Best AI Agent Observability & Eval Tools (2026)
Tracing, evaluation, guardrail and monitoring tools for seeing what your AI agents do and checking that they work. Below are the top 20 of 41 matching tools in the AgentScout directory, ranked.
Updated
How we ranked: Ranked by GitHub stars as recorded on each AgentScout listing (link checks 2026-10-21). Tools without a tracked public repo come after, in alphabetical order. Stars measure developer popularity, not quality or fit for your job, so read each listing before you choose. No paid placements.
Quick comparison Top 10 of 20 listed below. Pricing as the maker states it; blank means we don't have it.
| Tool | Pricing | Best for | Open source |
|---|---|---|---|
 MLflow | Open source + cloud | Automate workflows | Yes |
 Opik | Open source + cloud | Automate workflows | Yes |
 Arize Phoenix | Source-available + cloud | Automate workflows | Source-available |
 SWE-bench | Open source | Write code | Yes |
 Kiln | Source-available | Control a computer | Source-available |
 Agenta | Open source + cloud | Monitor & evaluate agents | Yes |
 Latitude | Open source + cloud | Monitor & evaluate agents | Yes |
 TruLens | Open source | Monitor & evaluate agents | Yes |
 Laminar | Open source + cloud | Monitor & evaluate agents | Yes |
 Pezzo | Open source | Monitor & evaluate agents | Yes |
1. MLflow
Open-source platform for tracing, evaluating and managing agents, LLM apps and ML models.
Pricing (as stated): Open source + cloud · Mature
2. Opik
Comet's open-source platform for tracing, evaluating and monitoring LLM apps, RAG systems and agent workflows, self-hosted or in the cloud.
Pricing (as stated): Open source + cloud · Mature
3. Arize Phoenix
Open-source tracing and evaluation for LLM apps.
Pricing (as stated): Source-available · Mature
4. SWE-bench
Benchmark that tests whether language models and coding agents can resolve real GitHub issues, with multimodal and verified variants.
Pricing (as stated): Free and open source (MIT) · Mature
5. Kiln
Free desktop app and open-source library for building AI systems with evals, RAG, agents, fine-tuning and synthetic data in one workbench.
Pricing (as stated): Source-available · Mature
6. Agenta
Open-source LLMOps platform for prompt management, evaluation and observability.
Pricing (as stated): Open source + cloud · Active
7. Latitude
Observability platform for AI agents that captures traces, groups failures into signals and verifies fixes against real traces.
Pricing (as stated): Open source + cloud · Active
8. TruLens
Evaluation and tracking for LLM experiments and AI agents.
Pricing (as stated): Open source · Active
9. Laminar
Open-source observability platform for AI agents with OpenTelemetry tracing, plain-English behavior tracking and alerts.
Pricing (as stated): Open source + cloud · Active
10. Pezzo
Cloud-native LLMOps platform for prompt design, versioning, delivery, observability and cost monitoring.
Pricing (as stated): Open source · Active
11. OSWorld
Benchmark for multimodal computer-use agents on open-ended tasks in real desktop environments.
Pricing (as stated): Open source · Active
12. OpenLIT
Open-source platform to trace, evaluate and guard agents and LLM apps.
Pricing (as stated): Open source · Active
13. MCPJam Inspector
Open-source testing and evals platform for MCP servers, MCP apps and ChatGPT apps across many clients and models.
Pricing (as stated): Source-available + cloud · Active
14. Future AGI
Open-source platform for evaluating, tracing, simulating and guarding LLM and AI agent applications, self-hostable or cloud.
Pricing (as stated): Open source + cloud · Active
15. Superlog
Superlog runs AI agents on routine engineering work around production. You set up automations with triggers and connectors, for example rating each new Sentry issue, posting a plain-language summary to Slack and opening a pull request with the fix, comparing error rates and latency against their normal range every hour, adding missing logs and spans to hard-to-debug code paths, or answering community questions from your code and docs. You choose the model and agent harness and bring your own tokens or subscriptions. The core is open source (Apache-2.0) with a hosted version.
Pricing (as stated): Open source (Apache-2.0) to self-host; hosted plans and enterprise on the pricing page; bring your own model tokens or subscriptions · Active
16. BrowserGym
ServiceNow's Gym environment for building, testing and evaluating web agents across browser benchmarks.
Pricing (as stated): Open source · Active
17. AI Beat
An open-source AI red-teaming suite: PromptBeat attacks models and prompts, and AgentBeat runs black-box security evaluations against HTTP-exposed agents.
Pricing (as stated): Open source · Active
18. OpenInference
OpenTelemetry-based instrumentation that traces LLM and agent framework calls so any observability backend can show them.
Pricing (as stated): Open source · Active
19. Tracely
Tracely is open-source, trace-native CI/CD for AI agents: it grades every production trace with evaluators, clusters failures into issues, freezes bad runs into replayable test cases and blocks pull requests that would reintroduce them.
Pricing (as stated): Self-host free (MIT); hosted Free $0 (20k traces/month), Team $49/mo; LLM judges run on your own OpenRouter key · Active
20. Agent Memory Leaderboard
Public leaderboard and open evaluation protocol, run by a group of universities and labs, for comparing long-term memory systems for agents in recurring submission rounds.
Pricing (as stated): Open source · Active
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Related: Monitoring agents in production · Evaluating agents · Langfuse vs LangSmith
Related searches: Open-source LLM observability and eval tools · Free AI agent evaluation tools
More best-of lists: All best lists · Best AI Coding Agents · Best AI Agent Frameworks · Best AI Browser Agents · Best Open-Source MCP Servers · Most-Starred Open-Source AI Agent Projects · Best Self-Hosted AI Agents · Best Free AI Agents (Free Plans) · Best No-Code AI Agent Builders · Best AI Voice Agent Platforms · Best Personal AI Agents · Best AI Agents for Business Teams · Best Crypto AI Agents
Facts come from our directory listings; pricing is as each maker states it and GitHub stars are as recorded on each listing. Check official sites before you choose.