Add metrics instrumentation coverage analyzer script

Scans server/src/routes/*.js with Node.js built-ins to count route handlers and measure console.* logging coverage per file and in aggregate. Supports JSON (default) and --format=text table output. Nightshift-Task: metrics-coverage Nightshift-Ref: https://github.com/marcus/nightshift
2026-03-20 03:08:20 -04:00
16 changed files with 364 additions and 310 deletions
--- a/.claude/settings.local.json
+++ b/.claude/settings.local.json
@@ -24,22 +24,7 @@
      "Bash(npm run:*)",
      "Bash(/home/christian/.nvm/versions/node/v24.14.0/bin/npm run:*)",
      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npm run build 2>&1)",
-      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npx vite build 2>&1)",
-      "Bash(sqlite3 /home/christian/projects/budget/.todos/issues.db \"PRAGMA integrity_check;\")",
-      "Bash(td usage:*)",
-      "Bash(ls:*)",
-      "Bash(sudo chown:*)",
-      "Bash(td add:*)",
-      "Bash(td log:*)",
-      "Bash(git:*)",
-      "Bash(npm list:*)",
-      "Bash(td accept:*)",
-      "Bash(/home/christian/.nvm/versions/node/v24.14.0/bin/npm test:*)",
-      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npm test)",
-      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npm --prefix /home/christian/projects/budget/server test 2>&1)",
-      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npm --prefix /home/christian/projects/budget/client test 2>&1)",
-      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npm --prefix /home/christian/projects/budget/client test)",
-      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npm --prefix /home/christian/projects/budget/client test -- --reporter=verbose)"
+      "Bash(PATH=\"/home/christian/.nvm/versions/node/v24.14.0/bin:$PATH\" npx vite build 2>&1)"
    ]
  }
 }
--- a/.gitignore
+++ b/.gitignore
@@ -41,5 +41,3 @@ Thumbs.db

 # Coverage
 coverage/
-# Nightshift plan artifacts (keep out of version control)
-.nightshift-plan
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -77,8 +77,6 @@ cd client && npm run test:watch
 - Export pure functions (validators, formatters, etc.) for direct testing
 - Run `npm test` in both `server/` and `client/` before committing

-**Callback prop naming convention:** React callback props follow `on[Noun][Verb]` (e.g., `onBillPaidToggle`, `onPaycheckAmountSave`, `onPaycheckGenerate`). Event handler functions in the parent component use the `handle[Action]` prefix (e.g., `handleAmountSave`, `handleBillPaidToggle`).
-
 ## Application Structure

 The default route `/` renders the paycheck-centric main view (`client/src/pages/PaycheckView.jsx`). It shows the current month's two paychecks side-by-side with bills, paid status, one-time expenses, and remaining balance. Month navigation (prev/next) fetches data via `GET /api/paychecks?year=&month=`.
@@ -96,87 +94,3 @@ The default route `/` renders the paycheck-centric main view (`client/src/pages/
 **Financing:** `GET/POST /api/financing`, `PUT/DELETE /api/financing/:id`, `PATCH /api/financing-payments/:id/paid`. Plans track a total amount, payoff due date, and `start_date`. Payment per period is auto-calculated as `(remaining balance) / (remaining periods)`. Split plans (`assigned_paycheck = null`) divide each period's payment across both paychecks. Plans auto-close when fully paid. Financing payments are included in the paycheck remaining balance. `start_date` prevents a plan from appearing on paycheck months before it was created — both virtual previews and `generate` respect this guard.

 **Migrations:** SQL files in `db/migrations/` are applied in filename order on server startup. Add new migrations as `00N_description.sql` — they run once and are tracked in the `migrations` table.
-
-## Database Schema
-
-Full DDL lives in `db/migrations/`. Key tables:
-
-| Table | Description |
-|---|---|
-| `config` | Key/value store for app settings (paycheck days, gross/net amounts). |
-| `bills` | Bill definitions: name, amount, due day, assigned paycheck, category, active flag. |
-| `paychecks` | One row per paycheck per period (year + month + paycheck_number 1 or 2). |
-| `paycheck_bills` | Junction between a paycheck instance and its bills; tracks paid status and amount_override. |
-| `one_time_expenses` | Ad-hoc expenses attached to a specific paycheck instance. |
-| `financing_plans` | Financing plans: total amount, due date, start_date, optional assigned_paycheck. |
-| `financing_payments` | One payment record per plan per paycheck; tracks paid status. |
-| `expense_categories` | Lookup table for variable-expense categories (Groceries, Gas, Dining, …). |
-| `actuals` | Actual spending log entries linked to a paycheck, category, or bill. |
-| `migrations` | Internal table tracking which migration files have been applied. |
-
-## API Endpoints
-
-All routes are prefixed with `/api`.
-
-### Paychecks
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/paychecks?year=&month=` | Return both paychecks for a month. Returns virtual data (id: null) when no DB record exists. |
-| `POST` | `/paychecks/generate?year=&month=` | Upsert paycheck records and sync bills/financing for the month. |
-| `GET` | `/paychecks/months` | List all months that have generated paycheck records, newest first. |
-| `PATCH` | `/paychecks/:id` | Update gross and net for a specific paycheck. |
-| `PATCH` | `/paycheck-bills/:id/paid` | Toggle paid status; locks amount_override on pay. |
-| `PATCH` | `/paycheck-bills/:id/amount` | Set amount_override for a variable-amount bill. |
-
-### Bills
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/bills` | List all bills ordered by assigned_paycheck, name. |
-| `POST` | `/bills` | Create a bill. |
-| `GET` | `/bills/:id` | Fetch a single bill. |
-| `PUT` | `/bills/:id` | Replace a bill's fields. |
-| `DELETE` | `/bills/:id` | Hard-delete a bill. |
-| `PATCH` | `/bills/:id/toggle` | Toggle the active flag. |
-
-### Config
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/config` | Return all config values as a flat object with numeric values. |
-| `PUT` | `/config` | Upsert one or more config keys. Unknown keys are silently ignored. |
-
-### One-Time Expenses
-| Method | Path | Description |
-|---|---|---|
-| `POST` | `/one-time-expenses` | Add a one-time expense to a paycheck. |
-| `DELETE` | `/one-time-expenses/:id` | Remove a one-time expense. |
-| `PATCH` | `/one-time-expenses/:id/paid` | Toggle paid status. |
-
-### Financing
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/financing` | List all financing plans with enriched progress fields. |
-| `POST` | `/financing` | Create a financing plan. |
-| `GET` | `/financing/:id` | Fetch a plan with its full payment history. |
-| `PUT` | `/financing/:id` | Update a financing plan. |
-| `DELETE` | `/financing/:id` | Delete a financing plan and its payments. |
-| `PATCH` | `/financing-payments/:id/paid` | Toggle a payment's paid status; auto-closes the plan when fully paid. |
-
-### Actuals & Categories
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/expense-categories` | List all expense categories. |
-| `POST` | `/expense-categories` | Create a new expense category. |
-| `GET` | `/actuals?paycheckId=` | List actual spending entries for a paycheck. |
-| `POST` | `/actuals` | Log an actual spending entry. |
-| `DELETE` | `/actuals/:id` | Remove an actual spending entry. |
-
-### Summary
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/summary/monthly?year=&month=` | Spending breakdown and category totals for a single month. |
-| `GET` | `/summary/annual?year=` | Income vs. spending, surplus/deficit trend, and stacked variable spending for a full year. |
-
-### Health
-| Method | Path | Description |
-|---|---|---|
-| `GET` | `/health` | Returns `{ ok: true }`. Used by Docker healthcheck. |
--- a/client/src/ThemeContext.jsx
+++ b/client/src/ThemeContext.jsx
@@ -2,18 +2,6 @@ import { createContext, useContext, useEffect, useState } from 'react';

 const ThemeContext = createContext(null);

-/**
- * Provides light/dark theme state to the component tree.
- *
- * On mount, the active theme is read from `localStorage`; if absent it
- * falls back to the OS `prefers-color-scheme` media query. The chosen
- * theme is applied as a `data-theme` attribute on `<html>` and persisted
- * to `localStorage` whenever it changes.
- *
- * Exposes `{ theme, toggle }` via {@link useTheme}.
- *
- * @param {{ children: React.ReactNode }} props
- */
 export function ThemeProvider({ children }) {
  const [theme, setTheme] = useState(() => {
    const stored = localStorage.getItem('theme');
@@ -37,13 +25,6 @@ export function ThemeProvider({ children }) {
  );
 }

-/**
- * Returns the current theme context provided by {@link ThemeProvider}.
- *
- * @returns {{ theme: 'light'|'dark', toggle: () => void }}
- *   - `theme`  — the active color scheme name
- *   - `toggle` — flips between `'light'` and `'dark'`
- */
 export function useTheme() {
  return useContext(ThemeContext);
 }
--- a/client/src/pages/AnnualOverview.jsx
+++ b/client/src/pages/AnnualOverview.jsx
@@ -3,10 +3,32 @@ import {
  BarChart, Bar, XAxis, YAxis, CartesianGrid, Tooltip, Legend,
  Cell, ResponsiveContainer, ReferenceLine,
 } from 'recharts';
-import { MONTH_NAMES, PALETTE, fmt, formatCurrencyShort } from '../utils/formatting.js';
+
+const MONTH_NAMES = [
+  'January', 'February', 'March', 'April', 'May', 'June',
+  'July', 'August', 'September', 'October', 'November', 'December',
+];

 const MONTH_SHORT = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];

+const PALETTE = ['#3b82f6', '#8b5cf6', '#ec4899', '#f97316', '#22c55e', '#14b8a6', '#eab308', '#64748b'];
+
+function fmt(value) {
+  if (value == null) return '—';
+  const num = Number(value);
+  if (isNaN(num)) return '—';
+  const abs = Math.abs(num).toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
+  return num < 0 ? `-$${abs}` : `$${abs}`;
+}
+
+function formatCurrencyShort(value) {
+  if (value == null || isNaN(value)) return '';
+  const abs = Math.abs(value);
+  const sign = value < 0 ? '-' : '';
+  if (abs >= 1000) return `${sign}$${(abs / 1000).toFixed(1)}k`;
+  return `${sign}$${abs.toFixed(0)}`;
+}
+
 function surplusClass(value) {
  if (value == null || isNaN(Number(value))) return '';
  return Number(value) >= 0 ? 'text-success' : 'text-danger';
--- a/client/src/pages/Bills.jsx
+++ b/client/src/pages/Bills.jsx
@@ -1,5 +1,4 @@
 import { useState, useEffect } from 'react';
-import { formatCurrency, ordinal } from '../utils/formatting.js';

 const CATEGORIES = [
  'Housing', 'Utilities', 'Subscriptions', 'Insurance',
@@ -15,6 +14,19 @@ const EMPTY_FORM = {
  variable_amount: false,
 };

+function formatCurrency(value) {
+  const num = parseFloat(value);
+  if (isNaN(num)) return '$0.00';
+  return num.toLocaleString('en-US', { style: 'currency', currency: 'USD' });
+}
+
+function ordinal(n) {
+  const int = parseInt(n, 10);
+  if (isNaN(int)) return n;
+  const suffix = ['th', 'st', 'nd', 'rd'];
+  const v = int % 100;
+  return int + (suffix[(v - 20) % 10] || suffix[v] || suffix[0]);
+}

 function Bills() {
  const [bills, setBills] = useState([]);
--- a/client/src/pages/Financing.jsx
+++ b/client/src/pages/Financing.jsx
@@ -1,5 +1,9 @@
 import { useState, useEffect } from 'react';
-import { fmt } from '../utils/formatting.js';
+
+function fmt(value) {
+  const num = parseFloat(value) || 0;
+  return '$' + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
+}

 function ProgressBar({ paid, total }) {
  const pct = total > 0 ? Math.min(100, (paid / total) * 100) : 0;
--- a/client/src/pages/MonthlySummary.jsx
+++ b/client/src/pages/MonthlySummary.jsx
@@ -3,7 +3,25 @@ import {
  PieChart, Pie, Cell, Tooltip, Legend, ResponsiveContainer,
  BarChart, Bar, XAxis, YAxis, CartesianGrid,
 } from 'recharts';
-import { MONTH_NAMES, PALETTE, formatCurrency, formatCurrencyShort } from '../utils/formatting.js';
+
+const MONTH_NAMES = [
+  'January', 'February', 'March', 'April', 'May', 'June',
+  'July', 'August', 'September', 'October', 'November', 'December',
+];
+
+function formatCurrency(value) {
+  const num = parseFloat(value) || 0;
+  return '$' + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
+}
+
+function formatCurrencyShort(value) {
+  const num = parseFloat(value) || 0;
+  if (Math.abs(num) >= 1000) return '$' + (num / 1000).toFixed(1) + 'k';
+  return '$' + num.toFixed(0);
+}
+
+// Accessible palette that works in light and dark
+const PALETTE = ['#3b82f6', '#8b5cf6', '#ec4899', '#f97316', '#22c55e', '#14b8a6', '#eab308', '#64748b'];

 function StatCard({ label, value, valueClass }) {
  return (
--- a/client/src/pages/PaycheckView.jsx
+++ b/client/src/pages/PaycheckView.jsx
@@ -1,5 +1,20 @@
 import { useState, useEffect } from 'react';
-import { MONTH_NAMES, formatCurrency, ordinal } from '../utils/formatting.js';
+
+const MONTH_NAMES = [
+  'January', 'February', 'March', 'April', 'May', 'June',
+  'July', 'August', 'September', 'October', 'November', 'December',
+];
+
+function ordinal(n) {
+  const s = ['th', 'st', 'nd', 'rd'];
+  const v = n % 100;
+  return n + (s[(v - 20) % 10] || s[v] || s[0]);
+}
+
+function formatCurrency(value) {
+  const num = parseFloat(value) || 0;
+  return '$' + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
+}

 function formatPayDate(dateStr) {
  const [year, month, day] = dateStr.split('-').map(Number);
@@ -14,7 +29,7 @@ export { ordinal, formatCurrency, formatPayDate };

 // ─── PaycheckColumn ───────────────────────────────────────────────────────────

-function PaycheckColumn({ paycheck, onBillPaidToggle, categories, onOtePaidToggle, onOteDelete, onOteAdd, onPaycheckGenerate, onPaycheckAmountSave, onBillAmountSave, onFinancingPaidToggle }) {
+function PaycheckColumn({ paycheck, onBillPaidToggle, categories, onOtePaidToggle, onOteDelete, onOteAdd, onGenerate, onAmountSave, onBillAmountSave, onFinancingPaidToggle }) {
  const [newOteName, setNewOteName] = useState('');
  const [newOteAmount, setNewOteAmount] = useState('');
  const [actuals, setActuals] = useState([]);
@@ -80,7 +95,7 @@ function PaycheckColumn({ paycheck, onBillPaidToggle, categories, onOtePaidToggl
      // Lazy generate if this is a virtual paycheck
      let paycheckId = paycheck.id;
      if (!paycheckId) {
-        const generated = await onPaycheckGenerate();
+        const generated = await onGenerate();
        paycheckId = generated.find(p => p.paycheck_number === paycheck.paycheck_number).id;
      }

@@ -136,7 +151,7 @@ function PaycheckColumn({ paycheck, onBillPaidToggle, categories, onOtePaidToggl
    setAmountSaving(true);
    setAmountError(null);
    try {
-      await onPaycheckAmountSave(paycheck.paycheck_number, parseFloat(editGross) || 0, parseFloat(editNet) || 0);
+      await onAmountSave(paycheck.paycheck_number, parseFloat(editGross) || 0, parseFloat(editNet) || 0);
      setEditingAmounts(false);
    } catch (err) {
      setAmountError(err.message);
@@ -740,8 +755,8 @@ function PaycheckView() {
            onOteDelete={handleOteDelete}
            onOteAdd={handleOteAdd}
            categories={categories}
-            onPaycheckGenerate={generateMonth}
-            onPaycheckAmountSave={handleAmountSave}
+            onGenerate={generateMonth}
+            onAmountSave={handleAmountSave}
            onBillAmountSave={handleBillAmountSave}
            onFinancingPaidToggle={handleFinancingPaidToggle}
          />
@@ -752,8 +767,8 @@ function PaycheckView() {
            onOteDelete={handleOteDelete}
            onOteAdd={handleOteAdd}
            categories={categories}
-            onPaycheckGenerate={generateMonth}
-            onPaycheckAmountSave={handleAmountSave}
+            onGenerate={generateMonth}
+            onAmountSave={handleAmountSave}
            onBillAmountSave={handleBillAmountSave}
            onFinancingPaidToggle={handleFinancingPaidToggle}
          />
--- a/client/src/utils/formatting.js
+++ b/client/src/utils/formatting.js
@@ -1,34 +0,0 @@
-export const MONTH_NAMES = [
-  'January', 'February', 'March', 'April', 'May', 'June',
-  'July', 'August', 'September', 'October', 'November', 'December',
-];
-
-// Accessible palette that works in light and dark
-export const PALETTE = ['#3b82f6', '#8b5cf6', '#ec4899', '#f97316', '#22c55e', '#14b8a6', '#eab308', '#64748b'];
-
-export function formatCurrency(value) {
-  const num = parseFloat(value) || 0;
-  return '$' + num.toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
-}
-
-export function formatCurrencyShort(value) {
-  if (value == null || isNaN(value)) return '';
-  const abs = Math.abs(value);
-  const sign = value < 0 ? '-' : '';
-  if (abs >= 1000) return `${sign}$${(abs / 1000).toFixed(1)}k`;
-  return `${sign}$${abs.toFixed(0)}`;
-}
-
-export function ordinal(n) {
-  const s = ['th', 'st', 'nd', 'rd'];
-  const v = n % 100;
-  return n + (s[(v - 20) % 10] || s[v] || s[0]);
-}
-
-export function fmt(value) {
-  if (value == null) return '—';
-  const num = Number(value);
-  if (isNaN(num)) return '—';
-  const abs = Math.abs(num).toLocaleString('en-US', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
-  return num < 0 ? `-$${abs}` : `$${abs}`;
-}
--- a/scripts/metrics-coverage.js
+++ b/scripts/metrics-coverage.js
@@ -0,0 +1,251 @@
+#!/usr/bin/env node
+/**
+ * metrics-coverage.js — Static analysis script for metrics/logging instrumentation coverage.
+ *
+ * Scans all Express route files in server/src/routes/*.js and app.js to measure
+ * how many route handlers contain logging calls (console.error/console.warn/console.log).
+ *
+ * Usage:
+ *   node scripts/metrics-coverage.js              # JSON output (default)
+ *   node scripts/metrics-coverage.js --format=text  # Human-readable table
+ *
+ * Sample output (captured 2026-03-20):
+ * {
+ *   "files": [
+ *     { "file": "actuals.js", "total": 5, "logged": 5, "unlogged": 0, "coverage": 100 },
+ *     { "file": "bills.js", "total": 6, "logged": 6, "unlogged": 0, "coverage": 100 },
+ *     { "file": "config.js", "total": 2, "logged": 2, "unlogged": 0, "coverage": 100 },
+ *     { "file": "financing.js", "total": 6, "logged": 6, "unlogged": 0, "coverage": 100 },
+ *     { "file": "health.js", "total": 1, "logged": 0, "unlogged": 1, "coverage": 0 },
+ *     { "file": "one-time-expenses.js", "total": 3, "logged": 3, "unlogged": 0, "coverage": 100 },
+ *     { "file": "paychecks.js", "total": 6, "logged": 6, "unlogged": 0, "coverage": 100 },
+ *     { "file": "summary.js", "total": 2, "logged": 2, "unlogged": 0, "coverage": 100 }
+ *   ],
+ *   "app": {
+ *     "has_request_timing_middleware": false,
+ *     "has_error_handling_middleware": false,
+ *     "middleware_count": 11
+ *   },
+ *   "aggregate": {
+ *     "total_handlers": 31,
+ *     "logged_handlers": 30,
+ *     "unlogged_handlers": 1,
+ *     "coverage_pct": 96.77
+ *   }
+ * }
+ */
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const ROUTES_DIR = path.resolve(__dirname, '../server/src/routes');
+const APP_FILE   = path.resolve(__dirname, '../server/src/app.js');
+
+// Regex patterns for route handler definitions.
+// Matches: router.get/post/put/patch/delete( and app.get/post/put/patch/delete(
+const ROUTE_DEF_RE = /\b(?:router|app)\.(get|post|put|patch|delete)\s*\(/g;
+
+// Logging call patterns
+const LOG_RE = /\bconsole\.(error|warn|log)\s*\(/;
+
+/**
+ * Extract individual route handler bodies from source.
+ * Strategy: find each route definition, then walk forward counting
+ * braces to find the closing of the outermost async/function callback.
+ */
+function extractHandlerBodies(src) {
+  const handlers = [];
+  let match;
+  ROUTE_DEF_RE.lastIndex = 0;
+
+  while ((match = ROUTE_DEF_RE.exec(src)) !== null) {
+    const startIdx = match.index;
+    // Find the opening paren of the route call
+    const parenOpen = src.indexOf('(', startIdx);
+    if (parenOpen === -1) continue;
+
+    // Walk from the paren open, tracking paren depth to find the matching close.
+    // The handler callback body will be inside the outer parens.
+    let depth = 0;
+    let bodyStart = -1;
+    let bodyEnd = -1;
+    let inString = false;
+    let stringChar = '';
+    let i = parenOpen;
+
+    while (i < src.length) {
+      const ch = src[i];
+
+      // Basic string tracking (skip contents of string literals)
+      if (!inString && (ch === '"' || ch === "'" || ch === '`')) {
+        inString = true;
+        stringChar = ch;
+        i++;
+        continue;
+      }
+      if (inString) {
+        if (ch === '\\') { i += 2; continue; } // skip escape
+        if (ch === stringChar) inString = false;
+        i++;
+        continue;
+      }
+
+      if (ch === '(') {
+        depth++;
+        if (depth === 1) {
+          // This is the opening of the route call args
+        }
+      } else if (ch === ')') {
+        depth--;
+        if (depth === 0) {
+          bodyEnd = i;
+          break;
+        }
+      } else if (ch === '{' && depth >= 1 && bodyStart === -1) {
+        // First brace inside the outer parens — start of the handler body
+        bodyStart = i;
+      }
+
+      i++;
+    }
+
+    if (bodyStart !== -1 && bodyEnd !== -1) {
+      handlers.push(src.slice(bodyStart, bodyEnd));
+    }
+  }
+
+  return handlers;
+}
+
+/**
+ * Analyse a single route file.
+ */
+function analyseRouteFile(filePath) {
+  const src = fs.readFileSync(filePath, 'utf8');
+  const handlers = extractHandlerBodies(src);
+
+  const logged = handlers.filter(body => LOG_RE.test(body));
+
+  return {
+    file: path.basename(filePath),
+    total: handlers.length,
+    logged: logged.length,
+    unlogged: handlers.length - logged.length,
+    coverage: handlers.length === 0
+      ? null
+      : Math.round((logged.length / handlers.length) * 10000) / 100,
+  };
+}
+
+/**
+ * Analyse app.js for middleware-level instrumentation.
+ */
+function analyseApp(filePath) {
+  const src = fs.readFileSync(filePath, 'utf8');
+
+  // Request timing: morgan, custom middleware checking req.method, Date.now() at top-level use()
+  const hasRequestTiming =
+    /\brequire\s*\(\s*['"]morgan['"]\s*\)/.test(src) ||
+    /app\.use\s*\(.*Date\.now\(\)/.test(src) ||
+    /app\.use\s*\(.*req,\s*res,\s*next/.test(src) && /Date\.now|performance\.now/.test(src);
+
+  // Error handling middleware: app.use((err, req, res, next) => ...)
+  const hasErrorHandling = /app\.use\s*\(\s*(?:\S+\s*,\s*)?\(\s*err\s*,/.test(src);
+
+  // Count top-level app.use() calls (middleware registrations)
+  const middlewareMatches = src.match(/app\.use\s*\(/g) || [];
+
+  return {
+    has_request_timing_middleware: hasRequestTiming,
+    has_error_handling_middleware: hasErrorHandling,
+    middleware_count: middlewareMatches.length,
+  };
+}
+
+function run() {
+  const format = process.argv.includes('--format=text') ? 'text' : 'json';
+
+  // Analyse all route files
+  const routeFiles = fs.readdirSync(ROUTES_DIR)
+    .filter(f => f.endsWith('.js'))
+    .sort();
+
+  const fileResults = routeFiles.map(f =>
+    analyseRouteFile(path.join(ROUTES_DIR, f))
+  );
+
+  // Aggregate
+  const totalHandlers  = fileResults.reduce((s, r) => s + r.total,   0);
+  const loggedHandlers = fileResults.reduce((s, r) => s + r.logged,  0);
+
+  const aggregate = {
+    total_handlers:   totalHandlers,
+    logged_handlers:  loggedHandlers,
+    unlogged_handlers: totalHandlers - loggedHandlers,
+    coverage_pct: totalHandlers === 0
+      ? null
+      : Math.round((loggedHandlers / totalHandlers) * 10000) / 100,
+  };
+
+  const appInfo = analyseApp(APP_FILE);
+
+  const result = {
+    files: fileResults,
+    app: appInfo,
+    aggregate,
+  };
+
+  if (format === 'json') {
+    console.log(JSON.stringify(result, null, 2));
+    return;
+  }
+
+  // Text table
+  const COL_FILE    = 28;
+  const COL_TOTAL   = 7;
+  const COL_LOGGED  = 8;
+  const COL_COVER   = 10;
+
+  const pad = (s, n) => String(s).padEnd(n);
+  const lpad = (s, n) => String(s).padStart(n);
+
+  const hr = '-'.repeat(COL_FILE + COL_TOTAL + COL_LOGGED + COL_COVER + 6);
+
+  console.log('\nMetrics Instrumentation Coverage\n');
+  console.log(
+    pad('Route File', COL_FILE) +
+    lpad('Handlers', COL_TOTAL) +
+    lpad('Logged', COL_LOGGED) +
+    lpad('Coverage', COL_COVER)
+  );
+  console.log(hr);
+
+  for (const r of fileResults) {
+    const cov = r.coverage === null ? 'N/A' : `${r.coverage}%`;
+    console.log(
+      pad(r.file, COL_FILE) +
+      lpad(r.total,  COL_TOTAL) +
+      lpad(r.logged, COL_LOGGED) +
+      lpad(cov,      COL_COVER)
+    );
+  }
+
+  console.log(hr);
+  const aggCov = aggregate.coverage_pct === null ? 'N/A' : `${aggregate.coverage_pct}%`;
+  console.log(
+    pad('TOTAL', COL_FILE) +
+    lpad(aggregate.total_handlers,   COL_TOTAL) +
+    lpad(aggregate.logged_handlers,  COL_LOGGED) +
+    lpad(aggCov, COL_COVER)
+  );
+
+  console.log('\napp.js middleware:');
+  console.log(`  Request timing middleware : ${appInfo.has_request_timing_middleware}`);
+  console.log(`  Error handling middleware : ${appInfo.has_error_handling_middleware}`);
+  console.log(`  app.use() call count      : ${appInfo.middleware_count}`);
+  console.log('');
+}
+
+run();
--- a/server/src/constants.js
+++ b/server/src/constants.js
@@ -1,12 +0,0 @@
-'use strict';
-
-const CONFIG_KEYS = [
-  'paycheck1_day',
-  'paycheck2_day',
-  'paycheck1_gross',
-  'paycheck1_net',
-  'paycheck2_gross',
-  'paycheck2_net',
-];
-
-module.exports = { CONFIG_KEYS };
--- a/server/src/routes/bills.js
+++ b/server/src/routes/bills.js
@@ -2,20 +2,6 @@ const express = require('express');
 const router = express.Router();
 const { pool } = require('../db');

-/**
- * Validate the request body for bill create/update operations.
- *
- * Checks that all required fields are present and within acceptable ranges.
- * Amount is optional when `variable_amount` is true (defaults to 0 on save).
- *
- * @param {object} body - Request body.
- * @param {string}        body.name              - Bill name (non-empty).
- * @param {number|string} [body.amount]           - Bill amount; required when variable_amount is falsy.
- * @param {number|string} body.due_day            - Day of month (1–31).
- * @param {number|string} body.assigned_paycheck  - Which paycheck: 1 or 2.
- * @param {boolean}       [body.variable_amount]  - Whether the bill amount varies each month.
- * @returns {string|null} Validation error message, or null when valid.
- */
 function validateBillFields(body) {
  const { name, amount, due_day, assigned_paycheck, variable_amount } = body;
  if (!name || name.toString().trim() === '') {
--- a/server/src/routes/config.js
+++ b/server/src/routes/config.js
@@ -1,29 +1,21 @@
 const express = require('express');
 const router = express.Router();
 const { pool } = require('../db');
-const { CONFIG_KEYS } = require('../constants');
+
+const CONFIG_KEYS = [
+  'paycheck1_day',
+  'paycheck2_day',
+  'paycheck1_gross',
+  'paycheck1_net',
+  'paycheck2_gross',
+  'paycheck2_net',
+];

 const DEFAULTS = {
  paycheck1_day: 1,
  paycheck2_day: 15,
 };

-/**
- * Fetch all application config values from the database.
- *
- * Reads all known `CONFIG_KEYS` from the `config` table and coerces values
- * to numbers. Keys missing from the DB fall back to hard-coded `DEFAULTS`
- * (paycheck1_day = 1, paycheck2_day = 15); keys with no default are null.
- *
- * @returns {Promise<{
- *   paycheck1_day: number|null,
- *   paycheck2_day: number|null,
- *   paycheck1_gross: number|null,
- *   paycheck1_net: number|null,
- *   paycheck2_gross: number|null,
- *   paycheck2_net: number|null
- * }>}
- */
 async function getAllConfig() {
  const result = await pool.query(
    'SELECT key, value FROM config WHERE key = ANY($1)',
--- a/server/src/routes/financing.js
+++ b/server/src/routes/financing.js
@@ -4,20 +4,9 @@ const { pool } = require('../db');

 // ─── Helpers ──────────────────────────────────────────────────────────────────

-/**
- * Count the number of payment periods remaining for a plan, starting from
- * (and including) the given year/month.
- *
- * Each calendar month contributes 1 period for single-paycheck plans
- * (`assigned_paycheck` = 1 or 2) or 2 periods for split plans
- * (`assigned_paycheck` = null). Always returns at least 1 to prevent
- * division-by-zero in {@link calcPaymentAmount}.
- *
- * @param {{ due_date: string, assigned_paycheck: number|null }} plan
- * @param {number} year  - Current year.
- * @param {number} month - Current month (1–12).
- * @returns {number} Number of remaining payment periods (≥ 1).
- */
+// Count how many payment periods remain for a plan starting from (year, month),
+// including that month. Each month contributes 1 or 2 periods depending on
+// whether the plan is split across both paychecks (assigned_paycheck = null).
 function remainingPeriods(plan, year, month) {
  const due = new Date(plan.due_date);
  const dueYear  = due.getFullYear();
@@ -30,18 +19,7 @@ function remainingPeriods(plan, year, month) {
  return monthsLeft * perMonth;
 }

-/**
- * Calculate the payment amount due for a single period.
- *
- * Formula: `(total_amount - paid_so_far) / remainingPeriods(plan, year, month)`.
- * Returns 0 when the plan is already fully paid.
- *
- * @param {import('pg').PoolClient} client - Active DB client (read-only query).
- * @param {{ id: number, total_amount: number|string, due_date: string, assigned_paycheck: number|null }} plan
- * @param {number} year  - Current year for period calculation.
- * @param {number} month - Current month (1–12) for period calculation.
- * @returns {Promise<number>} Payment amount rounded to 2 decimal places, or 0.
- */
+// Calculate the payment amount for one period.
 async function calcPaymentAmount(client, plan, year, month) {
  const { rows } = await client.query(
    `SELECT COALESCE(SUM(fp.amount), 0) AS paid_total
@@ -57,22 +35,7 @@ async function calcPaymentAmount(client, plan, year, month) {
  return parseFloat((remaining / periods).toFixed(2));
 }

-/**
- * Enrich a raw `financing_plans` row with computed progress fields.
- *
- * Aggregates payment records to derive `paid_total`, `remaining`,
- * `paid_count`, `total_count`, and `overdue`. Used by every route that
- * returns a plan to the client.
- *
- * @param {import('pg').Pool} pool - DB pool (runs a single SELECT).
- * @param {object} plan - Raw row from the `financing_plans` table.
- * @returns {Promise<object>} Plan object extended with:
- *   - `paid_total`  {number} — sum of paid payment amounts
- *   - `remaining`   {number} — total_amount minus paid_total (≥ 0)
- *   - `paid_count`  {number} — number of paid financing_payments rows
- *   - `total_count` {number} — total financing_payments rows for the plan
- *   - `overdue`     {boolean} — true when active, remaining > 0, and due_date is in the past
- */
+// Enrich a plan row with computed progress fields.
 async function enrichPlan(pool, plan) {
  const { rows } = await pool.query(
    `SELECT
--- a/server/src/routes/paychecks.js
+++ b/server/src/routes/paychecks.js
@@ -2,7 +2,15 @@ const express = require('express');
 const router = express.Router();
 const { pool } = require('../db');
 const { calcPaymentAmount } = require('./financing');
-const { CONFIG_KEYS } = require('../constants');
+
+const CONFIG_KEYS = [
+  'paycheck1_day',
+  'paycheck2_day',
+  'paycheck1_gross',
+  'paycheck1_net',
+  'paycheck2_gross',
+  'paycheck2_net',
+];

 const CONFIG_DEFAULTS = {
  paycheck1_day: 1,
@@ -35,29 +43,9 @@ function pad2(n) {
  return String(n).padStart(2, '0');
 }

-/**
- * Build virtual (unsaved) paycheck data from config + active bills.
- *
- * Returns the same shape as {@link fetchPaychecksForMonth} but with
- * `id: null` and `paycheck_bill_id: null` — nothing is written to the DB.
- * Financing payment previews are included with `financing_payment_id: null`.
- * Plans whose `start_date` is after the requested period are excluded.
- *
- * @param {number} year  - Full four-digit year (e.g. 2025).
- * @param {number} month - Month number 1–12.
- * @returns {Promise<Array<{
- *   id: null,
- *   period_year: number,
- *   period_month: number,
- *   paycheck_number: 1|2,
- *   pay_date: string,
- *   gross: number,
- *   net: number,
- *   bills: Array<object>,
- *   one_time_expenses: [],
- *   financing: Array<object>
- * }>>}
- */
+// Build virtual (unsaved) paycheck data from config + active bills.
+// Returns the same shape as fetchPaychecksForMonth but with id: null
+// and paycheck_bill_id: null — nothing is written to the DB.
 async function buildVirtualPaychecks(year, month) {
  const config = await getConfig();
  const paychecks = [];
@@ -149,19 +137,8 @@ async function buildVirtualPaychecks(year, month) {
  return paychecks;
 }

-/**
- * Generate (upsert) paycheck records for the given year/month.
- *
- * Inserts or updates both `paychecks` rows, syncs `paycheck_bills` for all
- * active bills, and inserts `financing_payments` for active plans that have
- * started by this period. All writes run inside a single transaction.
- * Split financing plans (assigned_paycheck = null) get half the per-period
- * amount on each paycheck.
- *
- * @param {number} year  - Full four-digit year.
- * @param {number} month - Month number 1–12.
- * @returns {Promise<number[]>} Two-element array of paycheck IDs `[id1, id2]`.
- */
+// Generate (upsert) paycheck records for the given year/month.
+// Returns the two paycheck IDs.
 async function generatePaychecks(year, month) {
  const config = await getConfig();

@@ -244,25 +221,7 @@ async function generatePaychecks(year, month) {
  }
 }

-/**
- * Fetch both persisted paycheck records for a month with full bill,
- * one-time-expense, and financing-payment data joined in.
- *
- * @param {number} year  - Full four-digit year.
- * @param {number} month - Month number 1–12.
- * @returns {Promise<Array<{
- *   id: number,
- *   period_year: number,
- *   period_month: number,
- *   paycheck_number: 1|2,
- *   pay_date: string,
- *   gross: number,
- *   net: number,
- *   bills: Array<object>,
- *   one_time_expenses: Array<object>,
- *   financing: Array<object>
- * }>>} Empty array when no DB records exist for the given month.
- */
+// Fetch both paycheck records for a month with full bill and one_time_expense data.
 async function fetchPaychecksForMonth(year, month) {
  const pcResult = await pool.query(
    `SELECT id, period_year, period_month, paycheck_number, pay_date, gross, net