diff --git a/packages/api/src/cli/commands/install.ts b/packages/api/src/cli/commands/install.ts
index 72e9febe..553c79cf 100644
--- a/packages/api/src/cli/commands/install.ts
+++ b/packages/api/src/cli/commands/install.ts
@@ -4,7 +4,6 @@ import { Command, Option } from 'commander';
 import figures from 'figures';
 import Oas from 'oas';
 import ora from 'ora';
-import validateNPMPackageName from 'validate-npm-package-name';
 
 import Fetcher from '../../fetcher';
 import codegen from '../codegen';
@@ -18,6 +17,7 @@ cmd
   .name('install')
   .description('install an API SDK into your codebase')
   .argument('<uri>', 'an API to install')
+  .option('-i, --identifier <identifier>', 'API identifier (eg. `@api/petstore`)')
   .addOption(
     new Option('-l, --lang <language>', 'SDK language').choices([
       'js', // User generally wants JS, we'll prompt if they want CJS or ESM files.
@@ -27,7 +27,7 @@ cmd
     ])
   )
   .addOption(new Option('-y, --yes', 'Automatically answer "yes" to any prompts printed'))
-  .action(async (uri: string, options: { lang: string; yes?: boolean }) => {
+  .action(async (uri: string, options: { identifier?: string; lang: string; yes?: boolean }) => {
     let language: SupportedLanguages;
     if (options.lang) {
       language = options.lang as SupportedLanguages;
@@ -69,7 +69,12 @@ cmd
     }
 
     let identifier;
-    if (Fetcher.isAPIRegistryUUID(uri)) {
+    if (options.identifier) {
+      // `Storage.isIdentifierValid` will throw an exception if an identifier is invalid.
+      if (Storage.isIdentifierValid(options.identifier)) {
+        identifier = options.identifier;
+      }
+    } else if (Fetcher.isAPIRegistryUUID(uri)) {
       identifier = Fetcher.getProjectPrefixFromRegistryUUID(uri);
     } else {
       ({ value: identifier } = await promptTerminal({
@@ -82,19 +87,11 @@ cmd
             return false;
           }
 
-          // Is this identifier already in storage?
-          if (Storage.isInLockFile({ identifier: value })) {
-            return `"${value}" is already taken in your \`.api/\` directory. Please enter another identifier.`;
-          }
-
-          const isValidForNPM = validateNPMPackageName(`@api/${value}`);
-          if (!isValidForNPM.validForNewPackages) {
-            // `prompts` doesn't support surfacing multiple errors in a `validate` call so we can
-            // only surface the first to the user.
-            return isValidForNPM.errors[0];
+          try {
+            return Storage.isIdentifierValid(value, true);
+          } catch (err) {
+            return err.message;
           }
-
-          return true;
         },
       }));
     }
diff --git a/packages/api/src/cli/storage.ts b/packages/api/src/cli/storage.ts
index 0be205dd..c8993894 100644
--- a/packages/api/src/cli/storage.ts
+++ b/packages/api/src/cli/storage.ts
@@ -5,6 +5,7 @@ import path from 'path';
 
 import makeDir from 'make-dir';
 import ssri from 'ssri';
+import validateNPMPackageName from 'validate-npm-package-name';
 
 import Fetcher from '../fetcher';
 import { PACKAGE_VERSION } from '../packageInfo';
@@ -105,6 +106,22 @@ export default class Storage {
     return Storage.lockfile;
   }
 
+  static isIdentifierValid(identifier: string, prefixWithAPINamespace?: boolean) {
+    // Is this identifier already in storage?
+    if (Storage.isInLockFile({ identifier })) {
+      throw new Error(`"${identifier}" is already taken in your \`.api/\` directory. Please try another identifier.`);
+    }
+
+    const isValidForNPM = validateNPMPackageName(prefixWithAPINamespace ? `@api/${identifier}` : identifier);
+    if (!isValidForNPM.validForNewPackages) {
+      // `prompts` doesn't support surfacing multiple errors in a `validate` call so we can only
+      // surface the first to the user.
+      throw new Error(`Identifier cannot be used for an NPM package: ${isValidForNPM.errors[0]}`);
+    }
+
+    return true;
+  }
+
   static isInLockFile(search: { identifier?: string; source?: string }) {
     // Because this method may run before we initialize a new storage object we should make sure
     // that we have a storage directory present.
diff --git a/packages/api/test/cli/storage.test.ts b/packages/api/test/cli/storage.test.ts
index c343568c..e0af901d 100644
--- a/packages/api/test/cli/storage.test.ts
+++ b/packages/api/test/cli/storage.test.ts
@@ -53,6 +53,39 @@ describe('storage', () => {
     });
   });
 
+  describe('#isIdentifierValid', () => {
+    it('should allow an identifier that is valid', () => {
+      expect(Storage.isIdentifierValid('buster')).toBe(true);
+      expect(Storage.isIdentifierValid('buster', true)).toBe(true);
+    });
+
+    it('should throw an error for when an identifier is already being used', async () => {
+      fetchMock.get('https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx', petstoreSimple);
+
+      const source = '@petstore/v1.0#n6kvf10vakpemvplx';
+      const storage = new Storage(source, 'petstore');
+
+      expect(Storage.isInLockFile({ source })).toBe(false);
+
+      await storage.load();
+
+      expect(() => {
+        Storage.isIdentifierValid('petstore');
+      }).toThrow('"petstore" is already taken in your `.api/` directory. Please try another identifier.');
+    });
+
+    it("should throw an error when an identifier can't be used on npm", () => {
+      expect(() => {
+        Storage.isIdentifierValid('.buster');
+      }).toThrow('Identifier cannot be used for an NPM package: name cannot start with a period');
+
+      expect(() => {
+        // `true` here will try to check it as `@api/  buster`, `@api/.buster` is valid apparently!
+        Storage.isIdentifierValid('  buster', true);
+      }).toThrow('Identifier cannot be used for an NPM package: name can only contain URL-friendly characters');
+    });
+  });
+
   describe('#isInLockFile', () => {
     it('should be able to look up in the lockfile by a given source', async () => {
       fetchMock.get('https://dash.readme.com/api/v1/api-registry/n6kvf10vakpemvplx', petstoreSimple);