Add dedicated help menu for uvx (#4770)

Closes #4749

crates/uv-cli/src/lib.rs

@@ -1902,9 +1902,16 @@ pub struct ToolNamespace {
 
 #[derive(Subcommand)]
 pub enum ToolCommand {
-    /// Run a tool
+    /// Run a tool.
     Run(ToolRunArgs),
-    /// Install a tool
+    /// Hidden alias for `uv tool run` for invocation from the `uvx` command
+    #[command(
+        hide = true,
+        override_usage = "uvx [OPTIONS] <COMMAND>",
+        about = "Run a tool."
+    )]
+    Uvx(ToolRunArgs),
+    /// Install a tool.
     Install(ToolInstallArgs),
     /// List installed tools.
     List(ToolListArgs),

crates/uv/src/bin/uvx.rs

@@ -11,7 +11,7 @@ fn run() -> Result<ExitStatus, anyhow::Error> {
         bail!("Could not determine the location of the `uvx` binary")
     };
     let uv = bin.join("uv");
-    let args = ["tool", "run"]
+    let args = ["tool", "uvx"]
         .iter()
         .map(OsString::from)
         // Skip the `uvx` name

crates/uv/src/main.rs

@@ -785,7 +785,7 @@ async fn run() -> Result<ExitStatus> {
             Ok(ExitStatus::Success)
         }
         Commands::Tool(ToolNamespace {
-            command: ToolCommand::Run(args),
+            command: ToolCommand::Run(args) | ToolCommand::Uvx(args),
         }) => {
             // Resolve the settings from the command-line arguments and workspace configuration.
             let args = settings::ToolRunSettings::resolve(args, filesystem);