🌿 Fern Scribe: Add a comprehensive list of all extension headers...

fern/products/openapi-def/pages/extensions/parameter-names.mdx

@@ -1,16 +1,48 @@
 ---
 title: Customize parameter names
-description: Use `x-fern-parameter-name` to customize query parameter, header and path parameter naming.
+description: Learn how to customize parameter naming in generated SDKs using OpenAPI extensions.
 ---
 
 <Note>
-  The `x-fern-parameter-name` extension allows you to customize the variable names of parameters in your generated SDKs.
+  Fern provides several extensions to customize how API parameters are handled in your generated SDKs.
 </Note>
 
-## Headers
+## Parameter Naming Extensions
 
-In the example below, the header `X-API-Version` is renamed to `version` in the
-generated SDK. The rename makes the SDK more human readable.
+### x-fern-parameter-name
+
+Use `x-fern-parameter-name` to customize how individual parameters are named in your SDK, making them more readable and intuitive.
+
+```yaml
+paths:
+  "/users":
+    get:
+      parameters:
+        - in: header
+          name: X-API-Version  
+          x-fern-parameter-name: version
+          schema:
+            type: string
+```
+
+### x-fern-sdk-variables
+
+Use `x-fern-sdk-variables` to define parameters that should be passed through the SDK client constructor rather than individual method calls.
+
+```yaml
+components:
+  x-fern-sdk-variables:
+    project_id:
+      type: string
+      description: "The project ID to use for all API calls"
+      pattern: "^proj_[a-zA-Z0-9]+$"
+```
+
+## Usage Examples
+
+### Headers
+
+Rename HTTP headers to be more readable in your SDK:
 
 ```yaml {8}
 paths:
@@ -26,10 +58,9 @@ paths:
           required: true
 ```
 
-## Query parameters
+### Query Parameters 
 
-In the example below, the query parameter `q` is renamed to `search_terms` in the
-generated SDK. The rename makes the parameter more approachable for end users.
+Make query parameter names more descriptive:
 
 ```yaml {8}
 paths:
@@ -45,10 +76,9 @@ paths:
           required: false
 ```
 
-## Path parameters
+### Path Parameters
 
-In the example below, the path parameter `userId` is renamed to `id` in the
-generated SDK. The rename makes the SDK less verbose.
+Simplify path parameter names:
 
 ```yaml {8}
 paths:
@@ -63,3 +93,44 @@ paths:
             type: string
           required: false
 ```
+
+### Constructor Variables
+
+Define parameters that should be set once in the client constructor:
+
+```yaml
+components:
+  x-fern-sdk-variables:
+    project_id:
+      type: string
+      description: "Project identifier used across all API calls"
+      pattern: "^proj_[a-zA-Z0-9]+$"
+
+paths:
+  "/v1/connect/{project_id}/accounts":
+    parameters:
+      - name: project_id
+        in: path
+        required: true
+        schema:
+          type: string
+          pattern: "^proj_[a-zA-Z0-9]+$"
+        x-fern-sdk-variable: project_id
+```
+
+This allows you to initialize the client with the project ID once:
+
+```python
+client = YourAPIClient(project_id="proj_123")
+```
+
+Rather than passing it to every method:
+
+```python
+# Not needed when using x-fern-sdk-variables
+client.get_accounts(project_id="proj_123") 
+```
+
+<Note>
+  The `x-fern-sdk-variables` extension is supported in Python SDKs version 4.24.0 and later.
+</Note>

fern/products/sdks/overview/python/configuration.mdx

@@ -21,13 +21,15 @@ groups:
 ## SDK Configuration Options
 
 <ParamField path="additional_init_exports" type="array" default="null" required={false} toc={true}>
+  Additional exports to include in the package's __init__.py file.
 </ParamField>
 
 <ParamField path="default_bytes_stream_chunk_size" type="number" default="null" required={false} toc={true}>
   The chunk size to use (if any) when processing a response bytes stream within `iter_bytes` or `aiter_bytes` results in: `for chunk in response.iter_bytes(chunk_size=<default_bytes_stream_chunk_size>):`
 </ParamField>
 
 <ParamField path="exclude_types_from_init_exports" type="bool" default="false" required={false} toc={true}>
+  When enabled, type definitions will not be exported in the package's __init__.py file.
 </ParamField>
 
 <ParamField path="extra_dependencies" type="object" default="{}" required={false} toc={true}>
@@ -40,58 +42,69 @@ groups:
 </ParamField>
 
 <ParamField path="extra_dev_dependencies" type="object" default="{}" required={false} toc={true}>
+  Additional development dependencies to include in the generated package.
 </ParamField>
 
 <ParamField path="extras" type="object" default="{}" required={false} toc={true}>
+  Define optional feature sets and their dependencies.
 </ParamField>
 
 <ParamField path="flat_layout" type="bool" default="false" required={false} toc={true}>
+  When enabled, generates a flatter directory structure without nested resource folders.
 </ParamField>
 
 <ParamField path="follow_redirects_by_default" type="bool" default="true" required={false} toc={true}>
   Whether to follow redirects by default in HTTP requests.
 </ParamField>
 
 <ParamField path="improved_imports" type="bool" default="true" required={false} toc={true}>
-  Feature flag that improves imports in the Python SDK by removing nested `resources` directory
+  Feature flag that improves imports in the Python SDK by removing nested `resources` directory.
 </ParamField>
 
 <ParamField path="include_legacy_wire_tests" type="bool" default="false" required={false} toc={true}>
-  Whether or not to include legacy wire tests in the generated SDK
+  Whether or not to include legacy wire tests in the generated SDK.
 </ParamField>
 
 <ParamField path="include_union_utils" type="bool" default="false" required={false} toc={true}>
+  When enabled, generates utility methods for working with union types.
 </ParamField>
 
 <ParamField path="inline_path_params" type="bool" default="false" required={false} toc={true}>
-  If true, treats path parameters as named parameters in endpoint functions.
+  If true, treats path parameters as named parameters in endpoint functions. This allows using common variables like project_id across multiple endpoints:
+
+  ```yaml
+  config:
+    inline_path_params: true
+    x-fern-sdk-variables:
+      project_id:
+        type: string
+        description: The project ID to use for all requests
+  ```
 </ParamField>
 
 <ParamField path="inline_request_params" type="bool" default="true" required={false} toc={true}>
   Feature flag that removes the usage of request objects, and instead uses parameters in function signatures where possible.
 </ParamField>
 
 <ParamField path="package_name" type="string" default="null" required={false} toc={true}>
-
-Specifies the Python package name that users will import your generated client
-from.
+  Specifies the Python package name that users will import your generated client from.
 
-For example, setting `package_name: "my_custom_package"` enables users to use
-`my_custom_package import Client` to import your client:
-
-```yaml {7-10}
-default-group: local
-groups:
-  local:
-    generators:
-      - name: fernapi/fern-python
+  For example, setting `package_name: "my_custom_package"` enables users to use `my_custom_package import Client` to import your client:
+
+  ```yaml {7-10}
+  default-group: local
+  groups:
+    local:
+      generators:
+        - name: fernapi/fern-python
         version: 0.7.1
         config:
           package_name: "my_custom_package"
-```
+  ```
 </ParamField>
 
 <ParamField path="pydantic_config" type="SdkPydanticModelCustomConfig" default="SdkPydanticModelCustomConfig()" required={false} toc={true}>
+  Customize how Pydantic models are generated.
 </ParamField>
 
 <ParamField path="pydantic_config.include_union_utils" type="bool" default="false" required={false} toc={true}>
@@ -112,8 +125,8 @@ groups:
   # Visit every case in the union
   shape = get_shape()
   shape.visit(
-    circle: lambda circle: do_something_with_circle(circle),
-    triangle: lambda triangle: do_something_with_triangle(triangle),
+    circle=lambda circle: do_something_with_circle(circle),
+    triangle=lambda triangle: do_something_with_triangle(triangle),
   )
   ```
 
@@ -140,20 +153,23 @@ groups:
 </ParamField>
 
 <ParamField path="pyproject_toml" type="string" default="null" required={false} toc={true}>
+  Custom pyproject.toml content to include in the generated package.
 </ParamField>
 
 <ParamField path="should_generate_websocket_clients" type="bool" default="false" required={false} toc={true}>
   Feature flag that enables generation of Python websocket clients.
 </ParamField>
 
 <ParamField path="skip_formatting" type="bool" default="false" required={false} toc={true}>
+  When true, skips code formatting of generated files.
 </ParamField>
 
 <ParamField path="timeout_in_seconds" type="number | 'infinity'" default="60" required={false} toc={true}>
   By default, the generator generates a client that times out after 60 seconds. You can customize this value by providing a different number or setting to `infinity` to get rid of timeouts.
 </ParamField>
 
 <ParamField path="use_api_name_in_package" type="bool" default="false" required={false} toc={true}>
+  When enabled, includes the API name in the generated package name.
 </ParamField>
 
 <ParamField path="use_inheritance_for_extended_models" type="bool" default="true" required={false} toc={true}>