The Shift: Context Is an Attack Surface, Not Just Memory
A recurring theme in agent-engineering discussion this week is a reframing of what "context" means for a long-running agent. Text an agent reloads as background — old tickets, README files, summaries of prior runs — has traditionally been treated as inert memory. The emerging argument is that anything an agent did not generate itself, and anything it re-ingests from an external or shared source, has effectively crossed a trust boundary and should be evaluated the same way untrusted user input is.
Why It Is Gaining Traction Now
The practical trigger is a string of incidents where agents treated instructions embedded in retrieved documents, chat logs, or third-party messages as legitimate commands, simply because the text arrived inside the agent's own context window rather than through an explicit "instruction" channel.
The Emerging Best Practice
Teams building production agents are increasingly tagging every context source with its trust level at ingestion time, and requiring an explicit, out-of-band confirmation before an agent escalates its own privileges or trust boundaries based on something it merely read.