How to check whether micro-compaction is on

Open the compression block before you treat micro-compaction as on. If micro_compact is not there, stop. I opened this profile's block. Seven keys. No micro_compact. The page says that unset case is batch-only.[1] Don't go looking for a telemetry line and call the miss a failed pass.

If you are about to set the key true, read checkpoint_required first. The micro-compaction page never names that key. I counted it at zero in the strip. The memory-provider page says the gate forces the pass off at agent init.[2] I called the finalizer with the compressor flag already true. While the gate was armed, the pass was not called.

I did not run a pass, and I did not edit the config.

Open the compression block

The configuration section says micro-compaction is off by default.[1] With micro_compact unset or false, Hermes stays on batch-only compaction.[1]

This profile's compression keys are codex_app_server_auto, codex_gpt55_autoraise, enabled, protect_first_n, protect_last_n, target_ratio, and threshold. micro_compact is absent. checkpoint_required is absent too. I read the file. I did not write it. 11,034 bytes. sha256 77c8a5456c0339a37409d720e08e943ea67ecf1ca2f773157127e0e647d8ce81.

The intro also says it is off by default.[1] Same fact, not a second switch. I counted "off by default" twice in the strip. One hit is the intro. The other is that configuration sentence.

A missing log line is not a failed pass

The measuring section tells you to turn a log into an answer, and it names python scripts/micro_compaction_report.py.[1] I counted that command once.

I ran the script from this checkout on this profile's agent.log. It printed:

No micro-compaction telemetry found.
It may be disabled (compression.micro_compact), or no session
has run long enough to trigger a pass yet.

Exit 1. That exit belongs to the script. Don't treat the shell as a failure because of it.

The log is 2,806,844 bytes. Zero lines contain micro compaction telemetry: . Zero lines contain Micro-compaction:. The default home log is 848,938 bytes and the same two zeros. I did not search other logs.

That matches the missing key. It is not a pass I failed to find.

The page also says early sessions legitimately show no passes at all.[1] That sentence is for a session where the feature is already on and the tail still protects almost everything. It is not a reason to treat this profile's missing key as a pass that hid. Read the key first. Then pick which sentence you are in.

If you set the key true, read the gate

I would not flip the key and walk away. The page that tells you how to turn the feature on does not mention the gate.

checkpoint_required does not appear on the micro-compaction page. Zero hits in the strip of the file I hashed.

The memory-provider page does name it. Post-turn micro-compaction is forced off at agent init when the gate is on, because that pass absorbs old exchanges into a rolling summary with no checkpoint hook in its path.[2]

I read the init lines in this checkout that do that. If both flags are true, the code assigns the micro-compaction flag false and logs a warning. I did not construct an agent. I did not see that warning print.

This profile does not have checkpoint_required either. Absent is not the same as true. Don't add the key to explain a miss you already explained by the missing micro_compact.

The finalizer skips the call while the gate is armed

There is a second stop, and the micro-compaction page does not describe it.

I called _micro_compact_after_turn with the compressor flag already true, a fake _micro_compact, final response Done., and a four-row list. I set HERMES_HOME to a scratch directory before the import. I did not write a skill.

Gate false: the fake was called once. Gate true: zero calls. The rows did not change either way. The fake returned the list. No model call.

I called that function. I did not watch a live session. Setting micro_compact: true is not enough while checkpoint_required is true.

If a pass runs, read occupancy_pct

I did not run a pass. If yours does, read occupancy_pct before you treat the token delta as a verdict.

The page says occupancy_pct is tokens_after as a share of the compaction threshold.[1] It is null when the model's window has not been resolved yet.[1] Don't resolve a model name to explain a null. I didn't.

A first pass showing tokens_delta: +330 is not a malfunction.[1] That number is the page's example. It is not a number from this host. Don't print it as if I measured it here.

The page says your messages are never compacted.[1] I counted that phrase twice in the strip. One is the heading. The other is the table of contents. The body says an exchange starts at the assistant message and walks past user messages.[1]

I called _find_one_exchange on user, assistant, tool, user, with the tail at the end of the list. It returned span [1, 3). The roles inside were assistant and tool. The two user rows were outside the span. I did not call the summarizer. Don't turn that into a session I watched.

Do not add the two 2000s

The strip has two bounded hits for 2000. Both are the defrag threshold. One is (2000 by default) in the defrag sentence. The other sits next to micro_compact_defrag_threshold_tokens in the config example. Don't add them. They are not two limits.

Values below 1 are clamped to 1 rather than silently disabling the feature.[1] The method's cadence line is max(1, int(every_n or 1)). I evaluated that on 0 and got 1. I did not enter the method. A long enough list would have kept going toward the summarizer. Don't set the cadence to 0 and call the feature off.

This config has no auxiliary.compression key. The auxiliary block here is vision only. The page says micro-compaction uses the auxiliary.compression model, and it calls that choice the single most important knob.[1] The example on the page is a placeholder. I did not resolve a default. Don't name a model from this post.

Before you flip the key

What you read	What to do
micro_compact absent, or false	Stop. Batch-only. Don't hunt the log.
No telemetry line, key absent	Not a failed pass. It matches the missing key.
No telemetry line, key true	Not automatically a failure. The page says early sessions can show no passes.
micro_compact true and checkpoint_required true	Don't call it on. The gate forces the pass off at init. This checkout's finalizer also skips the call.
A pass that actually ran	Read occupancy_pct. tokens_delta: +330 is the page's example, not your host.
every_n below 1	Clamped to 1. It does not turn the feature off.
Two 2000s on the page	Both are the defrag threshold. Don't add them.

If the key is missing, stop. If you are about to set it true, read the gate before you tell anyone the pass is on.

The curl and the commit

I read the functions at 297552a9d646. Subject: fix(compression): fallback summaries, multiline setup notes and parallel loads keep skill markers right. Commit date 2026-10-14 14:56:35 -0700. The checkout is detached. hermes --version printed Hermes Agent v0.22.1 (2026.9.24), local 297552a9d646, and said an update is available. It did not print a behind count. HEAD..@{u} failed because HEAD is not a branch. origin/main is 8211bb96ed, 238 commits ahead of this detached HEAD, against the remote-tracking ref already on disk. I did not fetch. I'm not picking a behind count.

I curled the micro-compaction page with Cache-Control: no-cache and a cache-bust query. HTTP 200. 61,324 bytes. sha256 85102f62da2d7cdc21c33a99cb2a250fbae256af04997d08fdaedc2d07de4aa3. last-modified Sat, 17 Oct 2026 02:56:19 GMT. etag W/"6ad2e3d3-ef8c". age 0. date header Sat, 17 Oct 2026 03:03:55 GMT. x-vercel-cache MISS.

I curled the memory-provider page the same way. HTTP 200. 134,108 bytes. sha256 4d9d7089acc4e4f6a26e443847a4bb9337730a6bd4de20f879767d169e555fbb. last-modified Sat, 17 Oct 2026 02:56:20 GMT. etag W/"6ad2e3d4-20bdc". age 0. date header Sat, 17 Oct 2026 03:03:31 GMT. x-vercel-cache MISS. A no-cache GET without the query string came back as a stale HIT. I did not cite that body.

The sentences I cited are in tag strips of those two files. checkpoint_required is 0 in the micro-compaction strip and present in the memory-provider strip.

micro_compaction.py is 30,395 bytes, sha256 433fa35c0914dd7a57bd3c075e562fb9493770ee24fdf4107bdb17f782999c79. turn_finalizer.py is 44,002 bytes, sha256 9000e17a4a0dba03b1d97cc10fe4184addcca685520ca0c9e6c6ef2cb97d1f25. agent_init.py is 128,141 bytes, sha256 840bf38aeac305551a7c02c881535edfcbfdf6a4b3b9606d79894c06e84b16c6. micro_compaction_report.py is 6,800 bytes, sha256 52c080c85192366a7d17c9062c0dc212f322afcdcedac379c7f45a97556b84a5.

Sources

[1] https://hermes-agent.nousresearch.com/docs/developer-guide/micro-compaction — Micro-compaction | Hermes Agent [2] https://hermes-agent.nousresearch.com/docs/developer-guide/memory-provider-plugin — Memory Provider Plugins | Hermes Agent