codemem-mcp 0.4.0

MCP server for Codemem (JSON-RPC 2.0 over stdio)
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145

//! Protocol types for the MCP JSON-RPC server.

use serde::{Deserialize, Serialize};
use serde_json::Value;

// ── JSON-RPC Types ──────────────────────────────────────────────────────────

/// JSON-RPC 2.0 request.
#[derive(Debug, Deserialize)]
pub struct JsonRpcRequest {
    pub jsonrpc: String,
    /// Absent for notifications (no response expected).
    pub id: Option<Value>,
    pub method: String,
    #[serde(default)]
    pub params: Option<Value>,
}

/// JSON-RPC 2.0 response.
#[derive(Debug, Serialize)]
pub struct JsonRpcResponse {
    pub jsonrpc: String,
    pub id: Value,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub result: Option<Value>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub error: Option<JsonRpcError>,
}

/// JSON-RPC 2.0 error object.
#[derive(Debug, Serialize)]
pub struct JsonRpcError {
    pub code: i64,
    pub message: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub data: Option<Value>,
}

impl JsonRpcResponse {
    pub(crate) fn success(id: Value, result: Value) -> Self {
        Self {
            jsonrpc: "2.0".to_string(),
            id,
            result: Some(result),
            error: None,
        }
    }

    pub(crate) fn error(id: Value, code: i64, message: impl Into<String>) -> Self {
        Self {
            jsonrpc: "2.0".to_string(),
            id,
            result: None,
            error: Some(JsonRpcError {
                code,
                message: message.into(),
                data: None,
            }),
        }
    }
}

// ── Tool Result Types ───────────────────────────────────────────────────────

/// MCP tool result (content array + isError flag).
#[derive(Debug, Serialize)]
pub struct ToolResult {
    pub content: Vec<ToolContent>,
    #[serde(rename = "isError")]
    pub is_error: bool,
}

/// A single content block in a tool result.
#[derive(Debug, Serialize)]
pub struct ToolContent {
    #[serde(rename = "type")]
    pub content_type: String,
    pub text: String,
}

impl ToolResult {
    pub(crate) fn text(msg: impl Into<String>) -> Self {
        Self {
            content: vec![ToolContent {
                content_type: "text".to_string(),
                text: msg.into(),
            }],
            is_error: false,
        }
    }

    pub(crate) fn tool_error(msg: impl Into<String>) -> Self {
        Self {
            content: vec![ToolContent {
                content_type: "text".to_string(),
                text: msg.into(),
            }],
            is_error: true,
        }
    }
}

// ── Index Cache ─────────────────────────────────────────────────────────────

/// Cached code-index results for structural queries.
pub(crate) struct IndexCache {
    pub(crate) symbols: Vec<codemem_index::Symbol>,
    pub(crate) root_path: String,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn parse_json_rpc_request() {
        let json = r#"{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}"#;
        let req: JsonRpcRequest = serde_json::from_str(json).unwrap();
        assert_eq!(req.method, "initialize");
        assert!(req.id.is_some());
    }

    #[test]
    fn parse_notification_no_id() {
        let json = r#"{"jsonrpc":"2.0","method":"notifications/initialized"}"#;
        let req: JsonRpcRequest = serde_json::from_str(json).unwrap();
        assert!(req.id.is_none());
    }

    #[test]
    fn tool_result_serialization() {
        let result = ToolResult::text("hello");
        let json = serde_json::to_value(&result).unwrap();
        assert_eq!(json["content"][0]["type"], "text");
        assert_eq!(json["content"][0]["text"], "hello");
        assert_eq!(json["isError"], false);
    }

    #[test]
    fn tool_error_serialization() {
        let result = ToolResult::tool_error("something went wrong");
        let json = serde_json::to_value(&result).unwrap();
        assert_eq!(json["isError"], true);
    }
}