Initial import NDC_1C

docs/slot3_recon_2026-03-22.md

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+# Slot3 Recon Report (2026-03-22)
+
+## Scope
+
+Target hard check:
+
+`posting -> subconto[1..3] -> counterparty / contract / item`
+
+Source artifacts:
+
+- `scripts/recon_slot3_gap.py`
+- `logs/slot3_recon_report.json`
+- `logs/deep_accounting_mvp_gate.json`
+
+Endpoint:
+
+- `http://localhost/buh_test/odata/standard.odata/`
+
+## Numeric Result
+
+From `logs/slot3_recon_report.json`:
+
+- `sets_with_slot3_fields`: `11`
+- `sets_with_data_rows`: `5`
+- `sets_with_non_null_slot3`: `0`
+- `sets_with_joined_slot3_rows`: `0`
+- `rows_with_non_null_slot3_total`: `0`
+- `rows_with_joined_slot3_total`: `0`
+
+Recon strategy:
+
+- Baseline sample read (`$top`) for each candidate set.
+- Additional targeted reads per slot3 field with `$filter: <slot3_field> ne null`.
+
+Interpretation:
+
+- Metadata contains slot `3` fields in multiple document line entity sets.
+- In current sampled data, slot `3` is always empty.
+- Because slot `3` has no non-null values, reproducible posting-linked evidence for slot `3` cannot be produced.
+
+## Gate Impact
+
+Hard gate #2 remains `fail` for objective data reasons:
+
+- Slots `1` and `2` are proven.
+- Slot `3` is not provable on current OData sample because observed values are null.
+
+This is consistent with:
+
+- `docs/mvp_gate_3_hard_checks_2026-03-22.md`
+- `docs/decision_report_odata_vs_deeper_access.md`
+
+## What Must Change To Close Check #2
+
+At least one posted document line is needed where all conditions hold:
+
+1. Slot `3` field is non-null.
+2. The line can be joined to accounting posting by:
+   - `Ref_Key = Recorder`
+   - `Recorder_Type`
+   - `LineNumber`
+3. The slot `3` value can be categorized into one of required semantic dimensions (`counterparty`, `contract`, `item`) or explicitly mapped as equivalent analytics dimension for the canonical model.
+
+## Next Action
+
+1. Use Universal Tools in test copy to identify document types and posting scenarios that actually fill slot `3`.
+2. Reproduce the same scenario through OData extraction and rerun:
+   - `scripts/recon_slot3_gap.py`
+   - `scripts/deep_probe_accounting_mvp_gate.py`
+3. If slot `3` remains opaque in OData despite known non-null data in 1C internals, continue FoxyLink PoC as deeper access closure path.