docs: refine user-facing wording for clarity and consistency

1 files changed, 5 insertions, 5 deletions

diff --git a/internal/config/config.go b/internal/config/config.go
index e94b5ea..69173fd 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -176,21 +176,21 @@ func applyEnv(cfg *Config) {
 
 func (c Config) Validate() error {
 	if c.Mode != ModeResolver && c.Mode != ModeMirror && c.Mode != ModeThin {
-		return fmt.Errorf("invalid mode %q", c.Mode)
+		return fmt.Errorf("mode must be one of mirror, resolver, or thin (got %q)", c.Mode)
 	}
 
 	switch c.VerifyPolicy {
 	case VerifyFull, VerifyLazy, VerifyStateOnly:
 	default:
-		return fmt.Errorf("invalid verify policy %q", c.VerifyPolicy)
+		return fmt.Errorf("verify must be one of full, lazy, or state-only (got %q)", c.VerifyPolicy)
 	}
 
 	if c.DataDir == "" {
-		return errors.New("data_dir is required")
+		return errors.New("set data_dir in the config file")
 	}
 
 	if c.PLCSource == "" {
-		return errors.New("plc_source is required")
+		return errors.New("set plc_source in the config file")
 	}
 
 	if c.ZstdLevel < 1 || c.ZstdLevel > 22 {
@@ -226,7 +226,7 @@ func (c Config) Validate() error {
 	}
 
 	if c.ListenAddr == "" {
-		return errors.New("listen_addr is required")
+		return errors.New("set listen_addr in the config file")
 	}
 
 	if c.PollInterval <= 0 {