if c.Providers.Copilot.MonthlyLimit > 0 {
+		return c.Providers.Copilot.MonthlyLimit
+	}
+
+	// Plan-based preset
+	if c.Providers.Copilot.CopilotPlan != "" {
+		if limit, ok := CopilotPlanLimits[c.Providers.Copilot.CopilotPlan]; ok {
+			return limit
+		}
+	}
+
+	// Fallback: derive from weekly token budget
+	return int64(c.GetProviderBudget("copilot")) * 4
+}
+
 // IsTaskEnabled checks if a task type is enabled.
 func (c *Config) IsTaskEnabled(task string) bool {
 	// Check if explicitly disabled

internal/config/config_test.go

@@ -154,6 +154,99 @@ func TestGetProviderBudget(t *testing.T) {
 	}
 }
 
+func TestGetCopilotMonthlyLimit(t *testing.T) {
+	tests := []struct {
+		name     string
+		cfg      Config
+		expected int64
+	}{
+		{
+			name: "explicit monthly limit takes priority",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{
+						MonthlyLimit: 500,
+						CopilotPlan:  "pro", // ignored when MonthlyLimit is set
+					},
+				},
+				Budget: BudgetConfig{WeeklyTokens: 100},
+			},
+			expected: 500,
+		},
+		{
+			name: "plan preset: free",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{CopilotPlan: "free"},
+				},
+			},
+			expected: 50,
+		},
+		{
+			name: "plan preset: pro",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{CopilotPlan: "pro"},
+				},
+			},
+			expected: 300,
+		},
+		{
+			name: "plan preset: pro_plus",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{CopilotPlan: "pro_plus"},
+				},
+			},
+			expected: 1500,
+		},
+		{
+			name: "plan preset: business",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{CopilotPlan: "business"},
+				},
+			},
+			expected: 300,
+		},
+		{
+			name: "plan preset: enterprise",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{CopilotPlan: "enterprise"},
+				},
+			},
+			expected: 1000,
+		},
+		{
+			name: "fallback to weekly tokens * 4",
+			cfg: Config{
+				Budget: BudgetConfig{WeeklyTokens: 200},
+			},
+			expected: 800,
+		},
+		{
+			name: "unknown plan falls back to weekly tokens * 4",
+			cfg: Config{
+				Providers: ProvidersConfig{
+					Copilot: ProviderConfig{CopilotPlan: "unknown_plan"},
+				},
+				Budget: BudgetConfig{WeeklyTokens: 150},
+			},
+			expected: 600,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := tt.cfg.GetCopilotMonthlyLimit()
+			if got != tt.expected {
+				t.Errorf("GetCopilotMonthlyLimit() = %d, want %d", got, tt.expected)
+			}
+		})
+	}
+}
+
 func TestNormalizeBudgetConfig(t *testing.T) {
 	cfg := &Config{
 		Budget: BudgetConfig{