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+# Intermediary Lease Transaction Packet (ILTP)
+
+## Core decision
+Use a **Markdown wrapper with an embedded canonical YAML block** (`lease_packet.md`).
+
+- Markdown stays human-readable for brokers, legal, and back office.
+- YAML remains deterministic for validators, generators, and AI agents.
+- The packet is the source of truth; Word, DocuSign, and PMS records are downstream artifacts.
+
+## System role
+The ILTP is the canonical, versioned transaction-state object connecting:
+
+1. LOI intake/extraction
+2. Lease document generation (DOCX/PDF)
+3. DocuSign envelope creation and execution
+4. Yardi/AppFolio payload generation/import
+5. Audit + closeout evidence
+
+## State machine
+
+```yaml
+state_machine:
+  states:
+    - loi_received
+    - extraction_pending
+    - packet_draft
+    - validation_failed
+    - backoffice_review
+    - legal_review_required
+    - ready_for_document_generation
+    - lease_doc_generated
+    - internal_approval_pending
+    - ready_for_docusign
+    - sent_for_signature
+    - partially_executed
+    - fully_executed
+    - pms_payload_ready
+    - pms_imported
+    - closeout_complete
+    - canceled
+    - superseded
+  terminal_states:
+    - closeout_complete
+    - canceled
+    - superseded
+```
+
+## Canonical packet shape
+
+```yaml
+packet:
+  packet_id: lease_2026_000142
+  packet_type: commercial_small_bay_lease
+  status: packet_draft
+  version: 0.1.0
+  created_at: 2026-05-13T12:00:00-07:00
+  updated_at: 2026-05-13T12:00:00-07:00
+source: {}
+parties: {}
+property: {}
+premises: {}
+deal_terms: {}
+economics: {}
+legal_terms: {}
+brokerage: {}
+document_generation: {}
+docusign: {}
+pms_mapping: {}
+exceptions: {}
+approvals: {}
+artifacts: {}
+audit_events: []
+```
+
+## Architectural invariants
+
+1. Packet is canonical deal state; downstream outputs cannot drift.
+2. No DocuSign send while blocker exceptions exist.
+3. No PMS payload generation before signed lease artifact exists.
+4. Tenant legal name must reconcile across packet, lease, DocuSign, and PMS payload.
+5. Packet hash change marks generated artifacts stale.
+6. Manual overrides must emit audit events.
+
+## Validation tiers
+
+- **Blockers**: required fields and preconditions for generation/sending/import.
+- **Consistency**: date/order/math reconciliation checks.
+- **Risk**: legal-review and approval trigger checks.
+
+## Artifact strategy
+Each generated artifact stores:
+
+- source packet version/hash
+- generated timestamp
+- template/profile id
+- artifact hash
+- staleness status
+
+## Mapping strategy
+Use profile-driven PMS mappings rather than one hard-coded schema.
+
+- `yardi_voyager_commercial_v1`
+- `appfolio_commercial_v1`
+
+Flow: `canonical packet fields -> mapping profile -> PMS-specific payload`.
+
+## Agent model (Software 1.0 / 2.0 / 3.0)
+
+- **Software 1.0**: deterministic validation + generation code.
+- **Software 2.0**: extraction/classification/search over LOIs and packet evidence.
+- **Software 3.0**: natural-language operator layer for exception analysis, drafting, and patch proposals.
+
+Operating pattern:
+
+- AI proposes
+- Validator blocks
+- Human approves
+- Generator emits
+- Audit records
+
+## MVP implementation passes
+
+1. Packet template (`lease_packet.md`)
+2. Deterministic validator (`validate_packet.py`)
+3. Lease generation (`generate_docx.py`)
+4. DocuSign payload generation (`generate_docusign_payload.py`)
+5. PMS export (`generate_pms_payload.py`)
+
+## Recommended repository layout
+
+```text
+lease-packet-engine/
+  packets/
+  schemas/
+  templates/
+  mappings/
+  artifacts/
+  src/
+  tests/
+```
+
+## Executive thesis
+The ILTP is not a prettier lease draft. It is a bounded-context transaction compiler IR that preserves negotiated intent, normalizes it into validated fields, generates downstream artifacts without drift, and proves what happened during audit/closeout.