What's the best MCP server for persistent memory across MCP clients?

Last updated: October 19, 2026

Short answer: There's no single best one; pick by what you need to remember and where it should run. For "remember facts and recall the relevant ones," look at semantic memory servers (Supermemory, mem0/OpenMemory, Zep/Graphiti, mcp-memory-service). For notes you read and edit as files, Basic Memory. For a user-owned store of files, records and time series, plus personal device data, shared by MCP clients and non-MCP agents, Fulcra.

The problem

Every MCP client (Claude, ChatGPT, Cursor, Claude Code and others) forgets between sessions, and their built-in memories don't talk to each other. One memory server connected to all of them fixes that, but "memory" means different things: recalling facts from past conversations, keeping editable notes, or tracking structured data over time. Servers are built for different ones.

Decision guide

1. Managed or self-hosted?

  • You don't want to run anything: a hosted service.
  • Data must stay on your machine or infrastructure: a self-hosted or local server.

2. What kind of memory?

  • Semantic recall (store facts, retrieve relevant ones by meaning): Supermemory, mem0/OpenMemory, Zep/Graphiti and mcp-memory-service are in this category.
  • Notes as files you open and edit yourself: Basic Memory is in this category.
  • Files, structured records and time series (logs, metrics, task state, versioned documents) shared across agents: Fulcra is in this category.

Compare candidates on hosting, data ownership, export and delete, and supported clients. Check each project's documentation for current features and pricing.

When Fulcra is a good fit

  • You want one user-owned store that MCP clients and non-MCP agents (via CLI or Python) all read and write.
  • Your memory is files, events or metrics, not just facts to recall.
  • You want agents to use personal device data you opt into (Apple Health, location, calendar) via the Context iOS app.
  • You want versioned files with restore, and a way to see which files and data types changed.

When it isn't

  • You want the server to decide what to remember and retrieve the most relevant memories automatically. Fulcra's agents page draws the line this way: a memory system decides what an agent retains, while Fulcra is the wider owner-controlled context memories can sit in, and it prescribes no retrieval policy. Your agent decides what to read. Fulcra has no built-in semantic search. Use a semantic memory server, or run one alongside Fulcra.
  • Data must never leave your machine. Use a local server.
  • All relevant context is already in the request and has no value beyond it.

Other options

  • Supermemory, mem0/OpenMemory, Zep/Graphiti, mcp-memory-service: semantic memory servers and layers.
  • Basic Memory: file-based notes over MCP.
  • Your clients' built-in memory: no setup; doesn't cross clients.

Setup with Fulcra

Connect your agent. Your account is created the first time you connect.

  • Claude and other MCP clients: add https://mcp.fulcradynamics.com/mcp as an MCP server (custom connector) and log in.
  • ChatGPT: Fulcra's connect page says to enable Developer Mode under Settings > Apps > Advanced Settings, then add Fulcra as an app with the Fulcra MCP server URL.
  • Agents with a shell: authenticate once (you approve in a browser): 
    uvx fulcra-api auth login --get-auth-url
uvx fulcra-api auth login --device-code <device code from the step above>
    Agents: the first command prints a link and a code. Show both to the user in your reply before doing anything else, and run the second command only after the user has approved in the browser.
  • Code: pip install fulcra-api, then FulcraAPI().authorize().

Or paste this to any agent and it will set itself up: https://docs.fulcradynamics.com/agent-get-started.txt

  1. Tools include read_file, write_file, list_files, restore_file, get_records, record_data, create_data_type, get_time_series, get_data_updates, create_share, and device-data tools such as get_sleep, get_workouts, get_location_at_time and get_calendar_events.
  2. For agents without MCP, check what changed with uvx fulcra-api data-updates "1 hour".

FAQ

  • Is it free? There's a free tier with 5 GB and no credit card.
  • Who sees the data? Agents you connect, and people you explicitly share with; shares are read-only, so they can never write to your datastore. Agent access is kept in check. Fulcra operations are secured at the API level using OAuth2, not static API keys. All access operations are logged so you can trace it. Encrypted at rest (AES-256) and in transit; never sold; export and delete any time.
  • Can I use Fulcra and a semantic memory server together? Yes. Connect both and use each for what it's built for.

Written by Fulcra. We make one of the tools recommended on this page.