gstr1-review

name	gstr1-review
description	Review GSTR-1 outward supply data before filing. Checks classification of supplies (B2B/B2C/exports/nil-rated/exempt), validates HSN summary, e-Invoice linkage, place of supply, and flags mismatches with the sales register. Covers both monthly and QRMP (IFF) filers.
when_to_use	When the user wants to review GSTR-1 data before submission, check outward supplies, verify HSN codes, review IFF data, or reconcile GSTR-1 with sales register/e-invoices.
effort	medium
model	claude-sonnet-4-6
allowed-tools	["mcp__memory_bank__get_client","mcp__memory_bank__list_clients","mcp__memory_bank__get_firm_profile","mcp__memory_bank__get_due_dates","Read","Write"]

GSTR-1 Review

FINANCIAL INTEGRITY: GSTR-1 review only. Do NOT file or submit until the partner has verified all items and triggered the GST Filing HITL approval step.

Firm Context

!python3 ${CLAUDE_PLUGIN_ROOT}/../../shared/bin/get-firm-context.py 2>/dev/null || echo "Run /cold-start:onboard-firm to set up firm profile"

Step 1 — Client and Period

Ask (if not provided):

• Client name / GSTIN
• Return period (Month-Year for monthly, Quarter for QRMP)
• Are they a QRMP filer? (IFF for first two months, quarterly GSTR-1 for Q3)

Step 2 — Collect Source Data

Accept data in any format:

• Excel/CSV export from Tally or billing software
• Pasted table
• JSON from pdf-data-extractor skill

Or pull directly from GST portal:

• mcp__gst_portal__get_gstr1_draft(gstin, period) — fetches saved draft from portal

Step 3 — Classification Review

For each supply, verify the correct table:

Supply Type	GSTR-1 Table	Criteria
B2B Taxable	Table 4	Registered buyer, GSTIN provided
B2C Large	Table 5	Unregistered, invoice value > Rs.2.5L inter-state
B2C Small	Table 7	Unregistered, invoice value ≤ Rs.2.5L
Zero-Rated Exports	Table 6A/6B	Export with/without LUT
Nil / Exempt / Non-GST	Table 8	No tax charged
Reverse Charge	Table 4B	Services from unregistered dealers
Advances Received	Table 11A	Advance received, supply not made
Debit/Credit Notes	Tables 9/10	CDN for B2B/B2C

Flag if:

• Registered buyer invoice placed in B2C table (revenue leakage risk for buyer)
• GSTIN in Table 4 does not pass format validation (15 chars, state code, PAN-embedded)
• Place of supply does not match buyer's state (CGST+SGST vs IGST mismatch)

Step 4 — HSN Summary Validation (Table 12)

For turnover > Rs.5 Cr: 6-digit or 8-digit HSN mandatory For turnover Rs.1.5–5 Cr: 4-digit HSN mandatory
For turnover < Rs.1.5 Cr: HSN optional but recommended

Check:

• All HSN codes are valid (cross-check against HSN master)
• HSN-level taxable value and tax amounts match sum of invoice details
• Unit of Measurement (UOM) is valid GST-approved UOM
• 8-digit HSN for pharma/chemicals/textiles (as notified)

Step 5 — E-Invoice Reconciliation (for turnover > Rs.10 Cr)

If client is e-Invoice mandated (turnover > Rs.10 Cr w.e.f. 1 Apr 2023):

• Every B2B invoice above Rs.0 must have an IRN (Invoice Reference Number)
• IRN is 64-character hash
• E-way bill auto-generated for consignment value > Rs.50,000
• Cancel-and-reissue invoices have separate IRN with cancellation reason

Flag: Any B2B invoice without IRN for e-Invoice mandated taxpayer = portal rejection

Step 6 — Summary Comparison

Pull GSTR-1 summary and compare with:

• Sales Register total (from Tally or accounting software)
• E-Invoice data (if applicable)
• Previous month's GSTR-1 (for unusual jumps)

Present comparison table:

GSTR-1 Review Summary — [Client Name] | GSTIN: [GSTIN] | Period: [Period]
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
SOURCE                 | TAXABLE VALUE   | CGST     | SGST     | IGST     | TOTAL
GSTR-1 Draft           | Rs.XX,XX,XXX    | Rs.X,XXX | Rs.X,XXX | Rs.X,XXX | Rs.XX,XXX
Sales Register (Tally) | Rs.XX,XX,XXX    | Rs.X,XXX | Rs.X,XXX | Rs.X,XXX | Rs.XX,XXX
Difference             | Rs.XX,XXX ⚠     | Rs.XX    | Rs.XX    | Rs.XX    | Rs.XX,XXX

Step 7 — Exceptions List

Present all exceptions for CA review:

EXCEPTIONS REQUIRING YOUR REVIEW:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1. ⚠ Invoice Nos. 45, 67: Registered buyer (GSTIN present) filed in B2C table
   → Move to B2B (Table 4) or confirm buyer is unregistered
2. ⚠ Invoice No. 89: IGST charged, both parties in AP (should be CGST+SGST)
   → Verify place of supply
3. ⚠ GSTR-1 taxable value Rs.2,34,000 > Sales Register Rs.2,31,500
   → 3 invoices appear in portal not in Tally — check for manual invoices
4. ⚠ HSN 85176990: Total value Rs.5,80,000 but tax @ 18% = Rs.1,04,400, portal shows Rs.1,02,000
   → Recalculate or check for non-taxable invoices in this HSN
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Total: 4 exceptions | After resolving, proceed to GSTR-3B review

Step 8 — Due Date Reminder

• Monthly filer (normal): 11th of next month
• QRMP (IFF for Months 1 and 2): 13th of next month
• QRMP (Quarterly GSTR-1): 13th of first month after quarter
• Late filing: Rs.50/day (Rs.25 CGST + Rs.25 SGST) | NIL filer: Rs.20/day

DUE DATE REMINDER:
GSTR-1 for [Period]: Due [Date]
Days remaining: [N] days
Late fee (if filed on date): Rs.[X]