From 76a95595147e49922dfcdd71657b3354bd170017 Mon Sep 17 00:00:00 2001
From: Christian Hood <christianhood@gmail.com>
Date: Fri, 20 Mar 2026 02:45:14 -0400
Subject: [PATCH] Docs: update CLAUDE.md with perf tooling notes

Nightshift-Task: perf-regression
Nightshift-Ref: https://github.com/marcus/nightshift
---
 CLAUDE.md | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/CLAUDE.md b/CLAUDE.md
index 1ddc338..de7d963 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -94,3 +94,16 @@ 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.
+
+## Performance Tooling
+
+**Timing middleware** (`server/src/middleware/timing.js`): Registered early in `app.js`. Logs every request's method, path, status code, and duration. Emits a `[SLOW]` warning for responses exceeding 200 ms.
+
+**Benchmark script** (`scripts/perf-benchmark.js`): Hits `GET /api/paychecks`, `GET /api/financing`, and `GET /api/summary/annual` five times each and reports min/mean/max latency. Exits non-zero if any mean exceeds the threshold (default 500 ms, override via `SLOW_THRESHOLD_MS` env var). Target server URL defaults to `http://localhost:3001` (override via `BENCHMARK_URL`).
+
+```bash
+cd server && npm run perf          # run against localhost:3001
+BENCHMARK_URL=http://localhost:3000 npm run perf
+```
+
+**Performance indexes** (`db/migrations/005_performance_indexes.sql`): Adds indexes on `paychecks(period_year, period_month)`, `paycheck_bills(paycheck_id)`, `actuals(paycheck_id)`, `one_time_expenses(paycheck_id)`, `financing_payments(plan_id)`, and `financing_plans(active)` — applied automatically on server startup.