Glossary · Security & governance
Trust Boundary
An interface where data, instructions, identity, or authority crosses between components or principals that operate under different trust assumptions.
Why it matters
A boundary crossing is where the system must authenticate actors, validate data, constrain permissions, and decide which claims can influence action.
In practice
Draw boundaries around users, model context, retrieval sources, tools, networks, and data stores, then specify validation and authorization for every crossing.
Common confusion
A network boundary is only one kind of trust boundary. Untrusted document text entering a privileged agent context also crosses one.
Related terms
Sources
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