Lucy

Lucy is an in-app AI assistant that inspects your traces to diagnose errors, latency issues, and high costs. It replaces manual scrolling with automated root-cause analysis.

Quick Start

Lucy is available globally in the vLLora dashboard.

1. Open any Trace Details or Thread.
2. Click the Lucy icon in the bottom right corner.
3. Ask a question (e.g., "What went wrong here?").

Example Commands

• General Debugging: "What is wrong with this thread?"
• Performance: "Show me the slowest operations."
• Cost Analysis: "Why is this run costing so much?"
• Specific Errors: "Why did the research_flights tool fail?"

Failure Detection Capabilities

Lucy automatically detects specific patterns common in Agentic workflows:

Issue Type	Description
Schema Mismatches	The model is hallucinating arguments (e.g., checkinDate vs check_in_date) or sending wrong data types.
Prompt Contradictions	The system prompt contains conflicting instructions (e.g., "Use tools" vs "Do not use external data").
Silent Truncation	The model output was cut off by max_tokens, but the HTTP request appeared successful.
Retry Loops	The agent is repeatedly failing the same step without changing its approach.

Example Analysis

Lucy provides a structured breakdown of issues found in the trace, sorted by severity.

In the example above, Lucy detected:

1. High Severity: A schema mismatch where the model used invalid arguments for a tool call.
2. Medium Severity: A logic conflict in the system prompt causing the agent to hesitate.
3. Low Severity: Output truncation in a data extraction step.