Enum McpCallError 

pub enum McpCallError {
    ResponseTooLarge,
    Internal {
        message: &'static str,
    },
    AuthExpired,
    Mcp {
        message: String,
    },
    Upstream {
        status: u16,
        body: String,
    },
    Transport(String),
    Local(String),
}

Why an outbound MCP tools/call failed. The host fn maps each to a catchable script error (see [mcp_error_to_throw]).

Variants

ResponseTooLarge

The tool ran but its response exceeded the host’s bounded output buffer.

Internal

Internal initialization, allocation or serialization failure; never a guest exception.

Fields

message: &'static str

AuthExpired

OAuth authentication failed. A provider rejection may be transient; surfaces to the script as a catchable McpAuthExpiredError.

Mcp

The server reported a tool-level or JSON-RPC error.

Fields

message: String

Upstream

A non-2xx HTTP response from the server.

Fields

status: u16

body: String

Transport(String)

The request never completed (connection / transport failure).

Local(String)

Refused by this host’s own configuration before anything was sent: unavailable credentials, or the network policy. Reads as a transport error to the script.

Trait Implementations

impl Debug for McpCallError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.