Use both. Here's where each one wins.

Observability tools see failures. Pisama acts on them. They are precondition layers; we are the action layer above. The comparison below is honest about where each one is stronger, not a zero-sum claim.

Pisama vs Patronus AI

Patronus published the TRAIL benchmark (the canonical dataset for agent failure detection) and ships Percival, a proprietary agent eval product. They are the closest competitor by problem framing.

On their own benchmark, Pisama's 20 core heuristic detectors achieve 59.9% joint accuracy at $0 cost. The best frontier LLM (which underpins Percival's judge) achieves 11.6%. The 5x lead comes from heuristic-first design. Most failures have structural signatures that do not require an LLM to detect.

Where Patronus AI wins
  • Authored TRAIL: deepest expertise in agent failure taxonomy
  • Strong managed-service offering (Percival, Lynx, Glider)
  • Enterprise sales motion and design partner program
Where Pisama wins
  • 59.9% on TRAIL vs 11.6% best frontier (the model class Percival relies on)
  • Open-source detectors: F1 published per detector, dataset reproducible
  • Heuristic-first: median trace cost <$0.01, vs Percival's LLM-judge cost per call
  • Multi-framework: LangGraph, CrewAI, AutoGen, OpenAI Agents, Claude Agent SDK, Bedrock, ADK

At a glance

DimensionPatronus AIPisama
TRAIL accuracy11.6% (best frontier judge)59.9% (heuristic detectors only)
Cost per traceLLM judge cost per call<$0.01 median (T1–T3 free)
OpennessProprietary judgesMIT detectors, F1 per detector public
Framework coverageAPI-based; framework-agnostic12 first-class adapters + OTel ingest
AuditabilityBlack-box gradersDetector logic in repo, calibration data published

Recommendation

For teams that want the deepest agent failure taxonomy in production, Pisama is the open implementation. Patronus is strong for enterprise teams that want a managed service and are comfortable with proprietary graders.

FAQ

Did Pisama use the TRAIL dataset to calibrate?
TRAIL is the evaluation benchmark, not the calibration set. Pisama detectors are calibrated on 7,212 traces from 13 external sources (none of which are TRAIL). TRAIL is held out for measurement, which is why the 59.9% number is a fair test against the published benchmark.
Can I use both?
Yes. Run Patronus for managed evals on outputs and Pisama for in-flight structural detectors on the trace. The categories are complementary.