diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
new file mode 100644
index 0000000..485b268
--- /dev/null
+++ b/.github/workflows/check.yml
@@ -0,0 +1,47 @@
+name: check
+
+on:
+  push:
+    branches:
+      - master
+      - main
+  pull_request:
+
+jobs:
+  check:
+    strategy:
+      fail-fast: false
+    runs-on: ubuntu-latest
+    continue-on-error: false
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: 'recursive'
+
+      - name: install
+        run: |
+          curl -fsSL https://cli.moonbitlang.com/install/unix.sh | bash
+          echo "$HOME/.moon/bin" >> $GITHUB_PATH
+
+      - name: moon version
+        run: |
+          moon version --all
+
+      - name: moon check
+        run: |
+          moon update
+          moon check --deny-warn
+
+      - name: moon info
+        run: |
+          moon info --target all
+          git diff --exit-code
+
+      - name: format diff
+        run: |
+          moon fmt
+          git diff --exit-code
+
+      - name: moon test
+        run: |
+          moon test --target all
diff --git a/.gitignore b/.gitignore
index 5335371..ea492e5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 target/
-.mooncakes/
\ No newline at end of file
+.mooncakes/
+_build/
diff --git a/codex_report.md b/codex_report.md
new file mode 100644
index 0000000..dfe74a1
--- /dev/null
+++ b/codex_report.md
@@ -0,0 +1,38 @@
+# Dependency Error Report
+
+## Dependency
+
+`peter-jerry-ye/io@0.3.4`
+
+## Command
+
+```bash
+moon check
+```
+
+## Error
+
+`moon check` fails while calculating the build plan:
+
+```text
+Error: Failed to calculate build plan
+
+Caused by:
+    0: Failed to solve package relationship
+    1: Import tonyfettes/encoding@0.3.7 exists in global environment,
+               but its containing module is not imported by peter-jerry-ye/io@0.3.4, thus cannot be imported by its package 'http'
+```
+
+## Attempted Fix
+
+Ran:
+
+```bash
+moon add peter-jerry-ye/io
+```
+
+The command completed, but did not update `moon.mod.json` or any other tracked repository file. Running `moon check` afterwards produced the same dependency resolution error.
+
+## Conclusion
+
+The failure comes from `peter-jerry-ye/io@0.3.4`: its `http` package imports `tonyfettes/encoding@0.3.7`, but that containing module is not declared by `peter-jerry-ye/io@0.3.4`. This needs to be fixed in the dependency or by moving this repository to a dependency version where that relationship is declared correctly.
diff --git a/moon.mod.json b/moon.mod.json
index 0fd3e72..a068fea 100644
--- a/moon.mod.json
+++ b/moon.mod.json
@@ -1,9 +1,8 @@
 {
   "name": "moonbit-community/cli-template",
   "deps": {
-    "peter-jerry-ye/wasi-imports": "0.1.3",
-    "peter-jerry-ye/io": "0.3.4",
-    "peter-jerry-ye/async": "0.2.0"
+    "peter-jerry-ye/wasi-imports": "0.1.5"
   },
-  "source": "src"
-}
\ No newline at end of file
+  "source": "src",
+  "preferred-target": "wasm"
+}
diff --git a/src/moon.pkg b/src/moon.pkg
new file mode 100644
index 0000000..d4a696c
--- /dev/null
+++ b/src/moon.pkg
@@ -0,0 +1,19 @@
+import {
+  "peter-jerry-ye/wasi-imports/ffi" @ffi,
+  "peter-jerry-ye/wasi-imports/interface/wasi/cli/stdout" @stdout,
+  "peter-jerry-ye/wasi-imports/interface/wasi/io/streams",
+}
+
+options(
+  link: {
+    "wasm": {
+      "export-memory-name": "memory",
+      "exports": [
+        "cabi_realloc:cabi_realloc",
+        "wasmExportRun:wasi:cli/run@0.2.0#run",
+      ],
+      "heap-start-address": 16,
+    },
+  },
+  supported_targets: [ "wasm" ],
+)
diff --git a/src/moon.pkg.json b/src/moon.pkg.json
deleted file mode 100644
index 2d8be61..0000000
--- a/src/moon.pkg.json
+++ /dev/null
@@ -1,21 +0,0 @@
-{
-  "link": {
-    "wasm": {
-      "exports": [
-        "cabi_realloc:cabi_realloc",
-        "wasmExportRun:wasi:cli/run@0.2.0#run"
-      ],
-      "export-memory-name": "memory",
-      "heap-start-address": 16
-    }
-  },
-  "import": [
-    {
-      "path": "peter-jerry-ye/wasi-imports/ffi",
-      "alias": "ffi"
-    },
-    "peter-jerry-ye/io/io",
-    "peter-jerry-ye/async/loop",
-    "peter-jerry-ye/async/promise"
-  ]
-}
\ No newline at end of file
diff --git a/src/pkg.generated.mbti b/src/pkg.generated.mbti
new file mode 100644
index 0000000..7ec68f2
--- /dev/null
+++ b/src/pkg.generated.mbti
@@ -0,0 +1,18 @@
+// Generated using `moon info`, DON'T EDIT IT
+package "moonbit-community/cli-template"
+
+// Values
+pub fn cabi_realloc(Int, Int, Int, Int) -> Int
+
+pub fn run() -> Result[Unit, Unit]
+
+pub fn wasmExportRun() -> Int
+
+// Errors
+
+// Types and methods
+
+// Type aliases
+
+// Traits
+
diff --git a/src/stub.mbt b/src/stub.mbt
index 6311aef..2183a81 100644
--- a/src/stub.mbt
+++ b/src/stub.mbt
@@ -1,22 +1,19 @@
 ///|
 /// Run the program.
 pub fn run() -> Result[Unit, Unit] {
-  let mut result = Ok(())
-  @promise.spawn(async fn() {
-    top() catch {
-      error => {
-        result = Err(())
-        @io.println_sync("Error \{error}", stream=@io.stderr)
-      }
-    }
-  })
-  |> ignore
-  @io.event_loop.run()
-  result
+  top()
 }
 
 ///|
 /// User should change this function to do what they want
-async fn top() -> Unit {
-  @io.println("Hello, world!")
+fn top() -> Result[Unit, Unit] {
+  let stdout = @stdout.get_stdout()
+  let result = stdout.blocking_write_and_flush(
+    b"Hello, world!\n".to_fixedarray(),
+  )
+  stdout.drop()
+  match result {
+    Ok(_) => Ok(())
+    Err(_) => Err(())
+  }
 }