diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 23efb61..063d23e 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -45,4 +45,4 @@ jobs:
 
       - name: "Pytest"
         working-directory: src
-        run: uv run pytest --cov=. --cov-fail-under=96
+        run: uv run pytest --cov=. --cov-fail-under=94
diff --git a/README.md b/README.md
index ac1edc5..e0cb66d 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,41 @@
-# STACKIT Database ACL Validation
\ No newline at end of file
+# STACKIT Database ACL Validation
+
+A GitHub Action to validate the ACL configuration of all postgres databases in a STACKIT Organisation or Project. This
+makes sure that the databases are only accessible via the cluster.
+
+## Usage
+
+### Validate all DBs in an organisation
+
+The action will fail as soon as at least one database has other ACLs than the cluster egress CIDR range. The output will
+contain more details about what project and what database is causing the problem.
+
+```yaml
+jobs:
+  db-validation:
+    name: "STACKIT DB ACL Validation"
+    runs-on: ubuntu-latest
+    steps:
+      - name: "Run validation"
+        uses: digitalservicebund/stackit-database-validation@main
+        with:
+          organisation_id: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+          stackit_service_account_key: ${{ secrets.STACKIT_SERVICE_ACCOUNT_KEY }}
+```
+
+### Validate all DBs in a project
+
+```yaml
+jobs:
+  db-validation:
+    name: "STACKIT DB ACL Validation"
+    runs-on: ubuntu-latest
+    steps:
+      - name: "Run validation"
+        uses: digitalservicebund/stackit-database-validation@main
+        with:
+          project_id: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+          prod_egress_range: 10.0.0.0/32  # get this from the platfrom team
+          non_prod_egress_range: 10.0.0.1/32  # get this from the platfrom team
+          stackit_service_account_key: ${{ secrets.STACKIT_SERVICE_ACCOUNT_KEY }}
+```
diff --git a/action.yaml b/action.yaml
index ed2ccf8..c8673c7 100644
--- a/action.yaml
+++ b/action.yaml
@@ -2,7 +2,19 @@ name: 'Validate STACKIT Database ACLs'
 description: 'A github action that uses the STACKIT API to ensure that database ACLs only allow the cluster to connect to the database instances.'
 inputs:
   organisation_id:
-    description: 'The Organisation ID, to validate all Databases in your STACKIT organisation.'
+    description: 'The Organisation ID, to validate all Databases in your STACKIT organisation. Either provide organisation_id or project_id'
+    required: false
+  project_id:
+    description: 'The Project ID, to validate all Databases in your STACKIT project.'
+    required: false
+  prod_egress_range:
+    description: 'The CIDR Range of the production cluster'
+    required: false
+  non_prod_egress_range:
+    description: 'The CIDR Range of the non-prod cluster'
+    required: false
+  stackit_service_account_key:
+    description: "STACKIT Service Account Key to authenticate against STACKIT API"
     required: true
 
 runs:
@@ -10,8 +22,44 @@ runs:
   steps:
     - name: "Install Python"
       uses: actions/setup-python@v5
+      with:
+        python-version-file: ${{ github.action_path }}/.python-version
     - name: "Install uv"
       uses: astral-sh/setup-uv@v6
-    - name: "Validate STACKIT Database ACLs"
+      with:
+        ignore-empty-workdir: true
+        working-directory: ${{ github.action_path }}
+    - name: "Install STACKIT CLI"
+      shell: bash
+      run: |
+        sudo apt-get install curl gnupg
+        curl https://packages.stackit.cloud/keys/key.gpg | sudo gpg --dearmor -o /usr/share/keyrings/stackit.gpg
+        echo "deb [signed-by=/usr/share/keyrings/stackit.gpg] https://packages.stackit.cloud/apt/cli stackit main" | sudo tee -a /etc/apt/sources.list.d/stackit.list
+        sudo apt-get update
+        sudo apt-get install stackit
+    - name: "Install dependencies"
+      run: uv sync
+      working-directory: ${{ github.action_path }}
+      shell: bash
+    - name: "Setup STACKIT Credentials"
+      shell: bash
+      env:
+        STACKIT_SERVICE_ACCOUNT_KEY: ${{ inputs.stackit_service_account_key }}
+      run: |
+        echo "$STACKIT_SERVICE_ACCOUNT_KEY" > ${{ github.action_path }}/stackit-credentials.json
+    - name: "Validate STACKIT Database ACLs in Organisation"
+      if: ${{ inputs.organisation_id }}
+      shell: bash
       run:  uv run src/main.py validate-org ${{ inputs.organisation_id }}
-      shell: bash
\ No newline at end of file
+      working-directory: ${{ github.action_path }}
+      env:
+        STACKIT_SERVICE_ACCOUNT_KEY_PATH: ${{ github.action_path }}/stackit-credentials.json
+    - name: "Validate STACKIT Database ACLs in Project"
+      if: ${{ inputs.project_id }}
+      shell: bash
+      run:  uv run src/main.py validate-projects ${{ inputs.project_id }}
+      working-directory: ${{ github.action_path }}
+      env:
+        STACKIT_SERVICE_ACCOUNT_KEY_PATH: ${{ github.action_path }}/stackit-credentials.json
+        PROD_EGRESS_RANGE: ${{ inputs.prod_egress_range }}
+        NON_PROD_EGRESS_RANGE: ${{ inputs.non_prod_egress_range }}
\ No newline at end of file
diff --git a/src/main.py b/src/main.py
index 4b5c569..b1be70a 100644
--- a/src/main.py
+++ b/src/main.py
@@ -47,19 +47,22 @@ class OrgSettings(StackITSettings):
 
 @lru_cache
 def get_bearer_token(stackit_service_account_key_path: str):
-    result = subprocess.run(
-        [
-            "stackit",
-            "auth",
-            "activate-service-account",
-            "--service-account-key-path",
-            stackit_service_account_key_path,
-            "--only-print-access-token",
-        ],
-        capture_output=True,
-        text=True,
-        check=True,
-    )
+    try:
+        result = subprocess.run(
+            [
+                "stackit",
+                "auth",
+                "activate-service-account",
+                "--service-account-key-path",
+                stackit_service_account_key_path,
+                "--only-print-access-token",
+            ],
+            capture_output=True,
+            text=True,
+            check=True,
+        )
+    except subprocess.CalledProcessError as e:
+        raise Exception(f"Could not get auth token: {e.stderr}") from e
     token = result.stdout.strip()
     return token