feat: add tool annotations for build-in tools (#1939)

crates/goose-cli/src/commands/configure.rs

@@ -5,6 +5,7 @@ use goose::config::extensions::name_to_key;
 use goose::config::{Config, ConfigError, ExperimentManager, ExtensionEntry, ExtensionManager};
 use goose::message::Message;
 use goose::providers::{create, providers};
+use mcp_core::tool::ToolAnnotations;
 use mcp_core::Tool;
 use serde_json::{json, Value};
 use std::collections::HashMap;
@@ -349,6 +350,13 @@ pub async fn configure_provider_dialog() -> Result<bool, Box<dyn Error>> {
                     "location": {"type": "string"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Get weather".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
         vec![sample_tool]
     } else {

crates/goose-mcp/src/computercontroller/mod.rs

@@ -13,7 +13,7 @@ use mcp_core::{
     prompt::Prompt,
     protocol::ServerCapabilities,
     resource::Resource,
-    tool::Tool,
+    tool::{Tool, ToolAnnotations},
     Content,
 };
 use mcp_server::router::CapabilitiesBuilder;
@@ -74,6 +74,13 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Web Scrape".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: true,
+            }),
         );
 
         let computer_control_desc = match std::env::consts::OS {
@@ -139,6 +146,7 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            None,
         );
 
         let quick_script_desc = match std::env::consts::OS {
@@ -189,6 +197,7 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            None,
         );
 
         let cache_tool = Tool::new(
@@ -215,6 +224,7 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            None,
         );
 
         let pdf_tool = Tool::new(
@@ -242,6 +252,13 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("PDF process".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: true,
+                open_world_hint: false,
+            }),
         );
 
         let docx_tool = Tool::new(
@@ -340,6 +357,7 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            None,
         );
 
         let make_presentation_tool = Tool::new(
@@ -380,6 +398,7 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            None,
         );
 
         let xlsx_tool = Tool::new(
@@ -441,6 +460,7 @@ impl ComputerControllerRouter {
                     }
                 }
             }),
+            None,
         );
 
         // choose_app_strategy().cache_dir()

crates/goose-mcp/src/developer/mod.rs

@@ -17,13 +17,16 @@ use tokio::process::Command;
 use url::Url;
 
 use include_dir::{include_dir, Dir};
-use mcp_core::prompt::{Prompt, PromptArgument, PromptTemplate};
 use mcp_core::{
     handler::{PromptError, ResourceError, ToolError},
     protocol::ServerCapabilities,
     resource::Resource,
     tool::Tool,
 };
+use mcp_core::{
+    prompt::{Prompt, PromptArgument, PromptTemplate},
+    tool::ToolAnnotations,
+};
 use mcp_server::router::CapabilitiesBuilder;
 use mcp_server::Router;
 
@@ -161,6 +164,7 @@ impl DeveloperRouter {
                     "command": {"type": "string"}
                 }
             }),
+            None,
         );
 
         let text_editor_tool = Tool::new(
@@ -199,6 +203,7 @@ impl DeveloperRouter {
                     "file_text": {"type": "string"}
                 }
             }),
+            None,
         );
 
         let list_windows_tool = Tool::new(
@@ -213,6 +218,13 @@ impl DeveloperRouter {
                 "required": [],
                 "properties": {}
             }),
+            Some(ToolAnnotations {
+                title: Some("List available windows".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let screen_capture_tool = Tool::new(
@@ -241,6 +253,13 @@ impl DeveloperRouter {
                     }
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Capture a full screen".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let image_processor_tool = Tool::new(
@@ -263,6 +282,13 @@ impl DeveloperRouter {
                     }
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Process Image".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: true,
+                open_world_hint: false,
+            }),
         );
 
         // Get base instructions and working directory

crates/goose-mcp/src/google_drive/mod.rs

@@ -4,6 +4,7 @@ pub mod storage;
 use anyhow::{Context, Error};
 use base64::Engine;
 use indoc::indoc;
+use mcp_core::tool::ToolAnnotations;
 use oauth_pkce::PkceOAuth2Client;
 use regex::Regex;
 use serde_json::{json, Value};
@@ -209,6 +210,13 @@ impl GoogleDriveRouter {
                 }
               },
             }),
+            Some(ToolAnnotations {
+                    title: Some("Search GDrive".to_string()),
+                    read_only_hint: true,
+                    destructive_hint: false,
+                    idempotent_hint: false,
+                    open_world_hint: false,
+                }),
         );
 
         let read_tool = Tool::new(
@@ -232,6 +240,13 @@ impl GoogleDriveRouter {
               },
               "required": ["uri"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Read GDrive".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let upload_tool = Tool::new(
@@ -270,6 +285,13 @@ impl GoogleDriveRouter {
               },
               "required": ["name", "mimeType"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Upload file to GDrive".to_string()),
+                read_only_hint: false,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let create_file_tool = Tool::new(
@@ -313,6 +335,13 @@ impl GoogleDriveRouter {
               },
               "required": ["name", "fileType"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Create new file in GDrive".to_string()),
+                read_only_hint: false,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let move_file_tool = Tool::new(
@@ -339,6 +368,13 @@ impl GoogleDriveRouter {
               },
               "required": ["fileId", "currentFolderId", "newFolderId"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Move file".to_string()),
+                read_only_hint: false,
+                destructive_hint: true,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let update_tool = Tool::new(
@@ -373,6 +409,13 @@ impl GoogleDriveRouter {
               },
               "required": ["fileId", "mimeType"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Update a file".to_string()),
+                read_only_hint: false,
+                destructive_hint: true,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let update_file_tool = Tool::new(
@@ -408,6 +451,13 @@ impl GoogleDriveRouter {
               },
               "required": ["fileId", "fileType"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Update a file".to_string()),
+                read_only_hint: false,
+                destructive_hint: true,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let sheets_tool = Tool::new(
@@ -468,6 +518,7 @@ impl GoogleDriveRouter {
               },
               "required": ["spreadsheetId", "operation"],
             }),
+            None,
         );
 
         let get_comments_tool = Tool::new(
@@ -486,6 +537,13 @@ impl GoogleDriveRouter {
               },
               "required": ["fileId"],
             }),
+            Some(ToolAnnotations {
+                title: Some("List file comments".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let create_comment_tool = Tool::new(
@@ -508,6 +566,13 @@ impl GoogleDriveRouter {
               },
               "required": ["fileId", "comment"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Create file comment".to_string()),
+                read_only_hint: false,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let reply_tool = Tool::new(
@@ -538,6 +603,13 @@ impl GoogleDriveRouter {
               },
               "required": ["fileId", "commentId", "content"],
             }),
+            Some(ToolAnnotations {
+                title: Some("Reply to a comment".to_string()),
+                read_only_hint: false,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let list_drives_tool = Tool::new(
@@ -555,6 +627,13 @@ impl GoogleDriveRouter {
                 }
               },
             }),
+            Some(ToolAnnotations {
+                title: Some("List shared google drives".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let instructions = indoc::formatdoc! {r#"

crates/goose-mcp/src/jetbrains/proxy.rs

@@ -237,6 +237,7 @@ impl JetBrainsProxy {
                         name: name.to_string(),
                         description: first_sentence,
                         input_schema,
+                        annotations: None,
                     })
                 } else {
                     debug!("Skipping invalid tool entry: {:?}", t);

crates/goose-mcp/src/memory/mod.rs

@@ -16,7 +16,7 @@ use mcp_core::{
     prompt::Prompt,
     protocol::ServerCapabilities,
     resource::Resource,
-    tool::{Tool, ToolCall},
+    tool::{Tool, ToolAnnotations, ToolCall},
     Content,
 };
 use mcp_server::router::CapabilitiesBuilder;
@@ -52,6 +52,13 @@ impl MemoryRouter {
                 },
                 "required": ["category", "data", "is_global"]
             }),
+            Some(ToolAnnotations {
+                title: Some("Remember Memory".to_string()),
+                read_only_hint: false,
+                destructive_hint: false,
+                idempotent_hint: true,
+                open_world_hint: false,
+            }),
         );
 
         let retrieve_memories = Tool::new(
@@ -65,6 +72,13 @@ impl MemoryRouter {
                 },
                 "required": ["category", "is_global"]
             }),
+            Some(ToolAnnotations {
+                title: Some("Retrieve Memory".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let remove_memory_category = Tool::new(
@@ -78,6 +92,13 @@ impl MemoryRouter {
                 },
                 "required": ["category", "is_global"]
             }),
+            Some(ToolAnnotations {
+                title: Some("Remove Memory Category".to_string()),
+                read_only_hint: false,
+                destructive_hint: true,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let remove_specific_memory = Tool::new(
@@ -92,6 +113,13 @@ impl MemoryRouter {
                 },
                 "required": ["category", "memory_content", "is_global"]
             }),
+            Some(ToolAnnotations {
+                title: Some("Remove Specific Memory".to_string()),
+                read_only_hint: false,
+                destructive_hint: true,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let instructions = formatdoc! {r#"

crates/goose-mcp/src/tutorial/mod.rs

@@ -10,7 +10,7 @@ use mcp_core::{
     protocol::ServerCapabilities,
     resource::Resource,
     role::Role,
-    tool::Tool,
+    tool::{Tool, ToolAnnotations},
 };
 use mcp_server::router::CapabilitiesBuilder;
 use mcp_server::Router;
@@ -45,6 +45,13 @@ impl TutorialRouter {
                     }
                 }
             }),
+            Some(ToolAnnotations {
+                    title: Some("Load Tutorial".to_string()),
+                    read_only_hint: true,
+                    destructive_hint: false,
+                    idempotent_hint: false,
+                    open_world_hint: false,
+                }),
         );
 
         // Get base instructions and available tutorials

crates/goose/examples/image_tool.rs

@@ -58,7 +58,7 @@ async fn main() -> Result<()> {
             .complete(
                 "You are a helpful assistant. Please describe any text you see in the image.",
                 &messages,
-                &[Tool::new("view_image", "View an image", input_schema)],
+                &[Tool::new("view_image", "View an image", input_schema, None)],
             )
             .await?;
 

crates/goose/src/agents/capabilities.rs

@@ -245,6 +245,7 @@ impl Capabilities {
                         format!("{}__{}", name, tool.name),
                         &tool.description,
                         tool.input_schema,
+                        tool.annotations,
                     ));
                 }
 

crates/goose/src/agents/permission_judge.rs

@@ -2,6 +2,7 @@ use crate::agents::capabilities::Capabilities;
 use crate::message::{Message, MessageContent, ToolRequest};
 use chrono::Utc;
 use indoc::indoc;
+use mcp_core::tool::ToolAnnotations;
 use mcp_core::{tool::Tool, TextContent};
 use serde_json::{json, Value};
 
@@ -50,6 +51,13 @@ fn create_read_only_tool() -> Tool {
             },
             "required": []
         }),
+        Some(ToolAnnotations {
+                title: Some("Check tool operation".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
     )
 }
 

crates/goose/src/agents/reference.rs

@@ -21,7 +21,7 @@ use anyhow::{anyhow, Result};
 use indoc::indoc;
 use mcp_core::prompt::Prompt;
 use mcp_core::protocol::GetPromptResult;
-use mcp_core::tool::Tool;
+use mcp_core::tool::{Tool, ToolAnnotations};
 use serde_json::{json, Value};
 
 /// Reference implementation of an Agent
@@ -102,6 +102,13 @@ impl Agent for ReferenceAgent {
                     "extension_name": {"type": "string", "description": "Optional extension name"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Read a resource".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let list_resources_tool = Tool::new(
@@ -120,6 +127,13 @@ impl Agent for ReferenceAgent {
                     "extension_name": {"type": "string", "description": "Optional extension name"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("List resources".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         if capabilities.supports_resources() {

crates/goose/src/agents/summarize.rs

@@ -3,6 +3,7 @@
 /// truncation method. Still cannot read resources.
 use async_trait::async_trait;
 use futures::stream::BoxStream;
+use mcp_core::tool::ToolAnnotations;
 use std::collections::HashMap;
 use std::sync::Arc;
 use tokio::sync::mpsc;
@@ -199,6 +200,13 @@ impl Agent for SummarizeAgent {
                     "extension_name": {"type": "string", "description": "Optional extension name"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Read a resource".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let list_resources_tool = Tool::new(
@@ -217,6 +225,13 @@ impl Agent for SummarizeAgent {
                     "extension_name": {"type": "string", "description": "Optional extension name"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("List resources".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         if capabilities.supports_resources() {

crates/goose/src/agents/truncate.rs

@@ -2,6 +2,7 @@
 /// It makes no attempt to handle context limits, and cannot read resources
 use async_trait::async_trait;
 use futures::stream::BoxStream;
+use mcp_core::tool::ToolAnnotations;
 use std::collections::HashMap;
 use std::sync::Arc;
 use tokio::sync::mpsc;
@@ -195,6 +196,13 @@ impl Agent for TruncateAgent {
                     "extension_name": {"type": "string", "description": "Optional extension name"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("Read a resource".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         let list_resources_tool = Tool::new(
@@ -213,6 +221,13 @@ impl Agent for TruncateAgent {
                     "extension_name": {"type": "string", "description": "Optional extension name"}
                 }
             }),
+            Some(ToolAnnotations {
+                title: Some("List resources".to_string()),
+                read_only_hint: true,
+                destructive_hint: false,
+                idempotent_hint: false,
+                open_world_hint: false,
+            }),
         );
 
         if capabilities.supports_resources() {

crates/goose/src/providers/formats/anthropic.rs

@@ -530,6 +530,7 @@ mod tests {
                         }
                     }
                 }),
+                None,
             ),
             Tool::new(
                 "weather",
@@ -543,6 +544,7 @@ mod tests {
                         }
                     }
                 }),
+                None,
             ),
         ];
 

crates/goose/src/providers/formats/databricks.rs

@@ -675,6 +675,7 @@ mod tests {
                 },
                 "required": ["input"]
             }),
+            None,
         );
 
         let spec = format_tools(&[tool])?;
@@ -766,6 +767,7 @@ mod tests {
                 },
                 "required": ["input"]
             }),
+            None,
         );
 
         let tool2 = Tool::new(
@@ -781,6 +783,7 @@ mod tests {
                 },
                 "required": ["input"]
             }),
+            None,
         );
 
         let result = format_tools(&[tool1, tool2]);

crates/goose/src/providers/formats/google.rs

@@ -351,6 +351,7 @@ mod tests {
             input_schema: json!({
                 "properties": params
             }),
+            annotations: None,
         }
     }
 
@@ -494,6 +495,7 @@ mod tests {
             input_schema: json!({
                 "properties": {}
             }),
+            annotations: None,
         }];
         let result = format_tools(&tools);
         assert_eq!(result.len(), 1);

crates/goose/src/providers/formats/openai.rs

@@ -550,6 +550,7 @@ mod tests {
                 },
                 "required": ["input"]
             }),
+            None,
         );
 
         let spec = format_tools(&[tool])?;
@@ -641,6 +642,7 @@ mod tests {
                 },
                 "required": ["input"]
             }),
+            None,
         );
 
         let tool2 = Tool::new(
@@ -656,6 +658,7 @@ mod tests {
                 },
                 "required": ["input"]
             }),
+            None,
         );
 
         let result = format_tools(&[tool1, tool2]);

crates/goose/src/token_counter.rs

@@ -310,6 +310,7 @@ mod tests {
                 },
                 "required": ["location"]
             }),
+            annotations: None,
         }];
 
         let token_count_without_tools = counter.count_chat_tokens(system_prompt, &messages, &[]);

crates/goose/tests/providers.rs

@@ -127,6 +127,7 @@ impl ProviderTester {
                     }
                 }
             }),
+            None,
         );
 
         let message = Message::user().with_text("What's the weather like in San Francisco?");

crates/mcp-client/src/client.rs

@@ -245,7 +245,7 @@ where
         capabilities: ClientCapabilities,
     ) -> Result<InitializeResult, Error> {
         let params = InitializeParams {
-            protocol_version: "2024-11-05".to_string(),
+            protocol_version: "2025-03-26".to_string(),
             client_info: info,
             capabilities,
         };

crates/mcp-core/src/tool.rs

@@ -3,6 +3,102 @@
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
+/// Additional properties describing a tool to clients.
+///
+/// NOTE: all properties in ToolAnnotations are **hints**.
+/// They are not guaranteed to provide a faithful description of
+/// tool behavior (including descriptive properties like `title`).
+///
+/// Clients should never make tool use decisions based on ToolAnnotations
+/// received from untrusted servers.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ToolAnnotations {
+    /// A human-readable title for the tool.
+    pub title: Option<String>,
+
+    /// If true, the tool does not modify its environment.
+    ///
+    /// Default: false
+    #[serde(default)]
+    pub read_only_hint: bool,
+
+    /// If true, the tool may perform destructive updates to its environment.
+    /// If false, the tool performs only additive updates.
+    ///
+    /// (This property is meaningful only when `read_only_hint == false`)
+    ///
+    /// Default: true
+    #[serde(default = "default_true")]
+    pub destructive_hint: bool,
+
+    /// If true, calling the tool repeatedly with the same arguments
+    /// will have no additional effect on its environment.
+    ///
+    /// (This property is meaningful only when `read_only_hint == false`)
+    ///
+    /// Default: false
+    #[serde(default)]
+    pub idempotent_hint: bool,
+
+    /// If true, this tool may interact with an "open world" of external
+    /// entities. If false, the tool's domain of interaction is closed.
+    /// For example, the world of a web search tool is open, whereas that
+    /// of a memory tool is not.
+    ///
+    /// Default: true
+    #[serde(default = "default_true")]
+    pub open_world_hint: bool,
+}
+
+impl Default for ToolAnnotations {
+    fn default() -> Self {
+        ToolAnnotations {
+            title: None,
+            read_only_hint: false,
+            destructive_hint: true,
+            idempotent_hint: false,
+            open_world_hint: true,
+        }
+    }
+}
+
+fn default_true() -> bool {
+    true
+}
+
+/// Implement builder methods for `ToolAnnotations`
+impl ToolAnnotations {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    pub fn with_title(mut self, title: impl Into<String>) -> Self {
+        self.title = Some(title.into());
+        self
+    }
+
+    pub fn with_read_only(mut self, read_only: bool) -> Self {
+        self.read_only_hint = read_only;
+        self
+    }
+
+    pub fn with_destructive(mut self, destructive: bool) -> Self {
+        self.destructive_hint = destructive;
+        self
+    }
+
+    pub fn with_idempotent(mut self, idempotent: bool) -> Self {
+        self.idempotent_hint = idempotent;
+        self
+    }
+
+    pub fn with_open_world(mut self, open_world: bool) -> Self {
+        self.open_world_hint = open_world;
+        self
+    }
+}
+
 /// A tool that can be used by a model.
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -13,11 +109,18 @@ pub struct Tool {
     pub description: String,
     /// A JSON Schema object defining the expected parameters for the tool
     pub input_schema: Value,
+    /// Optional additional tool information.
+    pub annotations: Option<ToolAnnotations>,
 }
 
 impl Tool {
     /// Create a new tool with the given name and description
-    pub fn new<N, D>(name: N, description: D, input_schema: Value) -> Self
+    pub fn new<N, D>(
+        name: N,
+        description: D,
+        input_schema: Value,
+        annotations: Option<ToolAnnotations>,
+    ) -> Self
     where
         N: Into<String>,
         D: Into<String>,
@@ -26,6 +129,7 @@ impl Tool {
             name: name.into(),
             description: description.into(),
             input_schema,
+            annotations,
         }
     }
 }

crates/mcp-server/src/main.rs

@@ -2,6 +2,7 @@ use anyhow::Result;
 use mcp_core::content::Content;
 use mcp_core::handler::{PromptError, ResourceError};
 use mcp_core::prompt::{Prompt, PromptArgument};
+use mcp_core::tool::ToolAnnotations;
 use mcp_core::{handler::ToolError, protocol::ServerCapabilities, resource::Resource, tool::Tool};
 use mcp_server::router::{CapabilitiesBuilder, RouterService};
 use mcp_server::{ByteTransport, Router, Server};
@@ -76,6 +77,13 @@ impl Router for CounterRouter {
                     "properties": {},
                     "required": []
                 }),
+                Some(ToolAnnotations {
+                    title: Some("Increment Tool".to_string()),
+                    read_only_hint: false,
+                    destructive_hint: false,
+                    idempotent_hint: false,
+                    open_world_hint: false,
+                }),
             ),
             Tool::new(
                 "decrement".to_string(),
@@ -85,6 +93,13 @@ impl Router for CounterRouter {
                     "properties": {},
                     "required": []
                 }),
+                Some(ToolAnnotations {
+                    title: Some("Decrement Tool".to_string()),
+                    read_only_hint: false,
+                    destructive_hint: false,
+                    idempotent_hint: false,
+                    open_world_hint: false,
+                }),
             ),
             Tool::new(
                 "get_value".to_string(),
@@ -94,6 +109,13 @@ impl Router for CounterRouter {
                     "properties": {},
                     "required": []
                 }),
+                Some(ToolAnnotations {
+                    title: Some("Get Value Tool".to_string()),
+                    read_only_hint: true,
+                    destructive_hint: false,
+                    idempotent_hint: false,
+                    open_world_hint: false,
+                }),
             ),
         ]
     }

crates/mcp-server/src/router.rs

@@ -116,7 +116,7 @@ pub trait Router: Send + Sync + 'static {
     ) -> impl Future<Output = Result<JsonRpcResponse, RouterError>> + Send {
         async move {
             let result = InitializeResult {
-                protocol_version: "2024-11-05".to_string(),
+                protocol_version: "2025-03-26".to_string(),
                 capabilities: self.capabilities().clone(),
                 server_info: Implementation {
                     name: self.name(),