Pi coding agent for Wasmer

Pi 0.87.1 uses published Edge.js, coreutils, fd, ripgrep, grep, sed, findutils and curl packages. Its command runs upstream's bundled CLI directly. Pi's JavaScript and package metadata are unchanged; the package contains no Bash adapter or embedded runtime/search-tool modules.

Dependency	Version	Purpose
wasmer/edgejs	=0.2.4	Node.js runtime, npm and pnpm
wasmer/bash	=1.0.25	Shell
wasmer/coreutils	=1.0.27	uutils commands including tail and nohup
wasmer/fd	=10.5.1	Pi's find tool
wasmer/ripgrep	=15.2.1	Pi's grep tool
wasmer/grep	=3.12.0	GNU grep for shell commands
wasmer/sed	=4.9.0	GNU sed for shell commands
wasmer/findutils	=0.10.1	uutils find, xargs, locate and updatedb
curl/curl	=8.4.0	HTTP/HTTPS requests and server checks

The tool packages are available on both wasmer.io and wasmer.wtf. Their source and reproducible build instructions live in wasix-org/fd, wasix-org/ripgrep, wasix-org/findutils, and wasix-org/coreutils. The existing GNU grep and sed packages are reused. Package license notices are mounted under /opt/<package>/licenses, leaving /usr available for command installation.

Use the published package

The package is published as wasmer/pi@0.87.1 on both wasmer.io and wasmer.wtf. The wasmer.sh and WasmerShell Pi examples load wasmer/pi@=0.87.1 from the registry; select Pi and run pi. No local package build is required to use either example.

Build from source

Install Node.js, npm and the Wasmer CLI, then run from the SDK repository root:

bash packages/pi/build.sh

The output is target/pi-0.87.1.webc. Pass another output path as the first argument to build.sh. To build directly into the browser example's assets:

bash packages/pi/build.sh wasmer-sh/public/packages/pi-0.87.1.webc

No Edge.js checkout or Rust build is required. Local WebC files are useful for package development; the browser and Swift example catalogs use the published registry package by default.

The build installs the locked Pi dependencies with lifecycle scripts disabled and omits native optional binaries. It then uses pinned optimize-deps@0.1.2 with NFT 1.11.0 to retain the conservative runtime layout from the size study. All provider and OAuth entrypoints, the public SDK runtime, extension support, image processing, themes, HTML export assets, docs, examples and license notices are preserved. Source maps and TypeScript declarations are omitted; runnable TypeScript examples remain.

Generated payloads live in .build/runtime and .build/licenses. .build/inventory.json records every retained runtime file's size and SHA-256; .build/build.json records optimizer versions and tracing warnings. The build verifies that retained files are byte-identical to the locked npm install. LICENSE.pi is the MIT license from upstream Pi's v0.87.1 tag.

Test and use

The SDK pins Wasmer's codex/pi-sdk-runtime integration at 5bd2b7d3182e816bd0ea330acc88e4e4733e167f. This includes the complete child-reaping fix (#6982), the filesystem timestamp fix, merged N-API fixes, exec signal ownership, corrected redirected stdio/socket-pair types, decoded Fetch response headers, and independent registration of package command aliases so an unavailable /usr/bin path does not break /bin/pi. It also includes missing-PID signal errors (#7045). Edge.js 0.2.4 handles detached spawning and signal errors in its native WASIX bindings, so no JavaScript preload is needed. A normal SDK build uses the pinned sources; WASMER_REPO is optional for local runtime development.

Both npm and pnpm invoke pnpm 10.34.5. Edge.js keeps real npm under edge-npm-internal for pnpm's delegated operations without recursing into the alias. To test:

WASMER_PI_SDK=/absolute/path/to/js/dist/node.js node packages/pi/test-sdk.mjs

The test loads only the Pi WebC, resolves its dependencies from the registry, checks the commands, search behavior, shell pipelines, curl, nohup, tail and nonblocking child waits, verifies shell launches with provider arguments, abort and timeout, then exercises all seven agent tools through pi with a local streaming model fixture. It uses no provider credentials or paid API calls. For the native CLI, set WASMER_BIN to a compatible Wasmer build and run node packages/pi/test.mjs.

The Bash tool runs without an adapter or NODE_OPTIONS preload. WASIX accepts detached: true as ordinary spawning; it does not create a Unix process group. Pi's cancellation falls back to terminating the immediate child, so descendant processes may remain. Use Restart to stop the entire sandbox.

In wasmer.sh, select Pi and run pi. Pi is ready from its WebC package, with the published runtime and tool dependencies. No npm installation or local pi-tools.webc is needed.

The example's browser regression is:

cd wasmer-sh
WASMER_EXAMPLE=pi npm run test:examples

Use /login inside Pi to connect an AI provider with a subscription or API key, then /model to choose a model. To expose all built-in tools, pass --tools read,write,edit,bash,grep,find,ls.

The size study documents remaining runtime limits: unbundled SDK JSON imports on the JavaScript N-API host, the experimental plugin bundler's native esbuild requirement, and tools such as Git that must be supplied by the surrounding environment. Moving fd and ripgrep to dependencies does not change those limits. The build and tests do not publish Pi.

To release the prepared package to both registries:

wasmer publish packages/pi --registry https://registry.wasmer.io/graphql --non-interactive --wait=container
wasmer publish packages/pi --registry https://registry.wasmer.wtf/graphql --non-interactive --wait=container

To test the published package instead of a local WebC:

node packages/pi/test-sdk.mjs wasmer/pi@=0.87.1

Runtime development

build-runtime.sh remains available for source work on Edge.js and the host. Set EDGEJS_REPO and WASMER_REPO to their source checkouts. The Pi package build itself uses the published Edge.js dependency.

The relevant runtime changes are Edge.js #155 and #156, libuv #15, Wasmer #7035, and N-API #76/#77. The standard WISP transport and released WASIX libc work with the example.