update docs for adding new API providers (#855)

# What does this PR do?

update docs for adding new API providers
![Screenshot 2025-01-23 at 11 21
42 AM](https://github.com/user-attachments/assets/0d4621d4-ef7e-43cd-9c4a-3e8e0b49242f)

docs/source/contributing/new_api_provider.md

@@ -1,27 +1,57 @@
 # Adding a New API Provider
 
-This guide contains references to walk you through adding a new API provider.
+This guide will walk you through the process of adding a new API provider to Llama Stack.
 
-1. First, decide which API your provider falls into (e.g. Inference, Safety, Agents, Memory).
-2. Decide whether your provider is a remote provider, or inline implementation. A remote provider is a provider that makes a remote request to a service. An inline provider is a provider where implementation is executed locally. Checkout the examples, and follow the structure to add your own API provider. Please find the following code pointers:
+## Getting Started
 
-    - {repopath}`Remote Providers::llama_stack/providers/remote`
-    - {repopath}`Inline Providers::llama_stack/providers/inline`
+1. **Choose Your API Category**
+   - Determine which API category your provider belongs to (Inference, Safety, Agents, VectorIO)
+   - Review the core concepts of Llama Stack in the [concepts guide](../concepts/index.md)
 
-3. [Build a Llama Stack distribution](https://llama-stack.readthedocs.io/en/latest/distributions/building_distro.html) with your API provider.
-4. Test your code!
+2. **Determine Provider Type**
+   - **Remote Provider**: Makes requests to external services
+   - **Inline Provider**: Executes implementation locally
 
-## Testing your newly added API providers
+   Reference existing implementations:
+   - {repopath}`Remote Providers::llama_stack/providers/remote`
+   - {repopath}`Inline Providers::llama_stack/providers/inline`
 
-1. Start with an _integration test_ for your provider. That means we will instantiate the real provider, pass it real configuration and if it is a remote service, we will actually hit the remote service. We **strongly** discourage mocking for these tests at the provider level. Llama Stack is first and foremost about integration so we need to make sure stuff works end-to-end. See {repopath}`tests/client-sdk` for an example.
+   Example PRs:
+   - [Grok Inference Implementation](https://github.com/meta-llama/llama-stack/pull/609)
+   - [Nvidia Inference Implementation](https://github.com/meta-llama/llama-stack/pull/355)
+   - [Model context protocol Tool Runtime](https://github.com/meta-llama/llama-stack/pull/665)
 
+3. **Register Your Provider**
+   - Add your provider to the appropriate {repopath}`Registry::llama_stack/providers/registry/`
+   - Specify any required pip dependencies
 
-2. In addition, if you want to unit test functionality within your provider, feel free to do so. You can find some tests in {repopath}`llama_stack/providers/tests/inference/test_text_inference.py`.
+4. **Integration**
+   - Update the run.yaml file to include your provider
+   - To make your provider a default option or create a new distribution, look at the teamplates in {repopath}`llama_stack/templates/` and run {repopath}`llama_stack/scripts/distro_codegen.py`
+   - Example PRs:
+     - [Adding Model Context Protocol Tool Runtime](https://github.com/meta-llama/llama-stack/pull/816)
 
-3. Test with a client-server Llama Stack setup. (a) Start a Llama Stack server with your own distribution which includes the new provider. (b) Send a client request to the server. These client scripts can serve as lightweight tests.
+## Testing Guidelines
 
-You can find more complex client scripts [llama-stack-apps](https://github.com/meta-llama/llama-stack-apps/tree/main) repo. Note down which scripts works and do not work with your distribution.
+### 1. Integration Testing
+- Create integration tests that use real provider instances and configurations
+- For remote services, test actual API interactions
+- Avoid mocking at the provider level
+- Reference examples in {repopath}`tests/client-sdk`
 
-## Submit your PR
+### 2. Unit Testing (Optional)
+- Add unit tests for provider-specific functionality
+- See examples in {repopath}`llama_stack/providers/tests/inference/test_text_inference.py`
 
-After you have fully tested your newly added API provider, submit a PR with the attached test plan. You must have a Test Plan in the summary section of your PR.
+### 3. End-to-End Testing
+1. Start a Llama Stack server with your new provider
+2. Test using client requests
+3. Verify compatibility with existing client scripts in the [llama-stack-apps](https://github.com/meta-llama/llama-stack-apps/tree/main) repository
+4. Document which scripts are compatible with your provider
+
+## Submitting Your PR
+
+1. Ensure all tests pass
+2. Include a comprehensive test plan in your PR summary
+3. Document any known limitations or considerations
+4. Submit your pull request for review