Evaluate the operating responsibility
The build-versus-buy decision is not just whether a team can extract terms or produce an answer from documents. It is who will sustain accurate, current, source-backed context as relationships and operating records change. Assess that responsibility separately from the workflows that consume it.
An internal prototype can be a useful way to learn. Give it a bounded question, known documents and explicit acceptance criteria. Then test what happens outside the demonstration: late amendments, conflicting entity names, changed access, incomplete families and requests for a position at an earlier date.
Three approaches to compare
Internal foundation
Control
You define the model, roadmap and implementation.
Responsibility
Your team owns document relationships, temporal logic, evidence, access and maintenance.
Pressure test
Who keeps context current after the original builders move on?
Dedicated foundation
Control
Evaluate the provider’s model and fit against your records.
Responsibility
Agree ownership, review processes and operating boundaries.
Pressure test
Can reviewers inspect evidence, gaps and the position at a prior date?
Hybrid approach
Control
Build customer-specific workflows around a governed foundation.
Responsibility
Define the boundary between context services and workflow owners.
Pressure test
What changes when either side’s model or access policy evolves?
Price the work beyond extraction
Entity resolution, document-family completeness and partial supersession are continuing concerns. A changed price may affect only one service from a particular date. The system must preserve unaffected provisions and show which evidence supports each part of the answer.
Include stewardship, exception review, testing, change history and access administration in the assessment. Ask who investigates a missing record, how a corrected mapping propagates and whether historical answers remain reconstructable. Avoid treating these responsibilities as a one-time implementation checklist.
Separate foundation from execution
- 01Resolve entities and document relationships.
- 02Determine effective dates and scope.
- 03Connect the operating records and cite evidence.
- 04Expose approved context to a separately governed workflow.
Use a real decision to test fit
Illustrative example: compare an amended service price with an invoice for a period spanning the change. Ask each approach to show the governing records, applicable scope and unresolved assumptions. Evaluate the work required to repeat the review when another amendment arrives.
LineageAI is PostSig’s shared foundation for relationships, dates, scope and source evidence. MCP provides approved access for assistants, tools and customer-built workflows. That access does not authorize autonomous payment, approval or execution. A sound choice makes both the evidence responsibility and the workflow authority explicit.