Retain

POST /api/v2/containers/{container_tag}/retain

Retain captures evidence and candidate memory. The runtime classifies junk, extracts atomic claims, and promotes only clean supported facts.

{
  "content": "The owner prefers MiniMax-backed search first for factual/current queries.",
  "source": "codex",
  "memory_plane": "task",
  "tags": ["search", "preference"]
}