diff --git a/packages/opencode/src/kilocode/session-export/worker/zlib-zstd.d.ts b/packages/opencode/src/kilocode/session-export/worker/zlib-zstd.d.ts
new file mode 100644
index 00000000000..9d01da9e972
--- /dev/null
+++ b/packages/opencode/src/kilocode/session-export/worker/zlib-zstd.d.ts
@@ -0,0 +1,4 @@
+declare module "node:zlib" {
+  export function zstdCompress(input: Uint8Array, callback: (err: Error | null, result: Buffer) => void): void
+  export function zstdDecompress(input: Uint8Array, callback: (err: Error | null, result: Buffer) => void): void
+}
diff --git a/packages/opencode/src/kilocode/session-export/worker/zstd.ts b/packages/opencode/src/kilocode/session-export/worker/zstd.ts
index 25662837416..f169236e0f6 100644
--- a/packages/opencode/src/kilocode/session-export/worker/zstd.ts
+++ b/packages/opencode/src/kilocode/session-export/worker/zstd.ts
@@ -1,15 +1,8 @@
+import { zstdCompress, zstdDecompress } from "node:zlib"
 import { promisify } from "node:util"
-import * as zlib from "node:zlib"
 
-type Zstd = (bytes: Uint8Array, cb: (err: Error | null, output: Uint8Array) => void) => void
-
-const api = zlib as unknown as {
-  zstdCompress: Zstd
-  zstdDecompress: Zstd
-}
-
-const compress = promisify(api.zstdCompress)
-const decompress = promisify(api.zstdDecompress)
+const compress = promisify(zstdCompress)
+const decompress = promisify(zstdDecompress)
 
 export async function compressZstd(bytes: Uint8Array): Promise<Uint8Array> {
   return compress(bytes) as Promise<Uint8Array>