chore: add pre-commit configuration and CI

.codespellignore

@@ -0,0 +1,4 @@
+mor
+tok
+fpan
+dpan

.github/workflows/linter.yml

@@ -0,0 +1,31 @@
+#   Copyright 2026 Google LLC
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+name: Lint
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  pre-commit:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: actions/setup-python@v5
+      with:
+        python-version: '3.x'
+    - uses: pre-commit/action@v3.0.1

.gitignore

@@ -0,0 +1,4 @@
+node_modules/
+dist/
+.DS_Store
+*.log

.pre-commit-config.yaml

@@ -0,0 +1,42 @@
+#   Copyright 2026 Google LLC
+#
+#   Licensed under the Apache License, Version 2.0 (the "License");
+#   you may not use this file except in compliance with the License.
+#   You may obtain a copy of the License at
+#
+#       http://www.apache.org/licenses/LICENSE-2.0
+#
+#   Unless required by applicable law or agreed to in writing, software
+#   distributed under the License is distributed on an "AS IS" BASIS,
+#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#   See the License for the specific language governing permissions and
+#   limitations under the License.
+
+exclude: '^(\.github/|\.vscode/|node_modules/).*|CODE_OF_CONDUCT\.md|CHANGELOG\.md'
+
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v6.0.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+        args: [--unsafe]
+      - id: check-json
+      - id: check-added-large-files
+      - id: check-shebang-scripts-are-executable
+      - id: check-executables-have-shebangs
+  - repo: https://github.com/pre-commit/mirrors-prettier
+    rev: v4.0.0-alpha.8
+    hooks:
+      - id: prettier
+        files: \.(ts|js|json|md|yaml|yml|html)$
+  - repo: https://github.com/koalaman/shellcheck-precommit
+    rev: v0.10.0
+    hooks:
+      - id: shellcheck
+  - repo: https://github.com/codespell-project/codespell
+    rev: v2.4.1
+    hooks:
+      - id: codespell
+        args: ["--skip", "package-lock.json", "-I", ".codespellignore"]

.prettierrc

@@ -0,0 +1,8 @@
+{
+  "tabWidth": 2,
+  "useTabs": false,
+  "singleQuote": false,
+  "trailingComma": "es5",
+  "bracketSameLine": false,
+  "printWidth": 80
+}

README.md

@@ -45,10 +45,12 @@ This project uses `npm` for package management and `typescript` for building.
 
 ### Generating Models
 
-The models are automatically generated from the JSON schemas in the [UCP
-Specification](https://ucp.dev).
+The models are automatically generated from the JSON schemas in the
+[UCP Specification](https://ucp.dev).
 
-To regenerate the models, you first need a local copy of the [UCP specification](https://github.com/Universal-Commerce-Protocol/ucp). If you don't have one, you can clone it via:
+To regenerate the models, you first need a local copy of the
+[UCP specification](https://github.com/Universal-Commerce-Protocol/ucp). If you
+don't have one, you can clone it via:
 
 ```bash
 git clone https://github.com/Universal-Commerce-Protocol/ucp.git
@@ -71,7 +73,9 @@ npm run build
 
 ## Contributing
 
-We welcome community contributions. See our [Contribution Guide](https://github.com/Universal-Commerce-Protocol/.github/blob/main/CONTRIBUTING.md) for details.
+We welcome community contributions. See our
+[Contribution Guide](https://github.com/Universal-Commerce-Protocol/.github/blob/main/CONTRIBUTING.md)
+for details.
 
 ## License
 

src/extensions.ts

@@ -30,7 +30,7 @@ export const PlatformConfigSchema = z.object({
 export type PlatformConfig = z.infer<typeof PlatformConfigSchema>;
 
 export const ExtendedCheckoutResponseSchema = CheckoutResponseSchema.extend(
-  CheckoutWithFulfillmentResponseSchema.pick({ fulfillment: true }).shape,
+  CheckoutWithFulfillmentResponseSchema.pick({ fulfillment: true }).shape
 )
   .extend(CheckoutWithDiscountResponseSchema.pick({ discounts: true }).shape)
   .extend(CheckoutWithBuyerConsentResponseSchema.pick({ buyer: true }).shape)
@@ -45,29 +45,27 @@ export type ExtendedCheckoutResponse = z.infer<
 
 export const ExtendedCheckoutCreateRequestSchema =
   CheckoutCreateRequestSchema.extend(
-    CheckoutWithFulfillmentCreateRequestSchema.pick({ fulfillment: true })
-      .shape,
+    CheckoutWithFulfillmentCreateRequestSchema.pick({ fulfillment: true }).shape
   )
     .extend(
-      CheckoutWithDiscountCreateRequestSchema.pick({ discounts: true }).shape,
+      CheckoutWithDiscountCreateRequestSchema.pick({ discounts: true }).shape
     )
     .extend(
-      CheckoutWithBuyerConsentCreateRequestSchema.pick({ buyer: true }).shape,
+      CheckoutWithBuyerConsentCreateRequestSchema.pick({ buyer: true }).shape
     );
 export type ExtendedCheckoutCreateRequest = z.infer<
   typeof ExtendedCheckoutCreateRequestSchema
 >;
 
 export const ExtendedCheckoutUpdateRequestSchema =
   CheckoutUpdateRequestSchema.extend(
-    CheckoutWithFulfillmentUpdateRequestSchema.pick({ fulfillment: true })
-      .shape,
+    CheckoutWithFulfillmentUpdateRequestSchema.pick({ fulfillment: true }).shape
   )
     .extend(
-      CheckoutWithDiscountUpdateRequestSchema.pick({ discounts: true }).shape,
+      CheckoutWithDiscountUpdateRequestSchema.pick({ discounts: true }).shape
     )
     .extend(
-      CheckoutWithBuyerConsentUpdateRequestSchema.pick({ buyer: true }).shape,
+      CheckoutWithBuyerConsentUpdateRequestSchema.pick({ buyer: true }).shape
     );
 export type ExtendedCheckoutUpdateRequest = z.infer<
   typeof ExtendedCheckoutUpdateRequestSchema