across-protocol · grasphoper · Mar 21, 2026 · Mar 21, 2026 · Mar 21, 2026 · Mar 21, 2026
diff --git a/.eslintrc.cjs b/.eslintrc.cjs
@@ -11,6 +11,15 @@ module.exports = {
   parserOptions: {
     ecmaVersion: 12,
   },
+  overrides: [
+    {
+      files: ["scripts/**/*.mjs"],
+      rules: {
+        "node/no-unsupported-features/es-builtins": ["error", { version: ">=16.0.0" }],
+        "node/no-unsupported-features/node-builtins": ["error", { version: ">=16.0.0" }],
+      },
+    },
+  ],
   rules: {
     "node/no-unsupported-features/es-syntax": ["error", { ignores: ["modules"] }],
     "@typescript-eslint/no-var-requires": 0,

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -0,0 +1,36 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [master]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v3
+        with:
+          node-version: "22.18.0"
+
+      - name: Install dependencies
+        run: yarn install --frozen-lockfile
+
+      - name: Lint
+        run: yarn lint
+
+      - name: Build
+        run: yarn build
+
+      - name: Verify legacy equivalence
+        run: yarn verify:legacy-equivalence
+
+      - name: Verify generated files are up to date
+        run: |
+          if ! git diff --exit-code src/; then
+            echo "::error::Generated files are out of date. Run 'yarn build' and commit the result."
+            git diff src/
+            exit 1
+          fi
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
@@ -41,6 +41,9 @@ jobs:
       - name: Build
         run: yarn build
 
+      - name: Verify legacy equivalence
+        run: yarn verify:legacy-equivalence
+
       - name: Update npm
         run: npm install -g npm@latest
 
@@ -74,4 +77,4 @@ jobs:
 
       - name: Publish tagged version
         if: steps.release.outputs.tag != ''
-        run: npm publish --tag ${{ steps.release.outputs.tag }}
+        run: npm publish --tag ${{ steps.release.outputs.tag }}
diff --git a/.prettierrc b/.prettierrc
@@ -1,7 +1,6 @@
 {
   "printWidth": 120,
   "bracketSpacing": true,
-  "explicitTypes": "preserve",
   "tabWidth": 2,
   "overrides": [
     {

diff --git a/AGENTS.md b/AGENTS.md
@@ -5,74 +5,124 @@ This repository contains `@across-protocol/constants` — a shared library expor
 ## How to use docs in this repo
 
 1. This file (`AGENTS.md`) for navigation and conventions.
-2. `src/index.ts` re-exports everything from `networks.ts` and `tokens.ts`.
+2. `data/constants.v1.json` is the canonical source of truth.
+3. `schema/constants.v1.schema.json` defines the canonical JSON contract.
+4. `src/index.ts` re-exports the backward-compatible legacy TypeScript surface.
+5. `src/canonical.ts` exposes the canonical TypeScript wrapper.
 
 ## Documentation maintenance
 
-Update this `AGENTS.md` when new source files are added or the build/publish process changes.
+Update this `AGENTS.md` when the source-of-truth files, generation flow, or publish process changes.
 
 ## Quick index
 
-- Entry point: `src/index.ts`
-- Network/chain definitions: `src/networks.ts`
-- Token mappings and metadata: `src/tokens.ts`
-- Build output: `dist/` (cjs, esm, types)
+- Canonical source data: `data/constants.v1.json`
+- Canonical schema: `schema/constants.v1.schema.json`
+- Legacy package entry point: `src/index.ts`
+- Canonical TS wrapper: `src/canonical.ts`
+- Generated canonical TS types: `src/generated/canonical-types.ts`
+- Generated canonical TS runtime module: `src/generated/constants.v1.ts`
+- Generated legacy networks: `src/networks.ts`
+- Generated legacy tokens: `src/tokens.ts`
+- Validation script: `scripts/validate-canonical.mjs`
+- Canonical runtime generator: `scripts/generate-canonical-module.mjs`
+- Legacy generator: `scripts/generate-legacy.mjs`
+- Upstream equivalence check: `scripts/verify-legacy-equivalence.mjs`
+- Build output: `dist/`
+- CI workflow: `.github/workflows/ci.yml`
 - Publish workflow: `.github/workflows/publish.yml`
 
 ## Source files
 
-| File              | Purpose            | Key exports                                                                                    |
-| ----------------- | ------------------ | ---------------------------------------------------------------------------------------------- |
-| `src/index.ts`    | Barrel re-export   | Re-exports `networks` and `tokens`                                                             |
-| `src/networks.ts` | Chain ID constants | Testnet and mainnet chain IDs, chain metadata (~620 lines)                                     |
-| `src/tokens.ts`   | Token definitions  | `TOKEN_SYMBOLS_MAP` with name, symbol, decimals, per-chain addresses, coingeckoId (~730 lines) |
+| File                                    | Purpose                                      | Key exports / outputs                                     |
+| --------------------------------------- | -------------------------------------------- | --------------------------------------------------------- |
+| `data/constants.v1.json`                | Canonical source of truth                    | Chains, networks, tokens, token equivalence mappings      |
+| `schema/constants.v1.schema.json`       | Canonical JSON Schema                        | Structural contract for canonical data                    |
+| `src/index.ts`                          | Barrel re-export                             | Re-exports legacy `networks` and `tokens`                 |
+| `src/canonical.ts`                      | Canonical TypeScript wrapper                 | `CONSTANTS_V1` and canonical TS type exports              |
+| `src/generated/canonical-types.ts`      | Generated canonical TS types                 | Schema-derived canonical interfaces and unions            |
+| `src/generated/constants.v1.ts`         | Generated canonical TS runtime module        | Runtime value backing `src/canonical.ts`                  |
+| `src/networks.ts`                       | Generated legacy chain/network definitions   | Legacy chain IDs, enum, network maps                      |
+| `src/tokens.ts`                         | Generated legacy token definitions           | Legacy token metadata map and token equivalence remapping |
+| `scripts/validate-canonical.mjs`        | Canonical validation                         | AJV schema validation plus semantic invariants            |
+| `scripts/generate-canonical-module.mjs` | Canonical JSON -> TS runtime generator       | Regenerates `src/generated/constants.v1.ts`               |
+| `scripts/generate-legacy.mjs`           | Canonical -> legacy TS generator             | Regenerates `src/networks.ts` and `src/tokens.ts`         |
+| `scripts/verify-legacy-equivalence.mjs` | Local vs upstream legacy compatibility check | Verifies built root exports match pinned upstream package |
 
 ## Directory tree
 
 ```text
-constants/
+json-constants/
+├── data/
+│   └── constants.v1.json
+├── schema/
+│   └── constants.v1.schema.json
 ├── src/
-│   ├── index.ts                      # Barrel export
-│   ├── networks.ts                   # Chain/network definitions
-│   └── tokens.ts                     # Token metadata and addresses
-├── dist/                             # Build output (generated)
-│   ├── cjs/                          # CommonJS build
-│   ├── esm/                          # ES Modules build
-│   └── types/                        # TypeScript declarations
-├── package.json                      # @across-protocol/constants, Yarn
-├── tsconfig.json                     # TypeScript config (strict, ES5 target)
-├── .eslintrc.cjs                     # ESLint config
-├── .prettierrc                       # Prettier (120 printWidth)
-└── .github/workflows/publish.yml     # NPM publish on GitHub release
+│   ├── canonical.ts
+│   ├── generated/
+│   │   ├── constants.v1.ts
+│   │   └── canonical-types.ts
+│   ├── index.ts
+│   ├── networks.ts
+│   └── tokens.ts
+├── scripts/
+│   ├── generate-canonical-module.mjs
+│   ├── generate-legacy.mjs
+│   ├── validate-canonical.mjs
+│   └── verify-legacy-equivalence.mjs
+├── dist/
+│   ├── cjs/
+│   ├── esm/
+│   └── types/
+├── package.json
+├── tsconfig.json
+├── .eslintrc.cjs
+├── .prettierrc
+└── .github/workflows/
+    ├── ci.yml
+    └── publish.yml
 ```
 
 ## Build and test
 
 ```bash
-# Build (CJS + ESM + types)
+# Build generated sources and package outputs
 yarn build
 
 # Lint
 yarn lint
 
-# Auto-fix
-yarn lint-fix
+# Compare built legacy exports to the pinned upstream package
+yarn verify:legacy-equivalence
 ```
 
-There are no tests — this is a pure data library.
+There are no application tests. The important verification gate is `verify:legacy-equivalence`, which ensures the generated legacy API matches the published upstream legacy package.
 
-## Adding new tokens or networks
+## Updating constants
 
-1. **New network**: Add chain ID constant to `src/networks.ts`.
-2. **New token**: Add entry to `TOKEN_SYMBOLS_MAP` in `src/tokens.ts` with name, symbol, decimals, per-chain addresses, and coingeckoId.
-3. Run `yarn lint-fix` and `yarn build` to verify.
+For normal constant additions or value changes, edit only `data/constants.v1.json`.
+
+Update `schema/constants.v1.schema.json` only when the shape changes, for example a new field, a type change, or a new enum value.
+
+Recommended flow:
+
+1. Edit `data/constants.v1.json`.
+2. If the shape changed, update `schema/constants.v1.schema.json`.
+3. Run `yarn build`.
+4. Run `yarn verify:legacy-equivalence`.
+
+Do not edit `src/generated/canonical-types.ts`, `src/generated/constants.v1.ts`, `src/networks.ts`, or `src/tokens.ts` by hand.
 
 ## Publish process
 
 - Published to npm via GitHub Actions on GitHub release.
-- Workflow validates semver, builds, and publishes with OIDC trusted publishing.
-- Pre-release versions supported for beta/canary tags.
+- `yarn build` validates canonical data, regenerates canonical and legacy TypeScript sources, and builds package outputs.
+- Canonical JSON and schema are published as package artifacts.
+- The root package API remains the legacy TypeScript surface for backward compatibility.
+- The `./canonical` export exposes the canonical TypeScript wrapper.
 
 ## Consumers
 
-This package is consumed by: relayer, indexer, frontend, and toolkit.
+- Existing TypeScript consumers should continue using the root package exports.
+- TypeScript consumers that want the language-agnostic shape can use `@across-protocol/constants/canonical`.
+- Non-TypeScript consumers should consume `data/constants.v1.json` against `schema/constants.v1.schema.json`.
diff --git a/README.md b/README.md
@@ -4,6 +4,14 @@
 
 Shared library exporting network, token, and address definitions used across the Across Protocol ecosystem.
 
+This package now has two public surfaces:
+
+- The root package, `@across-protocol/constants`, which preserves the existing TypeScript legacy API.
+- A canonical language-agnostic contract consisting of:
+  - `data/constants.v1.json`
+  - `schema/constants.v1.schema.json`
+  - `@across-protocol/constants/canonical`
+
 ## Installation
 
 ```bash
@@ -16,44 +24,79 @@ yarn add @across-protocol/constants
 
 ## Usage
 
-```typescript
-import { TOKEN_SYMBOLS_MAP } from "@across-protocol/constants";
+Legacy TypeScript surface:
+
+```ts
+import { TOKEN_SYMBOLS_MAP } from "@across-protocol/constants"
+
+const usdc = TOKEN_SYMBOLS_MAP.USDC
+console.log(usdc.decimals)
+console.log(usdc.addresses[1])
+```
+
+Canonical TypeScript surface:
 
-// Access token metadata
-const usdc = TOKEN_SYMBOLS_MAP.USDC;
-console.log(usdc.decimals); // 6
-console.log(usdc.addresses[1]); // Ethereum mainnet address
+```ts
+import { CONSTANTS_V1 } from "@across-protocol/constants/canonical"
+
+const mainnet = CONSTANTS_V1.networks.find((network) => network.chainId === 1)
+console.log(mainnet?.name)
 ```
 
-## What's Exported
+## Package Layout
+
+| Surface                                | Description                                        |
+| -------------------------------------- | -------------------------------------------------- |
+| `@across-protocol/constants`           | Backward-compatible legacy TypeScript exports      |
+| `@across-protocol/constants/canonical` | Canonical TypeScript wrapper around canonical JSON |
+| `data/constants.v1.json`               | Canonical source of truth                          |
+| `schema/constants.v1.schema.json`      | Canonical JSON Schema                              |
 
-| Module | Description |
-|--------|-------------|
-| `networks` | Chain ID constants for testnets and mainnets, chain metadata |
-| `tokens` | `TOKEN_SYMBOLS_MAP` — token name, symbol, decimals, per-chain addresses, coingeckoId |
+The canonical JSON is the source of truth. The legacy root TypeScript exports are generated from it during `yarn build`.
 
 ## Development
 
 ```bash
-# Build (CJS + ESM + TypeScript declarations)
+# Build generated sources and package outputs
 yarn build
 
 # Lint
 yarn lint
 
-# Auto-fix lint issues
-yarn lint-fix
+# Check canonical data against the published upstream legacy package
+yarn verify:legacy-equivalence
 ```
 
-## Adding Tokens or Networks
+## Updating Constants
+
+Most updates only require editing `data/constants.v1.json`.
+
+Edit `schema/constants.v1.schema.json` only when the shape changes, for example:
+
+- adding a new field
+- changing a field type
+- adding a new enum value
+- making a required field optional, or the reverse
+
+Typical update flow:
+
+1. Edit `data/constants.v1.json`.
+2. If the data shape changed, update `schema/constants.v1.schema.json`.
+3. Run `yarn build`.
+4. Run `yarn verify:legacy-equivalence`.
+
+Do not edit generated files in `src/generated/`, `src/networks.ts`, or `src/tokens.ts` by hand.
+
+## Validation And Generation
 
-1. **New network**: Add chain ID constant to `src/networks.ts`.
-2. **New token**: Add entry to `TOKEN_SYMBOLS_MAP` in `src/tokens.ts`.
-3. Run `yarn lint-fix && yarn build` to verify.
+- Canonical JSON is validated with `ajv`.
+- Canonical TypeScript types are generated from JSON Schema with `json-schema-to-typescript`.
+- The canonical TypeScript runtime module is generated from `data/constants.v1.json`.
+- Legacy TypeScript exports are generated from canonical JSON by `scripts/generate-legacy.mjs`.
 
 ## Publishing
 
-Published to npm automatically via GitHub Actions on [GitHub release](https://github.com/across-protocol/constants/releases). Supports pre-release versions for beta/canary tags.
+Published to npm automatically via GitHub Actions on [GitHub release](https://github.com/across-protocol/json-constants/releases). Pre-release versions are supported for beta/canary tags.
 
 ## License