diff --git a/apps/web/src/components/AddAccountDialog.tsx b/apps/web/src/components/AddAccountDialog.tsx
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+++ b/apps/web/src/components/AddAccountDialog.tsx
@@ -0,0 +1,289 @@
+import { useState, useEffect } from 'react'
+import { Loader2 } from 'lucide-react'
+import { toast } from 'sonner'
+import { trpc } from '@/lib/trpc'
+import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter } from '@/components/ui/dialog'
+import { Button } from '@/components/ui/button'
+import { Input } from '@/components/ui/input'
+import { Label } from '@/components/ui/label'
+import { Textarea } from '@/components/ui/textarea'
+import { Select, SelectTrigger, SelectValue, SelectContent, SelectItem } from '@/components/ui/select'
+
+interface AddAccountDialogProps {
+  open: boolean
+  onOpenChange: (open: boolean) => void
+}
+
+const EMAIL_REGEX = /^[^\s@]+@[^\s@]+\.[^\s@]+$/
+
+export function AddAccountDialog({ open, onOpenChange }: AddAccountDialogProps) {
+  const [tab, setTab] = useState<'token' | 'credentials'>('token')
+
+  // Tab A — token
+  const [email, setEmail] = useState('')
+  const [token, setToken] = useState('')
+  const [provider, setProvider] = useState('claude')
+
+  // Tab B — credentials JSON
+  const [credEmail, setCredEmail] = useState('')
+  const [credProvider, setCredProvider] = useState('claude')
+  const [configJsonText, setConfigJsonText] = useState('')
+  const [credentialsText, setCredentialsText] = useState('')
+
+  // Validation errors
+  const [emailError, setEmailError] = useState('')
+  const [tokenError, setTokenError] = useState('')
+  const [credEmailError, setCredEmailError] = useState('')
+  const [configJsonError, setConfigJsonError] = useState('')
+  const [credentialsError, setCredentialsError] = useState('')
+  const [serverError, setServerError] = useState('')
+
+  const utils = trpc.useUtils()
+  const providersQuery = trpc.listProviderNames.useQuery()
+
+  const addByToken = trpc.addAccountByToken.useMutation({
+    onSuccess: (data) => {
+      const msg = data.upserted
+        ? `Account updated — credentials refreshed for ${email}.`
+        : `Account added: ${email}.`
+      toast.success(msg)
+      void utils.systemHealthCheck.invalidate()
+      onOpenChange(false)
+    },
+    onError: (err) => {
+      setServerError(err.message)
+    },
+  })
+
+  const addAccount = trpc.addAccount.useMutation({
+    onSuccess: () => {
+      toast.success(`Account added: ${credEmail}.`)
+      void utils.systemHealthCheck.invalidate()
+      onOpenChange(false)
+    },
+    onError: (err) => {
+      if (err.message.toLowerCase().includes('already exists')) {
+        setCredEmailError(
+          "An account with this email already exists. Use 'Update credentials' on the existing account instead."
+        )
+      } else {
+        setServerError(err.message)
+      }
+    },
+  })
+
+  useEffect(() => {
+    if (open) {
+      setTab('token')
+      setEmail(''); setToken(''); setProvider('claude')
+      setCredEmail(''); setCredProvider('claude')
+      setConfigJsonText(''); setCredentialsText('')
+      setEmailError(''); setTokenError('')
+      setCredEmailError(''); setConfigJsonError(''); setCredentialsError('')
+      setServerError('')
+    }
+  }, [open])
+
+  function handleSubmit() {
+    setEmailError(''); setTokenError(''); setCredEmailError('')
+    setConfigJsonError(''); setCredentialsError(''); setServerError('')
+
+    if (tab === 'token') {
+      let hasError = false
+      if (email.trim() === '') {
+        setEmailError('Required')
+        hasError = true
+      } else if (!EMAIL_REGEX.test(email)) {
+        setEmailError('Enter a valid email address')
+        hasError = true
+      }
+      if (token.trim() === '') {
+        setTokenError('Required')
+        hasError = true
+      }
+      if (hasError) return
+      addByToken.mutate({ email, token, provider })
+    } else {
+      let hasError = false
+      if (credEmail.trim() === '') {
+        setCredEmailError('Required')
+        hasError = true
+      } else if (!EMAIL_REGEX.test(credEmail)) {
+        setCredEmailError('Enter a valid email address')
+        hasError = true
+      }
+      if (configJsonText.trim() !== '') {
+        try {
+          JSON.parse(configJsonText)
+        } catch {
+          setConfigJsonError('Invalid JSON')
+          hasError = true
+        }
+      }
+      if (credentialsText.trim() !== '') {
+        try {
+          JSON.parse(credentialsText)
+        } catch {
+          setCredentialsError('Invalid JSON')
+          hasError = true
+        }
+      }
+      if (hasError) return
+      addAccount.mutate({
+        email: credEmail,
+        provider: credProvider,
+        configJson: configJsonText.trim() || undefined,
+        credentials: credentialsText.trim() || undefined,
+      })
+    }
+  }
+
+  const isPending = tab === 'token' ? addByToken.isPending : addAccount.isPending
+
+  function renderProviderSelect(value: string, onChange: (v: string) => void) {
+    if (providersQuery.isError) {
+      return <Input value={value} onChange={(e) => onChange(e.target.value)} />
+    }
+    return (
+      <Select value={value} onValueChange={onChange}>
+        <SelectTrigger><SelectValue /></SelectTrigger>
+        <SelectContent>
+          {(providersQuery.data ?? ['claude']).map((p) => (
+            <SelectItem key={p} value={p}>{p}</SelectItem>
+          ))}
+        </SelectContent>
+      </Select>
+    )
+  }
+
+  return (
+    <Dialog open={open} onOpenChange={onOpenChange}>
+      <DialogContent>
+        <DialogHeader>
+          <DialogTitle>Add Account</DialogTitle>
+        </DialogHeader>
+
+        <div className="flex border-b">
+          <button
+            type="button"
+            onClick={() => {
+              setTab('token')
+              setCredEmail('')
+              setCredProvider('claude')
+              setConfigJsonText('')
+              setCredentialsText('')
+              setCredEmailError('')
+              setConfigJsonError('')
+              setCredentialsError('')
+              setServerError('')
+            }}
+            className={`px-4 py-2 text-sm font-medium border-b-2 transition-colors ${
+              tab === 'token'
+                ? 'border-primary text-foreground'
+                : 'border-transparent text-muted-foreground hover:text-foreground'
+            }`}
+          >
+            By token
+          </button>
+          <button
+            type="button"
+            onClick={() => {
+              setTab('credentials')
+              setEmail('')
+              setToken('')
+              setEmailError('')
+              setTokenError('')
+              setServerError('')
+            }}
+            className={`px-4 py-2 text-sm font-medium border-b-2 transition-colors ${
+              tab === 'credentials'
+                ? 'border-primary text-foreground'
+                : 'border-transparent text-muted-foreground hover:text-foreground'
+            }`}
+          >
+            By credentials JSON
+          </button>
+        </div>
+
+        {tab === 'token' ? (
+          <div className="space-y-4">
+            <div className="space-y-2">
+              <Label>Email</Label>
+              <Input
+                value={email}
+                onChange={(e) => setEmail(e.target.value)}
+                placeholder="user@example.com"
+              />
+              {emailError && <p className="text-sm text-destructive">{emailError}</p>}
+            </div>
+            <div className="space-y-2">
+              <Label>Setup token (from `claude setup-token`)</Label>
+              <Input
+                value={token}
+                onChange={(e) => setToken(e.target.value)}
+              />
+              {tokenError && <p className="text-sm text-destructive">{tokenError}</p>}
+              {serverError && <p className="text-sm text-destructive">{serverError}</p>}
+            </div>
+            <div className="space-y-2">
+              <Label>Provider</Label>
+              {renderProviderSelect(provider, setProvider)}
+            </div>
+          </div>
+        ) : (
+          <div className="space-y-4">
+            <div className="space-y-2">
+              <Label>Email</Label>
+              <Input
+                value={credEmail}
+                onChange={(e) => setCredEmail(e.target.value)}
+                placeholder="user@example.com"
+              />
+              {credEmailError && <p className="text-sm text-destructive">{credEmailError}</p>}
+            </div>
+            <div className="space-y-2">
+              <Label>Provider</Label>
+              {renderProviderSelect(credProvider, setCredProvider)}
+            </div>
+            <div className="space-y-2">
+              <Label>Config JSON (`.claude.json` content)</Label>
+              <Textarea
+                value={configJsonText}
+                onChange={(e) => setConfigJsonText(e.target.value)}
+                placeholder={`{ "oauthAccount": { ... } }`}
+              />
+              {configJsonError && <p className="text-sm text-destructive">{configJsonError}</p>}
+            </div>
+            <div className="space-y-2">
+              <Label>Credentials JSON (`.credentials.json` content)</Label>
+              <Textarea
+                value={credentialsText}
+                onChange={(e) => setCredentialsText(e.target.value)}
+                placeholder={`{ "claudeAiOauth": { ... } }`}
+              />
+              {credentialsError && <p className="text-sm text-destructive">{credentialsError}</p>}
+            </div>
+            <p className="text-xs text-muted-foreground">
+              Run `cw account extract` in your terminal to obtain these values.
+            </p>
+            {serverError && <p className="text-sm text-destructive">{serverError}</p>}
+          </div>
+        )}
+
+        <DialogFooter>
+          <Button variant="outline" onClick={() => onOpenChange(false)}>
+            Cancel
+          </Button>
+          <Button
+            type="submit"
+            disabled={isPending}
+            onClick={handleSubmit}
+          >
+            {isPending && <Loader2 className="mr-2 h-4 w-4 animate-spin" />}
+            Add Account
+          </Button>
+        </DialogFooter>
+      </DialogContent>
+    </Dialog>
+  )
+}