greentic-mcp-client 1.2.1

Client for remote MCP servers over Streamable HTTP (JSON-RPC 2.0)
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

//! Error types shared by the sans-io proto layer and the native client.

use thiserror::Error;

/// Failure decoding a JSON-RPC envelope from an HTTP body.
#[derive(Debug, Error)]
pub enum ProtoError {
    #[error("response body is not UTF-8: {0}")]
    NotUtf8(#[from] std::str::Utf8Error),
    #[error("decode JSON-RPC response: {0}")]
    Decode(#[from] serde_json::Error),
    #[error("no JSON-RPC response found in SSE stream")]
    NoEnvelope,
    #[error("JSON-RPC response has neither result nor error")]
    MissingResult,
}

/// A JSON-RPC `error` object returned by the server.
#[derive(Debug, Error, PartialEq, Eq)]
#[error("JSON-RPC error {code}: {message}")]
pub struct ServerError {
    pub code: i64,
    pub message: String,
}

/// A `tools/call` result carrying `isError: true`. The message is the
/// server-provided error payload (structured content stringified, or the
/// joined text blocks).
#[derive(Debug, Error, PartialEq, Eq)]
#[error("{message}")]
pub struct ToolCallError {
    pub message: String,
}

/// Unified error surface for the native client. The sans-io layer returns the
/// narrower types above; `McpError` wraps them via `From` so `?` flows.
#[derive(Debug, Error)]
pub enum McpError {
    #[cfg(feature = "native")]
    #[error("transport: {0}")]
    Transport(#[from] reqwest::Error),
    /// Failed to launch a stdio MCP server subprocess (e.g. command not found).
    #[cfg(feature = "native")]
    #[error("failed to spawn stdio MCP server `{command}`: {source}")]
    Spawn {
        command: String,
        source: std::io::Error,
    },
    /// A stdio transport fault: a broken pipe, a read timeout, or the child
    /// exiting before answering a request.
    #[cfg(feature = "native")]
    #[error("stdio transport: {0}")]
    StdioTransport(String),
    #[error("protocol: {0}")]
    Proto(#[from] ProtoError),
    #[error(transparent)]
    Server(#[from] ServerError),
    #[error("tool call failed: {0}")]
    ToolCall(#[from] ToolCallError),
    #[error("initialize result malformed: {0}")]
    BadInitialize(String),
}