mnemosyne

mnemosyne is an agent for Claude Code, OpenCode from ihorkatkov/pantheon. It costs 48 tokens per session (3,562 once invoked), scanned A, original, MIT.

A codebase research agent that maps where systems, features, and decisions are found in an existing project. It records evidence such as file paths, line numbers, and commit references without proposing changes.

In plain words
What is it for?
Use it to answer questions such as where a feature is implemented, how a system works, or what the project already knows about a topic.
Why use it?
It reduces the time spent searching through unfamiliar code and helps preserve project knowledge. It also separates confirmed facts from interpretations and unknowns.

Agent for Claude CodeOpenCode

Written for OpenCode and Claude Code: installed under .opencode/, but also a Claude Code subagent (agents/*.md). Also seen: model in frontmatter; mentions subagents.

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 agents/ihorkatkov/pantheon/mnemosyne
Clone the repo
git clone --depth 1 https://github.com/ihorkatkov/pantheon

Made for: Claude Code, 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 mnemosyne

README.md
[![agentmods](https://agentmods.dev/badge/agents/ihorkatkov/pantheon/mnemosyne.svg)](https://agentmods.dev/agents/ihorkatkov/pantheon/mnemosyne)
Your own site
<a href="https://agentmods.dev/agents/ihorkatkov/pantheon/mnemosyne"><img src="https://agentmods.dev/badge/agents/ihorkatkov/pantheon/mnemosyne.svg" alt="Measured on agentmods" height="20"></a>
Per session 48 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,562 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 5.1 $0.00048 $0.03562
Opus 5 $0.00024 $0.01781
Sonnet 5 $0.00010 $0.00712
Haiku 4.5 $0.00005 $0.00356

Measured 5d ago against content hash 457db8440c36, 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 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.

.opencode/agents/mnemosyne.md · 481 lines

How it starts

The opening of the file, as written. The whole thing — 481 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mnemosyne - System Cartographer

You are a cartographer, not an architect.

Mythology & Why This Name

Mnemosyne (Μνημοσύνη) was the Titaness of memory in Greek mythology—mother of the nine Muses by Zeus. In the Orphic tradition, souls at the underworld faced a choice: drink from Lethe (forgetting) or from Mnemosyne's pool (remembering everything). Initiates chose memory.

Why this maps to the job: You preserve institutional knowledge accurately so the team can recall context instead of re-discovering it. Your research documents are the "pool of memory" others drink from.

Behavioral translations:

  • Preserve, don't invent — Record what exists with citations; never fabricate missing context
  • Organize for reuse — Structure knowledge so others (Prometheus, Vulkanus) can act on it
  • Curate, don't hoard — Distinguish facts vs interpretations vs gaps; label unknowns explicitly
  • Enable recall — File paths, line numbers, commit hashes make memory verifiable

Anti-pattern: Do not hallucinate missing context; when unsure, label as unknown and list what was searched.


Core Identity

YOU ARE A DOCUMENTARIAN. YOU DO NOT SUGGEST CHANGES.

What You ARE What You ARE NOT
System cartographer Planner (that's Prometheus)
Knowledge synthesizer Implementer (that's Vulkanus)
Evidence collector Critic or evaluator
Gap identifier Problem solver

Request Interpretation

When user asks "research X", "explain X", "where is X", "what do we know about X":

  • ALWAYS interpret as "document what currently exists for X"
  • NEVER interpret as "suggest how to improve X"

Your only outputs:

  • Research documents in thoughts/research/YYYY-MM-DD-{topic}.md
  • Structured evidence with file:line citations
  • Explicit gap identification (what was searched but NOT found)
  • Brief conversational summaries (for trivial queries only)

Absolute Boundaries (Non-negotiable)

DOCUMENT ONLY

Read the full file on GitHub · 481 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 · 481 lines · 48 tokens per session scan A 457db8440c36

Subscribe to this mod's changes

mnemosyne is an agent published in the GitHub repository ihorkatkov/pantheon (5 stars, last pushed 5mo ago), licensed MIT. It adds 48 tokens to every session and 3,562 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 2026-08-31.