diff --git a/action.yml b/action.yml
index 4cc3c3c..ab905fa 100644
--- a/action.yml
+++ b/action.yml
@@ -21,11 +21,14 @@ inputs:
     required: false
     default: "update_flake_lock_action"
   path-to-flake-dir:
-    description: "The path of the directory containing `flake.nix` file within your repository. Useful when `flake.nix` cannot reside at the root of your repository."
+    description: |
+      The path of the directory containing `flake.nix` file within your repository.
+      Useful when `flake.nix` cannot reside at the root of your repository.
     required: false
   flake-dirs:
     description: |
-      A space-separated list of directories containing `flake.nix` files within your repository. Useful when you have multiple flakes in your repository.
+      A space-separated list of directories containing `flake.nix` files within your repository.
+      Useful when you have multiple flakes in your repository.
     required: false
     default: ""
   pr-title:
diff --git a/dist/index.js b/dist/index.js
index 621bc2c..e31754f 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -94798,11 +94798,12 @@ var UpdateFlakeLockAction = class extends DetSysAction {
         await this.updateFlake(directory);
       }
     } else {
-      await this.updateFlake(this.pathToFlakeDir);
+      const flakeDir = this.pathToFlakeDir ?? ".";
+      await this.updateFlake(flakeDir);
     }
   }
-  async updateFlake(directory) {
-    core.debug(`Running flake lock update in directory ${directory}`);
+  async updateFlake(flakeDir) {
+    core.debug(`Running flake lock update in directory ${flakeDir}`);
     const nixCommandArgs = makeNixCommandArgs(
       this.nixOptions,
       this.flakeInputs,
@@ -94810,7 +94811,7 @@ var UpdateFlakeLockAction = class extends DetSysAction {
     );
     core.debug(
       JSON.stringify({
-        directory,
+        directory: flakeDir,
         options: this.nixOptions,
         inputs: this.flakeInputs,
         message: this.commitMessage,
@@ -94818,7 +94819,7 @@ var UpdateFlakeLockAction = class extends DetSysAction {
       })
     );
     const execOptions = {
-      cwd: directory
+      cwd: flakeDir
     };
     const exitCode = await exec.exec("nix", nixCommandArgs, execOptions);
     if (exitCode !== 0) {
@@ -94826,11 +94827,11 @@ var UpdateFlakeLockAction = class extends DetSysAction {
         exitCode
       });
       core.setFailed(
-        `non-zero exit code of ${exitCode} detected while updating directory ${directory}`
+        `non-zero exit code of ${exitCode} detected while updating directory ${flakeDir}`
       );
     } else {
       core.info(
-        `flake.lock file in ${directory} was successfully updated`
+        `flake.lock file in ${flakeDir} was successfully updated`
       );
     }
   }
diff --git a/dist/index.js.map b/dist/index.js.map
index 10d75b7..a200775 100644
--- a/dist/index.js.map
+++ b/dist/index.js.map
@@ -1 +1 @@
-{"version":3,"sources":["../src/nix.ts","../src/index.ts"],"sourcesContent":["// Build the Nix args out of inputs from the Actions environment\nexport function makeNixCommandArgs(\n  nixOptions: string[],\n  flakeInputs: string[],\n  commitMessage: string,\n): string[] {\n  const flakeInputFlags = flakeInputs.flatMap((input) => [\n    \"--update-input\",\n    input,\n  ]);\n\n  const updateLockMechanism = flakeInputFlags.length === 0 ? \"update\" : \"lock\";\n\n  return nixOptions\n    .concat([\"flake\", updateLockMechanism])\n    .concat(flakeInputFlags)\n    .concat([\"--commit-lock-file\", \"--commit-lockfile-summary\", commitMessage]);\n}\n","import { makeNixCommandArgs } from \"./nix.js\";\nimport * as actionsCore from \"@actions/core\";\nimport * as actionsExec from \"@actions/exec\";\nimport { DetSysAction, inputs } from \"detsys-ts\";\n\nconst EVENT_EXECUTION_FAILURE = \"execution_failure\";\n\nclass UpdateFlakeLockAction extends DetSysAction {\n  private commitMessage: string;\n  private nixOptions: string[];\n  private flakeInputs: string[];\n  private pathToFlakeDir: string | null;\n  private flakeDirs: string[] | null;\n\n  constructor() {\n    super({\n      name: \"update-flake-lock\",\n      fetchStyle: \"universal\",\n      requireNix: \"fail\",\n    });\n\n    this.commitMessage = inputs.getString(\"commit-msg\");\n    this.flakeInputs = inputs.getArrayOfStrings(\"inputs\", \"space\");\n    this.nixOptions = inputs.getArrayOfStrings(\"nix-options\", \"space\");\n    this.pathToFlakeDir = inputs.getStringOrNull(\"path-to-flake-dir\");\n    this.flakeDirs = inputs.getArrayOfStrings(\"flake-dirs\", \"space\");\n\n    if (\n      this.flakeDirs !== null &&\n      this.flakeDirs.length > 0 &&\n      this.pathToFlakeDir !== \"\"\n    ) {\n      // TODO: improve this error message\n      throw new Error(\"Both path-to-flake-dir and flake-dirs is defined\");\n    }\n  }\n\n  async main(): Promise<void> {\n    await this.update();\n  }\n\n  // No post phase\n  async post(): Promise<void> {}\n\n  async update(): Promise<void> {\n    if (this.flakeDirs !== null && this.flakeDirs.length > 0) {\n      actionsCore.debug(\n        `Running flake lock update in multiple directories: ${this.flakeDirs}`,\n      );\n\n      for (const directory of this.flakeDirs) {\n        await this.updateFlake(directory);\n      }\n    } else {\n      await this.updateFlake(this.pathToFlakeDir!);\n    }\n  }\n\n  private async updateFlake(directory: string): Promise<void> {\n    actionsCore.debug(`Running flake lock update in directory ${directory}`);\n\n    // Nix command of this form:\n    // nix ${maybe nix options} flake ${\"update\" or \"lock\"} ${maybe --update-input flags} --commit-lock-file --commit-lockfile-summary ${commit message}\n    // Example commands:\n    // nix --extra-substituters https://example.com flake lock --update-input nixpkgs --commit-lock-file --commit-lockfile-summary \"updated flake.lock\"\n    // nix flake update --commit-lock-file --commit-lockfile-summary \"updated flake.lock\"\n    const nixCommandArgs: string[] = makeNixCommandArgs(\n      this.nixOptions,\n      this.flakeInputs,\n      this.commitMessage,\n    );\n\n    actionsCore.debug(\n      JSON.stringify({\n        directory,\n        options: this.nixOptions,\n        inputs: this.flakeInputs,\n        message: this.commitMessage,\n        args: nixCommandArgs,\n      }),\n    );\n\n    const execOptions: actionsExec.ExecOptions = {\n      cwd: directory,\n    };\n\n    const exitCode = await actionsExec.exec(\"nix\", nixCommandArgs, execOptions);\n\n    if (exitCode !== 0) {\n      this.recordEvent(EVENT_EXECUTION_FAILURE, {\n        exitCode,\n      });\n      actionsCore.setFailed(\n        `non-zero exit code of ${exitCode} detected while updating directory ${directory}`,\n      );\n    } else {\n      actionsCore.info(\n        `flake.lock file in ${directory} was successfully updated`,\n      );\n    }\n  }\n}\n\nfunction main(): void {\n  new UpdateFlakeLockAction().execute();\n}\n\nmain();\n"],"mappings":";AACO,SAAS,mBACd,YACA,aACA,eACU;AACV,QAAM,kBAAkB,YAAY,QAAQ,CAAC,UAAU;AAAA,IACrD;AAAA,IACA;AAAA,EACF,CAAC;AAED,QAAM,sBAAsB,gBAAgB,WAAW,IAAI,WAAW;AAEtE,SAAO,WACJ,OAAO,CAAC,SAAS,mBAAmB,CAAC,EACrC,OAAO,eAAe,EACtB,OAAO,CAAC,sBAAsB,6BAA6B,aAAa,CAAC;AAC9E;;;AChBA,YAAY,iBAAiB;AAC7B,YAAY,iBAAiB;AAC7B,SAAS,cAAc,cAAc;AAErC,IAAM,0BAA0B;AAEhC,IAAM,wBAAN,cAAoC,aAAa;AAAA,EAO/C,cAAc;AACZ,UAAM;AAAA,MACJ,MAAM;AAAA,MACN,YAAY;AAAA,MACZ,YAAY;AAAA,IACd,CAAC;AAED,SAAK,gBAAgB,OAAO,UAAU,YAAY;AAClD,SAAK,cAAc,OAAO,kBAAkB,UAAU,OAAO;AAC7D,SAAK,aAAa,OAAO,kBAAkB,eAAe,OAAO;AACjE,SAAK,iBAAiB,OAAO,gBAAgB,mBAAmB;AAChE,SAAK,YAAY,OAAO,kBAAkB,cAAc,OAAO;AAE/D,QACE,KAAK,cAAc,QACnB,KAAK,UAAU,SAAS,KACxB,KAAK,mBAAmB,IACxB;AAEA,YAAM,IAAI,MAAM,kDAAkD;AAAA,IACpE;AAAA,EACF;AAAA,EAEA,MAAM,OAAsB;AAC1B,UAAM,KAAK,OAAO;AAAA,EACpB;AAAA;AAAA,EAGA,MAAM,OAAsB;AAAA,EAAC;AAAA,EAE7B,MAAM,SAAwB;AAC5B,QAAI,KAAK,cAAc,QAAQ,KAAK,UAAU,SAAS,GAAG;AACxD,MAAY;AAAA,QACV,sDAAsD,KAAK,SAAS;AAAA,MACtE;AAEA,iBAAW,aAAa,KAAK,WAAW;AACtC,cAAM,KAAK,YAAY,SAAS;AAAA,MAClC;AAAA,IACF,OAAO;AACL,YAAM,KAAK,YAAY,KAAK,cAAe;AAAA,IAC7C;AAAA,EACF;AAAA,EAEA,MAAc,YAAY,WAAkC;AAC1D,IAAY,kBAAM,0CAA0C,SAAS,EAAE;AAOvE,UAAM,iBAA2B;AAAA,MAC/B,KAAK;AAAA,MACL,KAAK;AAAA,MACL,KAAK;AAAA,IACP;AAEA,IAAY;AAAA,MACV,KAAK,UAAU;AAAA,QACb;AAAA,QACA,SAAS,KAAK;AAAA,QACd,QAAQ,KAAK;AAAA,QACb,SAAS,KAAK;AAAA,QACd,MAAM;AAAA,MACR,CAAC;AAAA,IACH;AAEA,UAAM,cAAuC;AAAA,MAC3C,KAAK;AAAA,IACP;AAEA,UAAM,WAAW,MAAkB,iBAAK,OAAO,gBAAgB,WAAW;AAE1E,QAAI,aAAa,GAAG;AAClB,WAAK,YAAY,yBAAyB;AAAA,QACxC;AAAA,MACF,CAAC;AACD,MAAY;AAAA,QACV,yBAAyB,QAAQ,sCAAsC,SAAS;AAAA,MAClF;AAAA,IACF,OAAO;AACL,MAAY;AAAA,QACV,sBAAsB,SAAS;AAAA,MACjC;AAAA,IACF;AAAA,EACF;AACF;AAEA,SAAS,OAAa;AACpB,MAAI,sBAAsB,EAAE,QAAQ;AACtC;AAEA,KAAK;","names":[]}
\ No newline at end of file
+{"version":3,"sources":["../src/nix.ts","../src/index.ts"],"sourcesContent":["// Build the Nix args out of inputs from the Actions environment\nexport function makeNixCommandArgs(\n  nixOptions: string[],\n  flakeInputs: string[],\n  commitMessage: string,\n): string[] {\n  const flakeInputFlags = flakeInputs.flatMap((input) => [\n    \"--update-input\",\n    input,\n  ]);\n\n  const updateLockMechanism = flakeInputFlags.length === 0 ? \"update\" : \"lock\";\n\n  return nixOptions\n    .concat([\"flake\", updateLockMechanism])\n    .concat(flakeInputFlags)\n    .concat([\"--commit-lock-file\", \"--commit-lockfile-summary\", commitMessage]);\n}\n","import { makeNixCommandArgs } from \"./nix.js\";\nimport * as actionsCore from \"@actions/core\";\nimport * as actionsExec from \"@actions/exec\";\nimport { DetSysAction, inputs } from \"detsys-ts\";\n\nconst EVENT_EXECUTION_FAILURE = \"execution_failure\";\n\nclass UpdateFlakeLockAction extends DetSysAction {\n  private commitMessage: string;\n  private nixOptions: string[];\n  private flakeInputs: string[];\n  private pathToFlakeDir: string | null;\n  private flakeDirs: string[] | null;\n\n  constructor() {\n    super({\n      name: \"update-flake-lock\",\n      fetchStyle: \"universal\",\n      requireNix: \"fail\",\n    });\n\n    this.commitMessage = inputs.getString(\"commit-msg\");\n    this.flakeInputs = inputs.getArrayOfStrings(\"inputs\", \"space\");\n    this.nixOptions = inputs.getArrayOfStrings(\"nix-options\", \"space\");\n    this.pathToFlakeDir = inputs.getStringOrNull(\"path-to-flake-dir\");\n    this.flakeDirs = inputs.getArrayOfStrings(\"flake-dirs\", \"space\");\n\n    // Ensure that either path-to-flake-dir or flake-dirs is set to a meaningful value but not both\n    if (\n      this.flakeDirs !== null &&\n      this.flakeDirs.length > 0 &&\n      this.pathToFlakeDir !== \"\"\n    ) {\n      // TODO: improve this error message\n      throw new Error(\"Both path-to-flake-dir and flake-dirs is defined\");\n    }\n  }\n\n  async main(): Promise<void> {\n    await this.update();\n  }\n\n  // No post phase\n  async post(): Promise<void> {}\n\n  async update(): Promise<void> {\n    if (this.flakeDirs !== null && this.flakeDirs.length > 0) {\n      actionsCore.debug(\n        `Running flake lock update in multiple directories: ${this.flakeDirs}`,\n      );\n\n      for (const directory of this.flakeDirs) {\n        await this.updateFlake(directory);\n      }\n    } else {\n      // Set directory to root if not specified\n      const flakeDir = this.pathToFlakeDir ?? \".\";\n      await this.updateFlake(flakeDir);\n    }\n  }\n\n  private async updateFlake(flakeDir: string): Promise<void> {\n    actionsCore.debug(`Running flake lock update in directory ${flakeDir}`);\n\n    // Nix command of this form:\n    // nix ${maybe nix options} flake ${\"update\" or \"lock\"} ${maybe --update-input flags} --commit-lock-file --commit-lockfile-summary ${commit message}\n    // Example commands:\n    // nix --extra-substituters https://example.com flake lock --update-input nixpkgs --commit-lock-file --commit-lockfile-summary \"updated flake.lock\"\n    // nix flake update --commit-lock-file --commit-lockfile-summary \"updated flake.lock\"\n    const nixCommandArgs: string[] = makeNixCommandArgs(\n      this.nixOptions,\n      this.flakeInputs,\n      this.commitMessage,\n    );\n\n    actionsCore.debug(\n      JSON.stringify({\n        directory: flakeDir,\n        options: this.nixOptions,\n        inputs: this.flakeInputs,\n        message: this.commitMessage,\n        args: nixCommandArgs,\n      }),\n    );\n\n    const execOptions: actionsExec.ExecOptions = {\n      cwd: flakeDir,\n    };\n\n    const exitCode = await actionsExec.exec(\"nix\", nixCommandArgs, execOptions);\n\n    if (exitCode !== 0) {\n      this.recordEvent(EVENT_EXECUTION_FAILURE, {\n        exitCode,\n      });\n      actionsCore.setFailed(\n        `non-zero exit code of ${exitCode} detected while updating directory ${flakeDir}`,\n      );\n    } else {\n      actionsCore.info(\n        `flake.lock file in ${flakeDir} was successfully updated`,\n      );\n    }\n  }\n}\n\nfunction main(): void {\n  new UpdateFlakeLockAction().execute();\n}\n\nmain();\n"],"mappings":";AACO,SAAS,mBACd,YACA,aACA,eACU;AACV,QAAM,kBAAkB,YAAY,QAAQ,CAAC,UAAU;AAAA,IACrD;AAAA,IACA;AAAA,EACF,CAAC;AAED,QAAM,sBAAsB,gBAAgB,WAAW,IAAI,WAAW;AAEtE,SAAO,WACJ,OAAO,CAAC,SAAS,mBAAmB,CAAC,EACrC,OAAO,eAAe,EACtB,OAAO,CAAC,sBAAsB,6BAA6B,aAAa,CAAC;AAC9E;;;AChBA,YAAY,iBAAiB;AAC7B,YAAY,iBAAiB;AAC7B,SAAS,cAAc,cAAc;AAErC,IAAM,0BAA0B;AAEhC,IAAM,wBAAN,cAAoC,aAAa;AAAA,EAO/C,cAAc;AACZ,UAAM;AAAA,MACJ,MAAM;AAAA,MACN,YAAY;AAAA,MACZ,YAAY;AAAA,IACd,CAAC;AAED,SAAK,gBAAgB,OAAO,UAAU,YAAY;AAClD,SAAK,cAAc,OAAO,kBAAkB,UAAU,OAAO;AAC7D,SAAK,aAAa,OAAO,kBAAkB,eAAe,OAAO;AACjE,SAAK,iBAAiB,OAAO,gBAAgB,mBAAmB;AAChE,SAAK,YAAY,OAAO,kBAAkB,cAAc,OAAO;AAG/D,QACE,KAAK,cAAc,QACnB,KAAK,UAAU,SAAS,KACxB,KAAK,mBAAmB,IACxB;AAEA,YAAM,IAAI,MAAM,kDAAkD;AAAA,IACpE;AAAA,EACF;AAAA,EAEA,MAAM,OAAsB;AAC1B,UAAM,KAAK,OAAO;AAAA,EACpB;AAAA;AAAA,EAGA,MAAM,OAAsB;AAAA,EAAC;AAAA,EAE7B,MAAM,SAAwB;AAC5B,QAAI,KAAK,cAAc,QAAQ,KAAK,UAAU,SAAS,GAAG;AACxD,MAAY;AAAA,QACV,sDAAsD,KAAK,SAAS;AAAA,MACtE;AAEA,iBAAW,aAAa,KAAK,WAAW;AACtC,cAAM,KAAK,YAAY,SAAS;AAAA,MAClC;AAAA,IACF,OAAO;AAEL,YAAM,WAAW,KAAK,kBAAkB;AACxC,YAAM,KAAK,YAAY,QAAQ;AAAA,IACjC;AAAA,EACF;AAAA,EAEA,MAAc,YAAY,UAAiC;AACzD,IAAY,kBAAM,0CAA0C,QAAQ,EAAE;AAOtE,UAAM,iBAA2B;AAAA,MAC/B,KAAK;AAAA,MACL,KAAK;AAAA,MACL,KAAK;AAAA,IACP;AAEA,IAAY;AAAA,MACV,KAAK,UAAU;AAAA,QACb,WAAW;AAAA,QACX,SAAS,KAAK;AAAA,QACd,QAAQ,KAAK;AAAA,QACb,SAAS,KAAK;AAAA,QACd,MAAM;AAAA,MACR,CAAC;AAAA,IACH;AAEA,UAAM,cAAuC;AAAA,MAC3C,KAAK;AAAA,IACP;AAEA,UAAM,WAAW,MAAkB,iBAAK,OAAO,gBAAgB,WAAW;AAE1E,QAAI,aAAa,GAAG;AAClB,WAAK,YAAY,yBAAyB;AAAA,QACxC;AAAA,MACF,CAAC;AACD,MAAY;AAAA,QACV,yBAAyB,QAAQ,sCAAsC,QAAQ;AAAA,MACjF;AAAA,IACF,OAAO;AACL,MAAY;AAAA,QACV,sBAAsB,QAAQ;AAAA,MAChC;AAAA,IACF;AAAA,EACF;AACF;AAEA,SAAS,OAAa;AACpB,MAAI,sBAAsB,EAAE,QAAQ;AACtC;AAEA,KAAK;","names":[]}
\ No newline at end of file
diff --git a/src/index.ts b/src/index.ts
index 665eca9..e1b2b44 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -25,6 +25,7 @@ class UpdateFlakeLockAction extends DetSysAction {
     this.pathToFlakeDir = inputs.getStringOrNull("path-to-flake-dir");
     this.flakeDirs = inputs.getArrayOfStrings("flake-dirs", "space");
 
+    // Ensure that either path-to-flake-dir or flake-dirs is set to a meaningful value but not both
     if (
       this.flakeDirs !== null &&
       this.flakeDirs.length > 0 &&
@@ -52,12 +53,14 @@ class UpdateFlakeLockAction extends DetSysAction {
         await this.updateFlake(directory);
       }
     } else {
-      await this.updateFlake(this.pathToFlakeDir!);
+      // Set directory to root if not specified
+      const flakeDir = this.pathToFlakeDir ?? ".";
+      await this.updateFlake(flakeDir);
     }
   }
 
-  private async updateFlake(directory: string): Promise<void> {
-    actionsCore.debug(`Running flake lock update in directory ${directory}`);
+  private async updateFlake(flakeDir: string): Promise<void> {
+    actionsCore.debug(`Running flake lock update in directory ${flakeDir}`);
 
     // Nix command of this form:
     // nix ${maybe nix options} flake ${"update" or "lock"} ${maybe --update-input flags} --commit-lock-file --commit-lockfile-summary ${commit message}
@@ -72,7 +75,7 @@ class UpdateFlakeLockAction extends DetSysAction {
 
     actionsCore.debug(
       JSON.stringify({
-        directory,
+        directory: flakeDir,
         options: this.nixOptions,
         inputs: this.flakeInputs,
         message: this.commitMessage,
@@ -81,7 +84,7 @@ class UpdateFlakeLockAction extends DetSysAction {
     );
 
     const execOptions: actionsExec.ExecOptions = {
-      cwd: directory,
+      cwd: flakeDir,
     };
 
     const exitCode = await actionsExec.exec("nix", nixCommandArgs, execOptions);
@@ -91,11 +94,11 @@ class UpdateFlakeLockAction extends DetSysAction {
         exitCode,
       });
       actionsCore.setFailed(
-        `non-zero exit code of ${exitCode} detected while updating directory ${directory}`,
+        `non-zero exit code of ${exitCode} detected while updating directory ${flakeDir}`,
       );
     } else {
       actionsCore.info(
-        `flake.lock file in ${directory} was successfully updated`,
+        `flake.lock file in ${flakeDir} was successfully updated`,
       );
     }
   }