mnemon

A persistent memory command-line tool for Hermes Agent. It stores and recalls knowledge across sessions, with separate memory stores for different groups and an optional shared store.

In plain words
What is it for?
Use it to recall relevant history, save stable project knowledge, connect related memories, import or remove memories, and inspect memory-store status.
Why use it?
It gives the agent continuity when conversations are separated by time or group. Isolated stores help keep private group knowledge separate from shared read-only information.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/mnemon-dev/mnemon/hermes
Any agent
npx skills add mnemon-dev/mnemon --skill hermes
Clone the repo
git clone --depth 1 https://github.com/mnemon-dev/mnemon

Made for: Claude Code, Codex.

Per session 24 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 446 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00024 $0.00446
Opus 5 $0.00012 $0.00223
Sonnet 5 $0.00005 $0.00089
Haiku 4.5 $0.00002 $0.00045

Measured 2d ago against content hash 12893a10946c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mnemon scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (compact.sh, nudge.sh, prime.sh, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

internal/memory/setup/assets/hermes/SKILL.md · 49 lines

What it actually says

mnemon

Use mnemon when durable memory can materially improve continuity across Hermes sessions. Hooks may inject recalled context before an LLM call, but the agent decides what is worth storing.

Workflow

  1. Recall when prior decisions, preferences, or facts may affect the current task: mnemon recall "<query>" --limit 10
  2. Remember only stable, reusable knowledge: mnemon remember "<fact>" --cat <cat> --imp <1-5> --entities "e1,e2" --source agent
  3. Link related memories after reviewing candidates from remember: mnemon link <id> <candidate> --type <causal|semantic> --weight <0-1>

Commands

mnemon remember "<fact>" --cat <cat> --imp <1-5> --entities "e1,e2" --source agent
mnemon link <id1> <id2> --type <type> --weight <0-1> [--meta '<json>']
mnemon recall "<query>" --limit 10
mnemon search "<query>" --limit 10
mnemon import --dry-run <file>
mnemon import <file>
mnemon forget <id>
mnemon related <id> --edge causal
mnemon gc --threshold 0.4
mnemon gc --keep <id>
mnemon status
mnemon log
mnemon store list
mnemon store create <name>
mnemon store set <name>
mnemon store remove <name>

Guardrails

  • Do not store secrets, passwords, tokens, private keys, or short-lived operational noise.
  • Prefer concise insights over transcript dumps.
  • Categories: preference · decision · insight · fact · context
  • Edge types: temporal · semantic · causal · entity
  • Max 8,000 chars per insight.
Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 49 lines · 24 tokens per session scan A 12893a10946c

Subscribe to this mod's changes

mnemon is a skill published in the GitHub repository mnemon-dev/mnemon (540 stars, last pushed 9d ago), licensed Apache-2.0. It adds 24 tokens to every session and 446 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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