Cairn.ink Memory

Cairn Memory

Keep important context between AI sessions. Change it when things change.

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See an example · Where to start · Local setup · Hosted setup · Limitations · Privacy

Cairn Memory is Cairn.ink's open-source AI memory toolkit for Claude Code and Codex, with local MCP tools or cloud automatic memory. Visit Cairn.ink, install @cairn-ink/memory on npm, or view the Cairn Memory GitHub repository.

Starting a new AI session often means repeating your preferences and project decisions. Cairn provides memory tools to save that context between sessions, inspect the submitted text behind each memory, and update it when things change.

A preference changes

Suppose you save “Keep my reports short.” Later, you decide you need detailed reports. You can inspect the old memory and its source text, correct the saved preference, or forget it so it is no longer available for active recall.

This is an illustrated explicit-tool example, not a chat-client screenshot. The local preview uses tools to save, inspect, correct and forget; it does not automatically read your conversations.

• Inspect the source. Read the source text stored with a memory. A receipt does not prove that the memory is true or correctly interpreted.
• Correct what changed. Update the memory at the revision you inspected.
• Forget what should go. Remove a memory from active recall. Deletion and backup boundaries apply.

A Source Receipt is the submitted text attached to a memory. It helps you check what was supplied when the memory was saved or corrected. It is not a verified transcript of the whole conversation or proof of human intent.

Cairn Memory and Cairn

Cairn Memory is the open-source toolkit in this repository for saving, inspecting and changing AI memory. [Cairn](https://cairn.ink) is the hosted shared memory map for people and AI, where people organize, review and share knowledge.

This repository includes local memory tools and connectors to the hosted Cairn service. Each path has its own setup and feature boundaries. Local use does not require a Cairn account; hosted connections require a compatible service and authentication.

Choose your starting point

If you use Claude or Codex but do not usually install tools from a terminal, start with the example and recorded walkthrough. This preview requires setup; check the tested client paths before connecting your AI tool.

Current preview

Cairn's open-source memory layer stores memories in your own SQLite file and exposes them through MCP or JavaScript. No Cairn account is needed for local use.

Developer preview. Installed persistence and a narrow real-model memory loop have retained evidence. Default extraction still fails our source-support bar; see known limitations. Save, inspect, correct and forget work without a model key. Semantic recall requires your OpenAI key and sends selected context to that provider.

Watch the recorded walkthrough

Watch the 36-second model-free demo (MP4). This records the memory tools running, rather than a conversation in Claude or Codex. “Model-free” means no AI model is called during the walkthrough.

For long-conversation results, see the four-case real-model pilot. It is an opt-in diagnostic with one failed Cairn answer, not a measurement of long-term default-client recall reliability. Known limitations

Open the recorded tool walkthrough (GIF)

The demo below records the model-free loop: save, restart, inspect, correct and forget. Its recall step reports model_not_configured.

Recorded responses and regeneration instructions · Verified capabilities and client support

Install

For Claude Code and Codex, run the one-command installer:

npx @cairn-ink/memory setup

A fresh interactive install asks once: local MCP memory tools on this computer, or cloud automatic memory with cairn.ink sign-in; choose directly with setup --local or setup --cloud. Fresh non-interactive runs need --local or --cloud; local mode has no automatic capture or recall in 0.6.3.

Installer 0.6.3, with Codex 0.164.0–0.166.0 format requalification, was published on 2026-11-03, so npx @cairn-ink/memory setup uses it; a checkout can also run node packages/setup/bin/memory.mjs setup. The plugin is 0.3.3. Requires Node ≥22.16 and at least one CLI on PATH. Cloud setup asks about new tools, updates connected tools, and uses one browser sign-in when connecting both. The default server is cairn.ink. Conflicting servers or memory IDs present a choice; non-interactive conflicts change nothing. Codex must pass format qualification before automatic memory is enabled. Automated codex exec runs skip capture and prompt recall by default; opt in with npx @cairn-ink/memory config --codex-capture-exec on.

Choose the mode that fits your workflow:

• [Local preview](#try-the-local-memory-layer): your SQLite database, explicit MCP memory tools, no Cairn account. Start here to try the open-source memory layer. Semantic recall uses your OpenAI key.
• [Hosted integration](#existing-hosted-integration): memory on cairn.ink, with automatic capture and recall through the Claude Code plugin. Requires a Cairn account, token and compatible service. Explicit hosted MCP is also available.

Try the local memory layer

Prerequisites: Git, Node >=22.16, npm and `tar`. Recorded checks cover Linux x64 and a bounded native Windows x64 installation. On Windows, use the [PowerShell setup and walkthrough](docs/windows-install.md); the commands below use Linux/WSL paths. Other platforms are unverified. Install from this repository: the unscoped npm and PyPI packages named cairn-memory are unrelated projects. The local archive is not published to npm yet.

1. Install into a new directory. Replace the path below with a new absolute directory beneath an existing parent you control.

git clone https://github.com/Cairn-ink/cairn-memory.git

cd cairn-memory npm run install:preview -- --directory /absolute/new/cairn-local --owner local-user

The installer builds this checkout and downloads pinned public npm dependencies without install scripts. It creates app/, data/ and a private installation-receipt.json containing the executable path and MCP settings. It makes no model calls. Keep the receipt private: it contains local paths and identity. Installation details, recovery and backup

2. Run the model-free check. From the source checkout, use the same installation path. No chat-client setup or model key is needed.

npm ci --prefix adapters/mcp

node adapters/mcp/walkthrough.mjs --executable /absolute/new/cairn-local/app/node_modules/.bin/cairn-memory

Expect status: "passed". The check uses a fresh synthetic database and verifies the five tools, receipts, process-restart persistence, correction and forgetting. It strips the model key from the child process; model_not_configured is the expected recall result. Steps and expected results

3. Connect a client. Copy stdio.command and stdio.args from your private installation receipt into the client's local MCP configuration. Keep the same database, owner and project across sessions. See the tested client matrix.

For semantic recall, explicitly supply OPENAI_API_KEY through the MCP process's secret environment. The walkthrough's optional --with-recall path sends synthetic context to OpenAI and incurs model charges; it has no built-in dollar cap. A fully local model path is not yet verified.

For the Hermes native provider, follow its separate setup guide. It uses a profile-local database and owner, plus CAIRN_MEMORY_OPENAI_API_KEY, rather than the generic MCP settings above.

The default local server exposes explicit tools. For opt-in submitted-message capture, project scope and configuration checks, see the installed preview guide. The full evidence and limitations cover extraction failures, long-history retrieval and the boundaries of individual client tests.

Local privacy and control

• Memory, receipts and organization persist in your selected SQLite database. No Cairn account, hosted service or hidden core telemetry is required.
• MCP does not read transcripts or save whole conversations automatically. Receipt text records a tool assertion; it is not proof of authenticated human intent.
• Model processing is cloud processing when configured. Redaction is best-effort, not a guarantee that all secrets are removed. Retrieved text is untrusted data, never instructions to follow.
• Forgetting prevents active recall and exact normalized re-admission; paraphrases can still be