company-bas

company-bas

Routes through the tax-bunyip foundation hub — read its standing instructions first (skills/tax-bunyip/SKILL.md). This spoke produces the trading company's quarterly Business Activity Statement working paper (scripts/spokes/bas_gst.py). It is the suite's first output exercised end-to-end — it runs the attribution core, the company-pre-attributed ledger path, and the assembly substrate against a real company ledger. It collates and flags — it asserts no final tax number. The registered tax agent — or the lodging individual — finalises every figure; every computed line is marked [accountant to confirm].

Covers the whole BAS, not GST alone

Section	ATO label	Source	Rate
GST on sales	GST_G1_1A (G1 / 1A)	positive ledger lines	gst_rate (provisional)
GST on purchases	GST_G11_1B (G11 / 1B)	negative purchase/expense lines	gst_rate (provisional)
PAYG withholding W1	PAYG_W1	gross wages paid	— (cash figure)
PAYG withholding W2	PAYG_W2	amounts withheld	— (cash figure)
PAYG instalment T7	PAYG_T7	instalment income	payg_instalment_rate (provisional)

Registration gate — produce only when confirmed

A BAS obligation's figure is produced only when that obligation's registration is confirmed in the entity config:

entities:
  trading_company:
    registrations:
      gst:              { confirmed: true, registered: true, accounting_basis: accrual }
      payg_withholding: { confirmed: true, registered: true }
      payg_instalments: { confirmed: true, registered: true }

Registration is never assumed. A missing registrations block, a missing obligation, or confirmed: false reads as unconfirmed — the spoke asserts no figure for that obligation and emits an [accountant to confirm] registration flag (a finalization-block disposition: the draft still renders, the gap is named, no number is asserted). registration_status is the single accessor.

The company-pre-attributed ledger path

The company ledger is pre-attributed to the company (ingest.attribute_ledger_rows / is_pre_attributed) — it never runs through the attribution state machine. Pre-attribution to the company is a confirmed assignment, so the assembly lines this spoke builds carry confirmed-single (the gate-satisfying state assembly admits) with the pre_attributed_company provenance preserved on each line.

GST creditability is an open question, never decided here

A tag-less ledger line cannot carry the GST-creditable vs non-creditable distinction. This spoke does not decide it and does not pull the HITL loop forward for it — every purchase/expense line is surfaced as an accountant open question (gst-creditability-undetermined). The GST-on-purchases figure renders provisionally with the question attached; the accountant confirms.

Rates from config, provisional, never block

Every rate-derived figure pulls its rate from config/rates.yaml via the assembly substrate's rate_key mechanism (gst_rate, payg_instalment_rate). No rate literal appears in the spoke. All seeded rates are pending, so a fresh repo renders the BAS provisionally end-to-end (the first dry-run), every rate-derived figure flagged and listed in the pending-rate appendix — it never blocks. The PAYG-instalment rate is Commissioner-issued per entity (not a fixed statutory percentage); the accountant replaces the placeholder with the notified rate before any T-figure is treated as real.

The first-dry-run gate

This unit is the project's success signal: the registered tax agent — or the lodging individual — confirming this BAS is usable (or usable with named gaps). Its critical path is the full attribution core — "first output" means nothing renders before it. The first dry-run also reports a refusal-volume estimate and a company coverage probe (own-account total vs company-attributed feed lines); if refusals dominate or coverage is materially incomplete, that is a finding to act on, not a silent pass.

Entry points (scripts/spokes/bas_gst.py)

Canonical invocation: ${CLAUDE_PLUGIN_ROOT}/scripts/run.sh scripts/spokes/bas_gst.py

• produce_bas(ledger_df, entity=..., fy=..., entity_config=..., source_doc=...) → BasResult
• registration_status(entity_config, entity, obligation) → {obligation, confirmed, basis}
• build_bas_lines(ledger_df, entity=..., registrations=...) → (lines, creditability_questions)
• write_bas(result, base_dir=...) → atomic Markdown + Excel (delegates to the assembly substrate)
• BasResult.asserts_no_gst_figure / BasResult.summary()