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/assistant/src/slash_command/context_server_command.rs

@@ -1,3 +1,4 @@
+use super::create_label_for_command;
 use anyhow::{anyhow, Result};
 use assistant_slash_command::{
     AfterCompletion, ArgumentCompletion, SlashCommand, SlashCommandOutput,
@@ -6,9 +7,9 @@ use assistant_slash_command::{
 use collections::HashMap;
 use context_servers::{
     manager::{ContextServer, ContextServerManager},
-    protocol::PromptInfo,
+    types::Prompt,
 };
-use gpui::{Task, WeakView, WindowContext};
+use gpui::{AppContext, Task, WeakView, WindowContext};
 use language::{BufferSnapshot, CodeLabel, LspAdapterDelegate};
 use std::sync::atomic::AtomicBool;
 use std::sync::Arc;
@@ -18,11 +19,11 @@ use workspace::Workspace;
 
 pub struct ContextServerSlashCommand {
     server_id: String,
-    prompt: PromptInfo,
+    prompt: Prompt,
 }
 
 impl ContextServerSlashCommand {
-    pub fn new(server: &Arc<ContextServer>, prompt: PromptInfo) -> Self {
+    pub fn new(server: &Arc<ContextServer>, prompt: Prompt) -> Self {
         Self {
             server_id: server.id.clone(),
             prompt,
@@ -35,12 +36,28 @@ impl SlashCommand for ContextServerSlashCommand {
         self.prompt.name.clone()
     }
 
+    fn label(&self, cx: &AppContext) -> language::CodeLabel {
+        let mut parts = vec![self.prompt.name.as_str()];
+        if let Some(args) = &self.prompt.arguments {
+            if let Some(arg) = args.first() {
+                parts.push(arg.name.as_str());
+            }
+        }
+        create_label_for_command(&parts[0], &parts[1..], cx)
+    }
+
     fn description(&self) -> String {
-        format!("Run context server command: {}", self.prompt.name)
+        match &self.prompt.description {
+            Some(desc) => desc.clone(),
+            None => format!("Run '{}' from {}", self.prompt.name, self.server_id),
+        }
     }
 
     fn menu_text(&self) -> String {
-        format!("Run '{}' from {}", self.prompt.name, self.server_id)
+        match &self.prompt.description {
+            Some(desc) => desc.clone(),
+            None => format!("Run '{}' from {}", self.prompt.name, self.server_id),
+        }
     }
 
     fn requires_argument(&self) -> bool {
@@ -154,7 +171,7 @@ impl SlashCommand for ContextServerSlashCommand {
     }
 }
 
-fn completion_argument(prompt: &PromptInfo, arguments: &[String]) -> Result<(String, String)> {
+fn completion_argument(prompt: &Prompt, arguments: &[String]) -> Result<(String, String)> {
     if arguments.is_empty() {
         return Err(anyhow!("No arguments given"));
     }
@@ -170,7 +187,7 @@ fn completion_argument(prompt: &PromptInfo, arguments: &[String]) -> Result<(Str
     }
 }
 
-fn prompt_arguments(prompt: &PromptInfo, arguments: &[String]) -> Result<HashMap<String, String>> {
+fn prompt_arguments(prompt: &Prompt, arguments: &[String]) -> Result<HashMap<String, String>> {
     match &prompt.arguments {
         Some(args) if args.len() > 1 => Err(anyhow!(
             "Prompt has more than one argument, which is not supported"
@@ -199,7 +216,7 @@ fn prompt_arguments(prompt: &PromptInfo, arguments: &[String]) -> Result<HashMap
 /// MCP servers can return prompts with multiple arguments. Since we only
 /// support one argument, we ignore all others. This is the necessary predicate
 /// for this.
-pub fn acceptable_prompt(prompt: &PromptInfo) -> bool {
+pub fn acceptable_prompt(prompt: &Prompt) -> bool {
     match &prompt.arguments {
         None => true,
         Some(args) if args.len() <= 1 => true,