diff --git a/README.md b/README.md
index 0c905be..19122eb 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,29 @@ Runs healthchecks against local docker containers
 
 ## Usage
 
+### add command
+
+Add a healthcheck to an existing `app.json` file, specified by the `--app-json` flag. If the file does not exist, an empty `app.json` file will be assumed.
+
+```shell
+# creates a default startup uptime healthcheck
+# docker-container-healthchecker add $PROCESS_TYPE
+docker-container-healthchecker add web
+```
+
+By default, the output is written to `stdout`, though it can be written to the file specified via the `--in-place` flag.
+
+```shell
+docker-container-healthchecker add web --in-place
+```
+
+The `add` command supports adding a listening check, which optionally supports a `--port` flag (default: `5000`):
+
+```shell
+# listening check
+docker-container-healthchecker add web --listening-check --port 3000
+```
+
 ### check command
 
 After creating an app.json file, execute the healthchecker like so:
diff --git a/commands/add.go b/commands/add.go
index a25adf1..c608b43 100644
--- a/commands/add.go
+++ b/commands/add.go
@@ -19,7 +19,9 @@ type AddCommand struct {
 	ifEmpty        bool
 	inPlace        bool
 	listeningCheck bool
+	name           string
 	prettyPrint    bool
+	port           int
 	uptime         int
 	warn           bool
 }
@@ -70,9 +72,11 @@ func (c *AddCommand) FlagSet() *flag.FlagSet {
 	f.BoolVar(&c.ifEmpty, "if-empty", false, "only add if there are no healthchecks for the process")
 	f.BoolVar(&c.inPlace, "in-place", false, "modify any app.json file in place")
 	f.StringVar(&c.appJSONFile, "app-json", "app.json", "full path to app.json file to update")
+	f.StringVar(&c.name, "name", "", "name to use for added check")
 	f.StringVar(&c.checkType, "type", "startup", "check to interpret")
 	f.BoolVar(&c.listeningCheck, "listening-check", false, "use a listening instead of uptime check")
 	f.BoolVar(&c.warn, "warn-only", false, "only warn on error")
+	f.IntVar(&c.port, "port", 5000, "container port to use")
 	f.IntVar(&c.uptime, "uptime", 1, "amount of time the container should be running for at minimum")
 	return f
 }
@@ -84,6 +88,8 @@ func (c *AddCommand) AutocompleteFlags() complete.Flags {
 			"--app-json":  complete.PredictAnything,
 			"--if-empty":  complete.PredictNothing,
 			"--in-place":  complete.PredictNothing,
+			"--name":      complete.PredictAnything,
+			"--port":      complete.PredictAnything,
 			"--pretty":    complete.PredictNothing,
 			"--type":      complete.PredictSet("liveness", "readiness", "startup"),
 			"--uptime":    complete.PredictAnything,
@@ -113,8 +119,8 @@ func (c *AddCommand) Run(args []string) int {
 		if _, err := os.Stat(c.appJSONFile); err == nil {
 			contents, err = os.ReadFile(c.appJSONFile)
 			if err != nil {
-				c.Ui.Error(err.Error())
-				return 1
+				c.Ui.Warn(err.Error())
+				contents = []byte("{}")
 			}
 		}
 	}
@@ -142,8 +148,13 @@ func (c *AddCommand) Run(args []string) int {
 		Warn: c.warn,
 	}
 
+	if c.name != "" {
+		healthcheck.Name = c.name
+	}
+
 	if c.listeningCheck {
 		healthcheck.Listening = true
+		healthcheck.Port = c.port
 	} else {
 		healthcheck.Uptime = c.uptime
 	}
diff --git a/test.bats b/test.bats
index d7727f9..879524f 100644
--- a/test.bats
+++ b/test.bats
@@ -36,6 +36,18 @@ teardown() {
   echo "status: $status"
   assert_success
   assert_output '{"healthchecks":{"web":[{"name":"default","type":"startup","uptime":1}]}}'
+
+  run "$BIN_NAME" add --name custom-check
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output '{"healthchecks":{"web":[{"name":"custom-check","type":"startup","uptime":1}]}}'
+
+  run "$BIN_NAME" add --app-json non-existing.json
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output '{"healthchecks":{"web":[{"name":"default","type":"startup","uptime":1}]}}'
 }
 
 @test "[add] default in-place" {
@@ -107,7 +119,7 @@ teardown() {
   echo "output: $output"
   echo "status: $status"
   assert_success
-  assert_output '{"healthchecks":{"web":[{"listening":true,"name":"default","type":"startup"}]}}'
+  assert_output '{"healthchecks":{"web":[{"listening":true,"name":"default","port":5000,"type":"startup"}]}}'
 }
 
 @test "[add] default warn-only" {