Stop your agents from failing silently.

Built for engineers running agents in production, Tessary watches every trace, catches what broke, and shows you why.

start for free self-host

on Tessary Cloud · 10,000 traces a month · no credit card required

116: traces emitted in the last hour
3: sampled and evaluated
1: wrong, raised by a customer

how it works

Monitor every trace, not a sample.

Your agent already emits spans. Tessary reads all of them as they land – no sampling, no LLM call.

Filter down to what broke.

Twelve traces break the same way. Tessary groups them into one case.

Analyze them against your code.

We read the failing traces against your repo and find the change that explains it.

Know what to change.

You get the cause and the evidence behind it, minutes after the first bad trace.

case 1184 · checkout agent · 12 of 218 tracesreading repository…

tools/refund.py · changed in a1f9c2

11def resolve_refund(order, cust):

12payload = {"order": order.id}

13cust never reaches the payload

14return client.refund(payload)

all 12 failing traces hit line 13 · no healthy trace does

The refund payload lost customer_id.

12payload = {"order": order.id}

13payload["customer_id"] = cust.id

case: checkout agent · tool-call errors increased
change: 0.4% → 11.2% in four hours
affected traces: 218
likely cause: tool argument changed in commit a1f9c2
next step: restore customer_id in the refund payload

features

Observability
Monitor every production trace to understand how your agents behave over time.
Classifiers
Check every trace against focused conditions to detect failures, behavioral drift, and users frustrated with your agent.
Cases
Turn validated issues into cases your team can investigate, track, and resolve.
RCA
Trace issues to their root cause across prompts, tools, models, and agent code.

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