Why the separation is accelerating.
The same architecture improves security, privacy, auditability, and model portability.
Prompt visibility is too broad for secrets.
Model requests may pass through gateways, traces, evaluation systems, support tooling, caches, transcripts, and vendor infrastructure. Secret isolation reduces the number of systems that ever handle the raw value.
Design move: placeholders in model contextComputer-use agents observe more than they need.
Browser workflows can encounter passwords, payment fields, customer records, inboxes, health portals, and identity documents while pursuing an unrelated task. Capture policy must distinguish what the agent sees from what it is allowed to retain.
Design move: field-level capture controlsApprovals need context, not secret disclosure.
A person deciding whether to continue needs the site, action, purpose, amount, recipient, scope, and expiration. They rarely need the complete raw value copied into the approval message.
Design move: redacted decision packetsMemory makes accidental exposure persistent.
A value that reaches a summary, vector, profile, or learned rule can influence future actions long after the original workflow. Memory promotion gates keep temporary execution data from becoming durable personal context.
Design move: explicit memory boundariesTool-specific execution enables least privilege.
A secret token can be bound to one origin, field category, action, amount, browser session, user approval, and short expiration. The model cannot reuse it for another destination or later task.
Design move: scoped execution grants