refactor(workspace)!: move MCP crates under crates/mcp/ and update paths

This commit is contained in:
2025-10-17 00:31:35 +02:00
parent 3271697f6b
commit d4030dc598
14 changed files with 10 additions and 10 deletions

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[package]
name = "owlen-mcp-prompt-server"
version = "0.1.0"
edition.workspace = true
description = "MCP server that renders prompt templates (YAML) for Owlen"
license = "AGPL-3.0"
[dependencies]
owlen-core = { path = "../../owlen-core" }
serde = { workspace = true }
serde_json = { workspace = true }
serde_yaml = { workspace = true }
tokio = { workspace = true }
anyhow = { workspace = true }
handlebars = { workspace = true }
dirs = { workspace = true }
futures = { workspace = true }
[lib]
name = "owlen_mcp_prompt_server"
path = "src/lib.rs"

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//! MCP server for rendering prompt templates with YAML storage and Handlebars rendering.
//!
//! Templates are stored in `~/.config/owlen/prompts/` as YAML files.
//! Provides full Handlebars templating support for dynamic prompt generation.
use anyhow::{Context, Result};
use handlebars::Handlebars;
use serde::{Deserialize, Serialize};
use serde_json::{Value, json};
use std::collections::HashMap;
use std::fs;
use std::path::{Path, PathBuf};
use std::sync::Arc;
use tokio::sync::RwLock;
use owlen_core::mcp::protocol::{
ErrorCode, InitializeParams, InitializeResult, PROTOCOL_VERSION, RequestId, RpcError,
RpcErrorResponse, RpcRequest, RpcResponse, ServerCapabilities, ServerInfo, methods,
};
use owlen_core::mcp::{McpToolCall, McpToolDescriptor, McpToolResponse};
use tokio::io::{self, AsyncBufReadExt, AsyncWriteExt};
/// Prompt template definition
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PromptTemplate {
/// Template name
pub name: String,
/// Template version
pub version: String,
/// Optional mode restriction
#[serde(skip_serializing_if = "Option::is_none")]
pub mode: Option<String>,
/// Handlebars template content
pub template: String,
/// Template description
#[serde(skip_serializing_if = "Option::is_none")]
pub description: Option<String>,
}
/// Prompt server managing templates
pub struct PromptServer {
templates: Arc<RwLock<HashMap<String, PromptTemplate>>>,
handlebars: Handlebars<'static>,
templates_dir: PathBuf,
}
impl PromptServer {
/// Create a new prompt server
pub fn new() -> Result<Self> {
let templates_dir = Self::get_templates_dir()?;
// Create templates directory if it doesn't exist
if !templates_dir.exists() {
fs::create_dir_all(&templates_dir)?;
Self::create_default_templates(&templates_dir)?;
}
let mut server = Self {
templates: Arc::new(RwLock::new(HashMap::new())),
handlebars: Handlebars::new(),
templates_dir,
};
// Load all templates
server.load_templates()?;
Ok(server)
}
/// Get the templates directory path
fn get_templates_dir() -> Result<PathBuf> {
let config_dir = dirs::config_dir().context("Could not determine config directory")?;
Ok(config_dir.join("owlen").join("prompts"))
}
/// Create default template examples
fn create_default_templates(dir: &Path) -> Result<()> {
let chat_mode_system = PromptTemplate {
name: "chat_mode_system".to_string(),
version: "1.0".to_string(),
mode: Some("chat".to_string()),
description: Some("System prompt for chat mode".to_string()),
template: r#"You are Owlen, a helpful AI assistant. You have access to these tools:
{{#each tools}}
- {{name}}: {{description}}
{{/each}}
Use the ReAct pattern:
THOUGHT: Your reasoning
ACTION: tool_name
ACTION_INPUT: {"param": "value"}
When you have enough information:
FINAL_ANSWER: Your response"#
.to_string(),
};
let code_mode_system = PromptTemplate {
name: "code_mode_system".to_string(),
version: "1.0".to_string(),
mode: Some("code".to_string()),
description: Some("System prompt for code mode".to_string()),
template: r#"You are Owlen in code mode, with full development capabilities. You have access to:
{{#each tools}}
- {{name}}: {{description}}
{{/each}}
Use the ReAct pattern to solve coding tasks:
THOUGHT: Analyze what needs to be done
ACTION: tool_name (compile_project, run_tests, format_code, lint_code, etc.)
ACTION_INPUT: {"param": "value"}
Continue iterating until the task is complete, then provide:
FINAL_ANSWER: Summary of what was done"#
.to_string(),
};
// Save templates
let chat_path = dir.join("chat_mode_system.yaml");
let code_path = dir.join("code_mode_system.yaml");
fs::write(chat_path, serde_yaml::to_string(&chat_mode_system)?)?;
fs::write(code_path, serde_yaml::to_string(&code_mode_system)?)?;
Ok(())
}
/// Load all templates from the templates directory
fn load_templates(&mut self) -> Result<()> {
let entries = fs::read_dir(&self.templates_dir)?;
for entry in entries {
let entry = entry?;
let path = entry.path();
if path.extension().and_then(|s| s.to_str()) == Some("yaml")
|| path.extension().and_then(|s| s.to_str()) == Some("yml")
{
match self.load_template(&path) {
Ok(template) => {
// Register with Handlebars
if let Err(e) = self
.handlebars
.register_template_string(&template.name, &template.template)
{
eprintln!(
"Warning: Failed to register template {}: {}",
template.name, e
);
} else {
let mut templates = self.templates.blocking_write();
templates.insert(template.name.clone(), template);
}
}
Err(e) => {
eprintln!("Warning: Failed to load template {:?}: {}", path, e);
}
}
}
}
Ok(())
}
/// Load a single template from file
fn load_template(&self, path: &Path) -> Result<PromptTemplate> {
let content = fs::read_to_string(path)?;
let template: PromptTemplate = serde_yaml::from_str(&content)?;
Ok(template)
}
/// Get a template by name
pub async fn get_template(&self, name: &str) -> Option<PromptTemplate> {
let templates = self.templates.read().await;
templates.get(name).cloned()
}
/// List all available templates
pub async fn list_templates(&self) -> Vec<String> {
let templates = self.templates.read().await;
templates.keys().cloned().collect()
}
/// Render a template with given variables
pub fn render_template(&self, name: &str, vars: &Value) -> Result<String> {
self.handlebars
.render(name, vars)
.context("Failed to render template")
}
/// Reload all templates from disk
pub async fn reload_templates(&mut self) -> Result<()> {
{
let mut templates = self.templates.write().await;
templates.clear();
}
self.handlebars = Handlebars::new();
self.load_templates()
}
}
#[allow(dead_code)]
#[tokio::main]
async fn main() -> anyhow::Result<()> {
let mut stdin = io::BufReader::new(io::stdin());
let mut stdout = io::stdout();
let server = Arc::new(tokio::sync::Mutex::new(PromptServer::new()?));
loop {
let mut line = String::new();
match stdin.read_line(&mut line).await {
Ok(0) => break, // EOF
Ok(_) => {
let req: RpcRequest = match serde_json::from_str(&line) {
Ok(r) => r,
Err(e) => {
let err = RpcErrorResponse::new(
RequestId::Number(0),
RpcError::parse_error(format!("Parse error: {}", e)),
);
let s = serde_json::to_string(&err)?;
stdout.write_all(s.as_bytes()).await?;
stdout.write_all(b"\n").await?;
stdout.flush().await?;
continue;
}
};
let resp = handle_request(req.clone(), server.clone()).await;
match resp {
Ok(r) => {
let s = serde_json::to_string(&r)?;
stdout.write_all(s.as_bytes()).await?;
stdout.write_all(b"\n").await?;
stdout.flush().await?;
}
Err(e) => {
let err = RpcErrorResponse::new(req.id.clone(), e);
let s = serde_json::to_string(&err)?;
stdout.write_all(s.as_bytes()).await?;
stdout.write_all(b"\n").await?;
stdout.flush().await?;
}
}
}
Err(e) => {
eprintln!("Error reading stdin: {}", e);
break;
}
}
}
Ok(())
}
#[allow(dead_code)]
async fn handle_request(
req: RpcRequest,
server: Arc<tokio::sync::Mutex<PromptServer>>,
) -> Result<RpcResponse, RpcError> {
match req.method.as_str() {
methods::INITIALIZE => {
let params: InitializeParams =
serde_json::from_value(req.params.unwrap_or_else(|| json!({})))
.map_err(|e| RpcError::invalid_params(format!("Invalid init params: {}", e)))?;
if !params.protocol_version.eq(PROTOCOL_VERSION) {
return Err(RpcError::new(
ErrorCode::INVALID_REQUEST,
format!(
"Incompatible protocol version. Client: {}, Server: {}",
params.protocol_version, PROTOCOL_VERSION
),
));
}
let result = InitializeResult {
protocol_version: PROTOCOL_VERSION.to_string(),
server_info: ServerInfo {
name: "owlen-mcp-prompt-server".to_string(),
version: env!("CARGO_PKG_VERSION").to_string(),
},
capabilities: ServerCapabilities {
supports_tools: Some(true),
supports_resources: Some(false),
supports_streaming: Some(false),
},
};
let payload = serde_json::to_value(result).map_err(|e| {
RpcError::internal_error(format!("Failed to serialize initialize result: {}", e))
})?;
Ok(RpcResponse::new(req.id, payload))
}
methods::TOOLS_LIST => {
let tools = vec![
McpToolDescriptor {
name: "get_prompt".to_string(),
description: "Retrieve a prompt template by name".to_string(),
input_schema: json!({
"type": "object",
"properties": {
"name": {"type": "string", "description": "Template name"}
},
"required": ["name"]
}),
requires_network: false,
requires_filesystem: vec![],
},
McpToolDescriptor {
name: "render_prompt".to_string(),
description: "Render a prompt template with Handlebars variables".to_string(),
input_schema: json!({
"type": "object",
"properties": {
"name": {"type": "string", "description": "Template name"},
"vars": {"type": "object", "description": "Variables for Handlebars rendering"}
},
"required": ["name"]
}),
requires_network: false,
requires_filesystem: vec![],
},
McpToolDescriptor {
name: "list_prompts".to_string(),
description: "List all available prompt templates".to_string(),
input_schema: json!({"type": "object", "properties": {}}),
requires_network: false,
requires_filesystem: vec![],
},
McpToolDescriptor {
name: "reload_prompts".to_string(),
description: "Reload all prompts from disk".to_string(),
input_schema: json!({"type": "object", "properties": {}}),
requires_network: false,
requires_filesystem: vec![],
},
];
Ok(RpcResponse::new(req.id, json!(tools)))
}
methods::TOOLS_CALL => {
let call: McpToolCall = serde_json::from_value(req.params.unwrap_or_else(|| json!({})))
.map_err(|e| RpcError::invalid_params(format!("Invalid tool call: {}", e)))?;
let result = match call.name.as_str() {
"get_prompt" => {
let name = call
.arguments
.get("name")
.and_then(|v| v.as_str())
.ok_or_else(|| RpcError::invalid_params("Missing 'name' parameter"))?;
let srv = server.lock().await;
match srv.get_template(name).await {
Some(template) => match serde_json::to_value(template) {
Ok(serialized) => {
json!({"success": true, "template": serialized})
}
Err(e) => {
return Err(RpcError::internal_error(format!(
"Failed to serialize template '{}': {}",
name, e
)));
}
},
None => json!({"success": false, "error": "Template not found"}),
}
}
"render_prompt" => {
let name = call
.arguments
.get("name")
.and_then(|v| v.as_str())
.ok_or_else(|| RpcError::invalid_params("Missing 'name' parameter"))?;
let default_vars = json!({});
let vars = call.arguments.get("vars").unwrap_or(&default_vars);
let srv = server.lock().await;
match srv.render_template(name, vars) {
Ok(rendered) => json!({"success": true, "rendered": rendered}),
Err(e) => json!({"success": false, "error": e.to_string()}),
}
}
"list_prompts" => {
let srv = server.lock().await;
let templates = srv.list_templates().await;
json!({"success": true, "templates": templates})
}
"reload_prompts" => {
let mut srv = server.lock().await;
match srv.reload_templates().await {
Ok(_) => json!({"success": true, "message": "Prompts reloaded"}),
Err(e) => json!({"success": false, "error": e.to_string()}),
}
}
_ => return Err(RpcError::method_not_found(&call.name)),
};
let resp = McpToolResponse {
name: call.name,
success: result
.get("success")
.and_then(|v| v.as_bool())
.unwrap_or(false),
output: result,
metadata: HashMap::new(),
duration_ms: 0,
};
let payload = serde_json::to_value(resp).map_err(|e| {
RpcError::internal_error(format!("Failed to serialize tool response: {}", e))
})?;
Ok(RpcResponse::new(req.id, payload))
}
_ => Err(RpcError::method_not_found(&req.method)),
}
}

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prompt: |
Hello {{name}}!
Your role is: {{role}}.