diff --git a/internal/store/pg/secure_cli.go b/internal/store/pg/secure_cli.go
index 1d88d4b2..96c882d9 100644
--- a/internal/store/pg/secure_cli.go
+++ b/internal/store/pg/secure_cli.go
@@ -26,6 +26,11 @@ func NewPGSecureCLIStore(db *sql.DB, encryptionKey string) *PGSecureCLIStore {
 const secureCLISelectCols = `id, binary_name, binary_path, description, encrypted_env,
  deny_args, deny_verbose, timeout_seconds, tips, agent_id, enabled, created_by, created_at, updated_at`
 
+// secureCLISelectColsAliased is the same as secureCLISelectCols but prefixed with table alias "b."
+// Required for LookupByBinary which uses LEFT JOIN (ambiguous column names without prefix).
+const secureCLISelectColsAliased = `b.id, b.binary_name, b.binary_path, b.description, b.encrypted_env,
+ b.deny_args, b.deny_verbose, b.timeout_seconds, b.tips, b.agent_id, b.enabled, b.created_by, b.created_at, b.updated_at`
+
 func (s *PGSecureCLIStore) Create(ctx context.Context, b *store.SecureCLIBinary) error {
 	if err := store.ValidateUserID(b.CreatedBy); err != nil {
 		return err
@@ -271,7 +276,8 @@ func (s *PGSecureCLIStore) LookupByBinary(ctx context.Context, binaryName string
 	}
 
 	// Build query with optional LEFT JOIN for per-user credentials.
-	selectCols := secureCLISelectCols
+	// Use aliased columns (b.) to avoid ambiguous column reference with JOIN.
+	selectCols := secureCLISelectColsAliased
 	joinClause := ""
 	if userID != "" {
 		selectCols += ", uc.encrypted_env AS user_env"
diff --git a/internal/tools/credentialed_exec.go b/internal/tools/credentialed_exec.go
index 1fb41363..7d818d48 100644
--- a/internal/tools/credentialed_exec.go
+++ b/internal/tools/credentialed_exec.go
@@ -281,6 +281,7 @@ func formatCredentialedResult(binary string, args []string,
 // Returns the credential config and parsed args, or nil if not credentialed.
 func (t *ExecTool) lookupCredentialedBinary(ctx context.Context, command string) (*store.SecureCLIBinary, string, []string) {
 	if t.secureCLIStore == nil {
+		slog.Warn("secure_cli.lookup: store is nil, skipping credentialed exec", "command", command)
 		return nil, "", nil
 	}
 	binary, args, err := parseCommandBinary(command)
@@ -296,9 +297,15 @@ func (t *ExecTool) lookupCredentialedBinary(ctx context.Context, command string)
 	// Pass userID for per-user credential resolution (LEFT JOIN, zero extra queries).
 	userID := store.UserIDFromContext(ctx)
 	cred, err := t.secureCLIStore.LookupByBinary(ctx, binary, agentIDPtr, userID)
-	if err != nil || cred == nil {
+	if err != nil {
+		slog.Warn("secure_cli.lookup: query failed", "binary", binary, "agent_id", agentID, "error", err)
 		return nil, "", nil
 	}
+	if cred == nil {
+		slog.Warn("secure_cli.lookup: no credential found", "binary", binary, "agent_id", agentID)
+		return nil, "", nil
+	}
+	slog.Info("secure_cli.lookup: found credential", "binary", binary, "cred_id", cred.ID, "env_size", len(cred.EncryptedEnv))
 	return cred, binary, args
 }