diff --git a/dist/octokit.d.ts b/dist/octokit.d.ts
index d0bc258..83e2f6e 100644
--- a/dist/octokit.d.ts
+++ b/dist/octokit.d.ts
@@ -1,5 +1,5 @@
 import { Octokit } from '@octokit/core';
 declare const CustomOctokit: typeof Octokit & import("@octokit/core/dist-types/types").Constructor<import("@probot/octokit-plugin-config/dist-types/types").API>;
 export type CustomOctokit = InstanceType<typeof CustomOctokit>;
-export declare function getOctokit(token: string): Octokit & import("@probot/octokit-plugin-config/dist-types/types").API;
+export declare function getOctokit(token: string): CustomOctokit;
 export {};
diff --git a/dist/pull-request.js.map b/dist/pull-request.js.map
index 7324f7c..ff393d6 100644
--- a/dist/pull-request.js.map
+++ b/dist/pull-request.js.map
@@ -1 +1 @@
-{"version":3,"file":"pull-request.js","sourceRoot":"","sources":["../src/pull-request.ts"],"names":[],"mappings":"AAAA,OAAO,EAAE,KAAK,EAAE,OAAO,EAAE,MAAM,eAAe,CAAC;AAC/C,OAAO,EAAE,OAAO,EAAE,MAAM,iBAAiB,CAAC;AAE1C,OAAO,EAAE,QAAQ,EAAE,MAAM,YAAY,CAAC;AAGtC,MAAM,OAAO,WAAW;IAGtB,YACW,EAAU,EACV,OAAsB,EAC/B,QAAkB;QAFT,OAAE,GAAF,EAAE,CAAQ;QACV,YAAO,GAAP,OAAO,CAAe;QAG/B,IAAI,CAAC,SAAS,GAAG,QAAQ,CAAC;IAC5B,CAAC;IAED,IAAI,QAAQ;QACV,OAAO,IAAI,CAAC,SAAS,CAAC;IACxB,CAAC;IAED,SAAS;QACP,OAAO,CAAC,CAAC,IAAI,CAAC,QAAQ,CAAC,SAAS,IAAI,CAAC,CAAC,IAAI,CAAC,QAAQ,CAAC,GAAG,CAAC;IAC1D,CAAC;IAED,oBAAoB,CAAC,SAAmB,EAAE,GAAY;QACpD,KAAK,CAAC,gCAAgC,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QACjD,MAAM,WAAW,GAAG,GAAG,aAAH,GAAG,cAAH,GAAG,GAAI,IAAI,CAAC,QAAQ,CAAC,GAAG,CAAC;QAC7C,IAAI,WAAW,KAAK,SAAS;YAAE,KAAK,CAAC;QAErC,OAAO,SAAS,CAAC,IAAI,CAAC,KAAK,CAAC,EAAE,CAC5B,IAAI,MAAM,CAAC,KAAK,CAAC,CAAC,IAAI,CAAC,WAAqB,CAAC,CAC9C,CAAC;IACJ,CAAC;IAED,KAAK,CAAC,MAAM,CAAC,OAAe,EAAE,WAAmB;QAC/C,KAAK,CAAC,iBAAiB,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QAClC,MAAM,EAAE,GAAG,MAAM,IAAI,CAAC,cAAc,CAAC,OAAO,CAAC,CAAC;QAE9C,IAAI,CAAC,QAAQ,CAAC,SAAS,GAAG,EAAE,KAAK,SAAS,CAAC,CAAC,CAAC,EAAE,CAAC,CAAC,CAAC,EAAE,CAAC,QAAQ,EAAE,CAAC;QAChE,IAAI,CAAC,QAAQ,CAAC,GAAG,GAAG,WAAW,CAAC;QAChC,MAAM,IAAI,CAAC,QAAQ,CAAC,WAAW,EAAE,CAAC;IACpC,CAAC;IAED,KAAK,CAAC,QAAQ,CAAC,OAAe;QAC5B,KAAK,CAAC,mBAAmB,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QACpC,MAAM,EAAE,GAAG,MAAM,IAAI,CAAC,cAAc,CAAC,OAAO,CAAC,CAAC;QAE9C,IAAI,CAAC,QAAQ,CAAC,SAAS,GAAG,EAAE,KAAK,SAAS,CAAC,CAAC,CAAC,EAAE,CAAC,CAAC,CAAC,EAAE,CAAC,QAAQ,EAAE,CAAC;QAChE,MAAM,IAAI,CAAC,QAAQ,CAAC,WAAW,EAAE,CAAC;IACpC,CAAC;IAED,KAAK,CAAC,cAAc,CAAC,OAAe;QAClC,IAAI,IAAI,CAAC,QAAQ,CAAC,SAAS,EAAE;YAC3B,IAAI,CAAC,aAAa,CAAC,OAAO,CAAC,CAAC;YAC5B,OAAO;SACR;QAED,MAAM,cAAc,GAAG,MAAM,IAAI,CAAC,aAAa,CAAC,OAAO,CAAC,CAAC;QAEzD,IAAI,CAAC,cAAc,EAAE;YACnB,OAAO,CAAC,2BAA2B,CAAC,CAAC;YACrC,OAAO;SACR;QAED,OAAO,cAAc,CAAC,EAAE,CAAC;IAC3B,CAAC;IAED,KAAK,CAAC,aAAa,CAAC,IAAY;QAC9B,IAAI,CAAC,IAAI,IAAI,IAAI,KAAK,EAAE;YAAE,OAAO;QAEjC,KAAK,CAAC,6BAA6B,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QAE9C,MAAM,EAAE,IAAI,EAAE,GAAG,MAAM,IAAI,CAAC,OAAO,CAAC,OAAO,CACzC,2DAA2D,kCAEtD,OAAO,CAAC,IAAI,KACf,YAAY,EAAE,IAAI,CAAC,EAAE,EACrB,IAAI,IAEP,CAAC;QAEF,OAAO,IAAI,CAAC;IACd,CAAC;IAEO,KAAK,CAAC,aAAa,CAAC,IAAY;QACtC,IAAI,CAAC,IAAI,CAAC,QAAQ,CAAC,SAAS;YAAE,OAAO;QAErC,KAAK,CAAC,6BAA6B,IAAI,CAAC,QAAQ,CAAC,SAAS,EAAE,CAAC,CAAC;QAE9D,MAAM,EAAE,IAAI,EAAE,GAAG,MAAM,IAAI,CAAC,OAAO,CAAC,OAAO,CACzC,0DAA0D,kCAErD,OAAO,CAAC,IAAI,KACf,UAAU,EAAE,CAAC,IAAI,CAAC,QAAQ,CAAC,SAAS,EACpC,IAAI,IAEP,CAAC;QAEF,OAAO,IAAI,CAAC;IACd,CAAC;IAED,MAAM,CAAC,KAAK,CAAC,cAAc,CAAC,EAAU,EAAE,OAAsB;QAC5D,OAAO,IAAI,WAAW,CAAC,EAAE,EAAE,OAAO,EAAE,MAAM,QAAQ,CAAC,WAAW,CAAC,EAAE,CAAC,CAAC,CAAC;IACtE,CAAC;CACF"}
\ No newline at end of file
+{"version":3,"file":"pull-request.js","sourceRoot":"","sources":["../src/pull-request.ts"],"names":[],"mappings":"AAAA,OAAO,EAAE,KAAK,EAAE,OAAO,EAAE,MAAM,eAAe,CAAC;AAC/C,OAAO,EAAE,OAAO,EAAE,MAAM,iBAAiB,CAAC;AAE1C,OAAO,EAAE,QAAQ,EAAE,MAAM,YAAY,CAAC;AAGtC,MAAM,OAAO,WAAW;IAGtB,YACW,EAAU,EACV,OAAsB,EAC/B,QAAkB;QAFT,OAAE,GAAF,EAAE,CAAQ;QACV,YAAO,GAAP,OAAO,CAAe;QAG/B,IAAI,CAAC,SAAS,GAAG,QAAQ,CAAC;IAC5B,CAAC;IAED,IAAI,QAAQ;QACV,OAAO,IAAI,CAAC,SAAS,CAAC;IACxB,CAAC;IAED,SAAS;QACP,OAAO,CAAC,CAAC,IAAI,CAAC,QAAQ,CAAC,SAAS,IAAI,CAAC,CAAC,IAAI,CAAC,QAAQ,CAAC,GAAG,CAAC;IAC1D,CAAC;IAED,oBAAoB,CAAC,SAAmB,EAAE,GAAY;QACpD,KAAK,CAAC,gCAAgC,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QACjD,MAAM,WAAW,GAAG,GAAG,aAAH,GAAG,cAAH,GAAG,GAAI,IAAI,CAAC,QAAQ,CAAC,GAAG,CAAC;QAC7C,IAAI,WAAW,KAAK,SAAS;YAAE,KAAK,CAAC;QAErC,OAAO,SAAS,CAAC,IAAI,CAAC,KAAK,CAAC,EAAE,CAC5B,IAAI,MAAM,CAAC,KAAK,CAAC,CAAC,IAAI,CAAC,WAAqB,CAAC,CAC9C,CAAC;IACJ,CAAC;IAED,KAAK,CAAC,MAAM,CAAC,OAAe,EAAE,WAAmB;QAC/C,KAAK,CAAC,iBAAiB,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QAClC,MAAM,EAAE,GAAG,MAAM,IAAI,CAAC,cAAc,CAAC,OAAO,CAAC,CAAC;QAE9C,IAAI,CAAC,QAAQ,CAAC,SAAS,GAAG,EAAE,KAAK,SAAS,CAAC,CAAC,CAAC,EAAE,CAAC,CAAC,CAAC,EAAE,CAAC,QAAQ,EAAE,CAAC;QAChE,IAAI,CAAC,QAAQ,CAAC,GAAG,GAAG,WAAW,CAAC;QAChC,MAAM,IAAI,CAAC,QAAQ,CAAC,WAAW,EAAE,CAAC;IACpC,CAAC;IAED,KAAK,CAAC,QAAQ,CAAC,OAAe;QAC5B,KAAK,CAAC,mBAAmB,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QACpC,MAAM,EAAE,GAAG,MAAM,IAAI,CAAC,cAAc,CAAC,OAAO,CAAC,CAAC;QAE9C,IAAI,CAAC,QAAQ,CAAC,SAAS,GAAG,EAAE,KAAK,SAAS,CAAC,CAAC,CAAC,EAAE,CAAC,CAAC,CAAC,EAAE,CAAC,QAAQ,EAAE,CAAC;QAChE,MAAM,IAAI,CAAC,QAAQ,CAAC,WAAW,EAAE,CAAC;IACpC,CAAC;IAED,KAAK,CAAC,cAAc,CAAC,OAAe;QAClC,IAAI,IAAI,CAAC,QAAQ,CAAC,SAAS,EAAE;YAC3B,IAAI,CAAC,aAAa,CAAC,OAAO,CAAC,CAAC;YAC5B,OAAO;SACR;QAED,MAAM,cAAc,GAAG,MAAM,IAAI,CAAC,aAAa,CAAC,OAAO,CAAC,CAAC;QAEzD,IAAI,CAAC,cAAc,EAAE;YACnB,OAAO,CAAC,2BAA2B,CAAC,CAAC;YACrC,OAAO;SACR;QAED,OAAO,cAAc,CAAC,EAAE,CAAC;IAC3B,CAAC;IAED,KAAK,CAAC,aAAa,CAAC,IAAY;QAC9B,IAAI,CAAC,IAAI,IAAI,IAAI,KAAK,EAAE;YAAE,OAAO;QAEjC,KAAK,CAAC,6BAA6B,IAAI,CAAC,EAAE,EAAE,CAAC,CAAC;QAE9C,MAAM,EAAE,IAAI,EAAE,GAAG,MAAM,IAAI,CAAC,OAAO,CAAC,OAAO,CACzC,2DAA2D,kCAEtD,OAAO,CAAC,IAAI,KACf,YAAY,EAAE,IAAI,CAAC,EAAE,EACrB,IAAI,IAEP,CAAC;QAEF,OAAO,IAAI,CAAC;IACd,CAAC;IAEO,KAAK,CAAC,aAAa,CAAC,IAAY;QACtC,IAAI,CAAC,IAAI,CAAC,QAAQ,CAAC,SAAS;YAAE,OAAO;QAErC,KAAK,CAAC,6BAA6B,IAAI,CAAC,QAAQ,CAAC,SAAS,EAAE,CAAC,CAAC;QAE9D,MAAM,EAAE,IAAI,EAAE,GAAG,MAAM,IAAI,CAAC,OAAO,CAAC,OAAO,CACzC,0DAA0D,kCAErD,OAAO,CAAC,IAAI,KACf,UAAU,EAAE,CAAC,IAAI,CAAC,QAAQ,CAAC,SAAS,EACpC,IAAI,IAEP,CAAC;QAEF,OAAO,IAAI,CAAC;IACd,CAAC;IAED,MAAM,CAAC,KAAK,CAAC,cAAc,CACzB,EAAU,EACV,OAAsB;QAEtB,OAAO,IAAI,WAAW,CAAC,EAAE,EAAE,OAAO,EAAE,MAAM,QAAQ,CAAC,WAAW,CAAC,EAAE,CAAC,CAAC,CAAC;IACtE,CAAC;CACF"}
\ No newline at end of file
diff --git a/src/action.ts b/src/action.ts
index 939a449..f812d1c 100644
--- a/src/action.ts
+++ b/src/action.ts
@@ -5,7 +5,7 @@ import { CustomOctokit } from './octokit';
 import { PullRequest } from './pull-request';
 import { Tag } from './tag';
 
-async function action(octokit: CustomOctokit) /*: Promise<string>*/ {
+async function action(octokit: CustomOctokit): Promise<void> {
   const config = await Config.getConfig(octokit);
 
   const tag = new Tag(await Tag.getLatestTag());
diff --git a/src/config.ts b/src/config.ts
index b63d9b4..37940c6 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -35,7 +35,7 @@ export class Config {
     return new this(retrievedConfig);
   }
 
-  static isConfigEmpty(config: unknown) {
+  static isConfigEmpty(config: unknown): boolean {
     return config === null || config === undefined;
   }
 }
diff --git a/src/metadata.ts b/src/metadata.ts
index 2cf1975..1765e86 100644
--- a/src/metadata.ts
+++ b/src/metadata.ts
@@ -42,7 +42,7 @@ export class Metadata {
   static readonly metadataFreezingTag = 'freezing-tag';
   static readonly metadataCommentID = 'comment-id';
 
-  async setMetadata() {
+  async setMetadata(): Promise<void> {
     if (this.commentID !== undefined) {
       await this.controller.setMetadata(
         this.issueNumber,
@@ -59,7 +59,7 @@ export class Metadata {
     );
   }
 
-  static async getMetadata(issueNumber: number) {
+  static async getMetadata(issueNumber: number): Promise<Metadata> {
     const controller = new MetadataController('devel-freezer', {
       ...context.repo,
       headers: {
diff --git a/src/octokit.ts b/src/octokit.ts
index 1d2396f..3984f36 100644
--- a/src/octokit.ts
+++ b/src/octokit.ts
@@ -5,7 +5,7 @@ const CustomOctokit = Octokit.plugin(config);
 
 export type CustomOctokit = InstanceType<typeof CustomOctokit>;
 
-export function getOctokit(token: string) {
+export function getOctokit(token: string): CustomOctokit {
   return new CustomOctokit({
     auth: token,
   });
diff --git a/src/pull-request.ts b/src/pull-request.ts
index 5fa7705..d4036f9 100644
--- a/src/pull-request.ts
+++ b/src/pull-request.ts
@@ -19,11 +19,11 @@ export class PullRequest {
     return this._metadata;
   }
 
-  isFreezed() {
+  isFreezed(): boolean {
     return !!this.metadata.commentID && !!this.metadata.tag;
   }
 
-  isTagPolicyCompliant(tagPolicy: string[], tag?: string) {
+  isTagPolicyCompliant(tagPolicy: string[], tag?: string): boolean {
     debug(`Checking tag policy for PR: #${this.id}`);
     const freezingTag = tag ?? this.metadata.tag;
     if (freezingTag === undefined) false;
@@ -33,7 +33,7 @@ export class PullRequest {
     );
   }
 
-  async freeze(content: string, freezingTag: string) {
+  async freeze(content: string, freezingTag: string): Promise<void> {
     debug(`Freezing PR: #${this.id}`);
     const id = await this.publishComment(content);
 
@@ -42,7 +42,7 @@ export class PullRequest {
     await this.metadata.setMetadata();
   }
 
-  async unfreeze(content: string) {
+  async unfreeze(content: string): Promise<void> {
     debug(`Unfreezing PR: #${this.id}`);
     const id = await this.publishComment(content);
 
@@ -50,7 +50,7 @@ export class PullRequest {
     await this.metadata.setMetadata();
   }
 
-  async publishComment(content: string) {
+  async publishComment(content: string): Promise<number | undefined> {
     if (this.metadata.commentID) {
       this.updateComment(content);
       return;
@@ -100,7 +100,10 @@ export class PullRequest {
     return data;
   }
 
-  static async getPullRequest(id: number, octokit: CustomOctokit) {
+  static async getPullRequest(
+    id: number,
+    octokit: CustomOctokit
+  ): Promise<PullRequest> {
     return new PullRequest(id, octokit, await Metadata.getMetadata(id));
   }
 }
diff --git a/src/tag.ts b/src/tag.ts
index 1604b9d..44e16bc 100644
--- a/src/tag.ts
+++ b/src/tag.ts
@@ -16,7 +16,7 @@ export class Tag {
     return this._latest;
   }
 
-  isFreezed(tagPolicy: string[]) {
+  isFreezed(tagPolicy: string[]): boolean {
     if (this.latest === undefined) false;
 
     return tagPolicy.some(regex =>
@@ -24,7 +24,7 @@ export class Tag {
     );
   }
 
-  static async getLatestTag() {
+  static async getLatestTag(): Promise<string | undefined> {
     // Get latest tag sorted by date, currently impossible by using GitHub REST API
     const { stdout, stderr } = await promiseExec(
       // Get rid of new lines - it causes issues when regex is to explicit (including `$`)