Jack WildmanSenior Software EngineerFutureSearch
FutureSearch's research-agent platform, which uses LiteLLM for routing, fallback, retry and accounting and bills users from LiteLLM's spend logs.
FutureSearch blog, published Read the write-up (opens FutureSearch blog in a new tab)
Observation
At FutureSearch, a routine LiteLLM upgrade stopped usage billing for 6.5 days, and no alert fired because spend fell to zero.
- Takeaway
- Alert on billed spend falling as well as spiking, and read every LiteLLM upgrade's release notes for new defaults that change what reaches your spend logs.
- What happened
- On June 4, 2026 FutureSearch upgraded LiteLLM from v1.80.5.rc.2 to v1.83.14-stable.patch.3. A new allow_client_tags security setting, on by default, dropped the request tags its billing read, so usage billing stopped without an error (FutureSearch blog, Jun 10, 2026). The incident ran 6.5 days before anyone noticed: the team had alerts for runaway spend and none for spend falling to zero. It added that alert and stayed on LiteLLM at v1.86.4.
“A routine LiteLLM version bump turned off our usage billing for six and a half days. We had many alerts for runaway spend, but not for spend dropping to zero.”
- Public engineering write-up
- Incident length reported
Deployment details
FutureSearch's research-agent platform, which uses LiteLLM for routing, fallback, retry and accounting and bills users from LiteLLM's spend logs.
- Public engineering write-up
- Incident length reported
- Team
- FutureSearch engineering
- Duration
- 6.5 days without billed usage, from June 4, 2026
- Workload
- Routing, fallback, retry and accounting for a research-agent platform
- Product version
- LiteLLM v1.80.5.rc.2 to v1.83.14-stable.patch.3, later v1.86.4
- Measurement
- 6.5 days of usage not billed (Jun 10, 2026)





