fix(mcp): correct e-invoice capability guidance (#1580)

Closes #1577. Native Peppol and EN 16931 support remains tracked in #546.

extensions/general/mcp-server/__tests__/skills.test.ts

@@ -1,6 +1,8 @@
 /**
  * Tests for skills over MCP: registry, discovery tools, and resource exposure.
  */
+import { readFileSync } from 'node:fs'
+import { join } from 'node:path'
 import { describe, it, expect, vi, beforeEach } from 'vitest'
 import { tools } from '../server'
 import { workflowSkills, findSkill, SKILL_URI_PREFIX, skillUri, __resetAtomCache } from '../skills'
@@ -138,6 +140,25 @@ describe('Skills registry', () => {
     }
   })
 
+  it('does not advertise unsupported built-in e-invoice delivery', () => {
+    const invoiceComplianceAtom = readFileSync(
+      join(process.cwd(), '.claude/skills/swedish-invoice-compliance/SKILL.md'),
+      'utf8',
+    )
+    const allBodies = [...skills.map((skill) => skill.body), invoiceComplianceAtom].join('\n')
+
+    expect(allBodies).not.toMatch(/Accounted\s+(?:renders|generates|produces)[^.\n]*EN\s*16931/i)
+    expect(allBodies).not.toMatch(/Accounted\s+(?:handles|sends|delivers)[^.\n]*Peppol/i)
+
+    for (const slug of ['invoicing-rules', 'customer-onboarding']) {
+      const skill = skills.find((candidate) => candidate.slug === slug)
+      expect(skill?.body).toMatch(/external e-invoice provider/i)
+      expect(skill?.body).toContain('gnubok_mark_invoice_as_sent')
+    }
+    expect(invoiceComplianceAtom).toMatch(/external e-invoice provider/i)
+    expect(invoiceComplianceAtom).toContain('gnubok_mark_invoice_as_sent')
+  })
+
   it('findSkill resolves the workflow skill or null (sync workflow lookup)', async () => {
     const supabase = makeSupabaseWithEmptyAtomRegistry()
     expect(await findSkill('month-end-close', supabase as never)).toBeTruthy()

extensions/general/mcp-server/skills/customer-onboarding.ts

@@ -30,7 +30,7 @@ later: much cheaper to ask the customer once at onboarding.
 
 **Special cases:**
 
-- **B2G (Swedish municipality/agency)**: still \`swedish_business\`, but the invoice must be Peppol-formatted (legal requirement since 2019-04-01). Accounted handles Peppol when the customer record has a Peppol endpoint configured.
+- **B2G (Swedish municipality/agency)**: still \`swedish_business\`. If the customer requires Peppol or another e-invoice format, deliver the invoice through an external e-invoice provider, then use \`gnubok_mark_invoice_as_sent\` to record delivery. Accounted currently creates PDF/email invoices and does not generate or send Peppol invoices.
 - **Consumer customer in another EU country (B2C distance sale)**: \`eu_business\` does NOT apply. Charge Swedish VAT (25/12/6 %) below the OSS threshold; above the threshold the company must register for OSS. This is rare for sole traders: flag the user if turnover suggests they're approaching the threshold.
 
 ## Workflow

extensions/general/mcp-server/skills/invoicing-rules.ts

@@ -79,7 +79,7 @@ Returns staged operation. User approves in web app → invoice number is allocat
 
 \`gnubok_send_invoice(invoice_id)\`: emails the PDF to the customer. Requires email service configured (Resend) and customer email on file.
 
-If the user delivered the invoice manually (printed, e-faktura via Peppol, etc.), use \`gnubok_mark_invoice_as_sent\` instead: same booking effect, no email.
+If the user delivered the invoice manually (printed or sent through an external e-invoice provider), use \`gnubok_mark_invoice_as_sent\` instead: same booking effect, no email.
 
 ### Step 5: Record payment
 
@@ -110,9 +110,9 @@ For consumer-targeted services (RUT: städning, RUT) or construction (ROT):
 
 This data goes on the invoice; Accounted's invoice template renders it automatically when set on the customer.
 
-## Peppol / e-invoicing (B2G)
+## External e-invoicing (including B2G)
 
-Swedish authorities require e-invoices via Peppol BIS Billing 3.0 (Lag 2018:1277). For private B2B, the buyer's preference governs but Peppol is preferred. Accounted renders an EN 16931-compliant XML on demand.
+Accounted currently creates PDF invoices and can send them by email. It does not generate e-invoice XML or deliver invoices through Peppol. If the customer requires an e-invoice, deliver it through an external e-invoice provider, then use \`gnubok_mark_invoice_as_sent\` to record the delivery and apply the same booking effect without sending another email.
 
 ## Critical rules
 
@@ -142,7 +142,7 @@ Swedish authorities require e-invoices via Peppol BIS Billing 3.0 (Lag 2018:1277
 export const invoicingRulesSkill: Skill = {
   slug: 'invoicing-rules',
   name: 'Invoicing Rules',
-  summary: 'Mandatory invoice fields (ML 17 kap. 24 §), VAT treatment per customer type, ROT/RUT, Peppol, kreditfaktura.',
+  summary: 'Mandatory invoice fields (ML 17 kap. 24 §), VAT treatment, ROT/RUT, external e-invoicing, kreditfaktura.',
   tags: ['invoicing', 'vat', 'compliance', 'eu', 'rot-rut'],
   body,
   tier: 'workflow',