Context Servers: Protocol fixes and UI improvements (#19087)

This PR does two things. It fixes some minor inconsistencies in the
protocol. This is mostly about handling JSON RPC notifications correctly
and skipping fields when set to None.

Second part is about improving the rendering of context server commands,
by passing on the description
of the command to the slash command UI and showing the name of the
argument as a CodeLabel.

Release Notes:

- N/A

crates/context_servers/src/protocol.rs

@@ -11,8 +11,6 @@ use collections::HashMap;
 use crate::client::Client;
 use crate::types;
 
-pub use types::PromptInfo;
-
 const PROTOCOL_VERSION: u32 = 1;
 
 pub struct ModelContextProtocol {
@@ -26,7 +24,7 @@ impl ModelContextProtocol {
 
     pub async fn initialize(
         self,
-        client_info: types::EntityInfo,
+        client_info: types::Implementation,
     ) -> Result<InitializedContextServerProtocol> {
         let params = types::InitializeParams {
             protocol_version: PROTOCOL_VERSION,
@@ -96,7 +94,7 @@ impl InitializedContextServerProtocol {
     }
 
     /// List the MCP prompts.
-    pub async fn list_prompts(&self) -> Result<Vec<types::PromptInfo>> {
+    pub async fn list_prompts(&self) -> Result<Vec<types::Prompt>> {
         self.check_capability(ServerCapability::Prompts)?;
 
         let response: types::PromptsListResponse = self
@@ -107,6 +105,18 @@ impl InitializedContextServerProtocol {
         Ok(response.prompts)
     }
 
+    /// List the MCP resources.
+    pub async fn list_resources(&self) -> Result<types::ResourcesListResponse> {
+        self.check_capability(ServerCapability::Resources)?;
+
+        let response: types::ResourcesListResponse = self
+            .inner
+            .request(types::RequestType::ResourcesList.as_str(), ())
+            .await?;
+
+        Ok(response)
+    }
+
     /// Executes a prompt with the given arguments and returns the result.
     pub async fn run_prompt<P: AsRef<str>>(
         &self,