memsprout

A set of rules for using memsprout, a shared persistent memory system connected through MCP. It stores information that users, teammates, and other agents can find later.

In plain words
What is it for?
Use it to search existing memories, browse recent entries, save durable conclusions, and organize information into shared spaces and topics.
Why use it?
It helps prevent duplicate notes and keeps important decisions, procedures, and context available across tasks and agents.

Cursor rule

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/memsprout/agents/memsprout
Clone the repo
git clone --depth 1 https://github.com/memsprout/agents
Per session 519 This file is loaded in full into every session.
When invoked 519 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 $0.00519 $0.00519
Opus 5 $0.00260 $0.00260
Sonnet 5 $0.00104 $0.00104
Haiku 4.5 $0.00052 $0.00052

Measured yesterday against content hash cb78819acb4a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

memsprout 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 yesterday.

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/memsprout.mdc · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Using memsprout

memsprout is this team's persistent memory, connected as an MCP server. What you write there is read later by the user, by teammates in shared spaces, and by other AI agents across many tools. They trust it — treat it as shared memory, not a temporary scratchpad.

Search first

  • Call search_memories before assuming something isn't recorded, and before storing anything, so you don't create duplicates. It searches everything you can read by default.
  • Use list_memories for recency browsing instead of meaning-based lookup.
  • At the start of a substantive task, search memsprout for relevant prior context.

Capturing

Store memories liberally with store_memory, and default to giving each one a concise, descriptive title — especially anything durable: a decision, a procedure, a fact, a conclusion worth finding by name later, and anything going into a shared space. Leave the title off only for genuinely raw, ephemeral captures — a half-formed idea or fragment not meant to stand alone. You can promote a raw capture later by adding a title via update_memory.

At the end of a task, capture the durable conclusion — titled, so it's findable later — without waiting to be asked.

Memories are versioned: update_memory archives the prior state with an optional change_note, so revise freely — history is never lost.

Spaces and topics

Spaces are shared containers with member roles. Pass space_id to store_memory for shared work; omit it for the user's personal vault. Only pass a shared space_id when the user has named that Space in the current conversation — never infer a shared destination. No named Space means omit space_id, which defaults to personal.

Every space memory is assigned to a topic. When capturing into a space, check list_topics and pass the best-fitting existing topic; if nothing fits, create_topic first (with a description). Omit the topic only as a last resort — the server auto-classifies as a backup.

Files

Read the full file on GitHub · 56 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. yesterday First seen · 56 lines · 519 tokens per session scan A cb78819acb4a

Subscribe to this mod's changes

memsprout is a cursor rule published in the GitHub repository memsprout/agents (0 stars, last pushed 1mo ago), licensed MIT. It adds 519 tokens to every session, about $0.0026 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.