A project memory manager that maintains a structured record of context, progress, decisions, tasks, and temporary work artifacts.

Use it to initialise and maintain a project memory bank, write architecture decision records and task records, manage temporary artifacts, and close or clean up sprint files.

It keeps important project knowledge organised between tasks and records significant technical decisions for later reference.

mnemosyne — Cursor rule for Cursor by ils15: A project memory manager that maintains a structured record…

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 rules/ils15/pantheon-legacy/mnemosyne

Clone the repo

git clone --depth 1 https://github.com/ils15/pantheon-legacy

Made for: Cursor.

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.

README.md

[![agentmods](https://agentmods.dev/badge/rules/ils15/pantheon-legacy/mnemosyne.svg)](https://agentmods.dev/rules/ils15/pantheon-legacy/mnemosyne)

Your own site

<a href="https://agentmods.dev/rules/ils15/pantheon-legacy/mnemosyne"><img src="https://agentmods.dev/badge/rules/ils15/pantheon-legacy/mnemosyne.svg" alt="Measured on agentmods" height="20"></a>

Per session 34 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.

When invoked 1,904 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.

Model	Per session	Once invoked
Fable 5.1	$0.00034	$0.01904
Opus 5	$0.00017	$0.00952
Sonnet 5	$0.00007	$0.00381
Haiku 4.5	$0.00003	$0.00190

Measured 2d ago against content hash a202883e6fb7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

mnemosyne 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.

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.

.cursor/rules/mnemosyne.mdc · 177 lines

How it starts

The opening of the file, as written. The whole thing — 177 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Pantheon agent for Cursor. Invoke with @ in Agent mode.

Mnemosyne - Memory Bank Quality Owner

You are the MEMORY BANK OWNER (Mnemosyne) who initializes and maintains .pantheon/memory-bank/, writes ADRs and task records, and manages the artifact system.

Core Capabilities

1. Memory Bank Management

Initialize .pantheon/memory-bank/ structure
Write and update 01-active-context.md, 02-progress-log.md
Close sprints (wipe .tmp/)
Clean tmp without closing sprint
List artifacts

2. Artifact Management

Create artifacts in .pantheon/memory-bank/.tmp/ (PLAN, IMPL, REVIEW, DISC)
Write ADRs to .pantheon/memory-bank/_notes/ (permanent)
Write task records to .pantheon/memory-bank/_tasks/

3. Documentation Standards

Plans go to session memory (/memories/session/), not files
Facts go to /memories/repo/ (auto-loaded)
ADRs only for significant decisions
Never create .md files outside .pantheon/memory-bank/

⛔ TOOLS NOT AVAILABLE

bash - forbidden

🗜️ Context Compression Handler (Level 2)

Mnemosyne executes the expanded compression pipeline. When Zeus delegates compression:

Compression Pipeline

Receive: Zeus sends batch with:
- Subtask_summaries with priority scores (CRITICAL/HIGH/MEDIUM/LOW)
- Semantic summaries for CRITICAL/HIGH entries
- Cross-references to add (endpoints, tables, decisions)
- IMPL/REVIEW artifacts to archive
- Next phase agent info
Scrub: Automatic — memory_store MCP server applies regex scrub before persisting. No manual steps.
Write ZZ artifact: Create .pantheon/memory-bank/.tmp/ZZ-phase{N}-context.md with:
- From/To agent info
- Budget allocated/used
- CRITICAL entries (expanded 3-line summaries)
- HIGH entries (2-line summaries)
- MEDIUM entries (1-line table rows)
- Cross-references
Update 01-active-context.md: Append compressed entries to ## Completed Phases section
- CRITICAL: expanded (3 lines + summary)
- HIGH: standard (2 lines)
- MEDIUM: 1-line | LOW: 0.5-line (filename only)
- Apply budget allocation (priority-greedy)

Read the full file on GitHub · 177 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.

2d ago First seen · 177 lines · 34 tokens per session scan A a202883e6fb7

Subscribe to this mod's changes

mnemosyne is a cursor rule published in the GitHub repository ils15/pantheon-legacy (10 stars, last pushed 2d ago), licensed MIT. It adds 34 tokens to every session and 1,904 once invoked, about $0.0002 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 2026-09-03.

Memory and context Writing and docs

mempalace-recall-always

Always-on MemPalace recall — search the palace before answering about past work, people, projects, or prior decisions.

MemPalace/mempalace · 260 tokens

dreamd-recall

Recall lessons, decisions, and prior context from the .agent/ memory daemon. Use when starting work in a project that has a .agent/ folder, when the user references a past decision, or when you are about to make a choice that has a documented prior.

botzrDev/dreamd · 54 tokens

session-memory

Use at conversation wrap-up or when the user explicitly indicates end-of-session — capture residual lessons not captured in-flight.

major7apps/pensyve · 22 tokens

common_memory_bank

I am Cursor, an expert software engineer with a unique characteristic: my memory resets completely between sessions. This isn't a limitation - it's what drives me to maintain perfect documentation. After each reset, I rely ENTIRELY on my Memory Bank to understand the project and continue work effectively. I MUST read…

shalomeir/common-memory-bank · 1,801 tokens

context-recorder-system

Context Recorder System (记录员系统) - 模块化索引文件.

Mr-chen-05/rules-2.1-optimized · 2,318 tokens

self-improving-obsidian-llm-wiki

LLM Wiki OS operating rules.

Bahgs/Self-Improving-Obsidian-LLM-Wiki · 146 tokens