[cooper (czxtm)]

Summary

Adds a Cloudflare Worker written in Rust with workers-rs, deployed by the existing Alchemy stack. Alchemy does not compile Rust, so a Command.Build runs worker-build first and a bundle: false Worker uploads its output.

 crates/
 ├── alloy-web3-example/
+└── cloudflare-worker-example/   # workers-rs crate: GET / -> GREETING var, GET /artifacts -> R2 list
 packages/infra/
 ├── alchemy.run.ts               # + yield RustCloudflareWorker, output rustCloudflareWorkerUrl
 └── src/
+    └── rust-cloudflare-worker.ts # Command.Build(worker-build) -> Cloudflare.Worker(bundle: false)
 nix/flake/devShells/default.nix  # + pkgs.worker-build, pkgs.lld

alchemy deploy
  RustCloudflareWorkerBuild   worker-build --release in crates/cloudflare-worker-example
                    skipped when src/, crate + workspace Cargo.toml, Cargo.lock, .cargo/config.toml are unchanged
  RustCloudflareWorker        main = build.outdir/index.js, uploads index.js + index_bg.wasm
                    env: ARTIFACTS (the stack's R2 bucket), GREETING

The crate is a Cargo workspace member, so host cargo check/test --workspace covers it. It sets rust-version = "1.88" because workers-rs 0.8 pulls in wasm-streams 0.6.

Reference docs for the team: darkmatter/skills#20 (Alchemy skill, examples.md).

Evidence

Live on Cloudflare (Alchemy 2.0.0-beta.81, throwaway stages, destroyed after):

• First deploy: RustWorkerBuild created, then RustWorker created; GET / returned the greeting, GET /artifacts listed an object uploaded to the R2 bucket.
• Redeploy with no changes: RustWorkerBuild noop, RustWorker noop.
• Rust source edit: build updated, Worker updated, response showed the new text.
• Root Cargo.toml edit: RustWorkerBuild updated, RustWorker updated — Uploading worker (196.57 KB).
• alchemy dev: Worker served on localhost:1337 and reloaded after a manual worker-build --release.
• Destroy: Cloudflare API shows no leftover Workers, R2 buckets, D1 databases, or queues for the stages.

Checks in the Nix devshell, all exit 0: bun run check, bun run test, bun run lint, bun run fmt:check, cargo check --workspace, cargo test --workspace, cargo fmt --all -- --check, nix flake check.

Merge Danger

Door: two-way

Revert removes the crate, the stack entry, and the devshell packages.

Blast Radius: deploys

Every alchemy deploy/alchemy dev of packages/infra now creates this Worker and needs worker-build, the wasm32 std, and lld whenever the build runs. The Nix devshell provides them; a non-Nix machine does not. GitHub CI is unaffected: it runs no Alchemy and only builds the crate for the host on stable Rust.

[linear-code]

ENG-1227