FIELD NOTE / INSTAGRAM
Let agents move within real boundaries.
The short film, the complete written thought, and the evidence behind it.
Let agents move within real boundaries.
Short video caption
If a test agent has a production credential, 'use staging only' is an appeal. Give it staging-only authority, canary every enabled route, and inspect attempted crossings. Illustrative workflow. #EricFieldNotes
Full written post / accessible read
Agents are useful when they can act without asking permission at every step. That requires bounding what their identity can reach. If your test agent holds a production key, 'use staging only' is a request, not a boundary.
The team may have watched one successful staging test and assumed it was safe. But a different tool path or runtime can miss the hook while the same production credential still works.
A pre-tool hook can block the calls it intercepts. It cannot cover a route it never receives. In this illustrative workflow, staging-only credentials create a harder limit, while the trace records attempted crossings.
Give the test identity only staging access. Run a harmless deny canary through every enabled tool route and surface, then inspect the trace. Do this because the credential boundary survives a missed instruction or hook.
#EricFieldNotes
Evidence and boundary
On-screen boundary: ILLUSTRATIVE DATA ACCESS. The sources below support documented mechanisms and specifications; illustrative scenarios are not presented as measured incidents.
- Cursor hooks documentation (S04)
- Codex hooks reference (S44)
- Claude Code hooks reference (S45)