First slice: ledger-store (journal+blobs+sqlite) and ledger-mcp (18 tools, receipt policy)

crates/ledger-mcp/src/main.rs

@@ -0,0 +1,102 @@
+//! `ledger-mcp`: the AI-first bookkeeping interface, over stdio.
+//!
+//! Usage: `ledger-mcp [--data-dir PATH] [--config PATH]`
+//!
+//! The data dir holds `journal.jsonl` (the source of truth), `wanderbooks.db`
+//! (the disposable SQLite projection), `blobs/` (content-addressed receipts),
+//! and optionally `config.json`. If no store exists, one is created with the
+//! configured base currency.
+
+mod policy;
+mod server;
+mod types;
+
+use ledger_core::Currency;
+use ledger_store::Store;
+use policy::ReceiptPolicy;
+use rmcp::{ServiceExt, transport::stdio};
+use serde::Deserialize;
+use server::BooksServer;
+use std::path::PathBuf;
+
+/// Server configuration, JSON. All fields optional.
+#[derive(Debug, Default, Deserialize)]
+struct Config {
+    /// ISO 4217 base currency for a new store. Default "USD".
+    #[serde(default)]
+    base_currency: Option<String>,
+    /// Receipt policy. Defaults to require-receipts-above $25.00.
+    #[serde(default)]
+    receipt_policy: ReceiptPolicy,
+}
+
+fn default_data_dir() -> PathBuf {
+    let home = std::env::var("HOME").unwrap_or_else(|_| ".".to_string());
+    PathBuf::from(home).join(".local/share/wanderbooks")
+}
+
+fn print_usage() {
+    eprintln!("usage: ledger-mcp [--data-dir PATH] [--config PATH]");
+    eprintln!("  --data-dir  directory holding journal.jsonl (default ~/.local/share/wanderbooks)");
+    eprintln!("  --config    JSON config file (default <data-dir>/config.json, optional)");
+}
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let mut data_dir = default_data_dir();
+    let mut config_path: Option<PathBuf> = None;
+    let mut args = std::env::args().skip(1);
+    while let Some(arg) = args.next() {
+        match arg.as_str() {
+            "--data-dir" => {
+                data_dir = PathBuf::from(args.next().ok_or("--data-dir needs a path")?);
+            }
+            "--config" => {
+                config_path = Some(PathBuf::from(args.next().ok_or("--config needs a path")?));
+            }
+            "--help" | "-h" => {
+                print_usage();
+                return Ok(());
+            }
+            other => {
+                eprintln!("unknown argument: {other}");
+                print_usage();
+                std::process::exit(2);
+            }
+        }
+    }
+    let config_path = config_path.unwrap_or_else(|| data_dir.join("config.json"));
+    let config: Config = if config_path.exists() {
+        let raw = std::fs::read_to_string(&config_path)?;
+        serde_json::from_str(&raw)
+            .map_err(|e| format!("bad config {}: {e}", config_path.display()))?
+    } else {
+        Config::default()
+    };
+    // Logs go to stderr: stdout is the MCP channel.
+    eprintln!("ledger-mcp: data dir {}", data_dir.display());
+
+    let store = if data_dir.join(ledger_store::JOURNAL_FILE).exists() {
+        Store::open(&data_dir)?
+    } else {
+        let code = config.base_currency.as_deref().unwrap_or("USD");
+        let currency = Currency::new(code).map_err(|_| format!("bad base currency {code:?}"))?;
+        eprintln!("ledger-mcp: creating new store (base currency {code})");
+        Store::create(&data_dir, currency)?
+    };
+    // The journal is the source of truth: verify the chain and the
+    // projection before serving a single tool call.
+    store
+        .verify()
+        .map_err(|e| format!("store verify failed: {e}"))?;
+    eprintln!("ledger-mcp: store verified, serving over stdio");
+
+    let server = BooksServer::new(store, config.receipt_policy);
+    let rt = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()?;
+    rt.block_on(async {
+        let running = server.serve(stdio()).await?;
+        let _ = running.waiting().await;
+        Ok::<(), Box<dyn std::error::Error>>(())
+    })
+}