mcp

The estate's MCP layer over rmcp. A project depends on this crate and never names rmcp, so the SDK's version, fork and features are decided in one place, ../Cargo.toml.

Serving a command enum

A project that already takes commands as a serde enum gets an MCP server with no code per command:

/// Commands the daemon takes.
#[derive(Deserialize, JsonSchema)]
#[serde(tag = "type", rename_all = "snake_case")]
enum Command {
    /// Focus the column to the left.
    FocusLeft,
    /// Resize the focused column.
    Resize {
        /// Width delta in pixels.
        delta: i32,
    },
}

CommandServer::new(identity, "type", |command: Command| async move {
    send_to_daemon(command).await // Result<serde_json::Value, String>
})?
.without(&["subscribe"]) // commands that are not one call, one answer
.serve_stdio()
.await?;

Each variant is a tool named by its tag value. Its doc comment is the description, and its fields, with their doc comments, are the arguments. A variant added to the enum is a tool the next time the server starts.