feat!: migrate the monorepo to Bun and Biome (#327)

* feat!: migrate the monorepo to Bun and Biome

Replace pnpm/Jest with Bun for install, test, and CI, keep Biome as
the linter/formatter, and publish ESM-only packages to npm via Changesets.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix: harden Bun migration for publishing and CI

Restore runtime metadata, hermetic test isolation, package-scoped coverage, and artifact checks so the ESM-only release remains reproducible and reviewable.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(mcp-server): preserve hex identifiers after migration

Accept canonical hexadecimal chain and block values, make mock resets order-independent, and enforce packed CLI checks without network-resolved tooling.

Co-authored-by: Cursor <cursoragent@cursor.com>

* fix(mcp-server): reject ambiguous numeric identifiers

Keep hex support without treating blanks or exponent notation as chain data, and harden direct execution and ESM build checks against future regressions.

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: alexander-sei

.changeset/migrate-monorepo-to-bun.md

@@ -0,0 +1,13 @@
+---
+"@sei-js/precompiles": major
+"@sei-js/registry": major
+"@sei-js/sei-global-wallet": major
+"@sei-js/mcp-server": major
+"@sei-js/create-sei": major
+---
+
+Migrate the monorepo to Bun and publish ESM-only packages.
+
+**Breaking:** all packages drop CommonJS (`require`) entry points and flatten `dist/`. Consumers must use ESM `import`. `@sei-js/precompiles` now ships an `exports` map with working `./ethers`, `./viem`, and `./precompiles` subpaths. `@sei-js/sei-global-wallet` keeps the `./solana` entrypoint.
+
+Install, build, and test with Bun (`bun install`, `bun run build`, `bun run test`). `@sei-js/mcp-server` now requires Node.js 20 or newer. The MCP server and precompiles development toolchain pin Viem to `2.37.2`, the last compatible release that includes `seiDevnet`. Generated apps target the new `@sei-js/precompiles` major. Packages continue to publish to npm via Changesets.

.github/workflows/checks.yml

@@ -1,6 +1,13 @@
 name: Checks
 
-on: [push]
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
 
 jobs:
   build:
@@ -9,27 +16,32 @@ jobs:
     steps:
       - uses: actions/checkout@v4
         with:
-          fetch-depth: 0 # Fetch the full history instead of a shallow clone
+          fetch-depth: 0
           submodules: recursive
 
-      - uses: actions/setup-node@v4
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v4
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: '1.3.14'
 
       - name: Install system dependencies
         run: sudo apt-get update && sudo apt-get install -y rsync
 
       - name: Install dependencies
-        run: pnpm install --frozen-lockfile
+        run: bun install --frozen-lockfile
+
+      - name: Lint, Format & Type Check
+        run: bun run check
 
       - name: Build All Packages
-        run: pnpm build:all
+        run: bun run build
 
       - name: Test
-        run: pnpm test:all
+        run: bun run test
 
       - name: Validate Published Packages
-        run: pnpm lint:pack:all
+        run: bun run lint:pack:all

.github/workflows/coverage.yml

@@ -2,49 +2,53 @@ name: Run & Upload Test Coverage
 
 on:
   push:
-    branches:
-      - main
+    branches: [main]
   pull_request:
-    branches:
-      - main
-      - feature/**
 
 jobs:
   run-tests:
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - package: precompiles
+            flag: precompiles
+          - package: registry
+            flag: registry
+          - package: sei-global-wallet
+            flag: sei-global-wallet
+          - package: mcp-server
+            flag: mcp-server
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          fetch-depth: 0 # Fetch the full history instead of a shallow clone
+          fetch-depth: 0
           submodules: recursive
-      - name: Use Node.js
+
+      - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
           node-version-file: '.nvmrc'
 
-      - uses: browser-actions/setup-chrome@v1
-      - run: chrome --version
-
-      - name: Install pnpm
-        uses: pnpm/action-setup@v4
-
-      - name: Install system dependencies
-        run: sudo apt-get update && sudo apt-get install -y rsync
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: '1.3.14'
 
       - name: Install dependencies
-        run: pnpm install --frozen-lockfile
-
-      - name: Build packages
-        run: pnpm build:all
+        run: bun install --frozen-lockfile
 
-      - name: Run Jest tests
-        run: pnpm test:coverage
+      - name: Run ${{ matrix.package }} tests with coverage
+        run: bun test --isolate --coverage --coverage-reporter=lcov --coverage-dir=coverage/${{ matrix.flag }} packages/${{ matrix.package }}/src
 
-      - name: Upload coverage reports to Codecov
+      - name: Upload ${{ matrix.package }} coverage to Codecov
         uses: codecov/codecov-action@v4
         with:
-          files: '**/coverage-final.json'
+          files: coverage/${{ matrix.flag }}/lcov.info
+          flags: ${{ matrix.flag }}
+          name: ${{ matrix.flag }}
+          disable_search: true
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true

.github/workflows/release.yml

@@ -26,29 +26,29 @@ jobs:
       - name: Setup Node.js (for npm OIDC publishing)
         uses: actions/setup-node@v4
         with:
-          node-version: '24'
+          node-version-file: '.nvmrc'
           registry-url: 'https://registry.npmjs.org'
 
-      - name: Install pnpm
-        uses: pnpm/action-setup@v4
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: '1.3.14'
 
       - name: Install system dependencies
         run: sudo apt-get update && sudo apt-get install -y rsync
 
       - name: Install Dependencies
-        run: pnpm install --frozen-lockfile
+        run: bun install --frozen-lockfile
 
       - name: Build Packages
-        run: pnpm build:all
+        run: bun run build
 
       - name: Validate Published Packages
-        run: pnpm lint:pack:all
+        run: bun run lint:pack:all
 
       - name: Create Release Pull Request or Publish to npm
         id: changesets
         uses: changesets/action@v1
         with:
-          # Release builds the packages and calls changeset publish
-          publish: pnpm release
+          publish: bun run release
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -2,6 +2,7 @@
 
 # testing
 packages/*/coverage
+packages/*/coverage.json
 
 examples/
 

.nvmrc

@@ -1 +1 @@
-v20
+24

README.md

@@ -6,31 +6,39 @@ SeiJS is a monorepo that contains multiple NPM libraries for writing application
 
 SeiJS consists of smaller NPM packages within the @sei-js namespace. See the package READMEs below for usage details.
 
-| Package                                                 | Description                                                                                                                     |
-|---------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------|
-| [@sei-js/precompiles](packages/precompiles)             | Typescript library containing helper functions for interacting with Sei's precompile contracts.                                  |
-| [@sei-js/create-sei](packages/create-sei)               | CLI Tool used to quickly spin up Sei Projects and dApps in either the cosmos or EVM ecosystem                                   |
-| [@sei-js/mcp-server](packages/mcp-server)               | MCP server for interacting with Sei via LLM's and agents                                                                        |
-| [@sei-js/sei-global-wallet](packages/sei-global-wallet) | A global wallet conforming to EIP-6963 allowing for AA across dApps.                                                            |
+| Package                                                 | Description                                                                                                                    |
+| ------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ |
+| [@sei-js/precompiles](packages/precompiles)             | Typescript library containing helper functions for interacting with Sei's precompile contracts.                                |
+| [@sei-js/create-sei](packages/create-sei)               | CLI Tool used to quickly spin up Sei Projects and dApps in either the cosmos or EVM ecosystem                                  |
+| [@sei-js/mcp-server](packages/mcp-server)               | MCP server for interacting with Sei via LLM's and agents                                                                       |
+| [@sei-js/sei-global-wallet](packages/sei-global-wallet) | A global wallet conforming to EIP-6963 allowing for AA across dApps.                                                           |
+| [@sei-js/registry](packages/registry)                   | TypeScript library for Sei chain constants and assets.                                                                         |
 
 ## Development
 
+This project uses [Bun](https://bun.sh) for package management, tests, and scripts. Packages are still published to npm as ESM-only libraries.
+
 ### Prerequisites
 
-This project uses Yarn 4.7.0 with Corepack for package management. To get started:
+Install Bun 1.3.14: https://bun.sh/docs/installation
+
+Node.js 24 is pinned in `.nvmrc` for npm package validation and OIDC publishing; Bun remains the workspace package manager and test runner.
+
+### Install, build, test
 
-1. **Enable Corepack** (if not already enabled):
-   ```bash
-   corepack enable
-   ```
+```bash
+git submodule update --init --recursive
+bun install
+bun run build
+bun run test
+```
 
-2. **Install dependencies**:
-   ```bash
-   yarn install
-   ```
+Lint and format with Biome:
 
-The correct Yarn version will be automatically used thanks to the `packageManager` field in `package.json` and Corepack.
+```bash
+bun run check
+```
 
-### Building
+### Publishing
 
-To build all packages, run `pnpm install` then `pnpm build:all`
+Releases still go through Changesets and publish to npm (OIDC). Merging to `main` opens a Version Packages PR; merging that publishes.

REVIEW.md

@@ -1,7 +1,7 @@
 # Review guidelines for AI agents
 
 Repo-specific conventions for automated PR review (Codex, Cursor, Claude, and
-any other AI reviewer). This is a pnpm workspace that publishes five
+any other AI reviewer). This is a Bun workspace that publishes five
 independently versioned `@sei-js/*` packages to npm, so a defect ships to every
 downstream dApp that upgrades rather than to a single deployment we control.
 Calibrate accordingly: a wrong precompile address or a weakened wallet guard is
@@ -59,10 +59,9 @@ the code without releasing it, which is the common miss on this repo.
 Ask for a changeset when a published package's behaviour, types, or
 dependencies change. Docs-only, CI-only, and changes confined to
 `packages/create-sei/templates/**` generally don't need one, though the repo
-has deliberately added patch changesets across all six packages for
-release-note visibility (the `@asyncapi` pinning in `pnpm.overrides` is the
-precedent). Absence of a changeset on that kind of PR is a question, not a
-defect.
+has deliberately added patch changesets across all five packages for
+release-note visibility. Absence of a changeset on that kind of PR is a
+question, not a defect.
 
 ## 4. Known non-issues — do not flag these
 
@@ -88,22 +87,22 @@ defect.
   `submodules: recursive`; local source builds must initialize them explicitly.
   Their JSON is vendored upstream — review the TypeScript wrappers, not the
   data.
-- **Biome findings are not enforced anywhere.** `biome.json` configures tabs,
-  160-column lines, single quotes and no trailing commas, but no package
-  defines a `biome` script and `.github/workflows/checks.yml` runs only
-  `pnpm build:all` and `pnpm test:all`. Match the surrounding style; do not
-  file formatting-only findings as blocking.
+- **Biome is enforced in CI.** `bun run check` runs in `.github/workflows/checks.yml`
+  with tabs, 160-column lines, single quotes and no trailing commas. Match that
+  style; formatting-only findings that `biome check` already catches do not
+  need a separate review comment.
 - **Test file naming is inconsistent across packages.** `mcp-server` and
   `create-sei` use `*.test.ts`; `precompiles`, `registry` and
   `sei-global-wallet` use `*.spec.ts` under `__tests__/`. Follow the
   convention of the package being changed rather than proposing a repo-wide
   rename.
-- **`mcp-server` has no Codecov target.** `codecov.yml` defines 80% project
-  targets for the other four packages only. Thin coverage on an mcp-server PR
-  is worth mentioning on its merits, but it does not fail a gate.
+- **`mcp-server` and `create-sei` have no Codecov target.** `codecov.yml`
+  defines 80% project targets for the three library packages with meaningful
+  source coverage. Thin coverage elsewhere is worth mentioning on its merits,
+  but it does not fail a gate.
 - **`noImplicitAny: false` in `tsconfig.base.json`.** This is a deliberate
   repo-wide setting. Flag an untyped value when it actually causes an unsound
   path, not because the compiler permitted it.
-- **The `create-sei` templates are excluded from the root Biome config** and
-  carry their own toolchain. Do not apply root formatting rules to anything
-  under `packages/create-sei/templates/`.
+- **The `create-sei` templates and extensions are excluded from the root Biome
+  config** and carry their own toolchain. Do not apply root formatting rules to
+  scaffold sources under `packages/create-sei/{templates,extensions}/`.

biome.json

@@ -1,26 +1,33 @@
 {
-	"$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
+	"$schema": "https://biomejs.dev/schemas/2.5.8/schema.json",
 	"vcs": {
-		"enabled": false,
+		"enabled": true,
 		"clientKind": "git",
-		"useIgnoreFile": false
+		"useIgnoreFile": true
 	},
 	"files": {
 		"ignoreUnknown": false,
-		"ignore": ["*/coverage/*", "*/dist/*", "packages/create-sei/templates/**"]
+		"includes": [
+			"**",
+			"!**/coverage",
+			"!**/dist",
+			"!**/node_modules",
+			"!**/bun.lock",
+			"!packages/create-sei/templates",
+			"!packages/create-sei/extensions",
+			"!packages/registry/chain-registry",
+			"!packages/registry/community-assetlist"
+		]
 	},
 	"formatter": {
 		"enabled": true,
 		"indentStyle": "tab",
 		"lineWidth": 160
 	},
-	"organizeImports": {
-		"enabled": true
-	},
 	"linter": {
 		"enabled": true,
 		"rules": {
-			"recommended": true,
+			"preset": "recommended",
 			"correctness": {
 				"useExhaustiveDependencies": "off"
 			},
@@ -35,5 +42,32 @@
 			"jsxQuoteStyle": "double",
 			"trailingCommas": "none"
 		}
-	}
+	},
+	"assist": {
+		"actions": {
+			"source": {
+				"organizeImports": "on"
+			}
+		}
+	},
+	"overrides": [
+		{
+			"includes": ["**/*.test.ts", "**/*.spec.ts", "**/__tests__/**", "**/tests/**"],
+			"linter": {
+				"rules": {
+					"suspicious": {
+						"noExplicitAny": "off"
+					},
+					"style": {
+						"noNonNullAssertion": "off"
+					},
+					"correctness": {
+						"noUnusedFunctionParameters": "off",
+						"noUnusedImports": "off",
+						"noUnusedVariables": "off"
+					}
+				}
+			}
+		}
+	]
 }