Retention
What it is
Rules for how long knowledge, transcripts, files, and memory should remain available.
In plain terms
Different shelves in a fridge carry different expiration dates - milk a week, leftovers a few days, preserves for months. Hermes treats its own storage the same way: a scratch file, a cron job’s output log, and a finished chat session are each timed to expire on their own schedule rather than sitting around forever by default.
Why it matters
Privacy asks what’s allowed to be kept; retention asks a different question — how long it should stay before getting pruned. Transcripts, memory records, and generated files each need their own answer, since a cron job’s daily log has nothing like the useful lifespan of a curated long-term memory fact. Skip explicit retention policy and a personal wiki or memory store simply grows without bound, eventually undermining the selectivity curation was supposed to provide.
How it works
A dedicated disk-cleanup plugin (plugins/disk-cleanup/disk_cleanup.py) tracks ephemeral files by category and age: test files are deleted at session end, temp files after 7 days, cron output after 14 days, and research downloads older than 30 days are flagged for review except the 10 most recently added, which are left alone - all scoped strictly to HERMES_HOME plus /tmp/hermes-*, never touching logs. Separately, config settings govern longer-lived state: the filesystem-checkpoint feature (off by default) defaults its retention_days to 7 with auto-pruning on once a user enables it, while sessions.retention_days defaults to 90 but auto-pruning there is off by default, since session history feeds search recall and silently deleting it could surprise a user. Curated memory itself follows neither clock - it is bounded by the character limit described under knowledge curation, not by age.
A concrete example
A cron job writes its daily output to cron/output/ and that file is auto-deleted once it passes 14 days old. A finished chat session sits in state.db past the 90-day retention_days mark, but nothing happens to it unless the user has explicitly turned on sessions.auto_prune - Hermes never silently discards conversation history. Meanwhile a fact in MEMORY.md about the user’s preferred deploy process just stays put, since it is governed by curation and a char budget rather than an expiry date.
How it connects
This note belongs to the Memory family. Its closest neighboring concepts are: Knowledge Curation, Privacy, Agent Runtime, Personal OS.
Source evidence
vendor/hermes-agent/agent/memory_manager.py:505-515#MemoryManager.prefetch_all— Verified Source Map evidence for MemoryManager. MemoryManager callsprefetchon each registered provider in order, skips empty results, isolates individual provider failures, and merges the remaining text.
Workflows
- Slack Second Brain
Related articles
- No article currently mentions this concept by name/alias often enough to qualify (see mention-mining policy).