[MEDIUM] Truthy check on custom_name silently falls back to model_id when name is empty string

[bluet]

Summary

check.model.custom_name or check.model.model_id is used in several display contexts:

• arguslm/server/api/monitoring.py:215, 295-296, 338-339
• arguslm/server/api/benchmarks.py:329, 393, 440

custom_name is a user-set string. The PATCH endpoint update_custom_name accepts updates whenever "custom_name" in update_data.model_dump(exclude_unset=True) — so a user setting it to empty string "" is accepted. But the truthy check on "" is False, so the export and history will silently fall through to model_id instead of showing the user's (empty) name.

Impact

• User edits the custom name to clear it → next view shows the model_id, not nothing — confusing
• If empty string is meant to be valid (clear the override), the display silently substitutes
• If empty string is meant to be invalid, the validation should reject it at the API layer, not silently fall through at display time

Suggested fix

Decide the intent first:

Option A — empty string means "no override": validate at API layer (reject "" or convert to None), keep the display logic.

Option B — empty string is a legal display value: change all sites to:

display_name = check.model.custom_name if check.model.custom_name is not None else check.model.model_id

Reference

Found by silent-failure-hunter audit.
Files:

• arguslm/server/api/monitoring.py:215, 295-296, 338-339
• arguslm/server/api/benchmarks.py:329, 393, 440

[bluet]

Released as part of v0.3.3 — see https://github.com/bluet/arguslm/releases/tag/v0.3.3 for the full release notes covering all six closed issues.