Guide
Shared memory for Claude Code, Codex and Grok
In short
To give several coding agents the same memory, keep the state of each piece of work in 1 place and let every agent read and update it through MCP. brainplane keeps 1 shared brain per topic on your Mac and serves it to Claude Code, Codex and Grok with 10 MCP tools.
Updated 9 October 2026. Checked with brainplane 0.2.2.
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The problem
Each agent session starts empty. Claude Code has its own memory files, Codex its own, Grok its own. None of them knows what you settled in another tool yesterday. So you repeat the goal, the constraints and the answers, once per agent and once per session.
What to share, and what to keep out
| Share | Keep out |
|---|---|
| The goal of the work | Passwords, one-time codes, API keys |
| Where things stand: done, waiting on you, waiting on others, next step | Topics a vendor should not see |
| Settled decisions and answered questions | Raw session transcripts |
| People and the files agents touched | Anything you would not paste into a prompt |
brainplane stores the left column per topic, on your Mac. Its secret guard refuses a password, a one-time code or an API key in a note before it is stored, and masks IBANs to their last 4 characters.
How agents reach it: MCP
The Model Context Protocol lets an agent call tools from a local server. brainplane adds 1 MCP server entry named brainplane to each agent you connect, and keeps a backup of each file it changes. Each agent then gets 10 tools:
- Find the right topic
- Read its brief
- Update its state
- Log a decision
- Ask a question
- Raise a stop
- Register a draft
- Post a card
- Report a handoff as done
- Link its session to a topic
Agents can open cards. Only you can answer them. Any tool that speaks MCP can use the same server.
Keep the context small
A shared memory can grow until every session starts with a wall of text. brainplane sends each agent a context pack of 3,000 tokens at most. Binding items come first and older notes are trimmed first. After the first pack, the agent gets a delta pack: only the changes since its last one, plus the rules and settled decisions it must always see.
Keep some topics away from a vendor
Each topic belongs to a scope, such as work or family, set by the folder it lives in. A list per vendor says which scopes its agent may receive. A topic with no scope goes to no agent. You can preview any pack before it goes.
Start from the notes you have
If you already keep Markdown notes per project, brainplane imports them read-only. The dry run lists what it would read and changes nothing:
bp import --dry-runQuestions
Where is the shared memory stored?
In brainplane's own folder in ~/Library/Application Support on your Mac. Every change is 1 line in an append-only log.
Does brainplane read my agent sessions or prompts?
Only what it needs to track work. It reads Codex and Grok session lists (ids, folders and times), hook events and the paths of files agents touched. It never opens your transcript files. Agents write to the shared brain through the MCP tools.
Does it work with only 1 agent?
Yes. 1 agent that keeps asking the same things also gains from standing answers and the topic brief.