diff --git a/src/core.ts b/src/core.ts
index b8ba42f..96a73c1 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -2,6 +2,7 @@ import type { GetRepositoryMetadataQuery } from "./github/graphql/generated/oper
 import {
   createCommitOnBranchQuery,
   getRepositoryMetadata,
+  type Octokit,
 } from "./github/graphql/queries.ts";
 import type { CommitChangesOptions, CommitChangesResult } from "./types.ts";
 import { normalizeCommitMessage, resolveGitRef } from "./utils.ts";
@@ -17,7 +18,7 @@ type CreateCommit = (
  * Works in Node.js and browsers.
  */
 export async function commitChanges({
-  octokit,
+  octokit: partialOctokit,
   owner,
   repo,
   branch,
@@ -26,6 +27,7 @@ export async function commitChanges({
   message,
   fileChanges,
 }: CommitChangesOptions): Promise<CommitChangesResult> {
+  const octokit = partialOctokit as Octokit;
   const baseRef = resolveGitRef(base);
 
   const info = await getRepositoryMetadata(octokit, {
@@ -168,7 +170,10 @@ async function createOrForceUpdateTemporaryBranch({
   repo,
   tempBranch,
   baseSha,
-}: Pick<CommitChangesOptions, "octokit" | "owner" | "repo"> & {
+}: {
+  octokit: Octokit;
+  owner: string;
+  repo: string;
   tempBranch: string;
   baseSha: string;
 }) {
diff --git a/src/github/graphql/queries.ts b/src/github/graphql/queries.ts
index a711579..892773f 100644
--- a/src/github/graphql/queries.ts
+++ b/src/github/graphql/queries.ts
@@ -1,37 +1,17 @@
-// Octokit types are messy. To avoid adding any (peer)dependencies we rely on TS structural typing here
-export type Octokit = {
-  graphql: <T>(
-    query: string,
-    variables?: Record<string, unknown>,
-  ) => Promise<T>;
-  rest: {
-    git: {
-      createRef: (params: {
-        owner: string;
-        repo: string;
-        ref: string;
-        sha: string;
-      }) => Promise<{ data: { node_id?: string } }>;
-      updateRef: (params: {
-        owner: string;
-        repo: string;
-        ref: string;
-        sha: string;
-        force?: boolean;
-      }) => Promise<{ data: { node_id?: string } }>;
-      deleteRef: (params: {
-        owner: string;
-        repo: string;
-        ref: string;
-      }) => Promise<unknown>;
-      getRef?: (params: {
-        owner: string;
-        repo: string;
-        ref: string;
-      }) => Promise<unknown>;
-    };
-  };
-};
+import type { getOctokit } from "@actions/github";
+
+export type Octokit = ReturnType<typeof getOctokit>;
+
+/**
+ * Rough shape of the Octokit instance we need so we don't depend on the full
+ * dependency and types.
+ */
+export interface PartialOctokit {
+  request: unknown;
+  graphql: unknown;
+  rest: unknown;
+  paginate: unknown;
+}
 
 import type {
   CreateCommitOnBranchMutation,
diff --git a/src/types.ts b/src/types.ts
index b964ede..bcf9172 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -2,7 +2,7 @@ import type {
   CommitMessage,
   FileChanges,
 } from "./github/graphql/generated/types.ts";
-import type { Octokit } from "./github/graphql/queries.ts";
+import type { PartialOctokit } from "./github/graphql/queries.ts";
 
 export type GitRef = { branch: string } | { tag: string } | { commit: string };
 
@@ -12,7 +12,7 @@ export interface CommitChangesOptions {
    * from `@octokit/core`, `@octokit/plugin-rest-endpoint-methods`, and
    * `@octokit/plugin-paginate-rest`.
    */
-  octokit: Octokit;
+  octokit: PartialOctokit;
   /**
    * The owner of the repository.
    */
diff --git a/tsdown.config.ts b/tsdown.config.ts
index c8cafbd..1dd028b 100644
--- a/tsdown.config.ts
+++ b/tsdown.config.ts
@@ -11,6 +11,11 @@ export default defineConfig({
   clean: !process.argv.includes("--watch"),
   deps: {
     onlyBundle: [], // require explicitly listing inlined dependencies
+    neverBundle: [
+      // Referenced in internal types only and should be treeshaken away, but
+      // we need to specify it here to allow for linking before treeshaking
+      "@actions/github",
+    ],
   },
 
   sourcemap: !isCi,