vanish

An autonomous, self-editing coding agent that runs entirely in your browser. One Rust crate compiled to WebAssembly. No server, no serverless functions, no runtime dependencies.

The agent edits this repository — its own source — and commits the result to GitHub.

How it works

The same wasm binary is loaded twice:

browser tab
├── main thread   boot_ui()      src/ui/       DOM only
│        ▲ Event          │ Command            typed by src/protocol.rs
└── web worker    boot_worker()  src/worker.rs
                  ├── src/agent/mod.rs      the loop — no deadline
                  ├── src/agent/llm.rs      OpenRouter, streamed
                  ├── src/agent/github.rs   blobs → tree → commit → ref
                  ├── src/agent/tools.rs    the tool surface
                  └── src/platform/opfs.rs  the working tree, on disk

The loop runs in a Web Worker, so it has no request bounding it and no execution deadline. The working tree lives in the Origin Private File System, so a write is durable the moment it happens — it survives the run, a reload, a crash, and a closed tab.

Both halves compile against src/protocol.rs, so a UI/logic mismatch is a build error rather than a blank page.

See ARCHITECTURE.md for why the previous serverless design failed and how each of its failure modes is now structurally impossible.

Tools

tool	effect
read_file	read from the working tree, falling back to GitHub on first touch
write_file	create or overwrite; durable immediately
edit_file	exact substring replacement; refuses ambiguous matches
list_dir	list the branch, flagging locally modified files
git_status	what differs from the last synced blob
git_commit	every modified file as one atomic commit
sync_repo	refresh the branch listing
task_complete	declare the work finished

There is no run_command. Nothing executes shell commands in a browser.

Running it

wasm-pack build --target web --out-dir web/pkg --no-typescript
cargo run --features devserver --bin serve      # http://localhost:8787

src/bin/serve.rs is std-only Rust and exists only because wasm modules and workers need correct MIME types over HTTP. It is never deployed — web/ is static files.

Credentials

There is no backend, so there is no sign-in. GitHub OAuth cannot work here: the code-for-token exchange needs a client secret, and a secret shipped to a browser is not secret. Instead, in the settings panel:

• OpenRouter API key — from openrouter.ai/keys
• GitHub token — a fine-grained PAT scoped to this repository with Contents: read and write

Both are stored in your browser's localStorage, never in the deployed bundle. Saving verifies each against the real service and reports which half failed.

Deployment

Vercel hosts web/ as static files and compiles the Rust at build time (build.sh). The wasm is deliberately not committed: this repository edits itself, so a checked-in artifact would never reflect the agent's own changes.

The running build is stamped with its commit. The UI polls the branch head and, when a newer build exists, shows the changelog and reloads itself — deferring while a run is in flight.

Conventions

Write code in the casing correct for its language. There is no case policy. An earlier version enforced lowercase globally, which corrupted every identifier the agent generated; see D6 in memory/TASKBOARD.md.