Standalone mcp apps (#6458)

Co-authored-by: Douwe Osinga <douwe@squareup.com>

crates/goose-server/src/openapi.rs

@@ -355,11 +355,13 @@ derive_utoipa!(Icon as IconSchema);
         super::routes::config_management::get_pricing,
         super::routes::agent::start_agent,
         super::routes::agent::resume_agent,
+        super::routes::agent::stop_agent,
         super::routes::agent::restart_agent,
         super::routes::agent::update_working_dir,
         super::routes::agent::get_tools,
         super::routes::agent::read_resource,
         super::routes::agent::call_tool,
+        super::routes::agent::list_apps,
         super::routes::agent::update_from_session,
         super::routes::agent::agent_add_extension,
         super::routes::agent::agent_remove_extension,
@@ -533,8 +535,11 @@ derive_utoipa!(Icon as IconSchema);
         super::routes::agent::ReadResourceResponse,
         super::routes::agent::CallToolRequest,
         super::routes::agent::CallToolResponse,
+        super::routes::agent::ListAppsRequest,
+        super::routes::agent::ListAppsResponse,
         super::routes::agent::StartAgentRequest,
         super::routes::agent::ResumeAgentRequest,
+        super::routes::agent::StopAgentRequest,
         super::routes::agent::RestartAgentRequest,
         super::routes::agent::UpdateWorkingDirRequest,
         super::routes::agent::UpdateFromSessionRequest,
@@ -547,6 +552,8 @@ derive_utoipa!(Icon as IconSchema);
         super::tunnel::TunnelInfo,
         super::tunnel::TunnelState,
         super::routes::telemetry::TelemetryEventRequest,
+        goose::goose_apps::GooseApp,
+        goose::goose_apps::WindowProps,
         goose::goose_apps::McpAppResource,
         goose::goose_apps::CspMetadata,
         goose::goose_apps::UiMetadata,

crates/goose-server/src/routes/agent.rs

@@ -11,6 +11,7 @@ use axum::{
     Json, Router,
 };
 use goose::agents::ExtensionLoadResult;
+use goose::goose_apps::{fetch_mcp_apps, GooseApp, McpAppCache};
 
 use base64::Engine;
 use goose::agents::ExtensionConfig;
@@ -35,7 +36,7 @@ use std::path::PathBuf;
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
 use tokio_util::sync::CancellationToken;
-use tracing::error;
+use tracing::{error, warn};
 
 #[derive(Deserialize, utoipa::ToSchema)]
 pub struct UpdateFromSessionRequest {
@@ -933,6 +934,87 @@ async fn call_tool(
     }))
 }
 
+#[derive(Deserialize, utoipa::IntoParams, utoipa::ToSchema)]
+pub struct ListAppsRequest {
+    session_id: Option<String>,
+}
+
+#[derive(Serialize, utoipa::ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct ListAppsResponse {
+    pub apps: Vec<GooseApp>,
+}
+
+#[utoipa::path(
+    get,
+    path = "/agent/list_apps",
+    params(
+        ListAppsRequest
+    ),
+    responses(
+        (status = 200, description = "List of apps retrieved successfully", body = ListAppsResponse),
+        (status = 401, description = "Unauthorized - Invalid or missing API key", body = ErrorResponse),
+        (status = 500, description = "Internal server error", body = ErrorResponse),
+    ),
+    security(
+        ("api_key" = [])
+    ),
+    tag = "Agent"
+)]
+async fn list_apps(
+    State(state): State<Arc<AppState>>,
+    Query(params): Query<ListAppsRequest>,
+) -> Result<Json<ListAppsResponse>, ErrorResponse> {
+    let cache = McpAppCache::new().ok();
+
+    let Some(session_id) = params.session_id else {
+        let apps = cache
+            .as_ref()
+            .and_then(|c| c.list_apps().ok())
+            .unwrap_or_default();
+        return Ok(Json(ListAppsResponse { apps }));
+    };
+
+    let agent = state
+        .get_agent_for_route(session_id)
+        .await
+        .map_err(|status| ErrorResponse {
+            message: "Failed to get agent".to_string(),
+            status,
+        })?;
+
+    let apps = fetch_mcp_apps(&agent.extension_manager)
+        .await
+        .map_err(|e| ErrorResponse {
+            message: format!("Failed to list apps: {}", e.message),
+            status: StatusCode::INTERNAL_SERVER_ERROR,
+        })?;
+
+    if let Some(cache) = cache.as_ref() {
+        let active_extensions: std::collections::HashSet<String> = apps
+            .iter()
+            .filter_map(|app| app.mcp_server.clone())
+            .collect();
+
+        for extension_name in active_extensions {
+            if let Err(e) = cache.delete_extension_apps(&extension_name) {
+                warn!(
+                    "Failed to clean cache for extension {}: {}",
+                    extension_name, e
+                );
+            }
+        }
+
+        for app in &apps {
+            if let Err(e) = cache.store_app(app) {
+                warn!("Failed to cache app {}: {}", app.resource.name, e);
+            }
+        }
+    }
+
+    Ok(Json(ListAppsResponse { apps }))
+}
+
 pub fn routes(state: Arc<AppState>) -> Router {
     Router::new()
         .route("/agent/start", post(start_agent))
@@ -942,6 +1024,7 @@ pub fn routes(state: Arc<AppState>) -> Router {
         .route("/agent/tools", get(get_tools))
         .route("/agent/read_resource", post(read_resource))
         .route("/agent/call_tool", post(call_tool))
+        .route("/agent/list_apps", get(list_apps))
         .route("/agent/update_provider", post(update_agent_provider))
         .route("/agent/update_from_session", post(update_from_session))
         .route("/agent/add_extension", post(agent_add_extension))

crates/goose/src/goose_apps/mod.rs

@@ -1,9 +1,203 @@
-//! goose Apps module
-//!
-//! This module contains types and utilities for working with goose Apps,
-//! which are UI resources that can be rendered in an MCP server or native
-//! goose apps, or something in between.
-
 pub mod resource;
 
+use crate::agents::ExtensionManager;
+use crate::config::paths::Paths;
+use rmcp::model::ErrorData;
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+use std::fs;
+use std::path::PathBuf;
+use tokio_util::sync::CancellationToken;
+use tracing::warn;
+use utoipa::ToSchema;
+
 pub use resource::{CspMetadata, McpAppResource, ResourceMetadata, UiMetadata};
+
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct WindowProps {
+    pub width: u32,
+    pub height: u32,
+    pub resizable: bool,
+}
+
+/// A Goose App combining MCP resource data with Goose-specific metadata
+#[derive(Debug, Clone, Serialize, Deserialize, ToSchema)]
+#[serde(rename_all = "camelCase")]
+pub struct GooseApp {
+    #[serde(flatten)]
+    pub resource: McpAppResource,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub mcp_server: Option<String>,
+    #[serde(flatten, skip_serializing_if = "Option::is_none")]
+    pub window_props: Option<WindowProps>,
+}
+
+pub struct McpAppCache {
+    cache_dir: PathBuf,
+}
+
+impl McpAppCache {
+    pub fn new() -> Result<Self, std::io::Error> {
+        let config_dir = Paths::config_dir();
+        let cache_dir = config_dir.join("mcp-apps-cache");
+        Ok(Self { cache_dir })
+    }
+
+    fn cache_key(extension_name: &str, resource_uri: &str) -> String {
+        let input = format!("{}::{}", extension_name, resource_uri);
+        let hash = Sha256::digest(input.as_bytes());
+        format!("{}_{:x}", extension_name, hash)
+    }
+
+    pub fn list_apps(&self) -> Result<Vec<GooseApp>, std::io::Error> {
+        let mut apps = Vec::new();
+
+        if !self.cache_dir.exists() {
+            return Ok(apps);
+        }
+
+        for entry in fs::read_dir(&self.cache_dir)? {
+            let entry = entry?;
+            let path = entry.path();
+
+            if path.extension().and_then(|s| s.to_str()) == Some("json") {
+                match fs::read_to_string(&path) {
+                    Ok(content) => match serde_json::from_str::<GooseApp>(&content) {
+                        Ok(app) => apps.push(app),
+                        Err(e) => warn!("Failed to parse cached app from {:?}: {}", path, e),
+                    },
+                    Err(e) => warn!("Failed to read cached app from {:?}: {}", path, e),
+                }
+            }
+        }
+
+        Ok(apps)
+    }
+
+    pub fn store_app(&self, app: &GooseApp) -> Result<(), std::io::Error> {
+        fs::create_dir_all(&self.cache_dir)?;
+
+        if let Some(ref extension_name) = app.mcp_server {
+            let cache_key = Self::cache_key(extension_name, &app.resource.uri);
+            let app_path = self.cache_dir.join(format!("{}.json", cache_key));
+            let json = serde_json::to_string_pretty(app).map_err(std::io::Error::other)?;
+            fs::write(app_path, json)?;
+        }
+
+        Ok(())
+    }
+
+    pub fn get_app(&self, extension_name: &str, resource_uri: &str) -> Option<GooseApp> {
+        let cache_key = Self::cache_key(extension_name, resource_uri);
+        let app_path = self.cache_dir.join(format!("{}.json", cache_key));
+
+        if !app_path.exists() {
+            return None;
+        }
+
+        fs::read_to_string(&app_path)
+            .ok()
+            .and_then(|content| serde_json::from_str::<GooseApp>(&content).ok())
+    }
+
+    pub fn delete_extension_apps(&self, extension_name: &str) -> Result<usize, std::io::Error> {
+        let mut deleted_count = 0;
+
+        if !self.cache_dir.exists() {
+            return Ok(0);
+        }
+
+        for entry in fs::read_dir(&self.cache_dir)? {
+            let entry = entry?;
+            let path = entry.path();
+
+            if path.extension().and_then(|s| s.to_str()) == Some("json") {
+                if let Ok(content) = fs::read_to_string(&path) {
+                    if let Ok(app) = serde_json::from_str::<GooseApp>(&content) {
+                        if app.mcp_server.as_deref() == Some(extension_name)
+                            && fs::remove_file(&path).is_ok()
+                        {
+                            deleted_count += 1;
+                        }
+                    }
+                }
+            }
+        }
+
+        Ok(deleted_count)
+    }
+}
+
+pub async fn fetch_mcp_apps(
+    extension_manager: &ExtensionManager,
+) -> Result<Vec<GooseApp>, ErrorData> {
+    let mut apps = Vec::new();
+
+    let ui_resources = extension_manager.get_ui_resources().await?;
+
+    for (extension_name, resource) in ui_resources {
+        match extension_manager
+            .read_resource(&resource.uri, &extension_name, CancellationToken::default())
+            .await
+        {
+            Ok(read_result) => {
+                let mut html = String::new();
+                for content in read_result.contents {
+                    if let rmcp::model::ResourceContents::TextResourceContents { text, .. } =
+                        content
+                    {
+                        html = text;
+                        break;
+                    }
+                }
+
+                if !html.is_empty() {
+                    let mcp_resource = McpAppResource {
+                        uri: resource.uri.clone(),
+                        name: format_resource_name(resource.name.clone()),
+                        description: resource.description.clone(),
+                        mime_type: "text/html;profile=mcp-app".to_string(),
+                        text: Some(html),
+                        blob: None,
+                        meta: None,
+                    };
+
+                    let app = GooseApp {
+                        resource: mcp_resource,
+                        mcp_server: Some(extension_name),
+                        window_props: Some(WindowProps {
+                            width: 800,
+                            height: 600,
+                            resizable: true,
+                        }),
+                    };
+
+                    apps.push(app);
+                }
+            }
+            Err(e) => {
+                warn!(
+                    "Failed to read resource {} from {}: {}",
+                    resource.uri, extension_name, e
+                );
+            }
+        }
+    }
+
+    Ok(apps)
+}
+
+fn format_resource_name(name: String) -> String {
+    name.replace('_', " ")
+        .split_whitespace()
+        .map(|word| {
+            let mut chars = word.chars();
+            match chars.next() {
+                None => String::new(),
+                Some(first) => first.to_uppercase().chain(chars).collect(),
+            }
+        })
+        .collect::<Vec<_>>()
+        .join(" ")
+}