fix: sort list_all() output in ToolRouter and PromptRouter for deterministic ordering (#665)

ToolRouter::list_all() and PromptRouter::list_all() iterate over a
HashMap, which returns items in non-deterministic order. Since list_all()
backs the tools/list and prompts/list MCP protocol responses, this causes
MCP clients to receive differently-ordered results across calls and
process restarts, leading to intermittent tool discovery failures.

Sort the output alphabetically by name to guarantee stable ordering.

Author: p4fg

crates/rmcp/src/handler/server/router/prompt.rs

@@ -187,7 +187,9 @@ where
     }
 
     pub fn list_all(&self) -> Vec<crate::model::Prompt> {
-        self.map.values().map(|item| item.attr.clone()).collect()
+        let mut prompts: Vec<_> = self.map.values().map(|item| item.attr.clone()).collect();
+        prompts.sort_by(|a, b| a.name.cmp(&b.name));
+        prompts
     }
 }
 

crates/rmcp/src/handler/server/router/tool.rs

@@ -252,7 +252,9 @@ where
     }
 
     pub fn list_all(&self) -> Vec<crate::model::Tool> {
-        self.map.values().map(|item| item.attr.clone()).collect()
+        let mut tools: Vec<_> = self.map.values().map(|item| item.attr.clone()).collect();
+        tools.sort_by(|a, b| a.name.cmp(&b.name));
+        tools
     }
 
     /// Get a tool definition by name.

crates/rmcp/tests/test_prompt_routers.rs

@@ -103,3 +103,39 @@ fn test_prompt_router() {
     let prompts = test_prompt_router.list_all();
     assert_eq!(prompts.len(), 4);
 }
+
+#[test]
+fn test_prompt_router_list_all_is_sorted() {
+    let router = TestHandler::<()>::test_router()
+        .with_route(rmcp::handler::server::router::prompt::PromptRoute::new_dyn(
+            async_function_prompt_attr(),
+            |mut context| {
+                Box::pin(async move {
+                    use rmcp::handler::server::{
+                        common::FromContextPart, prompt::IntoGetPromptResult,
+                    };
+                    let params = Parameters::<Request>::from_context_part(&mut context)?;
+                    let result = async_function(params).await;
+                    result.into_get_prompt_result()
+                })
+            },
+        ))
+        .with_route(rmcp::handler::server::router::prompt::PromptRoute::new_dyn(
+            async_function2_prompt_attr(),
+            |context| {
+                Box::pin(async move {
+                    use rmcp::handler::server::prompt::IntoGetPromptResult;
+                    let result = async_function2(context.server).await;
+                    result.into_get_prompt_result()
+                })
+            },
+        ));
+    let prompts = router.list_all();
+    let names: Vec<&str> = prompts.iter().map(|p| p.name.as_ref()).collect();
+    let mut sorted = names.clone();
+    sorted.sort();
+    assert_eq!(
+        names, sorted,
+        "list_all() should return prompts sorted alphabetically by name"
+    );
+}

crates/rmcp/tests/test_tool_routers.rs

@@ -66,3 +66,20 @@ where
     H: CallToolHandler<S, A>,
 {
 }
+
+#[test]
+fn test_tool_router_list_all_is_sorted() {
+    let router: ToolRouter<TestHandler<()>> = ToolRouter::<TestHandler<()>>::new()
+        .with_route((async_function_tool_attr(), async_function))
+        .with_route((async_function2_tool_attr(), async_function2))
+        + TestHandler::<()>::test_router_1()
+        + TestHandler::<()>::test_router_2();
+    let tools = router.list_all();
+    let names: Vec<&str> = tools.iter().map(|t| t.name.as_ref()).collect();
+    let mut sorted = names.clone();
+    sorted.sort();
+    assert_eq!(
+        names, sorted,
+        "list_all() should return tools sorted alphabetically by name"
+    );
+}