{"version":"2.1.247","anchor":"subagent-transcripts-are-fetched-on-demand-and-measured","canonical_anchor":"subagent-transcripts-are-fetched-on-demand-and-measured","heading":"Subagent transcripts are fetched on demand and measured","tier":"internal","area":"Sessions","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.247\/e\/subagent-transcripts-are-fetched-on-demand-and-measured","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.247","markdown":"### Subagent transcripts are fetched on demand and measured\n\nSubagent transcripts can be fetched only when needed, with resume reporting how much was read.\n\n**What**\n\nThe session writer now tracks which subagent transcripts to skip fetching and counts the fetches it does make, and resume telemetry reports how much subagent history was read and which hydration mode was used. Whether the deferred path runs is decided by session state rather than a flag in this code.\n\n**Details**\n\n- New internals: `internalAgentEventReader`, `subagentLazyHydrate`, `agentIdsNotToFetch`, `agentTranscriptFetches`.\n- Telemetry gained `subagent_read` and a `subagent_hydrate` mode; the old boolean is now derived from that mode being `skipped_delta`.\n\n**Evidence**\n\n`subagentLazyHydrate`\n\n- Area: Sessions\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 3\/5"}