docs: add Perseus Vault (local-first encrypted memory via MCP) guide

content/docs/mcp_servers/index.mdx

@@ -10,6 +10,9 @@ Use these guides to configure specific MCP servers with the right transport, OAu
   <Cards.Card title="Google Workspace MCP" href="/docs/mcp_servers/google_workspace" arrow>
     Configure Gmail, Drive, Calendar, People, and Chat remote MCP servers with Google OAuth.
   </Cards.Card>
+  <Cards.Card title="Perseus Vault MCP" href="/docs/mcp_servers/perseus_vault" arrow>
+    Give agents durable, encrypted, local-first long-term memory with the Perseus Vault MCP server.
+  </Cards.Card>
   <Cards.Card title="Salesforce MCP" href="/docs/mcp_servers/salesforce" arrow>
     Configure Salesforce Hosted MCP servers with an External Client App and per-user OAuth.
   </Cards.Card>

content/docs/mcp_servers/meta.json

@@ -1,5 +1,5 @@
 {
   "title": "MCP Servers",
   "icon": "Blocks",
-  "pages": ["index", "google_workspace", "salesforce"]
+  "pages": ["index", "google_workspace", "perseus_vault", "salesforce"]
 }

content/docs/mcp_servers/perseus_vault.mdx

@@ -0,0 +1,135 @@
+---
+title: Perseus Vault MCP
+icon: Lock
+description: Give LibreChat agents durable, encrypted, local-first long-term memory with the Perseus Vault MCP server.
+---
+
+[Perseus Vault](https://github.com/Perseus-Computing-LLC/perseus-vault) is an open-source
+(MIT), local-first, encrypted memory engine that ships as a single binary and speaks MCP
+natively. This guide wires it into LibreChat so any **Agent** can remember and recall across
+conversations using a private store that never leaves your machine, with no cloud and no API keys.
+
+<Callout type="info" title="How this fits with LibreChat's built-in memory">
+  LibreChat ships a built-in *User Memory* system: a token-limited key/value store managed by an
+  internal memory agent (configured under the `memory:` key). That built-in agent takes a
+  provider/model but does **not** expose a pluggable storage backend or an MCP hookup, so this
+  guide does **not** replace LibreChat's memory store. Instead it gives your LibreChat **Agents**
+  the Perseus Vault MCP tools (`remember`, `recall`, `journal`, `timeline`, and more) as
+  first-class tools the agent calls directly. The two can coexist: keep LibreChat's lightweight
+  personalization memory on, and add Perseus Vault for long-term, private, structured recall.
+</Callout>
+
+## Prerequisites
+
+- A running LibreChat instance with `librechat.yaml` mounted or otherwise loaded.
+- The Perseus Vault binary installed (via the bootstrap script or Docker — see the
+  [Perseus Vault repository](https://github.com/Perseus-Computing-LLC/perseus-vault)).
+
+## Setup
+
+<Steps>
+  <Step>
+
+### Run Perseus Vault
+
+Perseus Vault runs as a local single binary. If LibreChat runs on the **same host** (not
+containerized), you can skip networking entirely and let LibreChat launch the binary over stdio
+(see Option A below).
+
+If LibreChat runs in **Docker**, expose Perseus Vault over its HTTP/SSE MCP transport so the
+container can reach it:
+
+```bash
+perseus-vault \
+  --db ~/.mimir/data/perseus-vault.db \
+  --transport sse \
+  --web-bind 127.0.0.1 \
+  --port 8765 \
+  --mcp-token "$(openssl rand -hex 32)"   # required for non-loopback binds
+  # optional encryption at rest:
+  # --encryption-key ~/.mimir/secret.key
+```
+
+  </Step>
+  <Step>
+
+### Add Perseus Vault to `librechat.yaml`
+
+Register the server under `mcpServers`. Choose the option that matches your deployment.
+
+#### Option A — stdio (LibreChat and Perseus Vault on the same host)
+
+```yaml
+mcpServers:
+  perseus-vault:
+    type: stdio
+    title: "Perseus Vault"
+    description: "Local-first encrypted long-term memory (remember / recall across sessions)."
+    command: perseus-vault
+    args:
+      - "--db"
+      - "/home/YOUR_USER/.mimir/data/perseus-vault.db"
+    timeout: 60000
+    initTimeout: 15000
+    chatMenu: true
+    serverInstructions: true   # surfaces Perseus Vault's tool usage guidance to the agent
+```
+
+#### Option B — SSE/HTTP (LibreChat in Docker, Perseus Vault on the host or another container)
+
+```yaml
+mcpServers:
+  perseus-vault:
+    type: sse   # or: streamable-http
+    title: "Perseus Vault"
+    description: "Local-first encrypted long-term memory (remember / recall across sessions)."
+    url: "http://host.docker.internal:8765/sse"
+    headers:
+      Authorization: "Bearer ${PERSEUS_VAULT_TOKEN}"   # matches --mcp-token
+    timeout: 60000
+    chatMenu: true
+    serverInstructions: true
+```
+
+For Option B, put `PERSEUS_VAULT_TOKEN=<the token from --mcp-token>` in your LibreChat `.env`.
+
+  </Step>
+  <Step>
+
+### Attach it to an Agent
+
+In the LibreChat **Agent Builder**, create or edit an agent and enable the **perseus-vault** MCP
+server under its tools. The agent can now call Perseus Vault to persist and retrieve memory.
+
+A good agent instruction:
+
+> At the start of a task, call Perseus Vault `recall` to load relevant prior context. When you
+> learn a durable fact, decision, or user preference, store it with `remember`. Use `journal` for
+> time-ordered notes.
+
+  </Step>
+  <Step>
+
+### Verify
+
+1. Start a chat with the agent and tell it a durable fact, for example:
+   "remember that our staging DB is `pg-eu-2`".
+2. Start a **new** conversation with the same agent and ask it to recall the fact. It should
+   retrieve it from Perseus Vault, proving cross-session persistence backed by the encrypted
+   local store.
+
+  </Step>
+</Steps>
+
+## Why this fits LibreChat
+
+- **Local-first and private:** data never leaves the box and is encrypted at rest — matching the
+  reasons self-hosters run LibreChat instead of a hosted assistant.
+- **No new infrastructure:** a single binary, with no Postgres, Redis, or vector database to
+  stand up.
+- **MCP-native:** uses LibreChat's first-class MCP support, so there is nothing custom to maintain.
+
+## Learn more
+
+- [Perseus Vault on GitHub](https://github.com/Perseus-Computing-LLC/perseus-vault) (MIT license)
+- [MCP overview in LibreChat](/docs/features/mcp)