diff --git a/agent/src/config.rs b/agent/src/config.rs
index 375a562..2f75ca8 100644
--- a/agent/src/config.rs
+++ b/agent/src/config.rs
@@ -105,6 +105,31 @@ impl Default for EncodingConfig {
 }
 
 impl Config {
+    /// Check if an explicit agent configuration file exists
+    /// This returns true only if there's a real config file, not generated defaults
+    pub fn has_agent_config() -> bool {
+        // Check for config in current directory
+        let local_config = PathBuf::from("guruconnect.toml");
+        if local_config.exists() {
+            return true;
+        }
+
+        // Check in program data directory (Windows)
+        #[cfg(windows)]
+        {
+            if let Ok(program_data) = std::env::var("ProgramData") {
+                let path = PathBuf::from(program_data)
+                    .join("GuruConnect")
+                    .join("agent.toml");
+                if path.exists() {
+                    return true;
+                }
+            }
+        }
+
+        false
+    }
+
     /// Load configuration from file or environment
     pub fn load() -> Result<Self> {
         // Try loading from config file
diff --git a/agent/src/main.rs b/agent/src/main.rs
index 7355c1b..7869e8b 100644
--- a/agent/src/main.rs
+++ b/agent/src/main.rs
@@ -221,14 +221,23 @@ fn main() -> Result<()> {
             if let Some(code) = cli.support_code {
                 run_agent_mode(Some(code))
             } else {
-                // No args: check if protocol handler is installed
-                // If not, run install mode (user likely downloaded from web)
+                // No args: check what mode to run
                 if !install::is_protocol_handler_registered() {
+                    // Protocol handler not registered - user likely downloaded from web
+                    // Run installer to set up protocol handler
                     info!("Protocol handler not registered, running installer");
                     run_install(false)
-                } else {
-                    // Protocol handler exists, run as agent
+                } else if config::Config::has_agent_config() {
+                    // Protocol handler exists AND agent config exists
+                    // This is an agent installation - run as agent
+                    info!("Agent config found, running as agent");
                     run_agent_mode(None)
+                } else {
+                    // Protocol handler exists but NO agent config
+                    // This is a viewer-only installation - just exit silently
+                    // The protocol handler will launch the viewer when needed
+                    info!("Viewer-only installation, exiting (use 'guruconnect agent' to run as agent)");
+                    Ok(())
                 }
             }
         }