# Final Architecture Approval: `sagent`

**Design session:** `01a015f7-89dc-7ce0-b9b7-62d7b85d2396`  
**Reviewer session:** `01a01665-6cc0-7d67-b635-d0f3cfc10444`  
**Approved documents:** [`ARCH_BLUEPRINT.md`](./ARCH_BLUEPRINT.md), [`prompt.md`](./prompt.md)

## Verdict

**APPROVED FOR PHASED IMPLEMENTATION.**

The architecture now explicitly adopts the Option B threat model:

- the active, human-approved extension and same-user interactive processes are trusted;
- unapproved candidates, generated patches, package scripts, builds, and tests are untrusted;
- the supervisor is candidate-isolated and tamper-evident, not claimed to be immutable against malicious same-user active code;
- autonomous code upgrades remain disabled by default.

All blocking findings from the base-architecture and autonomous self-improvement reviews are resolved within that stated threat model.

## Implementation Gate

Self-documentation and approval-gated persona candidates may be implemented before code self-upgrading. Autonomous code upgrades must remain disabled until platform-specific acceptance tests verify:

- fail-closed OS sandboxing;
- supply-chain controls and artifact digest binding;
- one-time human approval challenges;
- migration checkpoint recovery;
- five-point health verification and automatic rollback;
- kill switch, budgets, proposal deduplication, and documentation governance.

Any future expansion of the threat model to defend against a compromised active extension or hostile same-user process requires Option A privilege separation and a new security review.