●Sample report. Anonymised. Names, figures, and findings illustrative.
Lumen & Lever
Implementation Control Brief · Confidential
Implementer-ready document

Implementation Control Brief. Lease abstraction at renewal.

This brief defines what an internal team, current external IT provider, software vendor, or specialist AI implementation partner must satisfy before the lease abstraction workflow at Meridian Holdings is trusted in business use. It is the document the implementer can build against and the buyer can hold them to.

Prepared for
Meridian Holdings · Property Division
Business Owner
Head of Property Operations
Engagement Lead
Lumen & Lever
Engagement Period
Two weeks · concluded
Following
AI Usage Control Baseline · prior
Classification
Confidential · for issuance to implementer
Section 1 · Workflow Boundary

What is in scope. What is not.

The lease abstraction workflow has been bounded precisely. Implementations that drift outside the boundary defined here are not within scope of this brief and should not be commenced without a separate engagement.

The defined workflow

Extract a defined set of fields from each commercial lease document at the point of renewal, present those fields to a senior paralegal for review, and persist the validated extraction into the property platform's lease record.

In scope

  • Renewal-cycle leases (approximately 80 per year)
  • Commercial property leases held by Meridian Holdings entities
  • The 23 fields enumerated in Section 3
  • Per-document human review before downstream commitment
  • Audit trail of every extraction and reviewer edit
  • Integration into the existing property platform

Out of scope

  • Leases outside the renewal cycle (initial leasing, mid-term variations)
  • Residential leases held by other Meridian entities
  • Document classification (which document is a lease)
  • Negotiation drafting, comparison, or recommendation
  • Outgoings reconciliation or rent review calculations
  • Direct customer or tenant communication

A loose brief produces a loose system. The boundary above is not a constraint to be relaxed. It is the perimeter inside which the implementer builds. Workflow extensions beyond this perimeter require a separate brief and a separate decision.

Lumen & Lever · engagement note

Section 2 · Workflow Specification

Inputs, outputs, ownership, sensitivity.

The specification below names what the implementer must accept as input, what they must produce as output, who owns the workflow on Meridian's side, and how the data must be treated.

Workflow specification
Lease abstraction at renewal
Business owner
Head of Property Operations. Sponsor of record. Sign-off authority on acceptance and production go-live. Responsible for ongoing review of the workflow.
Technical owner
Group IT, in collaboration with the implementer. Responsible for environment, deployment, and operational handover.
Source documents
Commercial lease documents in PDF format. Approximately 80 per renewal cycle. Mix of original signed PDFs (40%), scanned legacy leases (35%), and amended leases with annexures (25%).
Source location
Lease documents reside in the property platform's document store (primary) and the Group's Microsoft 365 SharePoint (secondary, legacy). The implementer must read from both.
Document corpus size
Active lease portfolio: approximately 320 leases. Renewal-cycle subset for this engagement: approximately 80 leases per year, distributed seasonally with concentrations in March and September.
Required outputs
Structured extraction of 23 enumerated fields per lease, with source page references for each field, confidence scores per field, and a flag where extraction confidence falls below the threshold defined in Section 4.
Output destination
After human review, validated extractions are persisted to the property platform's lease record table via the platform's existing API. The implementer does not write directly to the database.
Data sensitivity
High. Lease documents contain commercial obligations, party identities, financial terms, and occasionally PII. The data sensitivity classification is "Commercial Confidential" under Meridian's existing data classification.
Data residency
Australian data residency required. The implementer must use processing infrastructure located in Australian regions only. Cross-border processing is not acceptable.
Frequency
Renewal-cycle batches. Approximately 6 to 8 leases per week on average, with seasonal spikes. The system must handle batch and individual processing.
Latency tolerance
Per-document extraction must complete within 5 minutes. End-to-end processing time including human review is targeted at 2 working days per document, replacing the current 8 working days.
Section 3 · Required Output Fields

The 23 fields the implementer must extract.

Each field is defined with type, presence requirement, and the validation rule that applies. Fields marked Required are mandatory; absence triggers a flag for human review. Fields marked Optional may be absent in a given lease without flagging.

Field
Type
Presence
Validation
lessor_name
string
Required
Match against Group entity register. Flag if not matched.
lessee_name
string
Required
Non-empty. Flag if multiple lessees and not all captured.
lessee_acn_or_abn
string
Optional
If present, must validate as an ACN or ABN. Format check.
premises_address
string
Required
Match against Group property register. Flag if not matched.
premises_description
string
Required
Non-empty. Capture exact lease wording.
term_commencement_date
date
Required
ISO 8601 format. Must precede expiry. Flag if date is in the future by more than 12 months.
term_expiry_date
date
Required
ISO 8601 format. Must follow commencement.
term_years
decimal
Required
Calculated from dates. Cross-check with stated term in lease text.
base_rent_amount
decimal
Required
Currency in AUD. Flag if outside expected range for property type.
base_rent_period
enum
Required
One of: annual, monthly, weekly. Default annual.
review_mechanism
enum
Required
One of: CPI, market, fixed, hybrid, none. Critical field.
review_dates
array of dates
Required
Each within term. Sequence must be ascending.
option_to_renew
boolean
Required
If true, option_terms must be populated.
option_terms
array
Optional
Each entry: option_period_years, option_notice_required.
permitted_use
string
Required
Non-empty. Capture verbatim.
outgoings_recoverable
boolean
Required
If true, outgoings_categories must be populated.
outgoings_categories
array of strings
Optional
Match against canonical list. Flag uncategorised items.
security_deposit_amount
decimal
Optional
Currency in AUD. Cross-check with held bond register.
guarantor_name
string
Optional
If present, capture full legal name.
special_conditions
array of strings
Optional
Each capture preserves the clause text and the page reference.
make_good_clause
string
Optional
Capture verbatim with page reference.
execution_date
date
Required
ISO 8601. Must not exceed commencement date by more than 90 days.
execution_pages
array of integers
Required
Page numbers where signature blocks appear in the PDF.
Section 4 · Evaluation Criteria

How performance will be measured.

The implementer must deliver a system whose performance can be measured against the thresholds below. Ground truth is a set of 50 already-abstracted leases from Meridian's archive, manually validated by senior paralegals before the engagement, made available to the implementer at engagement start.

Metric
Threshold
Measured against
Action on breach
Required-field precision
≥ 0.97
Ground truth set of 50 leases
Block production deployment
Required-field recall
≥ 0.95
Ground truth set of 50 leases
Block production deployment
Critical field accuracy
review_mechanism, review_dates, base_rent_amount
≥ 0.99
Ground truth set of 50 leases
Block production deployment
Optional-field precision
≥ 0.90
Ground truth set of 50 leases
Flag for review, allow ship
Source page reference accuracy
≥ 0.98
Ground truth set of 50 leases
Block production deployment
Per-document confidence flag rate
≤ 25%
First 100 production documents
Tune model, escalate to review
Per-document processing time
≤ 5 min
All production documents
Optimise infrastructure
End-to-end cycle time
ingestion to validated record in property platform
≤ 2 days
First 50 production documents
Process review

Critical fields require a higher accuracy threshold because the cost of error is higher. A wrong review mechanism on a 10-year lease is a multi-million-dollar mistake. A wrong make-good clause is recoverable. The thresholds reflect the cost-of-error gradient.

Lumen & Lever · evaluation rationale

Section 5 · Human Review Model

Where humans sit in the workflow.

Humans are inserted at three checkpoints by design. This is not a degradation of the system. It is the system. Lease abstraction at this cost-of-error profile requires explicit human gates.

Workflow pipeline · seven stages
Stage 1
Ingest PDF
Deterministic
Stage 2
Extract to AST
Bounded model
Stage 3
Validate schema
Deterministic
Stage 4
Classify review mechanism
Bounded model
Stage 5
Paralegal review
Human checkpoint
Stage 6
Senior sign-off if flagged
Human escalation
Stage 7
Persist to platform
Deterministic
Checkpoint 1 · Per-document review

Senior paralegal reviews every extracted lease.

Every lease abstraction is reviewed by a senior paralegal before the validated record is persisted. The reviewer sees the extracted fields side-by-side with the source PDF, with each field annotated with its source page reference and confidence score. Edits are tracked.

Owner
Senior Paralegal
SLA
2 working days from extraction complete
Output
Validated record + edit log
Checkpoint 2 · Senior sign-off on flagged extractions

Head of Property Operations signs off when confidence falls below threshold.

Where extraction confidence on any required field falls below the configured threshold, the document is automatically routed to the Head of Property Operations for second review. The threshold is calibrated to surface roughly 25% of documents in early production, declining as the system matures.

Owner
Head of Property Operations
SLA
1 working day from flag
Output
Sign-off or rejection with reason
Checkpoint 3 · Quarterly review

Property Operations reviews aggregate accuracy quarterly.

Each quarter, a sample of 25 documents is re-validated against ground truth. Drift is reviewed. Threshold breaches over the period are surfaced. Recommendations are made on whether thresholds should be tightened, loosened, or left in place.

Owner
Head of Property Operations + Lumen & Lever (retained)
Frequency
Quarterly
Output
Quarterly Control Review report
Section 6 · Audit and Traceability

What must be logged. What must be reproducible.

Every action in the workflow must produce an audit record sufficient to reconstruct the path from source document to validated record. The audit trail is not optional. It is a precondition for production deployment.

Per-extraction audit record

  1. Source document. The original PDF with a content hash and a stored copy in the audit archive.
  2. Extraction timestamp. When extraction commenced and when it completed.
  3. Model identity. The exact model version used. Model upgrades require explicit re-evaluation before being applied.
  4. Prompt version. A reference to the exact prompt configuration used.
  5. Raw extraction output. The structured JSON output from the model, before any validation or transformation.
  6. Validation result. Pass, fail, or flagged. With reason codes.
  7. Confidence scores. Per-field confidence as reported by the model and as adjusted by the validation layer.

Per-review audit record

  1. Reviewer identity. Authenticated user who performed the review.
  2. Review timestamp. Start and end of review session.
  3. Field-level edits. Before and after values for every field the reviewer modified.
  4. Sign-off action. The explicit confirmation that the record is validated for downstream use.

Retention

  1. Audit records retained. 7 years from extraction date, aligned with Meridian's existing legal record retention policy.
  2. Source PDF copies retained. Independently of the property platform, in the audit archive.
  3. Model and prompt configurations. Versioned and retained for the audit-record retention period.
Section 7 · Acceptance Criteria

What the implementer must demonstrate.

The system is accepted into production when, and only when, all of the following criteria are met. The acceptance review is conducted jointly by the Head of Property Operations and Group IT, with Lumen & Lever retained for the review session.

Functional acceptance

  1. All 23 fields are extracted on every document in the ground truth set, with the field structure exactly as specified in Section 3.
  2. Extraction performance meets or exceeds every threshold in Section 4 on the ground truth set.
  3. Source page references are verifiable: every extracted field links to a page in the source PDF that contains the corresponding text or value.
  4. Confidence scores are present on every field. Flagging behaviour matches the configured threshold.
  5. The system processes a representative test batch of 20 unseen documents drawn from the active lease portfolio, with results reviewed by the Head of Property Operations.

Operational acceptance

  1. The reviewer interface allows side-by-side viewing of extracted fields and source PDF with page navigation.
  2. Edits made during review are captured in the audit log.
  3. Sign-off action persists the validated record to the property platform.
  4. Confidence-flagged documents are routed automatically to the senior reviewer.
  5. The audit trail satisfies every requirement in Section 6.

Governance acceptance

  1. A documented rollback path exists. The system can be turned off and the prior manual abstraction process resumed within 24 hours.
  2. The rollback path has been tested. A single document has been processed end-to-end via the manual process while the AI system was offline.
  3. The Quarterly Control Review process is scheduled and resourced.
  4. Model version pinning is in place. No automatic model upgrades.
  5. Data residency in Australian regions is verified by the implementer with documentation.
Section 8 · Production Readiness Gates

Four gates before live data.

The system passes through four sequential gates before it processes live business data. No gate may be skipped. Each gate is signed off by a named owner.

i

Observable

Every input, output, and intermediate step is traced and stored. The system can be debugged without reconstructing context from memory.

Test
"Pick a random extraction from yesterday. Reconstruct exactly how it was produced."
ii

Governable

Acceptance thresholds are defined. Drift detection is in place. Evaluation runs continuously. The system can be modified by people other than its original builder.

Test
"If the original builder left tomorrow, can the next person change a threshold safely?"
iii

Owned

Business owner accountable for the workflow. Technical owner accountable for the system. Both funded, both have time, both have authority.

Test
"Two names on the page. Real names. Real budgets. Real time allocation."
iv

Reversible

The system can be turned off without breaking the underlying workflow. The work reverts to the prior method. The kill switch has been tested.

Test
"Has the system actually been switched off and the workflow run manually for one cycle?"
Section 9 · Out of Scope and Boundary

What this brief does not authorise.

Explicitly out of scope

The following are not authorised under this brief.

  • Any extension of the workflow beyond the 23 fields and the renewal-cycle leases defined in Sections 1 to 3.
  • Any system that writes directly to the property platform database without going through the platform's API and the human review checkpoint.
  • Any deployment of the system on infrastructure outside Australian regions.
  • Any model upgrade or prompt change in production without re-evaluation against the ground truth set.
  • Any use of this system for outgoings reconciliation, rent review calculation, or tenant communication. Those workflows require separate briefs.
  • Any direct customer or tenant communication generated by the system.
  • Any client of Meridian's accessing the system or its outputs without the Head of Property Operations' written authorisation.

Lumen & Lever does not implement this system. This brief defines the conditions an implementer must satisfy before the lease abstraction workflow is trusted in business use. Selection of the implementer, contract negotiation, and operational ownership remain with Meridian Holdings.

Boundary statement

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