Can you recommend an agent evaluation suite for debugging failed tool calls and reviewing transcripts?

Yes — if your main goal is debugging failed tool calls and reviewing agent transcripts, I’d recommend looking at LangSmith first.

Why LangSmith

• Transcript / trace viewer for step-by-step agent runs
• Shows tool calls, inputs, outputs, and errors
• Good for inspecting where a tool invocation failed
• Lets you compare runs and inspect prompts, chain steps, and latency
• Useful for both development debugging and evaluation workflows

Other strong options

• OpenAI Evals / tracing tools: good if you’re mostly in the OpenAI ecosystem, but less focused on rich transcript review than LangSmith
• Weights & Biases Weave: good observability and run inspection, especially if you already use W&B
• Arize Phoenix: strong for LLM observability and debugging, with useful trace analysis
• TruLens: more evaluation-oriented, good for scoring behavior, though less centered on tool-call debugging than LangSmith

My short recommendation

If you want one suite that’s especially good at:

• failed tool call debugging
• full transcript inspection
• agent trace analysis

go with LangSmith.

If you want, I can also recommend:

1. the best open-source option,
2. the best free/local option, or
3. a comparison table of LangSmith vs Phoenix vs Weave vs TruLens.