Portable Agent Memory: Carry Context Across Claude Code, Cursor, Codex & Gemini

Switch from Claude Code to Cursor mid-project and your agent forgets everything: the architecture decision you made last week, the bug you already fixed, the way you like commits written. The context didn't travel — it stayed locked inside the first tool. Portable agent memory is the pattern that fixes this: one memory layer your agents share, so context follows you across Claude Code, Cursor, Codex, and Gemini CLI instead of starting from zero each time you switch.

This guide explains what portable agent memory is, the main approaches to building it, how they trade off, and how to avoid getting locked in all over again.

What is portable agent memory?

Portable agent memory is a store of durable project context — decisions, fixes, conventions, and facts — that lives outside any single agent and is readable by all of them. Instead of each tool keeping its own siloed notes, your agents read and write to a shared pool.

The problem it solves is lock-in. Built-in memory keeps your context tied to one coding agent, and it stays behind when you switch tools. A great CLAUDE.md does nothing for Cursor; Cursor's notepads do nothing for Codex. Most teams now use more than one agent, so that stranded context is a real, recurring tax.

Portability means two things:

• Cross-tool: the same memory works in Claude Code, Codex, Cursor, Gemini CLI, and anything else that can read it.
• No vendor lock-in: you can leave a tool — or the memory layer itself — without rebuilding your knowledge.

Why context gets stranded when you switch

Each agent stores memory in its own format and location. Claude Code has one memory system; Cursor has another. When different agents know different things, the next session re-asks a question you already answered, or repeats a mistake it made before.

The underlying issue is that flat, tool-specific memory doesn't scale across agents. A note written for one client is invisible to the next. Multiply that by every tool switch, every new chat window, and every teammate on a different setup, and you get the same context being rebuilt again and again.

The main approaches to portable memory

There are three broad patterns in use today. They differ mostly in how they store context and how they connect to agents.

1. MCP-based memory servers

The most common approach wires a memory server to every agent through the Model Context Protocol (MCP). MCP gives any tool a standard way to connect to any agent, so one memory layer can serve many clients through the same protocol.

Open-source projects like agentmemory and Memorix take this route. agentmemory describes itself as persistent memory for Claude Code, Cursor, Gemini CLI, Codex CLI, and any MCP client, installed globally and registered as an MCP server. Memorix is a local-first shared memory layer that keeps project memory under the Git project rather than inside one chat window or tool.

The payoff: set it up once, and every MCP-capable agent sees the same memory. The trade-off is a running service and a dependency on MCP support in each client.

2. Flat-file, vendor-neutral vaults

A lighter approach skips databases and servers entirely. Agent Memory OS is a portable memory system built from plain Markdown files and a few small scripts, with no database and no service to run. It works with Claude Code, Codex, Gemini CLI, Cursor, or anything else that can read files, and keeps a deliberately vendor-neutral identity file so switching tools doesn't mean rebuilding your setup.

Retrieval here is usually lexical — a router ranks Markdown notes against your query and hands back the most relevant few — rather than embeddings. The payoff is simplicity, portability, and zero infrastructure. The trade-off is less sophisticated recall than a vector-backed system on large knowledge bases.

3. Hosted / protocol-backed memory layers

A third group offers managed memory with features like encryption, verifiable storage, and SDKs. These aim to be the durable, portable layer agents plug into, often with both an SDK and MCP integration so context travels across apps and sessions.

The payoff is less operational work and more built-in features; the trade-off is trusting an external service with your context and watching for a new kind of lock-in — this time at the memory layer itself.

How to choose — and avoid locking yourself in again

The point of portability is freedom to switch. Keep it that way:

• Prefer open formats. Markdown vaults and documented schemas are easy to read, migrate, and inspect. Proprietary blobs are not.
• Keep an export path. Whatever you adopt, confirm you can export your memory and move it elsewhere.
• Scope memory to the project, not the tool. Memory that lives under your Git project travels with the repo and survives tool switches, IDE changes, and new chat windows.
• Treat the "third-time" rule as a signal. When an agent makes the same mistake a third time, that's a missing memory note, not a bad model. Absorb recurring decisions and fixes into durable memory.
• Don't store secrets. Record where a secret lives and how it's used — never the value itself.

A quick way to compare options:

Where this is heading

Portable memory is quickly becoming a baseline expectation rather than a novelty. As teams run several agents side by side — one for terminal work, one in the IDE, one for scripts — the memory layer is turning into shared infrastructure, much like version control. The winners will be the layers that stay open, portable, and easy to leave.

Build a multi-agent workflow that remembers

Portable memory matters most when you're running more than one agent at once — which is exactly what a multi-agent workforce does. Eigent is an open-source, local "Cowork" desktop app that coordinates a team of AI agents on real workflows. It adds Memory you can scope to the user, workspace, or session and durable, multi-turn runs, so the context worth keeping is carried forward intentionally instead of getting stranded. If you're tired of re-explaining your project every time you switch tools, download Eigent and give your agents a shared place to remember.