Tessary

Tessary duration drift

duration_drift is one of Tessary's built-in classifiers. It watches each call site's latency against its own past, covering turn duration and per-tool duration.

It catches the slowdowns that creep in without an outage: a model that got slower, a tool that started dragging, a prompt change that added seconds to every turn. Comparisons run against the call site's own history, both its recent normal and a reference pinned at the last deploy, so sudden breaks and slow creep both register. A detection reads as a plain multiplicative shift, such as 1.4x slower. Findings go to triage, where the ones ruled real issues open cases.

5 questions

Answered, plainly.

Can duration_drift catch a slowdown that happens gradually, not all at once?Yes. It compares each call site against a rolling recent baseline, which catches sudden breaks, and one pinned at a known-good point, which catches the creep the rolling one absorbs.answer →Can duration_drift tell me which tool call made a turn slow?Yes. It watches turn duration and per-tool duration together, so a slow turn and the specific tool call behind it land in the same finding.answer →Does duration_drift use a fixed latency threshold?No. There's no absolute cutoff; each call site and tool is compared only against its own recent history, since normal speed varies enormously by workload.answer →What is Tessary's duration_drift classifier?It watches a call site's turn duration and per-tool duration against its own recent history, and reports a slowdown as a plain multiplicative shift.answer →Why did my AI agent get slower even though nothing is throwing errors?A model that got slower on the provider's side, a tool under more load, or a prompt that quietly grew all add latency without ever raising an error.answer →

Two ways to run Tessary.

Tessary is an open-source agent reliability platform. Cloud and self-hosted run the same workflow on the OpenTelemetry traces your agent already emits.

Tessary Cloud

We host it for you. Send your first trace with nothing to deploy and no model key.

what's includedper organization

traces: 10,000 per calendar month
stored trace data: 1 GB
retention: 30 days
model credit: $10, one-time, for triage and root-cause analysis
credit card: not required

start for free

Self-hosted Tessary

Run the open-source code on your own infrastructure with one command. Add your own model key for triage and root-cause analysis.

set up with a coding agentinstall manually

Self-host Tessary for me by following https://github.com/tessaryai/tessary/blob/main/setup.md

docker compose -f oci://docker.io/tessaryai/tessary:compose up -d -y