memento-os AGENTS.md

memento-os AGENTS.md is an instructions file for Claude Code, Codex, OpenCode from Aiyo28/memento-os. It costs 762 tokens per session, scanned A, original, MIT.

Repository instructions for Memento OS, a Claude Code plugin that stores persistent AI memory as structured reasoning notes. They describe the project, its conventions, and a rule to search stored notes before making decisions.

In plain words
What is it for?
Use them when changing Memento OS to understand its memory format, skills, commands, hooks, adapters, templates, and decision-making process.
Why use it?
They help an agent work consistently in the repository and avoid forgetting earlier decisions or ignoring existing project knowledge.

Instructions file for Claude CodeCodexOpenCode

Written for Claude Code and Codex and OpenCode: PreCompact hook event, but also the file is AGENTS.md. Also seen: mentions CLAUDE.md; mentions Claude Code.

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 instructions/aiyo28/memento-os/agents-md
Clone the repo
git clone --depth 1 https://github.com/Aiyo28/memento-os

Made for: Claude Code, Codex, OpenCode.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for memento-os AGENTS.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/aiyo28/memento-os/agents-md.svg)](https://agentmods.dev/instructions/aiyo28/memento-os/agents-md)
Your own site
<a href="https://agentmods.dev/instructions/aiyo28/memento-os/agents-md"><img src="https://agentmods.dev/badge/instructions/aiyo28/memento-os/agents-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 762 This file is loaded in full into every session.
When invoked 762 The same file — it is already loaded in full.
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 5.1 $0.00762 $0.00762
Opus 5 $0.00381 $0.00381
Sonnet 5 $0.00152 $0.00152
Haiku 4.5 $0.00076 $0.00076

Measured 5d ago against content hash 91b938547073, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

memento-os AGENTS.md 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 5d ago.

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.

AGENTS.md · 70 lines

How it starts

The opening of the file, as written. The whole thing — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Instructions — Memento OS

What This Repo Is

A Claude Code plugin for persistent AI memory. Core unit: reasoning artifacts ([D], [I], [E], [S]) with invalidation/activation triggers.

If You're Working On This Repo

  • Skills are in skills/*/SKILL.md — each namespaced as memento:*
  • Commands are in commands/memento/*.md
  • Hooks are in hooks/hooks.json (prompt-type hooks for Stop and PreCompact)
  • Plugin manifest is .claude-plugin/plugin.json (v2.0.0)
  • Adapters for non-Claude-Code tools are in adapters/ — each subdirectory maps to one AI tool
  • Starter vault templates are in starter/obsidian-vault/ — these define the vault structure users get

Conventions

  • Artifact format: [D] conclusion — invalidates if trigger [priority] [date]
  • Seed format: [S] idea — activates when condition [priority] [date]
  • Priority: confidence x impact → critical/volatile/settled/noise
  • Cap: 24 artifacts per project (Kobe rule). Evict noise first.
  • Skills produce artifacts as byproduct — grill-me surfaces [D]/[I], decide captures [D] or plants [S]

Retrieval-First Protocol

Skills that make decisions MUST search the vault before acting:

  • memento:decide → search for prior [D] artifacts before presenting options
  • memento:grill-me → load domain-relevant vault notes as context
  • Future decision-making skills → follow the same pattern

The vault is a retrieval source, not just a write destination. Search first, then fill gaps.

Confidence Gate

Before any implementation decision: self-assess "Do I have full context?" If < 96% → pause and retrieve before acting.

Protected domains (always retrieve, regardless of confidence):

  • Authentication / authorization patterns
  • Database schema / migration decisions
  • API contract decisions
  • Deployment / infrastructure choices
  • Pricing tiers / subscription logic
  • Tag architecture / taxonomy

Retrieval sequence:

  1. _context.md Active Reasoning Artifacts table — [D] entries matching domain
  2. Decisions/*{topic}* — full artifact files
  3. If found → surface: "Existing decision: [D] {statement} — {date}". Ask: reaffirm, revise, or override?
  4. If not found → fresh analysis

Read the full file on GitHub · 70 lines

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. 5d ago First seen · 70 lines · 762 tokens per session scan A 91b938547073

Subscribe to this mod's changes

memento-os AGENTS.md is an instructions file published in the GitHub repository Aiyo28/memento-os (3 stars, last pushed 2mo ago), licensed MIT. It adds 762 tokens to every session, about $0.0038 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 2026-08-31.