PI Protocol Reference

This page is the wire-level reference for glib <-> PI transport.

Transport

• Channel: stdin/stdout
• Framing: newline-delimited JSON (JSONL)
• Encoding: UTF-8 JSON objects, one object per line

Command schema

{
  "type": "prompt",
  "session_id": "repo:cloudboy-jh/glib",
  "text": "Summarize this staged diff"
}

Common command types:

• prompt
• abort
• steer
• new_session
• get_state
• set_model

Event schema

{
  "type": "text_delta",
  "session_id": "repo:cloudboy-jh/glib",
  "delta": "Here is what changed..."
}

Common event types:

• agent_start
• text_delta
• tool_execution_start
• tool_execution_update
• tool_execution_end
• agent_end
• auto_compaction_start
• auto_compaction_end
• auto_retry_start
• auto_retry_end
• extension_ui_request

Extension UI flow

1. PI emits extension_ui_request event.
2. glib renders requested UI surface.
3. glib returns user choice as command payload.

Error handling

• Invalid JSON line is treated as protocol failure.
• Broken pipe or process exit marks PI session crashed.
• glib surfaces crash state in footer and allows restart/new session.