fix(agent): the assistant reaches earlier räkenskapsår: period resolved from dates, years listed in the grounding (#2436)

Part 3 of #2185. A user with several imported years concluded the assistant
"only reads the period I am standing in". Nothing restricted it: the report
tools defaulted to the most recent fiscal period when no period_id was given
and then rejected any from_date/to_date/as_of_date outside it, and neither
the snapshot nor the chat identity block told the model which years existed
or how to address them.

- extensions/general/mcp-server/server.ts: resolveReportPeriod takes a date
  hint; without period_id, a date in the call resolves the fiscal period that
  contains it (findFiscalPeriodContaining, company-scoped), and a date no
  period covers fails with the company's span instead of the latest year's
  bounds. Income statement (from_date or to_date), balance sheet (as_of_date)
  and dimension P&L (to_date) use it. The range guard is unchanged. No schema
  change: tools/list sits at its token ceiling.
- lib/agent/fiscal-years.ts: one query and one line, "Räkenskapsår (senaste
  först): ... period_id=<uuid> (senaste|avslutat)", plus the rule on
  addressing an earlier year, shared by the single-call snapshot and the
  streaming chat's always-on identity block.
- lib/agent/intents/shared-rules.ts and TOOL_RULES: pass that year's
  period_id, one call per year, and say which räkenskapsår the answer covers.


Claude-Session: https://claude.ai/code/session_0179bdetHyofL6ATfQxB5wP5

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

lib/agent/ask/__tests__/snapshot.test.ts

@@ -141,6 +141,35 @@ describe('buildAssistantSnapshot', () => {
     expect(snap).toContain('Moms (2026-09-12)')
   })
 
+  it('lists the räkenskapsår newest first with their period_id (#2185)', async () => {
+    const periods = [
+      { id: 'fp-2026', name: '2026', period_start: '2026-01-01', period_end: '2026-12-31', is_closed: false },
+      { id: 'fp-2025', name: '2025', period_start: '2025-01-01', period_end: '2025-12-31', is_closed: true },
+    ]
+    const supabase = {
+      from: (table: string) => {
+        const chain = {
+          select: () => chain,
+          eq: () => chain,
+          order: () => chain,
+          limit: () => chain,
+          maybeSingle: async () => ({ data: null, error: null }),
+          then: (onFulfilled: (v: unknown) => unknown) =>
+            Promise.resolve(
+              table === 'fiscal_periods'
+                ? { data: periods, error: null }
+                : { count: null, error: null },
+            ).then(onFulfilled),
+        }
+        return chain
+      },
+    } as unknown as SupabaseClient
+    const snap = await buildAssistantSnapshot(supabase, 'c1')
+    expect(snap).toContain(
+      'Räkenskapsår (senaste först): 2026-01-01..2026-12-31 period_id=fp-2026 (senaste); 2025-01-01..2025-12-31 period_id=fp-2025 (avslutat).',
+    )
+  })
+
   it('returns an empty string when there is nothing to say', async () => {
     const snap = await buildAssistantSnapshot(supabaseWith(null), 'c1')
     expect(snap).toBe('')

lib/agent/ask/ask-service.ts

@@ -4,6 +4,7 @@ import { createLogger } from '@/lib/logger'
 import { EmptyModelAnswerError } from './errors'
 import { buildLedgerTools } from './ledger-tools'
 import { buildAssistantSnapshot } from './snapshot'
+import { FISCAL_YEAR_RULE } from '@/lib/agent/fiscal-years'
 
 const log = createLogger('agent.ask')
 
@@ -89,7 +90,8 @@ Regler:
 // With tools: the model can and should fetch the real figures itself.
 const TOOL_RULES = `
 Du har läsverktyg för bolagets faktiska bokföring: resultatrapport, balansrapport, momsrapport, huvudbok, transaktioner (query_journal), kund- och leverantörsreskontra, lönejournal, kontoplan, fakturor, dokumentinkorg med mera. När användaren frågar om siffror, belopp, poster, kategorier eller en period: ANROPA rätt verktyg och svara med de faktiska siffrorna, inte uppskattningar. Verktygen är skrivskyddade; för att bokföra eller ändra något hänvisar du användaren till rätt sida i appen.
-"Nuläge"-blocket nedan är bara grunddata (moms, deadlines), inte hela bokföringen: använd verktygen för siffror.`
+"Nuläge"-blocket nedan är bara grunddata (moms, deadlines, räkenskapsår), inte hela bokföringen: använd verktygen för siffror.
+${FISCAL_YEAR_RULE}`
 
 // Without tools (core-only build, or a text-only model): answer from what is
 // in the prompt and be honest about the rest.

lib/agent/ask/snapshot.ts

@@ -5,6 +5,7 @@ import {
   resolveEmployeeFacts,
   type EmployeeVerdict,
 } from '@/lib/agent/composer/employee-facts'
+import { loadFiscalYearInventory, renderFiscalYearInventory } from '@/lib/agent/fiscal-years'
 
 /**
  * A compact, always-on grounding block for the single-call assistant.
@@ -58,6 +59,8 @@ export async function buildAssistantSnapshot(
   companyId: string,
 ): Promise<string> {
   const lines: string[] = []
+  // Kicked off with the first round so it costs no extra latency; never rejects.
+  const fiscalYears = loadFiscalYearInventory(supabase, companyId)
 
   try {
     const [{ data }, activeEmployees] = await Promise.all([
@@ -118,5 +121,10 @@ export async function buildAssistantSnapshot(
     // best-effort: skip the deadlines line
   }
 
+  // Which years the ledger holds and how to address them: a company with
+  // several imported years otherwise reads as single-year (#2185).
+  const fiscalYearLine = renderFiscalYearInventory(await fiscalYears)
+  if (fiscalYearLine) lines.push(fiscalYearLine)
+
   return lines.join('\n')
 }