THE COMPARISON / A CLOSER LOOK
AgentEval vs LangSmith
Compare the listed plans, useful capabilities, and practical tradeoffs.
Prices and features reflect editorial records. Check vendor terms before you buy; documentary checks do not imply hands-on testing.
AgentEval
🔴DeveloperVoice AI Tools
Comprehensive .NET toolkit for AI agent evaluation featuring fluent assertions, stochastic testing, model comparison, and security evaluation built…
SOURCE-CHECK COVERAGE
No scoped source-check record shown. Check current pricing and vendor terms before buying.
Starting Price
FreeLangSmith
🔴DeveloperLLM Observability
LangSmith helps developers trace, evaluate, test, and monitor applications built with language models and agent workflows.
SOURCE-CHECK COVERAGE
No scoped source-check record shown. Check current pricing and vendor terms before buying.
Starting Price
FreeFeature Comparison
Focus the table and use arrow keys to scroll when columns extend beyond the screen.
The editorial take
Choose AgentEval if you want a free, MIT-licensed toolkit with trace record/replay, stochastic evaluation, and 192-probe security scanning running locally in .NET. Choose LangSmith if you need a fully managed observability platform with hosted dashboards, multi-user team collaboration, and deep LangChain/LangGraph integration, and you have budget for LangSmith's per-seat pricing.
AgentEval - Pros & Cons
Pros
- ✓Native .NET integration with full type safety and compile-time error checking, unlike Python alternatives that rely on runtime exceptions
- ✓Red Team module ships with 192 attack probes across 9 attack types covering 60% of OWASP LLM Top 10 2025 with MITRE ATLAS technique mapping
- ✓Stochastic evaluation asserts on pass rates across N runs (e.g., 10 runs at 85% threshold) for statistically meaningful results
- ✓Trace record/replay eliminates API costs in CI — record once with real API, replay infinitely for free with identical outputs
- ✓Model comparison generates markdown leaderboards with cost/1K-request rankings across GPT-4o, GPT-4o Mini, Claude, and other providers
- ✓MIT licensed with explicit public commitment to remain open source forever — no bait-and-switch license changes
- ✓27 detailed samples included from Hello World through Multi-Agent Workflows and Cross-Framework evaluation
- ✓First-class Microsoft Agent Framework (MAF) integration with automatic tool call tracking and token/cost telemetry
Cons
- ✗.NET-only — Python, JavaScript, and Go teams cannot use it and must rely on DeepEval, PromptFoo, or LangSmith instead
- ✗Red Team coverage is 60% of OWASP LLM Top 10, leaving 40% of categories uncovered compared to specialized security scanners
- ✗Commercial/Enterprise add-ons are still in planning phase, so enterprises requiring vendor SLAs and paid support have no tier to purchase
- ✗Small community relative to Python-era evaluation tools means fewer third-party integrations, tutorials, and Stack Overflow answers
- ✗Stochastic evaluation can become expensive — 100 tests × 50 repetitions equals 5,000 LLM calls per run if trace replay is not used
- ✗Tight coupling to Microsoft Agent Framework concepts means evolving with Microsoft's roadmap rather than remaining provider-neutral
LangSmith - Pros & Cons
Pros
- ✓Makes multi-step LLM failures easier to localize than application logs alone
- ✓Connects production traces, datasets, experiments, and evaluations in one workflow
- ✓Particularly natural for teams already building with LangChain or LangGraph
- ✓Supports repeatable release checks instead of subjective prompt spot-testing
Cons
- ✗Useful evaluations require ongoing dataset curation and carefully designed scoring criteria
- ✗LLM-as-judge results can be noisy and should not replace expert review for high-risk outputs
- ✗Captured traces may contain sensitive prompts, documents, and tool results
- ✗Current pricing and usage limits could not be verified from vendor pages in this environment
Not sure which to pick?
🎯 Take our quiz →🔒 Security & Compliance Comparison
Focus the table and use arrow keys to scroll when columns extend beyond the screen.
Price Alert Interest
Record the tools you want pricing updates for