diff --git a/lib/sandbox/__tests__/ensure-agent.test.ts b/lib/sandbox/__tests__/ensure-agent.test.ts
new file mode 100644
index 00000000..f8dab2d5
--- /dev/null
+++ b/lib/sandbox/__tests__/ensure-agent.test.ts
@@ -0,0 +1,36 @@
+import { describe, it, expect } from 'vitest'
+import { SANDBOX_AGENT_NAME, SANDBOX_PROFILE_SUMMARY } from '../ensure-agent'
+
+/**
+ * The sandbox assistant is called "Assistenten", not a first name: nobody in
+ * the sandbox chose a persona, so a first name implies a relationship the
+ * visitor never opted into.
+ *
+ * The pairing is the part worth pinning. profile_summary is the agent's own
+ * self-description inside the system prompt, so if it drifts from the display
+ * name the header says one thing and the assistant introduces itself as
+ * another in its first sentence: a mismatch nothing else in the stack checks.
+ */
+describe('sandbox agent persona', () => {
+  it('is named Assistenten', () => {
+    expect(SANDBOX_AGENT_NAME).toBe('Assistenten')
+  })
+
+  it('introduces itself by the same name the UI shows', () => {
+    expect(SANDBOX_PROFILE_SUMMARY).toContain(`Du är ${SANDBOX_AGENT_NAME}`)
+  })
+
+  it('does not still call itself Anna anywhere in the persona', () => {
+    expect(SANDBOX_AGENT_NAME).not.toContain('Anna')
+    expect(SANDBOX_PROFILE_SUMMARY).not.toContain('Anna')
+  })
+
+  it('keeps the demo company description the persona depends on', () => {
+    // The sandbox data is a Stockholm IT consultancy on the cash method with
+    // quarterly VAT. The summary is what makes the assistant's answers match
+    // the seeded books, so a rename must not quietly drop it.
+    expect(SANDBOX_PROFILE_SUMMARY).toContain('enskild firma')
+    expect(SANDBOX_PROFILE_SUMMARY).toContain('kontantmetoden')
+    expect(SANDBOX_PROFILE_SUMMARY).toContain('momsregistrerat')
+  })
+})
diff --git a/lib/sandbox/ensure-agent.ts b/lib/sandbox/ensure-agent.ts
index 7eea5e29..036784a0 100644
--- a/lib/sandbox/ensure-agent.ts
+++ b/lib/sandbox/ensure-agent.ts
@@ -3,6 +3,24 @@ import { createLogger } from '@/lib/logger'
 
 const log = createLogger('sandbox:ensure-agent')
 
+/**
+ * The sandbox assistant is called "Assistenten", not a first name.
+ *
+ * A named persona is right once someone has been through onboarding and chosen
+ * it: it is their assistant, and they named it. In the sandbox nobody chose
+ * anything, so a first name reads as a character the product invented and
+ * implies a relationship the visitor has not opted into. "Assistenten" says
+ * what it is.
+ *
+ * The summary is the agent's own self-description in the system prompt, so it
+ * has to agree with the display name: otherwise the header says one thing and
+ * the assistant introduces itself as another in its first sentence.
+ */
+export const SANDBOX_AGENT_NAME = 'Assistenten'
+
+export const SANDBOX_PROFILE_SUMMARY =
+  'Du är Assistenten, en revisorsassistent för en svensk enskild firma som tillhandahåller IT-konsulttjänster i Stockholm. Företaget är momsregistrerat (kvartalsvis), använder kontantmetoden och fakturerar både svenska och utländska kunder.'
+
 /**
  * Backfill a verified agent_profile for sandbox companies. Single source of
  * truth for the sandbox assistant's persona (name, avatar, atoms, summary):
@@ -35,7 +53,7 @@ export async function ensureSandboxAgentProfile(
 
     const { error } = await supabase.from('agent_profiles').insert({
       company_id: companyId,
-      display_name: 'Anna',
+      display_name: SANDBOX_AGENT_NAME,
       avatar_id: 'notionists-3',
       horizontal_atoms: [
         'horizontal/swedish-vat',
@@ -43,8 +61,7 @@ export async function ensureSandboxAgentProfile(
       ],
       vertical_atoms: ['vertical/consulting'],
       modifier_atoms: [],
-      profile_summary:
-        'Du är Anna, en revisorsassistent för en svensk enskild firma som tillhandahåller IT-konsulttjänster i Stockholm. Företaget är momsregistrerat (kvartalsvis), använder kontantmetoden och fakturerar både svenska och utländska kunder.',
+      profile_summary: SANDBOX_PROFILE_SUMMARY,
       source_signals: { is_sandbox: true },
       field_overrides: {},
       composer_model: 'sandbox-demo',