--- a/cmds/fleet/src/cmds/build_systems.rs
+++ b/cmds/fleet/src/cmds/build_systems.rs
@@ -120,6 +120,9 @@
 				"--json",
 				// "--show-trace",
 				"--no-link",
+				"--option",
+				"log-lines",
+				"200",
 			])
 			.comparg("--out-link", &built)
 			.arg(
--- a/cmds/fleet/src/command.rs
+++ b/cmds/fleet/src/command.rs
@@ -254,9 +254,12 @@
 							NixLog::Start { text, level: 1, typ: 111, .. } if text.starts_with("waiting for a machine to build ") => {
 								// Useless repeating notification about build
 							}
-							NixLog::Start { text, level: 3, typ: 111, .. } if text.starts_with("resolved derivation:  ") => {
+							NixLog::Start { text, level: 3, typ: 111, .. } if text.starts_with("resolved derivation: ") => {
 								// CA resolved
 							}
+							NixLog::Start { text, level: 1, typ: 111, .. } if text.starts_with("waiting for lock on ") => {
+								// Concurrent build of the same message
+							}
 							NixLog::Stop { .. } => {},
 							NixLog::Result { .. } => {},
 							_ => warn!("unknown log: {:?}", log)
--- a/cmds/fleet/src/main.rs
+++ b/cmds/fleet/src/main.rs
@@ -5,23 +5,56 @@
 
 mod fleetdata;
 
+use std::ffi::OsString;
 use std::io;
 
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, bail, Result};
 use clap::Parser;
 
 use cmds::{build_systems::BuildSystems, info::Info, secrets::Secrets};
 use host::{Config, FleetOpts};
+use tokio::fs;
+use tokio::process::Command;
 use tracing::{info, metadata::LevelFilter};
 use tracing_subscriber::EnvFilter;
 
 #[derive(Parser)]
+struct Prefetch {}
+impl Prefetch {
+	async fn run(&self, config: &Config) -> Result<()> {
+		let mut prefetch_dir = config.directory.to_path_buf();
+		prefetch_dir.push("prefetch");
+		if !prefetch_dir.is_dir() {
+			info!("nothing to prefetch: no prefetch directory");
+			return Ok(());
+		}
+		for entry in std::fs::read_dir(&prefetch_dir)? {
+			let entry = entry?;
+			if !entry.metadata()?.is_file() {
+				bail!("only files should exist in prefetch directory");
+			}
+			info!("prefetching {:?}", entry.file_name());
+			let mut path = OsString::new();
+			path.push("file://");
+			path.push(entry.path());
+			let status = Command::new("nix-prefetch-url").arg(path).status().await?;
+			if !status.success() {
+				bail!("failed with {status}");
+			}
+		}
+		Ok(())
+	}
+}
+
+#[derive(Parser)]
 enum Opts {
 	/// Prepare systems for deployments
 	BuildSystems(BuildSystems),
 	/// Secret management
 	#[clap(subcommand)]
 	Secrets(Secrets),
+	/// Upload prefetch directory to the nix store
+	Prefetch(Prefetch),
 	/// Config parsing
 	Info(Info),
 }
@@ -40,6 +73,7 @@
 		Opts::BuildSystems(c) => c.run(config).await?,
 		Opts::Secrets(s) => s.run(config).await?,
 		Opts::Info(i) => i.run(config).await?,
+		Opts::Prefetch(p) => p.run(config).await?,
 	};
 	Ok(())
 }