diff --git a/.github/workflows/argocd-diff-preview.yml b/.github/workflows/argocd-diff-preview.yml
index bc90347..0c76e5c 100644
--- a/.github/workflows/argocd-diff-preview.yml
+++ b/.github/workflows/argocd-diff-preview.yml
@@ -4,6 +4,9 @@
 #   - Helm-rendered repos: set helm_chart_path (and optionally helm_values_files) to pre-render before diffing
 # Posts the diff as a PR comment (updated in place on subsequent runs).
 #
+# For private repos, pass SSH_PRIVATE_KEY and REPO_SSH_URL secrets.
+# The caller is responsible for obtaining these (e.g. decrypting from SOPS) before calling this workflow.
+#
 # Requirements:
 #   - Caller must set `pull-requests: write` permission
 #   - Caller must pass a GitHub PAT (repo read access) via the GH_PAT secret
@@ -46,6 +49,12 @@ on:
       GH_PAT:
         description: 'GitHub PAT with repo read access (used by argocd-diff-preview to clone the private repo)'
         required: true
+      SSH_PRIVATE_KEY:
+        description: 'SSH private key for ArgoCD to clone the repo. Required for private repos.'
+        required: false
+      REPO_SSH_URL:
+        description: 'SSH URL of the repo (e.g. git@github.com:org/repo.git). Required when SSH_PRIVATE_KEY is set.'
+        required: false
 
 jobs:
   diff:
@@ -106,6 +115,25 @@ jobs:
             cp -r "$REPO_PATH/." /tmp/argocd-diff/base
           fi
 
+      - name: Prepare ArgoCD repo credentials
+        env:
+          SSH_PRIVATE_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
+          REPO_SSH_URL: ${{ secrets.REPO_SSH_URL }}
+        run: |
+          mkdir -p /tmp/argocd-diff/secrets
+          if [ -n "$SSH_PRIVATE_KEY" ] && [ -n "$REPO_SSH_URL" ]; then
+            yq -n '
+              .apiVersion = "v1" |
+              .kind = "Secret" |
+              .metadata.name = "private-repo" |
+              .metadata.namespace = "argocd" |
+              .metadata.labels["argocd.argoproj.io/secret-type"] = "repository" |
+              .stringData.type = "git" |
+              .stringData.url = strenv(REPO_SSH_URL) |
+              .stringData.sshPrivateKey = strenv(SSH_PRIVATE_KEY)
+            ' > /tmp/argocd-diff/secrets/repo-creds.yaml
+          fi
+
       - name: Run argocd-diff-preview
         env:
           REPO: ${{ github.repository }}
@@ -123,6 +151,7 @@ jobs:
             -v /tmp/argocd-diff/base:/base-branch
             -v /tmp/argocd-diff/target:/target-branch
             -v /tmp/argocd-diff/output:/output
+            -v /tmp/argocd-diff/secrets:/secrets
             -e REPO
             -e TARGET_BRANCH
             -e BASE_BRANCH
diff --git a/docs/workflows/argocd-diff-preview.md b/docs/workflows/argocd-diff-preview.md
index 9ecf8b0..fe7a76f 100644
--- a/docs/workflows/argocd-diff-preview.md
+++ b/docs/workflows/argocd-diff-preview.md
@@ -1,15 +1,23 @@
 # ArgoCD Diff Preview
 
-Reusable workflow that generates an ArgoCD manifest diff for pull requests and posts it as a PR comment. It pre-renders an umbrella Helm chart to extract `Application` manifests from both the base and target branches, then uses [argocd-diff-preview](https://github.com/dag-andersen/argocd-diff-preview) to spin up an ephemeral cluster, render the manifests through ArgoCD, and compute the diff.
+Reusable workflow that generates an ArgoCD manifest diff for pull requests and posts it as a PR comment. It uses [argocd-diff-preview](https://github.com/dag-andersen/argocd-diff-preview) to spin up an ephemeral Kind cluster, render manifests through ArgoCD, and compute the diff.
 
 The PR comment is created on first run and **updated in place** on subsequent runs — no comment spam.
 
+Supports two modes:
+
+- **Plain YAML** — point it at a directory that already contains `Application` manifests
+- **Helm-rendered** — provide a chart path and values files; the workflow pre-renders the chart before diffing
+
+For private repos, pass `SSH_PRIVATE_KEY` and `REPO_SSH_URL` secrets. The caller is responsible for obtaining these values (e.g. extracting from a secrets manager) before calling this workflow.
+
 ## How it works
 
-1. Checkout the PR branch → `helm template <chart>` → rendered Application manifests saved to a temp folder
-2. Checkout the base branch → same render → saved to another temp folder
-3. `argocd-diff-preview` spins up a Kind cluster, installs ArgoCD, applies both sets of manifests, and produces a `diff.md`
-4. The diff is posted (or updated) as a PR comment
+1. Checkout the PR branch → prepare manifests (copy or `helm template`) → saved to a temp folder
+2. Checkout the base branch → same preparation → saved to another temp folder
+3. If `SSH_PRIVATE_KEY` and `REPO_SSH_URL` are provided, generate an ArgoCD repository secret YAML in `/secrets/`
+4. `argocd-diff-preview` spins up a Kind cluster, installs ArgoCD (with the repo credentials), renders both sets of manifests, and produces a `diff.md`
+5. The diff is posted (or updated) as a PR comment
 
 > **Note**: The ephemeral cluster adds ~60–90 seconds to each run.
 
@@ -17,8 +25,9 @@ The PR comment is created on first run and **updated in place** on subsequent ru
 
 | Input | Description | Required | Default |
 | :--- | :--- | :--- | :--- |
-| `apps_chart_path` | Path to the umbrella Helm chart that generates ArgoCD `Application` manifests. | No | `apps/` |
-| `helm_values_files` | Space-separated list of values files to pass to `helm template` (e.g. `"apps/values/base.yaml apps/values/prod.yaml"`). | No | — |
+| `repo_path` | Directory containing `Application` manifests. Used when not rendering via Helm. | No | `.` |
+| `helm_chart_path` | Path to the Helm chart to render into `Application` manifests. When set, Helm rendering is enabled. | No | — |
+| `helm_values_files` | Space-separated list of values files for `helm template` (e.g. `"apps/values/base.yaml apps/values/prod.yaml"`). Only used when `helm_chart_path` is set. | No | — |
 | `base_branch` | Branch to compare against. | No | `main` |
 | `argocd_version` | ArgoCD Helm chart version to install in the ephemeral cluster. When empty, uses the latest. | No | — |
 | `timeout` | Timeout in seconds for argocd-diff-preview. | No | `300` |
@@ -27,7 +36,9 @@ The PR comment is created on first run and **updated in place** on subsequent ru
 
 | Secret | Required | Description |
 | :--- | :--- | :--- |
-| `GH_PAT` | Yes | GitHub PAT with `repo` (read) scope. Required because argocd-diff-preview needs to interact with the GitHub API for private repositories. |
+| `GH_PAT` | Yes | GitHub PAT with `repo` (read) scope. Required for argocd-diff-preview to interact with the GitHub API on private repositories. |
+| `SSH_PRIVATE_KEY` | No | SSH private key for ArgoCD to clone the repo. Required for private repos. |
+| `REPO_SSH_URL` | No | SSH URL of the repo (e.g. `git@github.com:org/repo.git`). Required when `SSH_PRIVATE_KEY` is set. |
 
 ## Caller permissions
 
@@ -41,7 +52,7 @@ permissions:
 
 ## Usage
 
-Basic usage with an umbrella chart and a single values file:
+### Plain YAML repo (public)
 
 ```yaml
 name: ArgoCD Diff Preview
@@ -49,9 +60,6 @@ name: ArgoCD Diff Preview
 on:
   pull_request:
     branches: [main]
-    paths:
-      - 'apps/**'
-      - 'components/**'
 
 permissions:
   contents: read
@@ -61,34 +69,43 @@ jobs:
   argocd-diff:
     uses: AutomationDojo/reusable-cicd/.github/workflows/argocd-diff-preview.yml@main
     with:
-      apps_chart_path: apps/
-      helm_values_files: apps/values/prod.yaml
-      base_branch: main
+      repo_path: apps/
     secrets:
       GH_PAT: ${{ secrets.GH_PAT }}
 ```
 
-With multiple values files (e.g. base + environment overlay):
+### Helm-rendered repo (private)
+
+For repos where `Application` manifests are generated by a Helm chart and the repo is private:
 
 ```yaml
+name: ArgoCD Diff Preview
+
+on:
+  pull_request:
+    branches: [main]
+    paths:
+      - 'apps/**'
+      - 'components/**'
+
+permissions:
+  contents: read
+  pull-requests: write
+
 jobs:
   argocd-diff:
     uses: AutomationDojo/reusable-cicd/.github/workflows/argocd-diff-preview.yml@main
     with:
-      apps_chart_path: apps/
-      helm_values_files: apps/values/base.yaml apps/values/prod.yaml
+      helm_chart_path: apps/
+      helm_values_files: apps/values/prod.yaml
     secrets:
       GH_PAT: ${{ secrets.GH_PAT }}
+      SSH_PRIVATE_KEY: ${{ secrets.ARGOCD_SSH_PRIVATE_KEY }}
+      REPO_SSH_URL: ${{ secrets.ARGOCD_REPO_SSH_URL }}
 ```
 
-## Requirements
-
-- The chart at `apps_chart_path` must render `kind: Application` manifests — argocd-diff-preview uses these to know what to render.
-- If your `Application` definitions are Helm templates (not committed as plain YAML), this pre-render step is **required**. The workflow handles it automatically.
-- The `GH_PAT` secret must be configured in the caller repository under **Settings → Secrets → Actions**.
-
 ## Notes
 
-- Only runs on pull requests — it has no effect on push events.
+- `SSH_PRIVATE_KEY` and `REPO_SSH_URL` should be stored as GitHub Actions secrets in the caller repository (**Settings → Secrets → Actions**).
 - The workflow uses Docker and requires a `ubuntu-latest` runner with Docker available (default on GitHub-hosted runners).
-- ArgoCD version can be pinned via `argocd_version` to ensure consistent rendering across runs.
+- ArgoCD version can be pinned via `argocd_version` to ensure consistent rendering across runs.
\ No newline at end of file