From 7836eb4eaa4af6075e2d38deb44652aa55adcca6 Mon Sep 17 00:00:00 2001
From: Bryan Helmkamp <bryan@brynary.com>
Date: Sat, 7 Mar 2026 11:31:12 -0500
Subject: [PATCH] Separate serve logs from CLI logs

`arc serve` writes to `serve-YYYY-MM-DD.log` and all other commands
write to `cli-YYYY-MM-DD.log` so the two are easy to tail independently.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 crates/arc-cli/src/logging.rs |  6 ++++--
 crates/arc-cli/src/main.rs    | 10 ++++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/crates/arc-cli/src/logging.rs b/crates/arc-cli/src/logging.rs
index 28cf23bdd..b0abdc305 100644
--- a/crates/arc-cli/src/logging.rs
+++ b/crates/arc-cli/src/logging.rs
@@ -1,7 +1,7 @@
 use anyhow::{Context, Result};
 use tracing_subscriber::{fmt, layer::SubscriberExt, util::SubscriberInitExt, EnvFilter};
 
-pub fn init_tracing(debug: bool) -> Result<()> {
+pub fn init_tracing(debug: bool, log_prefix: &str) -> Result<()> {
     let default_level = if debug { "debug" } else { "info" };
     let filter =
         EnvFilter::try_from_env("ARC_LOG").unwrap_or_else(|_| EnvFilter::new(default_level));
@@ -13,7 +13,9 @@ pub fn init_tracing(debug: bool) -> Result<()> {
     std::fs::create_dir_all(&log_dir)
         .with_context(|| format!("Failed to create log directory: {}", log_dir.display()))?;
 
-    let filename = chrono::Local::now().format("%Y-%m-%d.log").to_string();
+    let filename = chrono::Local::now()
+        .format(&format!("{log_prefix}-%Y-%m-%d.log"))
+        .to_string();
     let file_appender = tracing_appender::rolling::never(&log_dir, &filename);
 
     tracing_subscriber::registry()
diff --git a/crates/arc-cli/src/main.rs b/crates/arc-cli/src/main.rs
index 8bf06cc9b..4a0d971b4 100644
--- a/crates/arc-cli/src/main.rs
+++ b/crates/arc-cli/src/main.rs
@@ -125,10 +125,6 @@ async fn main() -> Result<()> {
         dotenvy::dotenv().ok();
     }
 
-    if let Err(err) = logging::init_tracing(cli.debug) {
-        eprintln!("Warning: failed to initialize logging: {err:#}");
-    }
-
     let command_name = match &cli.command {
         Command::Llm { .. } => "llm",
         Command::Agent(_) => "agent",
@@ -140,6 +136,12 @@ async fn main() -> Result<()> {
         Command::Doctor { .. } => "doctor",
         Command::Setup => "setup",
     };
+
+    let log_prefix = if command_name == "serve" { "serve" } else { "cli" };
+    if let Err(err) = logging::init_tracing(cli.debug, log_prefix) {
+        eprintln!("Warning: failed to initialize logging: {err:#}");
+    }
+
     debug!(command = %command_name, "CLI command started");
 
     match cli.command {