feat: add local agent MCP tools and optional source-grounded AI answers

crates/searchi-cli/src/main.rs

@@ -7,6 +7,7 @@ use clap::{Parser, Subcommand};
 use searchi_core::metrics::{MetricsMode, SearchResponse, TraceCollector};
 use searchi_core::{IndexOptions, SearchIndex, SearchOptions};
 use searchi_service::HybridSearch;
+mod mcp;
 
 #[derive(Debug, Parser)]
 #[command(name = "searchi", version, about = "Search your local files offline")]
@@ -17,6 +18,17 @@ struct Cli {
 
 #[derive(Debug, Subcommand)]
 enum Command {
+    /// Serve read-only local agent tools over MCP stdio (no HTTP listener).
+    Mcp {
+        #[arg(long)]
+        db: PathBuf,
+        #[arg(long, requires = "embedding_worker")]
+        model_dir: Option<PathBuf>,
+        #[arg(long, requires = "model_dir")]
+        embedding_worker: Option<PathBuf>,
+        #[arg(long,default_value_t=1,value_parser=clap::value_parser!(u8).range(1..=8))]
+        cpu_threads: u8,
+    },
     /// Set up the required Google model in the default local cache.
     Setup {
         /// Override the platform-local model cache directory.
@@ -112,6 +124,15 @@ enum Command {
 
 fn main() -> Result<()> {
     match Cli::parse().command {
+        Command::Mcp {
+            db,
+            model_dir,
+            embedding_worker,
+            cpu_threads,
+        } => {
+            require_existing_index(&db)?;
+            mcp::serve(db, model_dir, embedding_worker, usize::from(cpu_threads))?;
+        }
         Command::Setup { model_dir } => {
             let directory = model_dir
                 .map(Ok)