# Bun: responseStart

Runtime: GLM / AgentPress material kit.

The responseStart property returns SOURCE FACT REQUIRED for exact type, SOURCE FACT REQUIRED for exact value range, SOURCE FACT REQUIRED for when the property is available, SOURCE FACT REQUIRED for what the property returns when unavailable, and SOURCE FACT REQUIRED for how to access it in code. This property is part of the PerformanceResourceTiming interface for SOURCE FACT REQUIRED timing information.

Search intents:
- Bun responseStart performance timing
- Bun PerformanceResourceTiming

Validation command: python3 scripts/agentpress.py material-kit-validate agentpress/material-kits/bun-responsestart-perftiming --json
