diff --git a/.github/workflows/use-action.yaml b/.github/workflows/use-action.yaml
index 5fdd517..b3e01d6 100644
--- a/.github/workflows/use-action.yaml
+++ b/.github/workflows/use-action.yaml
@@ -18,15 +18,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Read service account key
-        id: sa-key
-        run: echo "content=$(cat github-actions-metrics-key.json | jq -c)" >> $GITHUB_OUTPUT
-
       - uses: ./
         with:
           github-token: ${{ github.token }}
           gcp-project-id: jason-chainguard
-          gcp-service-account-key: ${{ steps.sa-key.outputs.content }}
+          gcp-service-account-key-file: github-actions-metrics-key.json
 
       - uses: actions/setup-node@v4
         with:
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
new file mode 100644
index 0000000..05ea400
--- /dev/null
+++ b/.pre-commit-config.yaml
@@ -0,0 +1,16 @@
+repos:
+  - repo: local
+    hooks:
+      - id: npm-test
+        name: Run npm test
+        entry: npm test
+        language: system
+        pass_filenames: false
+        stages: [commit]
+
+      - id: npm-build
+        name: Run npm build
+        entry: npm run build
+        language: system
+        pass_filenames: false
+        stages: [commit]
diff --git a/README.md b/README.md
index 6e3c0d4..ebfc01a 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,11 @@ gcloud iam service-accounts keys create github-actions-metrics-key.json \
   --iam-account="github-actions-metrics@${PROJECT_ID}.iam.gserviceaccount.com"
 ```
 
-### 2. Add Service Account Key to GitHub Secrets
+### 2. Add Service Account Key to GitHub
+
+You have two options:
+
+**Option A: Use GitHub Secrets (Recommended for production)**
 
 1. Copy the contents of the JSON key file:
    ```bash
@@ -64,9 +68,34 @@ gcloud iam service-accounts keys create github-actions-metrics-key.json \
    rm github-actions-metrics-key.json
    ```
 
+**Option B: Commit the key file (For testing/demo only)**
+
+If you're testing in a personal repository, you can commit the key file directly:
+
+```bash
+git add github-actions-metrics-key.json
+git commit -m "Add service account key for metrics"
+git push
+```
+
+**⚠️ Warning:** Only do this in private repositories for testing. For production, always use secrets.
+
 ## Usage
 
-### Basic Usage
+### Authentication Methods
+
+This action supports two authentication methods:
+
+| Method | Best For | Works With | Setup Complexity |
+|--------|----------|------------|------------------|
+| **Service Account Key File** | Testing, forks, `pull_request` events | All workflow events | Simple - just create and store a key |
+| **Workload Identity Federation** | Production, security-conscious | `push`, `pull_request_target` only | Moderate - requires WIF setup |
+
+**Quick Decision:**
+- Using `pull_request` from forks? → **Use Service Account Key File**
+- Production workflows on `push`? → **Use Workload Identity Federation**
+
+### Basic Usage (with Service Account Key File)
 
 Add the action as one of the first steps in your workflow. The action will automatically collect metrics in a post-action phase after all other steps complete.
 
@@ -80,16 +109,22 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      # Checkout first
+      - uses: actions/checkout@v4
+
+      # Write secret to file
+      - name: Setup GCP credentials
+        run: echo '${{ secrets.GCP_SERVICE_ACCOUNT_KEY }}' > /tmp/gcp-key.json
+
       # Enable metrics collection
       - name: Setup OpenTelemetry Metrics
         uses: your-org/otel-action@v1
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           gcp-project-id: ${{ secrets.GCP_PROJECT_ID }}
-          gcp-service-account-key: ${{ secrets.GCP_SERVICE_ACCOUNT_KEY }}
+          gcp-service-account-key-file: /tmp/gcp-key.json
 
       # Your regular workflow steps
-      - uses: actions/checkout@v4
       - name: Install dependencies
         run: npm install
       - name: Run tests
@@ -100,6 +135,23 @@ jobs:
       # Metrics are automatically collected and exported after this job completes
 ```
 
+### Alternative: Using Committed Key File
+
+If you have the key file committed (for testing):
+
+```yaml
+steps:
+  - uses: actions/checkout@v4
+
+  - uses: your-org/otel-action@v1
+    with:
+      github-token: ${{ github.token }}
+      gcp-project-id: your-project-id
+      gcp-service-account-key-file: path/to/key.json
+
+  # Your workflow steps...
+```
+
 ### Advanced Configuration
 
 ```yaml
@@ -108,7 +160,7 @@ jobs:
   with:
     github-token: ${{ secrets.GITHUB_TOKEN }}
     gcp-project-id: ${{ secrets.GCP_PROJECT_ID }}
-    gcp-service-account-key: ${{ secrets.GCP_SERVICE_ACCOUNT_KEY }}
+    gcp-service-account-key-file: /tmp/gcp-key.json
 
     # Optional: Customize service name for resource attributes
     service-name: 'my-app-ci'
@@ -120,7 +172,7 @@ jobs:
     metric-prefix: 'ci.metrics'
 
     # Optional: Adjust export interval (milliseconds)
-    export-interval-millis: '5000'
+    export-interval-millis: '1000'
 ```
 
 ## Metrics Collected
@@ -184,36 +236,74 @@ custom.googleapis.com/github.actions/step.total
 | rate(1m)
 ```
 
-## Alternative: Using Workload Identity Federation
+## Alternative: Using Workload Identity Federation (Recommended)
 
-Instead of service account keys, you can use Workload Identity Federation (recommended for production):
+Instead of service account keys, you can use Workload Identity Federation (WIF). This is the **recommended** approach for production as it doesn't require managing service account key files.
+
+### Important: Workflow Event Limitations
+
+⚠️ **WIF requires `id-token: write` permission, which is only available for:**
+- `push` events
+- `pull_request_target` events (runs in the context of the target repo)
+
+❌ **WIF will NOT work with:**
+- `pull_request` events (runs in the context of the fork, cannot get OIDC tokens)
+
+For pull requests from forks, you must use service account keys instead.
+
+### WIF Configuration
 
 ```yaml
+name: CI with WIF
+
+on:
+  push:
+    branches: [ main ]
+  pull_request_target:  # Use pull_request_target, not pull_request
+    branches: [ main ]
+
 jobs:
   build:
     runs-on: ubuntu-latest
 
     permissions:
       contents: read
-      id-token: write
+      id-token: write  # Required for WIF
+      actions: read    # Required to read workflow/job info
 
     steps:
-      - name: Setup OpenTelemetry Metrics
-        uses: your-org/otel-action@v1
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          gcp-project-id: ${{ secrets.GCP_PROJECT_ID }}
-          # No service account key needed!
+      - uses: actions/checkout@v4
 
+      # Authenticate with GCP first
       - name: Authenticate to Google Cloud
         uses: google-github-actions/auth@v2
         with:
           workload_identity_provider: ${{ secrets.WIF_PROVIDER }}
           service_account: ${{ secrets.WIF_SERVICE_ACCOUNT }}
 
+      # Setup metrics collection (no key file needed)
+      - uses: your-org/otel-action@v1
+        with:
+          github-token: ${{ github.token }}
+          gcp-project-id: ${{ secrets.GCP_PROJECT_ID }}
+          # gcp-service-account-key-file is omitted - uses ADC from WIF
+
       # Your workflow steps...
+      - run: npm install
+      - run: npm test
 ```
 
+### Setting Up Workload Identity Federation
+
+1. Create a Workload Identity Pool and Provider in GCP
+2. Grant the service account permissions to the pool
+3. Add secrets to GitHub:
+   - `WIF_PROVIDER`: Full resource name of the workload identity provider
+   - `WIF_SERVICE_ACCOUNT`: Email of the service account
+   - `GCP_PROJECT_ID`: Your GCP project ID
+
+See [Google's documentation](https://github.com/google-github-actions/auth#workload-identity-federation) for detailed setup instructions.
+
 ## Development
 
 ### Install Dependencies
@@ -240,7 +330,31 @@ This creates:
 - `dist/index.js` - Main entry point
 - `dist/post/index.js` - Post-action with all dependencies
 
-**Important:** Always run `npm run build` before committing changes. The `dist/` directory must be committed for the action to work in GitHub Actions.
+**Important:** The `dist/` directory must be committed for the action to work in GitHub Actions.
+
+### Pre-commit Hooks
+
+This project uses [pre-commit](https://pre-commit.com/) to automatically run tests and build before each commit.
+
+**Setup:**
+
+```bash
+# Install pre-commit (if not already installed)
+brew install pre-commit  # macOS
+# or: pip install pre-commit  # other platforms
+
+# Install the git hook scripts
+pre-commit install
+```
+
+Now `npm test` and `npm run build` will run automatically before each commit. If either fails, the commit will be aborted.
+
+**Manual execution:**
+
+```bash
+# Run hooks on all files
+pre-commit run --all-files
+```
 
 ### Project Structure
 
diff --git a/action.yml b/action.yml
index c4cec3f..ae27052 100644
--- a/action.yml
+++ b/action.yml
@@ -12,8 +12,8 @@ inputs:
   gcp-project-id:
     description: 'Google Cloud Project ID where metrics will be exported'
     required: true
-  gcp-service-account-key:
-    description: 'Google Cloud service account key JSON (alternative to ADC/Workload Identity)'
+  gcp-service-account-key-file:
+    description: 'Path to Google Cloud service account key JSON file (alternative to ADC/Workload Identity)'
     required: false
   service-name:
     description: 'Service name for OpenTelemetry resource attributes'
diff --git a/dist/post/index.js b/dist/post/index.js
index de3ba0e..b1c6491 100644
--- a/dist/post/index.js
+++ b/dist/post/index.js
@@ -109,21 +109,36 @@ module.exports = { collectMetrics };
 /***/ ((module, __unused_webpack_exports, __nccwpck_require__) => {
 
 const core = __nccwpck_require__(37484);
+const fs = __nccwpck_require__(79896);
+const path = __nccwpck_require__(16928);
 
 /**
  * Parses and validates action configuration from inputs
  * @returns {Object} Configuration object
  */
 function getConfig() {
-  const serviceAccountKey = core.getInput('gcp-service-account-key');
+  const serviceAccountKeyFile = core.getInput('gcp-service-account-key-file');
+  let serviceAccountKey = null;
+
+  // Read service account key from file if provided
+  if (serviceAccountKeyFile) {
+    try {
+      const filePath = path.resolve(serviceAccountKeyFile);
+      core.info(`Reading service account key from: ${filePath}`);
+      serviceAccountKey = fs.readFileSync(filePath, 'utf8');
+    } catch (error) {
+      core.error(`Failed to read service account key file: ${error.message}`);
+      throw new Error(`Cannot read service account key file: ${serviceAccountKeyFile}`);
+    }
+  }
 
   const config = {
     gcpProjectId: core.getInput('gcp-project-id', { required: true }),
-    gcpServiceAccountKey: serviceAccountKey || null,
+    gcpServiceAccountKey: serviceAccountKey,
     serviceName: core.getInput('service-name') || 'github-actions',
     serviceNamespace: core.getInput('service-namespace') || 'ci',
     metricPrefix: core.getInput('metric-prefix') || 'github.actions',
-    exportIntervalMillis: parseInt(core.getInput('export-interval-millis') || '5000', 10),
+    exportIntervalMillis: parseInt(core.getInput('export-interval-millis') || '1000', 10),
   };
 
   // Validate configuration
diff --git a/lib/config.js b/lib/config.js
index 1780916..d9ce939 100644
--- a/lib/config.js
+++ b/lib/config.js
@@ -1,19 +1,34 @@
 const core = require('@actions/core');
+const fs = require('fs');
+const path = require('path');
 
 /**
  * Parses and validates action configuration from inputs
  * @returns {Object} Configuration object
  */
 function getConfig() {
-  const serviceAccountKey = core.getInput('gcp-service-account-key');
+  const serviceAccountKeyFile = core.getInput('gcp-service-account-key-file');
+  let serviceAccountKey = null;
+
+  // Read service account key from file if provided
+  if (serviceAccountKeyFile) {
+    try {
+      const filePath = path.resolve(serviceAccountKeyFile);
+      core.info(`Reading service account key from: ${filePath}`);
+      serviceAccountKey = fs.readFileSync(filePath, 'utf8');
+    } catch (error) {
+      core.error(`Failed to read service account key file: ${error.message}`);
+      throw new Error(`Cannot read service account key file: ${serviceAccountKeyFile}`);
+    }
+  }
 
   const config = {
     gcpProjectId: core.getInput('gcp-project-id', { required: true }),
-    gcpServiceAccountKey: serviceAccountKey || null,
+    gcpServiceAccountKey: serviceAccountKey,
     serviceName: core.getInput('service-name') || 'github-actions',
     serviceNamespace: core.getInput('service-namespace') || 'ci',
     metricPrefix: core.getInput('metric-prefix') || 'github.actions',
-    exportIntervalMillis: parseInt(core.getInput('export-interval-millis') || '5000', 10),
+    exportIntervalMillis: parseInt(core.getInput('export-interval-millis') || '1000', 10),
   };
 
   // Validate configuration