prismer-adapter-hermes 0.2.0

Prismer PARA adapter for Hermes (NousResearch) agents

prismer-adapter-hermes

Prismer PARA (Prismer Agent Runtime ABI) adapter for Hermes agents by NousResearch.

This is the first Python adapter in the Prismer SDK family.

What It Does

Translates all 14 Hermes hook events to PARA v0.1 event format and writes them to ~/.prismer/para/events.jsonl. The Prismer PARA runtime daemon reads this file to power the Evolution engine, mobile dashboards, and cross-agent memory.

Install

pip install prismer-adapter-hermes

Zero runtime dependencies — the wire types are vendored as pure dataclasses.

Basic Usage

In your Hermes plugin configuration, set the plugin module to prismer_adapter_hermes.register. Hermes calls register(ctx) automatically on plugin load.

# hermes_plugin.py — your Hermes plugin file
from prismer_adapter_hermes import register

# Hermes calls this at startup
def setup(ctx):
    register(ctx)

Or call it directly with a custom sink:

from prismer_adapter_hermes import register, default_jsonl_sink

def setup(ctx):
    adapter = register(ctx, sink=default_jsonl_sink)
    # adapter is a HermesParaAdapter instance

14 Hook Mappings (§4.6.2)

Hermes Hook	PARA Event	Notes
gateway:startup	agent.register	L1 Discovery — emits AgentDescriptor
session:start	agent.session.started	Deduped with on_session_start
session:end	agent.session.ended	Deduped with on_session_end
session:reset	agent.session.reset
agent:start	agent.prompt.submit	source mapped from platform context
agent:step	agent.turn.step	Per tool-loop iteration
agent:end	agent.turn.end
command:*	agent.command	Wildcard; commandKind normalized
pre_tool_call	agent.tool.pre
post_tool_call	agent.tool.post or agent.tool.failure	Split on result.success
pre_llm_call	agent.llm.pre	Cache-safe inject — see below
post_llm_call	agent.llm.post
on_session_start	agent.session.started	Alias — deduped, only one emit per session
on_session_end	agent.session.ended	Alias — deduped

pre_llm_call — Cache-Safe Context Injection (P11 Pattern)

pre_llm_call is Hermes's standout capability and PARA's P11 Pattern. The adapter's on_pre_llm_call method accepts an additional_context parameter and returns {"context": additional_context}.

Hermes injects this context string into the tail of the current user message — not into the system prompt. This preserves the prompt cache across turns because the system prompt block never changes.

# Hermes calls your handler like:
#   result = handler(ctx)
# If result["context"] is non-empty, Hermes appends it to the current user message.

# The adapter does this automatically when additional_context is provided:
adapter.on_pre_llm_call(ctx, additional_context="[prismer memory hint: ...]")
# → emits agent.llm.pre PARA event
# → returns {"context": "[prismer memory hint: ...]"}

Observability

Events are appended to ~/.prismer/para/events.jsonl (one JSON object per line). Set PRISMER_PARA_STDOUT=1 to also print events to stdout (useful in dev).

PRISMER_PARA_STDOUT=1 python -m hermes_agent run

Links

• PARA Spec §4.6.2 — Hermes 14 hook mappings
• Prismer Cloud
• Hermes Agent