diff --git a/lib/narn-lib.js b/lib/narn-lib.js
index c8abc54..540bd5c 100644
--- a/lib/narn-lib.js
+++ b/lib/narn-lib.js
@@ -1,6 +1,7 @@
 const fs = require("fs");
 const path = require("path");
 const minimist = require("minimist");
+const validateNpmPackageName = require("validate-npm-package-name");
 
 exports.detectYarn = function detectYarn() {
   return new Promise((resolve, reject) => {
@@ -63,7 +64,17 @@ exports.getNpmArgs = narnArgs => {
 };
 
 function transformNarnPackageString(packageToAdd) {
-  return packageToAdd.lastIndexOf("@") > 0
-    ? packageToAdd
-    : `${packageToAdd}@latest`;
+  const packageNameWithoutVersion = packageToAdd.slice(
+    0,
+    packageToAdd.indexOf("@") > 0
+      ? packageToAdd.lastIndexOf("@")
+      : packageToAdd.length + 1
+  );
+  const isValidPackageName = validateNpmPackageName(packageNameWithoutVersion)
+    .validForNewPackages;
+  if (isValidPackageName && packageNameWithoutVersion === packageToAdd) {
+    return `${packageToAdd}@latest`;
+  } else {
+    return packageToAdd;
+  }
 }
diff --git a/package.json b/package.json
index 5f75424..7ae31af 100644
--- a/package.json
+++ b/package.json
@@ -31,5 +31,7 @@
     "prettier": "^1.18.2",
     "pretty-quick": "^2.0.0"
   },
-  "dependencies": {}
+  "dependencies": {
+    "validate-npm-package-name": "^3.0.0"
+  }
 }
diff --git a/test/add.test.js b/test/add.test.js
index 4033b98..7bc2faf 100644
--- a/test/add.test.js
+++ b/test/add.test.js
@@ -69,4 +69,24 @@ describe("narn add", () => {
       "jest@latest"
     ]);
   });
+
+  it("supports installing from https urls", () => {
+    expect(
+      getNpmArgs(["add", "https://github.com/joeldenning/narn#master"])
+    ).toEqual([
+      "install",
+      "--save",
+      "https://github.com/joeldenning/narn#master"
+    ]);
+  });
+
+  it("supports installing from git urls", () => {
+    expect(
+      getNpmArgs(["add", "git@github.com:joeldenning/narn.git#master"])
+    ).toEqual([
+      "install",
+      "--save",
+      "git@github.com:joeldenning/narn.git#master"
+    ]);
+  });
 });
diff --git a/yarn.lock b/yarn.lock
index 0b0cd04..aa60b40 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -674,6 +674,11 @@ buffer-from@^1.0.0:
   resolved "https://registry.yarnpkg.com/buffer-from/-/buffer-from-1.1.1.tgz#32713bc028f75c02fdb710d7c7bcec1f2c6070ef"
   integrity sha512-MQcXEUbCKtEo7bhqEs6560Hyd4XaovZlO/k9V3hjVUF/zwW7KBVdSK4gIt/bzwS9MbR5qob+F5jusZsb0YQK2A==
 
+builtins@^1.0.3:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/builtins/-/builtins-1.0.3.tgz#cb94faeb61c8696451db36534e1422f94f0aee88"
+  integrity sha1-y5T662HIaWRR2zZTThQi+U8K7og=
+
 cache-base@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/cache-base/-/cache-base-1.0.1.tgz#0a7f46416831c8b662ee36fe4e7c59d76f666ab2"
@@ -3713,6 +3718,13 @@ validate-npm-package-license@^3.0.1:
     spdx-correct "^3.0.0"
     spdx-expression-parse "^3.0.0"
 
+validate-npm-package-name@^3.0.0:
+  version "3.0.0"
+  resolved "https://registry.yarnpkg.com/validate-npm-package-name/-/validate-npm-package-name-3.0.0.tgz#5fa912d81eb7d0c74afc140de7317f0ca7df437e"
+  integrity sha1-X6kS2B630MdK/BQN5zF/DKffQ34=
+  dependencies:
+    builtins "^1.0.3"
+
 verror@1.10.0:
   version "1.10.0"
   resolved "https://registry.yarnpkg.com/verror/-/verror-1.10.0.tgz#3a105ca17053af55d6e270c1f8288682e18da400"