diff --git a/deploy/healthcheck/README.md b/deploy/healthcheck/README.md
index ad2ed2f..e258fda 100644
--- a/deploy/healthcheck/README.md
+++ b/deploy/healthcheck/README.md
@@ -14,3 +14,10 @@ Default paths and ports are tuned for the current VPS layout. Override with env
 - `AUTH_PORT`
 - `CHANNEL_PORT`
 - `SMOKE_BIN`
+
+For richer ad-hoc testing, call `metin_login_smoke` directly. It now supports:
+- `--json`
+- `--expect-auth-failure=STATUS`
+- `--expect-channel-failure=STATUS`
+- `--create-character-name=NAME`
+- `--client-version=VERSION`
diff --git a/docs/healthchecks.md b/docs/healthchecks.md
index 02dcee6..43f2ae3 100644
--- a/docs/healthchecks.md
+++ b/docs/healthchecks.md
@@ -84,6 +84,24 @@ sudo -iu mt2.jakubkadlec.dev env METIN_LOGIN_SMOKE_PASSWORD='<password>' \
   --client-version=1215955205
 ```
 
+Useful direct flags:
+
+- `--json`
+  returns a machine-readable summary including timings and emitted events
+- `--expect-auth-failure=STATUS`
+  treats an auth failure such as `NOID` or `WRONGPWD` as a successful negative test
+- `--expect-channel-failure=STATUS`
+  treats a channel failure as a successful negative test
+
+Example negative auth test:
+
+```bash
+sudo -iu mt2.jakubkadlec.dev env METIN_LOGIN_SMOKE_PASSWORD='wrongpass' \
+  /home/mt2.jakubkadlec.dev/metin/build/server-src/bin/metin_login_smoke \
+  173.249.9.66 11000 11011 someuser --password-env=METIN_LOGIN_SMOKE_PASSWORD \
+  --expect-auth-failure=WRONGPWD --json
+```
+
 ## Security Notes
 
 This does not open a new public network surface. It is a local operational tool.