diff --git a/.vscode/launch.json b/.vscode/launch.json
new file mode 100644
index 0000000..84e1228
--- /dev/null
+++ b/.vscode/launch.json
@@ -0,0 +1,47 @@
+{
+  // Use IntelliSense to learn about possible attributes.
+  // Hover to view descriptions of existing attributes.
+  // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "node",
+      "request": "attach",
+      "name": "Attach",
+      "port": 9229,
+      "skipFiles": ["<node_internals>/**"]
+    },
+    {
+      "name": "Run All Tests",
+      "type": "node",
+      "request": "launch",
+      "protocol": "inspector",
+      "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
+      "args": ["--inspect", "--no-timeouts", "--colors", "test/**/*.test.ts"],
+      "env": {
+        "NODE_ENV": "development",
+        "SFDX_ENV": "development"
+      },
+      "sourceMaps": true,
+      "smartStep": true,
+      "internalConsoleOptions": "openOnSessionStart",
+      "preLaunchTask": "Compile"
+    },
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Run Current Test",
+      "sourceMaps": true,
+      "program": "${workspaceFolder}/node_modules/mocha/bin/_mocha",
+      "args": ["--inspect", "--no-timeouts", "--colors", "${file}"],
+      "env": {
+        "NODE_ENV": "development",
+        "SFDX_ENV": "development",
+        "OCLIF_TS_NODE": "0"
+      },
+      "smartStep": true,
+      "internalConsoleOptions": "openOnSessionStart",
+      "preLaunchTask": "Compile"
+    }
+  ]
+}
diff --git a/package.json b/package.json
index 9b6a6a3..5b80afb 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
   "dependencies": {
     "@oclif/core": "^1.20.4",
     "@oclif/test": "^2.2.10",
-    "@salesforce/core": "^3.31.17",
+    "@salesforce/core": "^3.32.1",
     "@salesforce/kit": "^1.8.0",
     "@salesforce/ts-types": "^1.7.1",
     "chalk": "^2.4.2"
@@ -71,4 +71,4 @@
   "publishConfig": {
     "access": "public"
   }
-}
\ No newline at end of file
+}
diff --git a/src/sfdxFlags.ts b/src/sfdxFlags.ts
index 0a9c366..c7fb135 100644
--- a/src/sfdxFlags.ts
+++ b/src/sfdxFlags.ts
@@ -23,7 +23,7 @@ import {
   Omit,
   Optional,
 } from '@salesforce/ts-types';
-import { CustomOptionFlag } from '@oclif/core/lib/interfaces/parser';
+import { CustomOptionFlag, FlagParser } from '@oclif/core/lib/interfaces/parser';
 import { Deprecation } from './ux';
 
 Messages.importMessagesDirectory(__dirname);
@@ -108,7 +108,7 @@ function merge<T>(
 function option<T>(
   kind: flags.Kind,
   options: flags.Option<T>,
-  parse: (val: string, ctx: unknown) => Promise<T>
+  parse: ((val: string, ctx: unknown) => Promise<T>) | FlagParser<T, string>
 ): flags.Discriminated<flags.Option<T>> {
   const flag = OclifFlags.option({ ...options, parse });
   return merge<T>(kind, flag, options);
@@ -221,7 +221,7 @@ function buildOption<T>(
 }
 
 function buildString(options: flags.String): flags.Discriminated<flags.String> {
-  return option('string', options, (val: string) => Promise.resolve(val));
+  return option('string', options, options.parse ?? ((val: string) => Promise.resolve(val)));
 }
 
 function buildVersion(options?: flags.BaseBoolean<boolean>): flags.Discriminated<flags.Boolean<void>> {
@@ -281,7 +281,7 @@ function buildMappedArray<T>(kind: flags.Kind, options: flags.MappedArray<T>): f
 function buildStringArray(kind: flags.Kind, options: flags.Array<string>): flags.Discriminated<flags.Option<string[]>> {
   const { options: values, ...rest } = options;
   const allowed = new Set(values);
-  return option(kind, rest, (val): Promise<string[]> => {
+  return option(kind, rest, (val: string): Promise<string[]> => {
     const vals = convertArrayFlagToArray(val, options.delimiter);
     validateArrayValues(kind, val, vals, options.validate);
     validateArrayOptions(kind, val, vals, allowed);
diff --git a/test/unit/sfdxFlags.test.ts b/test/unit/sfdxFlags.test.ts
index 690ed21..033b338 100644
--- a/test/unit/sfdxFlags.test.ts
+++ b/test/unit/sfdxFlags.test.ts
@@ -561,4 +561,16 @@ describe('SfdxFlags', () => {
       });
     });
   });
+
+  describe('parse', () => {
+    it('parse on string flag', async () => {
+      const flag = flags.string({
+        description: 'test',
+        parse: (input: string) => Promise.resolve(input.toUpperCase()),
+      });
+      if (!hasFunction(flag, 'parse')) throw new MissingPropertyError('parse', 'array');
+
+      expect(await flag.parse('foo', undefined, undefined)).to.equal('FOO');
+    });
+  });
 });
diff --git a/yarn.lock b/yarn.lock
index de7eb5a..2bd6c6f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -722,13 +722,13 @@
     mv "~2"
     safe-json-stringify "~1"
 
-"@salesforce/core@^3.31.17":
-  version "3.31.17"
-  resolved "https://registry.yarnpkg.com/@salesforce/core/-/core-3.31.17.tgz#83ab3c9c4730223943ceef4798aaa901fec7981e"
-  integrity sha512-rn3AYyePp3m1+IH+KVi+DWwMPcAPDYFiUxyJLh+Jr2hNj9i79eQBcUix6wunK3HaVz0N6Tm5FGIpjqfEVsU0cA==
+"@salesforce/core@^3.32.1":
+  version "3.32.1"
+  resolved "https://registry.yarnpkg.com/@salesforce/core/-/core-3.32.1.tgz#1a338a1985c58c1be819f99c6b33b24b32817cbe"
+  integrity sha512-hVcweKGy1CS3t0duS+0jxGVou5ZoQMXRZPQmcz1FyW31Oef5U07rhs3wTrwJqhCPHL817R/gm5V9wSRNcYdDtA==
   dependencies:
     "@salesforce/bunyan" "^2.0.0"
-    "@salesforce/kit" "^1.7.0"
+    "@salesforce/kit" "^1.8.0"
     "@salesforce/schemas" "^1.1.0"
     "@salesforce/ts-types" "^1.5.21"
     "@types/graceful-fs" "^4.1.5"
@@ -789,7 +789,7 @@
     typedoc-plugin-missing-exports "0.23.0"
     typescript "^4.1.3"
 
-"@salesforce/kit@^1.7.0", "@salesforce/kit@^1.8.0":
+"@salesforce/kit@^1.8.0":
   version "1.8.0"
   resolved "https://registry.yarnpkg.com/@salesforce/kit/-/kit-1.8.0.tgz#d5b8d83d5b0b866cb76840dc7a18e115589d86a0"
   integrity sha512-Pr9CWAIzVYKZRWvM76lyhEtF3CPmVdIfgbqRD7KT/YZdbLstX3KHYBxCyx3TyWZr5qROv96n+jRIBiIFI9LGGw==
@@ -981,16 +981,11 @@
   resolved "https://registry.yarnpkg.com/@types/parse-json/-/parse-json-4.0.0.tgz#2f8bb441434d163b35fb8ffdccd7138927ffb8c0"
   integrity sha512-//oorEZjL6sbPcKUaCdIGlIUeH26mgzimjBB77G6XRgnDl/L5wOnpyBGRe/Mmf5CVW3PwEBE1NjiMZ/ssFh4wA==
 
-"@types/semver@^7.3.12":
+"@types/semver@^7.3.12", "@types/semver@^7.3.9":
   version "7.3.13"
   resolved "https://registry.yarnpkg.com/@types/semver/-/semver-7.3.13.tgz#da4bfd73f49bd541d28920ab0e2bf0ee80f71c91"
   integrity sha512-21cFJr9z3g5dW8B0CVI9g2O9beqaThGQ6ZFBqHfwhzLDKUxaqTIy3vnfah/UPkfOiF2pLq+tGz+W8RyCskuslw==
 
-"@types/semver@^7.3.9":
-  version "7.3.12"
-  resolved "https://registry.yarnpkg.com/@types/semver/-/semver-7.3.12.tgz#920447fdd78d76b19de0438b7f60df3c4a80bf1c"
-  integrity sha512-WwA1MW0++RfXmCr12xeYOOC5baSC9mSb0ZqCquFzKhcoF4TvHu5MKOuXsncgZcpVFhB1pXd5hZmM0ryAoCp12A==
-
 "@types/sinon@*":
   version "10.0.13"
   resolved "https://registry.yarnpkg.com/@types/sinon/-/sinon-10.0.13.tgz#60a7a87a70d9372d0b7b38cc03e825f46981fb83"