Add basic docs

Author: codegen-bot

docs/building-with-codegen/parsing-codebases.mdx

@@ -9,21 +9,29 @@ The primary entrypoint to programs leveraging Codegen is the [Codebase](/api-ref
 
 ## Local Codebases
 
-Construct a Codebase by passing in a path to a local `git` repository.
+Construct a Codebase by passing in a path to a local `git` repository or any subfolder within it. The path must be within a git repository (i.e., somewhere in the parent directory tree must contain a `.git` folder).
 
 ```python
 from codegen import Codebase
+from codegen.sdk.enums import ProgrammingLanguage
 
-# Parse from a local directory
+# Parse from a git repository root
 codebase = Codebase("path/to/repository")
 
-# Parse from current directory
+# Parse from a subfolder within a git repository
+codebase = Codebase("path/to/repository/src/subfolder")
+
+# Parse from current directory (must be within a git repo)
 codebase = Codebase("./")
+
+# Specify programming language (instead of inferring from file extensions)
+codebase = Codebase("./", programming_language=ProgrammingLanguage.TYPESCRIPT)
 ```
 
 <Note>
-  This will automatically infer the programming language of the codebase and
-  parse all files in the codebase.
+  By default, Codegen will automatically infer the programming language of the codebase and
+  parse all files in the codebase. You can override this by passing the `programming_language` parameter
+  with a value from the `ProgrammingLanguage` enum.
 </Note>
 
 <Tip>
@@ -38,16 +46,18 @@ To fetch and parse a repository directly from GitHub, use the `from_repo` functi
 
 ```python
 import codegen
+from codegen.sdk.enums import ProgrammingLanguage
 
 # Fetch and parse a repository (defaults to /tmp/codegen/{repo_name})
 codebase = codegen.from_repo('fastapi/fastapi')
 
-# Customize temp directory, clone depth, or specific commit
+# Customize temp directory, clone depth, specific commit, or programming language
 codebase = codegen.from_repo(
     'fastapi/fastapi',
     tmp_dir='/custom/temp/dir',  # Optional: custom temp directory
-    commit='786a8ada7ed0c7f9d8b04d49f24596865e4b7901',
+    commit='786a8ada7ed0c7f9d8b04d49f24596865e4b7901',  # Optional: specific commit
     shallow=False,  # Optional: full clone instead of shallow
+    programming_language=ProgrammingLanguage.PYTHON  # Optional: override language detection
 )
 ```
 
@@ -56,6 +66,69 @@ codebase = codegen.from_repo(
   default. The clone is shallow by default for better performance.
 </Note>
 
+## Configuration Options
+
+You can customize the behavior of your Codebase instance by passing a `CodebaseConfig` object. This allows you to configure secrets (like API keys) and toggle specific features:
+
+```python
+from codegen import Codebase
+from codegen.sdk.codebase.config import CodebaseConfig, GSFeatureFlags, Secrets
+
+codebase = Codebase(
+    "path/to/repository",
+    config=CodebaseConfig(
+        secrets=Secrets(
+            openai_key="your-openai-key"  # For AI-powered features
+        ),
+        feature_flags=GSFeatureFlags(
+            sync_enabled=True,  # Enable graph synchronization
+            ...  # Add other feature flags as needed
+        )
+    )
+)
+```
+
+The `CodebaseConfig` allows you to configure:
+- `secrets`: API keys and other sensitive information needed by the codebase
+- `feature_flags`: Toggle specific features like language engines, dependency management, and graph synchronization
+
+For a complete list of available feature flags and configuration options, see the [source code on GitHub](https://github.com/codegen-sh/codegen-sdk/blob/develop/src/codegen/sdk/codebase/config.py).
+
+## Advanced Initialization
+
+For more complex scenarios, Codegen supports an advanced initialization mode using `ProjectConfig`. This allows for fine-grained control over:
+
+- Repository configuration
+- Base path and subdirectory filtering
+- Multiple project configurations
+
+Here's an example:
+
+```python
+from codegen import Codebase
+from codegen.git.repo_operator.local_repo_operator import LocalRepoOperator
+from codegen.git.schemas.repo_config import BaseRepoConfig
+from codegen.sdk.codebase.config import ProjectConfig
+from codegen.sdk.enums import ProgrammingLanguage
+
+codebase = Codebase(
+    projects = [
+        ProjectConfig(
+            repo_operator=LocalRepoOperator(
+                repo_path="/tmp/codegen-sdk",
+                repo_config=BaseRepoConfig(),
+                bot_commit=True
+            ),
+            programming_language=ProgrammingLanguage.TYPESCRIPT,
+            base_path="src/codegen/sdk/typescript",
+            subdirectories=["src/codegen/sdk/typescript"]
+        )
+    ]
+)
+```
+
+For more details on advanced configuration options, see the [source code on GitHub](https://github.com/codegen-sh/codegen-sdk/blob/develop/src/codegen/sdk/core/codebase.py).
+
 ## Supported Languages
 
 Codegen currently supports: