diff --git a/clients/clojure/sync/src/un.clj b/clients/clojure/sync/src/un.clj
index 20ad8aa..a733b60 100644
--- a/clients/clojure/sync/src/un.clj
+++ b/clients/clojure/sync/src/un.clj
@@ -118,17 +118,51 @@
     (or (second (re-find pattern-str json-str))
         (second (re-find pattern-num json-str)))))
 
+(def ^:dynamic *account-index* nil)
+
+(defn load-accounts-csv [path index]
+  (when (.exists (io/file path))
+    (try
+      (let [lines (str/split-lines (slurp path))
+            rows (->> lines
+                      (filter #(and (> (count %) 0)
+                                    (not (str/starts-with? % "#"))))
+                      (map #(str/split % #"," 2))
+                      (filter #(>= (count %) 2)))]
+        (when (< index (count rows))
+          (let [row (nth rows index)]
+            [(str/trim (first row)) (str/trim (second row))])))
+      (catch Exception _ nil))))
+
 (defn get-api-keys []
   (let [public-key (System/getenv "UNSANDBOX_PUBLIC_KEY")
         secret-key (System/getenv "UNSANDBOX_SECRET_KEY")
-        api-key (System/getenv "UNSANDBOX_API_KEY")]
+        api-key (System/getenv "UNSANDBOX_API_KEY")
+        home (System/getenv "HOME")
+        account-idx (or *account-index* 0)]
     (cond
+      ;; --account N: load row N from accounts.csv, bypasses env vars
+      (some? *account-index*)
+      (or (load-accounts-csv (str home "/.unsandbox/accounts.csv") account-idx)
+          (load-accounts-csv "./accounts.csv" account-idx)
+          (do
+            (binding [*out* *err*]
+              (println (str "Error: account " account-idx " not found in accounts.csv")))
+            (System/exit 1)))
+      ;; env vars
       (and public-key secret-key) [public-key secret-key]
       api-key [api-key nil]
-      :else (do
+      ;; accounts.csv fallback (row 0 or UNSANDBOX_ACCOUNT)
+      :else
+      (let [row-idx (if-let [acc (System/getenv "UNSANDBOX_ACCOUNT")]
+                      (try (Integer/parseInt acc) (catch Exception _ 0))
+                      0)]
+        (or (load-accounts-csv (str home "/.unsandbox/accounts.csv") row-idx)
+            (load-accounts-csv "./accounts.csv" row-idx)
+            (do
               (binding [*out* *err*]
                 (println "Error: UNSANDBOX_PUBLIC_KEY and UNSANDBOX_SECRET_KEY not set (or UNSANDBOX_API_KEY for backwards compat)"))
-              (System/exit 1)))))
+              (System/exit 1)))))))
 
 (defn get-api-key []
   (first (get-api-keys)))
@@ -1216,4 +1250,14 @@
       (recur (rest args) file env-vars artifacts out-dir network vcpu session-action session-id session-shell session-input-files
              service-action service-id service-name service-ports service-bootstrap service-bootstrap-file service-type service-input-files service-envs service-env-file service-unfreeze-on-demand key-extend image-action image-id image-source-type image-visibility image-name image-ports mode))))
 
-(parse-args *command-line-args*)
+(let [raw-args *command-line-args*
+      account-val (second (drop-while #(not= % "--account") raw-args))
+      account-idx (when account-val
+                    (try (Integer/parseInt account-val) (catch Exception _ nil)))
+      filtered-args (loop [in raw-args out []]
+                      (cond
+                        (empty? in) out
+                        (= (first in) "--account") (recur (drop 2 in) out)
+                        :else (recur (rest in) (conj out (first in)))))]
+  (binding [*account-index* account-idx]
+    (parse-args filtered-args)))
diff --git a/clients/lisp/sync/src/un.lisp b/clients/lisp/sync/src/un.lisp
index 67e2829..52f340e 100644
--- a/clients/lisp/sync/src/un.lisp
+++ b/clients/lisp/sync/src/un.lisp
@@ -343,16 +343,63 @@
   (curl-delete api-key (format nil "/services/~a/env" service-id))
   (format t "~aVault deleted: ~a~a~%" *green* service-id *reset*))
 
+(defparameter *account-index* nil)
+
+(defun load-accounts-csv (path index)
+  "Load row INDEX from a CSV file of public_key,secret_key pairs.
+   Skips blank lines and lines starting with #. Returns (list pk sk) or nil."
+  (when (probe-file path)
+    (handler-case
+      (with-open-file (stream path)
+        (let ((rows nil))
+          (loop for line = (read-line stream nil nil)
+                while line do
+                (let ((trimmed (string-trim '(#\Space #\Tab #\Return) line)))
+                  (when (and (> (length trimmed) 0)
+                             (not (char= (char trimmed 0) #\#)))
+                    (let ((comma-pos (position #\, trimmed)))
+                      (when comma-pos
+                        (push (list (string-trim '(#\Space #\Tab) (subseq trimmed 0 comma-pos))
+                                    (string-trim '(#\Space #\Tab) (subseq trimmed (1+ comma-pos))))
+                              rows))))))
+          (let ((rows (nreverse rows)))
+            (when (< index (length rows))
+              (nth index rows)))))
+      (error () nil))))
+
 (defun get-api-keys ()
   (let ((public-key (uiop:getenv "UNSANDBOX_PUBLIC_KEY"))
         (secret-key (uiop:getenv "UNSANDBOX_SECRET_KEY"))
-        (api-key (uiop:getenv "UNSANDBOX_API_KEY")))
+        (api-key (uiop:getenv "UNSANDBOX_API_KEY"))
+        (home (uiop:getenv "HOME")))
     (cond
+      ;; --account N: load row N from accounts.csv, bypasses env vars
+      ((not (null *account-index*))
+       (let ((result (or (load-accounts-csv
+                           (format nil "~a/.unsandbox/accounts.csv" home)
+                           *account-index*)
+                         (load-accounts-csv "./accounts.csv" *account-index*))))
+         (or result
+             (progn
+               (format *error-output* "Error: account ~a not found in accounts.csv~%" *account-index*)
+               (uiop:quit 1)))))
+      ;; env vars
       ((and public-key secret-key) (list public-key secret-key))
       (api-key (list api-key nil))
-      (t (progn
-           (format t "Error: UNSANDBOX_PUBLIC_KEY and UNSANDBOX_SECRET_KEY not set (or UNSANDBOX_API_KEY for backwards compat)~%")
-           (uiop:quit 1))))))
+      ;; accounts.csv fallback (row 0 or UNSANDBOX_ACCOUNT env var)
+      (t
+       (let* ((acc-env (uiop:getenv "UNSANDBOX_ACCOUNT"))
+              (row-idx (if acc-env
+                           (handler-case (parse-integer acc-env) (error () 0))
+                           0))
+              (result (or (load-accounts-csv
+                            (format nil "~a/.unsandbox/accounts.csv" home)
+                            row-idx)
+                          (load-accounts-csv "./accounts.csv" row-idx))))
+         (or result
+             (progn
+               (format *error-output* "Error: UNSANDBOX_PUBLIC_KEY and UNSANDBOX_SECRET_KEY not set (or UNSANDBOX_API_KEY for backwards compat)~%")
+               (uiop:quit 1))))))))
 
 (defun get-api-key ()
   (first (get-api-keys)))
@@ -912,8 +959,26 @@
                     do (format t "~a~%" (subseq array-content (1+ start) end))))
             (format t "")))))
 
+(defun strip-account-flag (args)
+  "Remove --account N from args, set *account-index* as side-effect. Returns filtered args."
+  (let ((result nil)
+        (i 0)
+        (vec (coerce args 'vector)))
+    (loop while (< i (length vec)) do
+      (cond
+        ((string= (aref vec i) "--account")
+         (when (< (+ i 1) (length vec))
+           (setf *account-index*
+                 (handler-case (parse-integer (aref vec (+ i 1))) (error () nil))))
+         (incf i 2))
+        (t
+         (push (aref vec i) result)
+         (incf i))))
+    (nreverse result)))
+
 (defun main ()
-  (let ((args (uiop:command-line-arguments)))
+  (let* ((raw-args (uiop:command-line-arguments))
+         (args (strip-account-flag raw-args)))
     (if (null args)
         (progn
           (format t "Usage: un.lisp [options] <source_file>~%")
diff --git a/clients/powershell/sync/src/un.ps1 b/clients/powershell/sync/src/un.ps1
index 4c54cd6..ad0ad95 100644
--- a/clients/powershell/sync/src/un.ps1
+++ b/clients/powershell/sync/src/un.ps1
@@ -61,7 +61,43 @@ $EXT_MAP = @{
     ".raku" = "raku"; ".m" = "objc"; ".awk" = "awk"
 }
 
+$script:AccountIndex = $null
+
+function Load-AccountsCSV {
+    param($Path, $Index)
+    if (-not (Test-Path $Path)) { return $null }
+    try {
+        $rows = @()
+        Get-Content $Path | Where-Object {
+            $_.Trim() -ne "" -and -not $_.TrimStart().StartsWith("#")
+        } | ForEach-Object {
+            $parts = $_ -split ",", 2
+            if ($parts.Count -ge 2) {
+                $rows += ,@($parts[0].Trim(), $parts[1].Trim())
+            }
+        }
+        if ($Index -lt $rows.Count) {
+            return $rows[$Index]
+        }
+    } catch {}
+    return $null
+}
+
 function Get-ApiKeys {
+    $home = $env:HOME
+    if (-not $home) { $home = $env:USERPROFILE }
+
+    # --account N: load row N from accounts.csv, bypasses env vars
+    if ($null -ne $script:AccountIndex) {
+        $result = Load-AccountsCSV -Path "$home/.unsandbox/accounts.csv" -Index $script:AccountIndex
+        if (-not $result) {
+            $result = Load-AccountsCSV -Path "./accounts.csv" -Index $script:AccountIndex
+        }
+        if ($result) { return $result }
+        Write-Error "Error: account $($script:AccountIndex) not found in accounts.csv"
+        exit 1
+    }
+
     $publicKey = $env:UNSANDBOX_PUBLIC_KEY
     $secretKey = $env:UNSANDBOX_SECRET_KEY
 
@@ -71,11 +107,27 @@ function Get-ApiKeys {
         $secretKey = ""
     }
 
-    if (-not $publicKey) {
-        Write-Error "Error: UNSANDBOX_PUBLIC_KEY or UNSANDBOX_API_KEY not set"
-        exit 1
+    if ($publicKey -and $secretKey) {
+        return @($publicKey, $secretKey)
     }
-    return @($publicKey, $secretKey)
+
+    if ($publicKey) {
+        return @($publicKey, "")
+    }
+
+    # accounts.csv fallback (row 0 or UNSANDBOX_ACCOUNT env var)
+    $rowIdx = 0
+    if ($env:UNSANDBOX_ACCOUNT) {
+        try { $rowIdx = [int]$env:UNSANDBOX_ACCOUNT } catch {}
+    }
+    $result = Load-AccountsCSV -Path "$home/.unsandbox/accounts.csv" -Index $rowIdx
+    if (-not $result) {
+        $result = Load-AccountsCSV -Path "./accounts.csv" -Index $rowIdx
+    }
+    if ($result) { return $result }
+
+    Write-Error "Error: UNSANDBOX_PUBLIC_KEY or UNSANDBOX_API_KEY not set"
+    exit 1
 }
 
 function Invoke-Api {
@@ -1179,38 +1231,49 @@ Key options:
     exit 0
 }
 
-if ($args[0] -eq "session") {
-    Invoke-Session -Args $args[1..($args.Count-1)]
-} elseif ($args[0] -eq "service") {
-    Invoke-Service -Args $args[1..($args.Count-1)]
-} elseif ($args[0] -eq "snapshot") {
-    Invoke-Snapshot -Args $args[1..($args.Count-1)]
-} elseif ($args[0] -eq "image") {
-    Invoke-Image -Args $args[1..($args.Count-1)]
-} elseif ($args[0] -eq "languages") {
-    Invoke-Languages -Args $args[1..($args.Count-1)]
-} elseif ($args[0] -eq "key") {
-    Invoke-Key -Args $args[1..($args.Count-1)]
+# Pre-parse --account N from args, strip from effective arg list
+$effectiveArgs = @()
+for ($i = 0; $i -lt $args.Count; $i++) {
+    if ($args[$i] -eq "--account" -and ($i + 1) -lt $args.Count) {
+        try { $script:AccountIndex = [int]$args[$i + 1] } catch {}
+        $i++
+    } else {
+        $effectiveArgs += $args[$i]
+    }
+}
+
+if ($effectiveArgs[0] -eq "session") {
+    Invoke-Session -Args $effectiveArgs[1..($effectiveArgs.Count-1)]
+} elseif ($effectiveArgs[0] -eq "service") {
+    Invoke-Service -Args $effectiveArgs[1..($effectiveArgs.Count-1)]
+} elseif ($effectiveArgs[0] -eq "snapshot") {
+    Invoke-Snapshot -Args $effectiveArgs[1..($effectiveArgs.Count-1)]
+} elseif ($effectiveArgs[0] -eq "image") {
+    Invoke-Image -Args $effectiveArgs[1..($effectiveArgs.Count-1)]
+} elseif ($effectiveArgs[0] -eq "languages") {
+    Invoke-Languages -Args $effectiveArgs[1..($effectiveArgs.Count-1)]
+} elseif ($effectiveArgs[0] -eq "key") {
+    Invoke-Key -Args $effectiveArgs[1..($effectiveArgs.Count-1)]
 } else {
     # Parse execute args
     $sourceFile = $null
     $envVars = @{}
     $network = $null
 
-    for ($i = 0; $i -lt $args.Count; $i++) {
-        switch ($args[$i]) {
+    for ($i = 0; $i -lt $effectiveArgs.Count; $i++) {
+        switch ($effectiveArgs[$i]) {
             "-e" {
-                $kv = $args[$i+1] -split "=", 2
+                $kv = $effectiveArgs[$i+1] -split "=", 2
                 $envVars[$kv[0]] = $kv[1]
                 $i++
             }
-            "-n" { $network = $args[$i+1]; $i++ }
+            "-n" { $network = $effectiveArgs[$i+1]; $i++ }
             default {
-                if ($args[$i].StartsWith("-")) {
-                    Write-Error "${RED}Unknown option: $($args[$i])${RESET}"
+                if ($effectiveArgs[$i].StartsWith("-")) {
+                    Write-Error "${RED}Unknown option: $($effectiveArgs[$i])${RESET}"
                     exit 1
                 } else {
-                    $sourceFile = $args[$i]
+                    $sourceFile = $effectiveArgs[$i]
                 }
             }
         }
diff --git a/clients/scheme/sync/src/un.scm b/clients/scheme/sync/src/un.scm
index c2e2d35..bdd572d 100644
--- a/clients/scheme/sync/src/un.scm
+++ b/clients/scheme/sync/src/un.scm
@@ -445,16 +445,72 @@
   (curl-delete api-key (format #f "/services/~a/env" service-id))
   (format #t "~aVault deleted for: ~a~a\n" green service-id reset))
 
+(define *account-index* #f)
+
+(define (load-accounts-csv path index)
+  "Load row INDEX from a CSV file of public_key,secret_key pairs.
+   Skips blank lines and lines starting with #. Returns (list pk sk) or #f."
+  (if (not (access? path R_OK))
+      #f
+      (catch #t
+        (lambda ()
+          (let ((port (open-input-file path))
+                (rows '()))
+            (let loop ()
+              (let ((line (read-line port)))
+                (when (not (eof-object? line))
+                  (let ((trimmed (string-trim-both line)))
+                    (when (and (> (string-length trimmed) 0)
+                               (not (char=? (string-ref trimmed 0) #\#)))
+                      (let ((comma-pos (string-index trimmed #\,)))
+                        (when comma-pos
+                          (set! rows (append rows
+                                             (list (list
+                                                    (string-trim-both (substring trimmed 0 comma-pos))
+                                                    (string-trim-both (substring trimmed (1+ comma-pos)))))))))))
+                  (loop))))
+            (close-input-port port)
+            (if (< index (length rows))
+                (list-ref rows index)
+                #f)))
+        (lambda (key . args) #f))))
+
 (define (get-api-keys)
   (let ((public-key (getenv "UNSANDBOX_PUBLIC_KEY"))
         (secret-key (getenv "UNSANDBOX_SECRET_KEY"))
-        (api-key (getenv "UNSANDBOX_API_KEY")))
+        (api-key (getenv "UNSANDBOX_API_KEY"))
+        (home (getenv "HOME")))
     (cond
+      ;; --account N: load row N from accounts.csv, bypasses env vars
+      ((not (eq? *account-index* #f))
+       (let ((result (or (load-accounts-csv
+                           (string-append home "/.unsandbox/accounts.csv")
+                           *account-index*)
+                         (load-accounts-csv "./accounts.csv" *account-index*))))
+         (or result
+             (begin
+               (format (current-error-port) "Error: account ~a not found in accounts.csv\n" *account-index*)
+               (exit 1)))))
+      ;; env vars
       ((and public-key secret-key) (list public-key secret-key))
       (api-key (list api-key #f))
-      (else (begin
-              (display "Error: UNSANDBOX_PUBLIC_KEY and UNSANDBOX_SECRET_KEY not set (or UNSANDBOX_API_KEY for backwards compat)\n" (current-error-port))
-              (exit 1))))))
+      ;; accounts.csv fallback (row 0 or UNSANDBOX_ACCOUNT env var)
+      (else
+       (let* ((acc-env (getenv "UNSANDBOX_ACCOUNT"))
+              (row-idx (if acc-env
+                           (catch #t
+                             (lambda () (string->number acc-env))
+                             (lambda (key . args) 0))
+                           0))
+              (row-idx (if (number? row-idx) (inexact->exact row-idx) 0))
+              (result (or (load-accounts-csv
+                            (string-append home "/.unsandbox/accounts.csv")
+                            row-idx)
+                          (load-accounts-csv "./accounts.csv" row-idx))))
+         (or result
+             (begin
+               (display "Error: UNSANDBOX_PUBLIC_KEY and UNSANDBOX_SECRET_KEY not set (or UNSANDBOX_API_KEY for backwards compat)\n" (current-error-port))
+               (exit 1)))))))
 
 (define (get-api-key)
   (car (get-api-keys)))
@@ -1286,4 +1342,15 @@
         (else
           (execute-cmd (car args))))))
 
-(main (cdr (command-line)))
+(define (strip-account-flag args)
+  "Remove --account N from args list, setting *account-index* as side-effect."
+  (let loop ((in args) (out '()))
+    (cond
+      ((null? in) (reverse out))
+      ((and (equal? (car in) "--account") (pair? (cdr in)))
+       (let ((n (string->number (cadr in))))
+         (set! *account-index* (if (number? n) (inexact->exact n) #f))
+         (loop (cddr in) out)))
+      (else (loop (cdr in) (cons (car in) out))))))
+
+(main (strip-account-flag (cdr (command-line))))