Hermes install only links memory_tencentdb into checkout tree; plugin can disappear after update and silently detach memory

[AustinZ29671]

Summary

install_hermes_memory_tencentdb.sh currently symlinks the Hermes plugin only into:

• $HERMES_AGENT_DIR/plugins/memory/memory_tencentdb

On Hermes hosts where the main checkout is updated/replaced, that symlink can disappear while memory.provider: memory_tencentdb remains configured.

When that happens:

• hermes memory status reports Plugin: NOT installed
• the Tencent sidecar on 127.0.0.1:8420 does not start
• new Hermes chats continue working, but Tencent vectors.db and gateway logs stop advancing

This is a high-severity operational bug because memory silently detaches while the main gateway still looks healthy.

Environment

• Host: Linux
• Hermes installed under: /home/admin/.hermes/hermes-agent
• Tencent plugin checkout: /home/admin/.memory-tencentdb/tdai-memory-openclaw-plugin
• Hermes config still points to memory.provider: memory_tencentdb
• memory LLM: deepseek-v4-flash
• embedding enabled

Verified live failure

Observed on a real Hermes host after the Tencent plugin had been working previously.

1) Hermes main gateway still healthy

systemctl is-active hermes-gateway.service
# active

So the main Hermes gateway is up.

2) Hermes memory status says provider configured but plugin missing

hermes memory status

Returned:

Memory status
────────────────────────────────────────
  Built-in:  always active
  Provider:  memory_tencentdb

  Plugin:    NOT installed ✗
  Install the 'memory_tencentdb' memory plugin to ~/.hermes/plugins/

3) Tencent sidecar not listening

curl http://127.0.0.1:8420/health
# connection refused

4) Hermes plugin path missing even though Tencent source plugin still exists

Missing:

/home/admin/.hermes/hermes-agent/plugins/memory/memory_tencentdb
/home/admin/.hermes/plugins/memory/memory_tencentdb

Still present:

/home/admin/.memory-tencentdb/tdai-memory-openclaw-plugin/hermes-plugin/memory/memory_tencentdb

5) Memory writes stopped completely until symlink was restored

Direct DB check on vectors.db showed no new records in the last ~48h while Hermes itself was still being used:

l0_conversations latest: 2026-06-05T01:29:31.656Z
l1_records latest:      2026-06-05T01:29:50.363Z
last 48h L0 additions:  0
last 48h L1 additions:  0

This means chat activity continued, but Tencent memory ingest did not.

Why this appears to happen

The installer currently links only into the Hermes checkout tree:

• scripts/install_hermes_memory_tencentdb.sh
• around Step 2.5:

HERMES_PLUGIN_DIR="$HERMES_AGENT_DIR/plugins/memory/memory_tencentdb"
PLUGIN_SRC_DIR="$TDAI_INSTALL_DIR/hermes-plugin/memory/memory_tencentdb"
rm -rf "$HERMES_PLUGIN_DIR"
ln -sf "$PLUGIN_SRC_DIR" "$HERMES_PLUGIN_DIR"

I do not see the installer also creating a user-scope plugin symlink under:

• ~/.hermes/plugins/memory/memory_tencentdb

So if the Hermes checkout under $HERMES_AGENT_DIR is replaced/updated, the only plugin mount can disappear.

Minimal recovery that worked immediately

Restoring the symlink fixed the issue.

mkdir -p /home/admin/.hermes/hermes-agent/plugins/memory
ln -sfn \
  /home/admin/.memory-tencentdb/tdai-memory-openclaw-plugin/hermes-plugin/memory/memory_tencentdb \
  /home/admin/.hermes/hermes-agent/plugins/memory/memory_tencentdb

To make it more resilient against Hermes checkout changes, I also added a user-scope symlink:

mkdir -p /home/admin/.hermes/plugins/memory
ln -sfn \
  /home/admin/.memory-tencentdb/tdai-memory-openclaw-plugin/hermes-plugin/memory/memory_tencentdb \
  /home/admin/.hermes/plugins/memory/memory_tencentdb

After that:

hermes memory status -> Plugin installed ✓, Status available ✓
curl 127.0.0.1:8420/health -> status ok

And a smoke test chat immediately wrote new L0 records into vectors.db again.

Expected behavior

If memory.provider: memory_tencentdb is configured and the Tencent plugin source directory still exists, a normal Hermes update/restart should not silently detach the memory provider.

Suggested fix

I think the installer should do at least one of these:

1. Create the plugin symlink under ~/.hermes/plugins/memory/memory_tencentdb (user-scope plugin dir) instead of relying only on the mutable Hermes checkout tree.
2. Or create both links:
   • $HERMES_AGENT_DIR/plugins/memory/memory_tencentdb
   • ~/.hermes/plugins/memory/memory_tencentdb
3. Add a post-install / post-start verification step that fails loudly if:
   • config says memory.provider: memory_tencentdb
   • but plugin discovery does not find memory_tencentdb

Severity

High operational severity.

This failure mode leaves users in a bad state where:

• Hermes gateway is still active
• chats still work
• but memory ingest/recall through Tencent is effectively detached until someone manually inspects plugin paths

Duplicate check

I searched current issues for Hermes plugin / sidecar / 8420 / provider missing / symlink related reports and did not find a matching existing issue.

[Maxwell-Code07]

Thanks for the detailed bug report! We've received your report about the Hermes plugin symlink issue and will investigate internally. We'll get back to you once we have results. Thank you for the detailed reproduction steps and recovery solution!