UI Walkthrough

The AgentEvals Web UI provides a visual interface for uploading traces, running evaluations, and inspecting results with interactive span trees.

Starting the UI

Installed bundle (port 8001):

agentevals serve

From source (two terminals):

uv run agentevals serve --dev      # Terminal 1
cd ui && npm install && npm run dev   # Terminal 2 → http://localhost:5173

Key Features

Trace Upload & Evaluation

Upload traces and eval sets, select metrics, and view results. Supports both Jaeger JSON and OTLP trace formats.

Interactive Span Trees

Drill into agent execution with interactive span trees showing:

• Span timing and hierarchy
• Tool calls with arguments and results
• LLM calls with prompts, completions, and token usage
• Evaluation overlay showing which spans matched criteria

Live Streaming

Live-streamed traces appear in the Local Dev tab, grouped by session ID. Connect any OTel-instrumented agent:

# Start the server with dev mode
uv run agentevals serve --dev

# Point your agent's OTel exporter to agentevals
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
export OTEL_RESOURCE_ATTRIBUTES="agentevals.session_name=my-agent"
python your_agent.py

Traces stream in real-time. Works with LangChain, Strands, Google ADK, or any OTel-compatible framework.

Session Management

Sessions are auto-created and grouped by agentevals.session_name. Set agentevals.eval_set_id to associate traces with an eval set for automatic evaluation.

REST API

While the server is running, interactive API documentation is available:

The OTLP receiver (port 4318) serves its own docs at http://localhost:4318/docs.