context_server: Update types to reflect latest protocol version (`2025-03-26`) (#32377)

Bennet Bo Fenner created 6 months ago

This updates the `types.rs` file to reflect the latest version of the
MCP spec. Next up is making use of some of these new capabilities. Would
also be great to add support for [Streamable HTTP
Transport](https://modelcontextprotocol.io/specification/2025-03-26/basic/transports#streamable-http)

Release Notes:

- N/A

Change summary

crates/agent/src/context_server_tool.rs |  3 ++
crates/context_server/src/protocol.rs   |  7 ++--
crates/context_server/src/types.rs      | 40 +++++++++++++++++++++++++-
3 files changed, 45 insertions(+), 5 deletions(-)

Detailed changes

crates/agent/src/context_server_tool.rs

@@ -123,6 +123,9 @@ impl Tool for ContextServerTool {
                         types::ToolResponseContent::Image { .. } => {
                             log::warn!("Ignoring image content from tool response");
                         }
+                        types::ToolResponseContent::Audio { .. } => {
+                            log::warn!("Ignoring audio content from tool response");
+                        }
                         types::ToolResponseContent::Resource { .. } => {
                             log::warn!("Ignoring resource content from tool response");
                         }

crates/context_server/src/protocol.rs

@@ -20,9 +20,10 @@ impl ModelContextProtocol {
     }
 
     fn supported_protocols() -> Vec<types::ProtocolVersion> {
-        vec![types::ProtocolVersion(
-            types::LATEST_PROTOCOL_VERSION.to_string(),
-        )]
+        vec![
+            types::ProtocolVersion(types::LATEST_PROTOCOL_VERSION.to_string()),
+            types::ProtocolVersion(types::VERSION_2024_11_05.to_string()),
+        ]
     }
 
     pub async fn initialize(

crates/context_server/src/types.rs

@@ -3,7 +3,8 @@ use serde::de::DeserializeOwned;
 use serde::{Deserialize, Serialize};
 use url::Url;
 
-pub const LATEST_PROTOCOL_VERSION: &str = "2024-11-05";
+pub const LATEST_PROTOCOL_VERSION: &str = "2025-03-26";
+pub const VERSION_2024_11_05: &str = "2024-11-05";
 
 pub mod request {
     use super::*;
@@ -291,13 +292,20 @@ pub enum MessageContent {
         #[serde(skip_serializing_if = "Option::is_none")]
         annotations: Option<MessageAnnotations>,
     },
-    #[serde(rename = "image")]
+    #[serde(rename = "image", rename_all = "camelCase")]
     Image {
         data: String,
         mime_type: String,
         #[serde(skip_serializing_if = "Option::is_none")]
         annotations: Option<MessageAnnotations>,
     },
+    #[serde(rename = "audio", rename_all = "camelCase")]
+    Audio {
+        data: String,
+        mime_type: String,
+        #[serde(skip_serializing_if = "Option::is_none")]
+        annotations: Option<MessageAnnotations>,
+    },
     #[serde(rename = "resource")]
     Resource {
         resource: ResourceContents,
@@ -394,6 +402,8 @@ pub struct ServerCapabilities {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub logging: Option<serde_json::Value>,
     #[serde(skip_serializing_if = "Option::is_none")]
+    pub completions: Option<serde_json::Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub prompts: Option<PromptsCapabilities>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub resources: Option<ResourcesCapabilities>,
@@ -438,6 +448,28 @@ pub struct Tool {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub description: Option<String>,
     pub input_schema: serde_json::Value,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub annotations: Option<ToolAnnotations>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ToolAnnotations {
+    /// A human-readable title for the tool.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub title: Option<String>,
+    /// If true, the tool does not modify its environment.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub read_only_hint: Option<bool>,
+    /// If true, the tool may perform destructive updates to its environment.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub destructive_hint: Option<bool>,
+    /// If true, calling the tool repeatedly with the same arguments will have no additional effect on its environment.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub idempotent_hint: Option<bool>,
+    /// If true, this tool may interact with an "open world" of external entities.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub open_world_hint: Option<bool>,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -582,6 +614,8 @@ pub struct ProgressParams {
     pub progress_token: ProgressToken,
     pub progress: f64,
     #[serde(skip_serializing_if = "Option::is_none")]
+    pub message: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub total: Option<f64>,
     #[serde(rename = "_meta", skip_serializing_if = "Option::is_none")]
     pub meta: Option<HashMap<String, serde_json::Value>>,
@@ -625,6 +659,8 @@ pub enum ToolResponseContent {
     Text { text: String },
     #[serde(rename = "image", rename_all = "camelCase")]
     Image { data: String, mime_type: String },
+    #[serde(rename = "audio", rename_all = "camelCase")]
+    Audio { data: String, mime_type: String },
     #[serde(rename = "resource")]
     Resource { resource: ResourceContents },
 }