diff --git a/TESTING.md b/TESTING.md
index 10e6f5d..96a5e6b 100644
--- a/TESTING.md
+++ b/TESTING.md
@@ -1,6 +1,16 @@
 # Pre-Commit Test Checklist
 
-Run through these checks before every commit to ensure consistent feature coverage.
+**Automated smoke test (same as CI):** run from the repo root:
+
+```bash
+./run-tests.sh
+```
+
+This builds the server and mudtool, starts the server with a temporary DB, runs the smoke test below (new player, persistence, admin, registration gate, combat), then cleans up. Use it locally to match what Gitea Actions run on push/pull_request. The script uses `MUD_TEST_DB` (default `./mudserver.db.test`) so it does not overwrite your normal `mudserver.db`.
+
+---
+
+Run through the checks below before every commit to ensure consistent feature coverage.
 
 ## Build
 - [ ] `cargo build` succeeds with no errors
@@ -227,9 +237,12 @@ Run through these checks before every commit to ensure consistent feature covera
 
 ## Quick Smoke Test Script
 
+The canonical implementation is **`./run-tests.sh`** (see top of this file). The following is the same sequence for reference; when writing or extending tests, keep `run-tests.sh` and this section in sync.
+
 ```bash
-# Start server in background
-RUST_LOG=info ./target/debug/mudserver &
+# Start server in background (use -d for test DB so you don't overwrite mudserver.db)
+TEST_DB=./mudserver.db.test
+RUST_LOG=info ./target/debug/mudserver -d "$TEST_DB" &
 SERVER_PID=$!
 sleep 2
 
@@ -256,12 +269,12 @@ stats
 quit
 EOF
 
-# Test 3: Admin via mudtool
-./target/debug/mudtool players list
-./target/debug/mudtool players set-admin smoketest true
-./target/debug/mudtool players show smoketest
-./target/debug/mudtool settings set registration_open false
-./target/debug/mudtool settings list
+# Test 3: Admin via mudtool (use same test DB)
+./target/debug/mudtool -d "$TEST_DB" players list
+./target/debug/mudtool -d "$TEST_DB" players set-admin smoketest true
+./target/debug/mudtool -d "$TEST_DB" players show smoketest
+./target/debug/mudtool -d "$TEST_DB" settings set registration_open false
+./target/debug/mudtool -d "$TEST_DB" settings list
 
 # Test 4: Admin commands in-game
 ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p 2222 smoketest@localhost <<'EOF'
@@ -273,14 +286,14 @@ quit
 EOF
 
 # Test 5: Registration gate
-./target/debug/mudtool settings set registration_open false
+./target/debug/mudtool -d "$TEST_DB" settings set registration_open false
 ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p 2222 newplayer@localhost <<'EOF'
 quit
 EOF
 
 # Test 6: Tick-based combat (connect and wait for ticks)
-./target/debug/mudtool settings set registration_open true
-./target/debug/mudtool players delete smoketest
+./target/debug/mudtool -d "$TEST_DB" settings set registration_open true
+./target/debug/mudtool -d "$TEST_DB" players delete smoketest
 ssh -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -p 2222 smoketest@localhost <<'EOF'
 1
 1
@@ -297,7 +310,7 @@ EOF
 # Verify XP changed (combat happened via ticks)
 
 # Cleanup
-./target/debug/mudtool settings set registration_open true
-./target/debug/mudtool players delete smoketest
+./target/debug/mudtool -d "$TEST_DB" settings set registration_open true
+./target/debug/mudtool -d "$TEST_DB" players delete smoketest
 kill $SERVER_PID
 ```
diff --git a/src/game.rs b/src/game.rs
index 5994cc2..fc0acce 100644
--- a/src/game.rs
+++ b/src/game.rs
@@ -157,7 +157,8 @@ pub fn resolve_npc_race_class(
             if candidates.is_empty() {
                 world.races.first().map(|r| r.id.clone()).unwrap_or_default()
             } else {
-                let idx = rng.next_range(0, candidates.len() as i32) as usize;
+                let len = candidates.len() as i32;
+                let idx = rng.next_range(0, len.saturating_sub(1)) as usize;
                 candidates[idx].id.clone()
             }
         }
@@ -187,7 +188,8 @@ pub fn resolve_npc_race_class(
             if candidates.is_empty() {
                 world.classes.first().map(|c| c.id.clone()).unwrap_or_default()
             } else {
-                let idx = rng.next_range(0, candidates.len() as i32) as usize;
+                let len = candidates.len() as i32;
+                let idx = rng.next_range(0, len.saturating_sub(1)) as usize;
                 candidates[idx].id.clone()
             }
         }