How it works
Read the stream in order.
The official SDK schemas define each event's discriminator and fields. Stream semantics add relationships across events: a message starts before content, tool arguments belong to an open call, and a finished run matches its start. This tool reports both layers without uploading your data.
Use raw SSE, JSONL, a JSON array or a single event. Start with parse errors, then required-field errors, then sequence diagnostics. A clean report means the pasted fixture passed this independent checker; replay it through your chosen SDK before production.
Useful next steps
- Paste the stream into the free validator.
- Check SSE framing and JSON payload parsing.
- Look up common lifecycle diagnostics.
- Compare behavior with the official AG-UI SDK used by your application.
AG-UI Event Lab is independent and is not affiliated with the AG-UI project or CopilotKit.