Add optional fetch_depth parameter for shallow clones (#8)

* Add optional fetch_depth parameter for shallow clones

* Fix formatting issues in README.md

Author: justinxu421

README.md

@@ -83,6 +83,7 @@ Each example includes a complete workflow file that you can copy to your `.githu
 | `model`                | Optional model to use for generation                  | No       | e.g. `sonnet4`, from `auggie --list-models`         |
 | `rules`                | JSON array of rules file paths forwarded to agent     | No       | `[".augment/rules.md"]`                             |
 | `mcp_configs`          | JSON array of MCP config paths forwarded to agent     | No       | `[".augment/mcp.md"]`                               |
+| `fetch_depth`          | Optional fetch depth for git checkout (default: 0)    | No       | `10` for shallow clones, `0` for full history       |
 
 ## How It Works
 
@@ -92,6 +93,20 @@ Each example includes a complete workflow file that you can copy to your `.githu
 4. **AI Processing**: Calls the Augment Agent to analyze the changes and generate a description
 5. **PR Update**: The Augment Agent updates the PR description with the generated content
 
+## Performance Optimization
+
+For large repositories with long history, you can use the `fetch_depth` parameter to speed up checkouts by limiting the git history fetched:
+
+```yaml
+- name: Generate PR Description
+  uses: augmentcode/describe-pr@v0
+  with:
+    # ... other inputs ...
+    fetch_depth: 50 # Only fetch last 50 commits
+```
+
+This can significantly reduce checkout time for repositories with extensive history while still providing enough context for PR description generation.
+
 ## Custom Guidelines
 
 You can add project-specific guidelines to any workflow by including the `custom_guidelines` input:

action.yml

@@ -30,6 +30,10 @@ inputs:
   mcp_configs:
     description: "Optional JSON array of MCP config file paths forwarded to augment-agent."
     required: false
+  fetch_depth:
+    description: "Optional fetch depth for git checkout. Default is 0 (full history). Set to a positive number for shallow clones."
+    required: false
+    default: "0"
 
 runs:
   using: "composite"
@@ -39,7 +43,7 @@ runs:
       with:
         token: ${{ inputs.github_token }}
         ref: refs/pull/${{ inputs.pull_number }}/head
-        fetch-depth: 0
+        fetch-depth: ${{ inputs.fetch_depth }}
 
     - name: Prepare Custom Context
       id: custom_context