| name | wasm-module-inspect |
| description | Inspect a compiled .wasm binary — validates structure, lists exports and imports, detects SIMD and threading opcodes, and reports binary size. Requires wabt; wasm-opt (Binaryen) is optional. |
| allowed-tools | Bash |
| argument-hint | <module.wasm> |
WASM Module Inspect
Inspect a compiled .wasm binary to verify it is valid, understand its public API surface, and detect compilation features (SIMD, threads).
Requirements
- wabt (
wasm-validate, wasm2wat) — install via brew install wabt (macOS), apt install wabt (Linux), or from https://github.com/WebAssembly/wabt/releases
- wasm-opt (optional, Binaryen) — install via
brew install binaryen for feature reporting
Instructions
The argument is in $ARGUMENTS. Pass it directly to the inspection script:
bash "$(dirname "$0")/inspect.sh" $ARGUMENTS
Output sections
| Section | What it reports |
|---|
SIZE | Binary size in bytes and KB |
VALID | Pass/fail from wasm-validate |
EXPORTS | All exported functions, memories, tables, globals |
IMPORTS | All imported functions (JS host functions the module depends on) |
SIMD | Whether v128 (WASM SIMD) opcodes are present |
THREADS | Whether atomic instructions are present (requires SharedArrayBuffer) |
FEATURES | Full feature list from wasm-opt --print-features (if available) |
Typical usage
bash inspect.sh build/my-dsp.wasm
bash inspect.sh dist/processor.wasm
What to look for
- Exports should be minimal — only the functions the JS/worklet layer calls (e.g.
_init, _process, _destroy). Unexpected exports indicate -s EXPORTED_FUNCTIONS was not set correctly.
- SIMD present confirms
-msimd128 was applied and the WASM binary actually contains vectorised code.
- Threads present means the page must be served with
COOP/COEP headers — flag this if the deployment environment does not support them.
- Large binary size may indicate the Emscripten filesystem (
-s FILESYSTEM=0 not set) or C++ RTTI/exceptions were not disabled.
