# Wasm Pack Build

> Opinionated wasm-pack wrapper that builds a Rust crate to wasm32-unknown-unknown with project-pinned flags (SIMD, LTO, panic=abort), applies a wasm-opt post-pass, and auto-invokes wasm-module-inspect on the result. Single entry point so the agent never reaches for raw wasm-pack and forgets a flag.

- **Type:** Skill
- **Install:** `agentstack add skill-gertsylvest-meta-team-wasm-pack-build`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [gertsylvest](https://agentstack.voostack.com/s/gertsylvest)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [gertsylvest](https://github.com/gertsylvest)
- **Source:** https://github.com/gertsylvest/meta-team/tree/main/library/skills/wasm-pack-build

## Install

```sh
agentstack add skill-gertsylvest-meta-team-wasm-pack-build
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# wasm-pack Build

The canonical Rust→WASM build path for browser audio. Builds with `wasm-pack` against `wasm32-unknown-unknown`, applies `wasm-opt` for size and performance, and runs `wasm-module-inspect` on the output to confirm exports are minimal, SIMD is present, and the module validates.

The flag set is fixed by this skill so every Rust WASM build in the project produces a binary with the same characteristics — no ad-hoc differences between developer machines or CI.

## Requirements

- **rustup** with stable toolchain and the `wasm32-unknown-unknown` target:
  ```bash
  rustup target add wasm32-unknown-unknown
  ```
- **wasm-pack** — install via `cargo install wasm-pack` or from https://rustwasm.github.io/wasm-pack/installer/.
- **wasm-opt** (Binaryen) — install via `brew install binaryen` (macOS) or `apt install binaryen` (Linux).
- The `wasm-module-inspect` skill from this library (the script invokes it for the final verification step).

## What it does

1. Verifies prerequisites (`wasm-pack`, `wasm-opt`, target installed).
2. Sets `RUSTFLAGS="-C target-feature=+simd128"` so WASM SIMD is enabled.
3. Runs `wasm-pack build --target web --release` (or `--dev` if `--dev` is passed) on the crate.
4. Runs `wasm-opt -O3 --enable-simd /_bg.wasm -o ` to apply Binaryen's optimisation pass over the wasm-bindgen-emitted module.
5. Invokes `wasm-module-inspect` on the optimised `.wasm`.

Release builds also implicitly use the project's `[profile.release]` settings — the crate is expected to declare `panic = "abort"`, `lto = "fat"`, `codegen-units = 1`, `opt-level = 3` per the rust-audio-engineer agent's standards.

## Instructions

The arguments are in `$ARGUMENTS`. Pass them directly to the build script:

```bash
bash "$(dirname "$0")/build.sh" $ARGUMENTS
```

Argument 1 is the crate directory. Optional second argument `--dev` switches to a debug build with source maps for browser debugging.

## Output sections

| Section | What it reports |
|---|---|
| `PREREQ` | Whether wasm-pack, wasm-opt, and the wasm32 target are present |
| `BUILD` | wasm-pack invocation result |
| `OPTIMISE` | wasm-opt size reduction |
| `INSPECT` | Full output of `wasm-module-inspect` |

## Typical usage

```bash
# Release build
bash build.sh ./rust/audio-wasm

# Debug build with DWARF source maps for browser debugging
bash build.sh ./rust/audio-wasm --dev
```

## What to look for

- **`PREREQ` failing** — the script tells you exactly what to install.
- **`BUILD` failing** — usually a Rust compile error or a missing `[lib] crate-type = ["cdylib", "rlib"]` in the crate's `Cargo.toml`.
- **`OPTIMISE` showing no size reduction** — wasm-opt may not have anything to do if wasm-pack already optimised aggressively, or LTO already collapsed the dead code. Not necessarily a problem.
- **`INSPECT` showing unexpected exports** — review the `#[wasm_bindgen]` and `#[no_mangle] extern "C"` exports in the Rust source. The worklet should only see the minimal API surface (`init`, `process`, `destroy`, and any control-plane functions).
- **`INSPECT` showing no SIMD** despite a release build — `RUSTFLAGS` did not propagate. Check that the script ran in an environment where it can set env vars, and check the crate does not override `RUSTFLAGS` via `.cargo/config.toml` in a conflicting way.

## Why a wrapper instead of raw wasm-pack

The flag set matters: `+simd128`, `--target web`, the wasm-opt post-pass, and the inspect step are all easy to forget individually. A wrapper makes the build reproducible across the team and CI without each caller having to remember the recipe.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [gertsylvest](https://github.com/gertsylvest)
- **Source:** [gertsylvest/meta-team](https://github.com/gertsylvest/meta-team)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-gertsylvest-meta-team-wasm-pack-build
- Seller: https://agentstack.voostack.com/s/gertsylvest
- Browse the marketplace: https://agentstack.voostack.com/browse

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