Langfuse

Langfuse observability for Hermes: one trace per turn, one generation per LLM call (usage and cost from Hermes' own pricing, cache and reasoning tokens included), one observation per tool call and subagent. Content capture is sanitized by default (metadata-only and full are opt-in); sends traces only to the Langfuse project whose keys you set. Formerly built into Hermes core as observability/langfuse; existing users are migrated automatically.

How to install

Install it. Hermes asks for any API keys it needs (this one needs HERMES_LANGFUSE_PUBLIC_KEY, HERMES_LANGFUSE_SECRET_KEY), then asks whether to turn it on.
hermes plugins install langfuse
Said no? Turn it on later:
hermes plugins enable langfuse
Restart Hermes so it loads the plugin.

Some plugins also need a sign-in or settings: see Full setup & settings. Memory plugins ask whether to become your memory provider instead. Steps follow the official plugins guide (opens in a new tab).

Category: Cost, speed & monitoring
Maintained by: NousResearch (Official)
Needs: HERMES_LANGFUSE_PUBLIC_KEY HERMES_LANGFUSE_SECRET_KEY API keys
Needs Hermes: 0.21.7 or newer
Version: 2.0.0
In the catalog: 2026-10-12, updated 2026-10-23
GitHub stars: 515

Full setup & settings ↗Source code ↗

More in cost, speed & monitoring

All cost, speed & monitoring plugins

New Hermes Agent updates every day on X. Follow @HermesWatcher

← All plugins