The source authority model defines what the assistant is allowed to trust and how strongly it may use each source.
This model is not a document inventory. It is a decision-control layer. It tells the assistant which material can support a decision, which material can only support a caveated recommendation, which material can only be used as background, and which material must be blocked until a human resolves the conflict.
The model should use tiers.
Tier 0: Mandatory governance authority
These sources define hard constraints. They may include AI policy, security policy, privacy and data-classification policy, quality or regulatory policy, legal requirements, records policy, procurement rules, and other mandatory governance sources. If a Tier 0 source applies, lower-tier material cannot override it.
Tier 1: Enterprise architecture authority
These sources define approved direction. They may include EA principles, reference architectures, approved platform standards, approved AI patterns, cloud standards, integration standards, identity and access standards, data standards, observability standards, and the technology catalog.
Tier 2: Prior decisions and exceptions
These sources preserve precedent. They include architecture review decisions, approved exceptions, lifecycle decisions, risk acceptances, pattern approvals, and roadmap decisions. They help the assistant identify consistency, drift, and exception boundaries.
Tier 3: Implementation guidance
These sources help teams implement approved direction. They may include engineering playbooks, platform guides, FAQs, training material, vendor implementation references, and practical notes. They can inform the review, but they do not override policy or architecture authority.
Tier 4: Discovery only
These sources may point to useful information, but they do not independently support an architecture decision. This includes email, chat, meeting notes, informal updates, draft decks, unowned pages, and “latest guidance” attachments with no official home.
Useful evidence, but not independent decision authority.