aldabra/crates/aldabra-mcp/src/main.rs

//! aldabra — MCP server entry point.
//!
//! Speaks MCP over stdio. Any MCP client (e.g. Claude Code)
//! launches this as a subprocess and gets a wallet's worth of tools.
//!
//! ## Phase 1 tools (target — server wiring lands in 1.7)
//!
//! - `wallet.address` — derived CIP-1852 base address
//! - `wallet.balance` — ADA + native-asset balance via chain backend
//! - `wallet.utxos`   — list UTXOs at the wallet address
//! - `wallet.network` — configured network selector
//!
//! ## Phase 2-4 tools
//!
//! See `ROADMAP.md` at the repo root.
//!
//! ## Logging
//!
//! Stderr only — stdout is the MCP transport, must stay clean.

mod bootstrap;
mod config;
mod tools;

use std::process::ExitCode;

use anyhow::Result;
use rmcp::{transport::stdio, ServiceExt};
use tracing_subscriber::EnvFilter;

use crate::config::Config;
use crate::tools::WalletService;

#[tokio::main]
async fn main() -> ExitCode {
    tracing_subscriber::fmt()
        .with_writer(std::io::stderr)
        .with_env_filter(EnvFilter::try_from_default_env().unwrap_or_else(|_| "info".into()))
        .init();

    match run().await {
        Ok(()) => ExitCode::SUCCESS,
        Err(e) => {
            tracing::error!("{e:#}");
            ExitCode::FAILURE
        }
    }
}

async fn run() -> Result<()> {
    let cfg = Config::load()?;
    tracing::info!(
        network = ?cfg.network,
        koios = %cfg.koios_base,
        koios_bearer_set = cfg.koios_bearer.is_some(),
        account = cfg.account,
        index = cfg.index,
        data_dir = %cfg.data_dir.display(),
        safe_reads_root = %cfg.safe_reads_root.display(),
        "aldabra starting"
    );

    // CRIT-2 audit fix (2026-05-12): make sure the sandbox root exists
    // and is daemon-only readable. Tools use canonicalize() against
    // this dir to validate `*_path` args, which requires the dir to
    // be a real directory on disk. Idempotent: create_dir_all is a
    // no-op when the dir already exists.
    //
    // Adversarial-review fix (2026-05-12): chmod is `?`'d not swallowed.
    // If the filesystem refuses chmod (noexec, selinux, broken mount),
    // we'd otherwise silently fall back to the umask default (commonly
    // 0o755) — making the security comment "daemon-only readable" a
    // lie. Fail loudly instead so the operator sees + investigates.
    if !cfg.safe_reads_root.exists() {
        std::fs::create_dir_all(&cfg.safe_reads_root).map_err(|e| {
            anyhow::anyhow!(
                "create safe_reads_root {}: {e}",
                cfg.safe_reads_root.display()
            )
        })?;
        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;
            std::fs::set_permissions(&cfg.safe_reads_root, std::fs::Permissions::from_mode(0o700))
                .map_err(|e| {
                    anyhow::anyhow!(
                        "chmod 0o700 safe_reads_root {}: {e}",
                        cfg.safe_reads_root.display()
                    )
                })?;
        }
    }

    // CLI mode flags — all out-of-band, before the MCP transport
    // takes over stdio.
    //
    // `--generate-mnemonic`   — print a fresh phrase, exit. No disk write.
    // `--bootstrap`           — paste an existing phrase, encrypt, derive.
    // `--bootstrap-new`       — generate, display, encrypt, derive (one shot).
    // `--bootstrap-from-xprv` — paste a root_xsk1... bech32 (cnode root.prv,
    //                          cardano-address output), encrypt, derive.
    //                          Power-user import path for keys that came
    //                          from outside the BIP-39 mnemonic flow.
    // (none)                  — load existing, start MCP server.
    let args: Vec<String> = std::env::args().collect();
    let generate_only = args.iter().any(|a| a == "--generate-mnemonic");
    let bootstrap_only = args.iter().any(|a| a == "--bootstrap");
    let bootstrap_new = args.iter().any(|a| a == "--bootstrap-new");
    let bootstrap_from_xprv = args.iter().any(|a| a == "--bootstrap-from-xprv");

    if generate_only {
        bootstrap::print_fresh_mnemonic()?;
        return Ok(());
    }

    let mnemonic_path = bootstrap::mnemonic_path(&cfg.data_dir);
    let xprv_path = bootstrap::root_xprv_path(&cfg.data_dir);
    let any_key_exists = mnemonic_path.exists() || xprv_path.exists();

    // L-2 audit fix: scope `root` to a block so its XPrv drops + wipes
    // as soon as we've extracted the keys we need.
    let (payment_key, stake_key, address) = {
        let root = if bootstrap_new {
            bootstrap::generate_and_save_root_key(&cfg.data_dir)?
        } else if bootstrap_from_xprv {
            bootstrap::import_root_xprv(&cfg.data_dir)?
        } else if any_key_exists || bootstrap_only {
            // Loads existing (or runs the mnemonic-paste flow on
            // first-run with --bootstrap). load_or_create_root_key
            // itself picks between mnemonic.age and root-xprv.age.
            bootstrap::load_or_create_root_key(&cfg.data_dir)?
        } else {
            anyhow::bail!(
                "no key at {}. run one of:\n  \
                 `aldabra --bootstrap`           (paste existing 24-word phrase)\n  \
                 `aldabra --bootstrap-new`       (generate a fresh wallet)\n  \
                 `aldabra --bootstrap-from-xprv` (paste a root_xsk1... bech32)",
                cfg.data_dir.display()
            );
        };

        let address =
            aldabra_core::derive_base_address(&root, cfg.network, cfg.account, cfg.index)?;
        let payment_key = aldabra_core::derive_payment_key(&root, cfg.account, cfg.index);
        let stake_key = aldabra_core::derive_stake_key(&root, cfg.account);
        (payment_key, stake_key, address)
        // root drops here — XPrv::Drop wipes the 96 bytes
    };
    tracing::info!(%address, "derived base address");

    if bootstrap_only || bootstrap_new {
        eprintln!("aldabra: bootstrap complete. address = {address}");
        return Ok(());
    }

    // Hand off to the MCP server. From this point on stdin/stdout
    // belong to the JSON-RPC transport — no more eprintln-prompting.
    let service = WalletService::new(
        cfg.network,
        address,
        cfg.koios_base,
        cfg.koios_bearer,
        payment_key,
        stake_key,
        cfg.max_send_lovelace,
        cfg.data_dir.clone(),
        cfg.safe_reads_root.clone(),
    );
    let server = service
        .serve(stdio())
        .await
        .map_err(|e| anyhow::anyhow!("rmcp serve failed: {e}"))?;
    server
        .waiting()
        .await
        .map_err(|e| anyhow::anyhow!("rmcp wait failed: {e}"))?;
    Ok(())
}