lean_ctx_server/engine/
mod.rs

1// SPDX-License-Identifier: Apache-2.0
2use std::path::PathBuf;
3use std::sync::atomic::{AtomicI64, Ordering};
4
5use anyhow::{Context, Result, anyhow};
6use rmcp::{
7    model::{
8        CallToolRequest, CallToolRequestParams, CallToolResult, ClientJsonRpcMessage,
9        ClientRequest, JsonRpcRequest, NumberOrString, ServerJsonRpcMessage, ServerResult,
10    },
11    service::RoleServer,
12    service::serve_directly,
13    transport::OneshotTransport,
14};
15use serde_json::{Map, Value};
16
17use crate::tools::LeanCtxServer;
18
19pub struct ContextEngine {
20    server: LeanCtxServer,
21    next_id: AtomicI64,
22}
23
24impl ContextEngine {
25    pub fn new() -> Self {
26        Self {
27            server: LeanCtxServer::new(),
28            next_id: AtomicI64::new(1),
29        }
30    }
31
32    pub fn with_project_root(project_root: impl Into<PathBuf>) -> Self {
33        let root = project_root.into().to_string_lossy().to_string();
34        Self {
35            server: LeanCtxServer::new_with_project_root(Some(&root)),
36            next_id: AtomicI64::new(1),
37        }
38    }
39
40    pub fn from_server(server: LeanCtxServer) -> Self {
41        Self {
42            server,
43            next_id: AtomicI64::new(1),
44        }
45    }
46
47    pub fn server(&self) -> &LeanCtxServer {
48        &self.server
49    }
50
51    pub fn manifest(&self) -> Value {
52        lean_ctx::core::mcp_manifest::manifest_value()
53    }
54
55    pub async fn call_tool_value(&self, name: &str, arguments: Option<Value>) -> Result<Value> {
56        let result = self.call_tool_result(name, arguments).await?;
57        serde_json::to_value(result).map_err(|e| anyhow!("serialize CallToolResult: {e}"))
58    }
59
60    pub async fn call_tool_result(
61        &self,
62        name: &str,
63        arguments: Option<Value>,
64    ) -> Result<CallToolResult> {
65        let id = self.next_id.fetch_add(1, Ordering::Relaxed);
66        let req_id = NumberOrString::Number(id);
67
68        let args_obj: Map<String, Value> = match arguments {
69            None => Map::new(),
70            Some(Value::Object(m)) => m,
71            Some(other) => {
72                return Err(anyhow!(
73                    "tool arguments must be a JSON object (got {other})"
74                ));
75            }
76        };
77
78        let params = CallToolRequestParams::new(name.to_string()).with_arguments(args_obj);
79        let call: CallToolRequest = CallToolRequest::new(params);
80        let client_req = ClientRequest::CallToolRequest(call);
81        let msg = ClientJsonRpcMessage::Request(JsonRpcRequest::new(req_id, client_req));
82
83        let (transport, mut rx) = OneshotTransport::<RoleServer>::new(msg);
84        let service = serve_directly(self.server.clone(), transport, None);
85        tokio::spawn(async move {
86            let _ = service.waiting().await;
87        });
88        let deadline = tokio::time::Instant::now() + std::time::Duration::from_mins(2);
89        loop {
90            let server_msg = match tokio::time::timeout_at(deadline, rx.recv()).await {
91                Ok(Some(msg)) => msg,
92                Ok(None) => return Err(anyhow!("no response from tool call")),
93                Err(_) => return Err(anyhow!("tool call timed out after 120s")),
94            };
95
96            match server_msg {
97                ServerJsonRpcMessage::Notification(_) => {}
98                ServerJsonRpcMessage::Response(r) => {
99                    return match r.result {
100                        ServerResult::CallToolResult(result) => Ok(result),
101                        other => Err(anyhow!("unexpected server result: {other:?}")),
102                    };
103                }
104                ServerJsonRpcMessage::Error(e) => {
105                    return Err(anyhow!("{e:?}")).context("tool call error");
106                }
107                ServerJsonRpcMessage::Request(_) => {
108                    return Err(anyhow!("unexpected request"));
109                }
110            }
111        }
112    }
113
114    pub async fn call_tool_text(&self, name: &str, arguments: Option<Value>) -> Result<String> {
115        let result = self.call_tool_result(name, arguments).await?;
116        let mut out = String::new();
117        for c in result.content {
118            if let Some(t) = c.as_text() {
119                out.push_str(&t.text);
120            }
121        }
122        if out.is_empty()
123            && let Some(v) = result.structured_content
124        {
125            out = v.to_string();
126        }
127        Ok(out)
128    }
129}
130
131impl Default for ContextEngine {
132    fn default() -> Self {
133        Self::new()
134    }
135}
136
137/// Stable Rust-native boundary over the existing Local operators.
138pub mod operators;
139
140#[cfg(test)]
141mod canary_sweep_tests;
142#[cfg(test)]
143mod transport_tests;
lean_ctx_server/engine/mod.rs

lean_ctx_server/engine/
mod.rs
