
Gstr1 Review
- 1 installs
- 2 repo stars
- Updated May 14, 2026
- eurth/claude-for-ca
Reviews GSTR-1 outward-supply data before filing, checking B2B/B2C/export classification, HSN summary, e-invoice linkage, and sales-register mismatches.
About
Validates Indian GST GSTR-1 return data before submission across supply classification, HSN codes, place of supply, and reconciliation with the sales register, for monthly and QRMP/IFF filers. A chartered accountant uses it to review outward supplies before filing, without submitting.
- Classifies supplies into the correct GSTR-1 tables (B2B, B2C, exports)
- Reviews only; filing requires partner-verified HITL approval
Gstr1 Review by the numbers
- 1 all-time installs (skills.sh)
- Ranked #909 of 1,106 Finance & Trading skills by installs in the Skillselion catalog
- Data as of Jul 8, 2026 (Skillselion catalog sync)
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| Installs | 1 |
|---|---|
| repo stars | ★ 2 |
| Last updated | May 14, 2026 |
| Repository | eurth/claude-for-ca ↗ |
What it does
Reviews GSTR-1 outward-supply data before filing, checking B2B/B2C/export classification, HSN summary, e-invoice linkage, and sales-register mismatches.
Files
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,XXXStep 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 reviewStep 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]