Cairn.ink Memory
ink.cairnPublished by cairn.inkOfficial publisherv0.1.0Updated Oct 24, 2026
Cross-session memory for AI agents with a Source Receipt for every memory, over MCP.
Overview
Hosted Cairn.ink memory server that lets an AI assistant save, inspect, correct, forget and recall context across sessions, with a Source Receipt per memory.
- What you can do
- Save a memory together with the submitted text behind it
- Search and fetch memory candidates, and read dated memory context within a token budget
- Recall current memories and their receipts, guided by a model
- List memories or inspect one by ID, revision and receipts
- Correct a memory at the revision you inspected, or logically delete it
- When to use it
- Useful when you keep repeating preferences and project decisions in new AI sessions and want that context stored, reviewable and editable rather than lost. Suited to Claude Code and Codex users who want explicit memory tools over the hosted service.
- Requirements
- Remote streamable HTTP endpoint at cairn.ink. A Cairn account and authentication are required: OAuth sign-in, or an Authorization bearer personal access token created in the Cairn settings. The README also documents a separate local mode needing Node 22.16 or newer, Git, npm and tar.
Installation
In SourceWeft
- Open Cairn.ink Memory in the dashboard and add it to a workspace.
- Connect the required credentials. They are stored privately and never shown on public pages.
- Enable the server for the chats that should use its tools.
Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.
Use with an agent
Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.
Read https://sourceweft.com/mcp/ink.cairn%2Fmemory/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.Other MCP clients
Add this to your client's mcpServers config. The client completes OAuth sign-in on first connect.
{
"mcpServers": {
"cairn-ink-memory": {
"type": "http",
"url": "https://cairn.ink/api/mcp"
}
}
}README
Cairn Memory
Keep important context between AI sessions. Change it when things change.
[CI] [Apache-2.0] [Hosted by Cairn.ink]
English · 繁體中文
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 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 model-free memory loop: save, inspect the source, restart, correct and forget]
Recorded responses and regeneration instructions · Verified capabilities and client support
Install
For Claude Code and Codex, run the one-command installer:
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 0.3.4.
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: 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: 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;
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.
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.
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 local MCP server and installer enable Raw retention for submitted captures,
Raw search, dated three-layer contextRead and its tools by default. Library
openMemoryCore keeps Raw off unless raw:true is supplied. Stores whose
attested layout cannot hold Raw run Memory-only. Use --no-raw,
--no-raw-search or --no-context-read to turn off those server defaults.
With OPENAI_API_KEY, the server also enables bounded embeddings. Without a
key, contextRead uses BM25. See
all defaults, costs and off switches.
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 admitted as new memories. It is not secure disk erasure: SQLite pages, receipts and backups have separate retention limits. Stop all writers before copying the database and sidecars for backup.
- Uninstalling the executable preserves the external database. See backup, upgrade and deletion boundaries, architecture, dependency notices and security reporting.
Existing hosted integration
The hosted plugin connects to cairn.ink, automatically captures allowlisted conversation text and has its own telemetry defaults. Its service has not been migrated to the local engine.
The v0.2.0 prerelease changes the hosted protocol. Matching server support remains a separate requirement; the release does not deploy a server or enable Codex lifecycle hooks. See release and client compatibility before upgrading.
Install for Claude Code (automatic memory)
Run the published installer from your terminal:
Installer 0.6.3 (plugin 0.3.3) is published, so these flows run through
npx. To run this checkout instead, use node packages/setup/bin/memory.mjs setup.
Without --client, setup finds both tools and asks only about new connections.
It updates connected tools. Close both tools and wait for background work before
confirming shared memory. The sign-in line shows the server (default cairn.ink).
There is no endpoint or daily-cap question; --endpoint remains available.
Conversations are saved after best-effort local masking. Each prompt sends a masked, length-limited copy for recall. Claude usage stats are on by default and can be turned off. Codex's sign-in is stored in an unencrypted user-only file. See privacy and controls.
A memory ID connects the same project across tools. Existing IDs are retained. Server conflicts offer two choices; unsafe Codex credential migrations require logout first. When two independent IDs exist, choose one; the other key is backed up only after successful sign-in and validation, never deleted. Old projects may no longer automatically match the old ID. Non-interactive conflicts write nothing. Setup never reads Claude native secret files. Adding Claude after Codex validates and reuses the installer credential; adding Codex after Claude needs one browser sign-in using the same account. Claude's existing sign-in is kept.
Automated codex exec runs skip both automatic capture and prompt recall by
default. Opt in with npx @cairn-ink/memory config --codex-capture-exec on;
use off to restore the default. This setting enables both capture and recall
for exec. status shows it only when enabled; rerunning setup preserves it.
The hooks read the transcript's session-bound session_meta.payload.source,
and also detect a native exec ancestor for exec resume of an older CLI thread.
If the header is missing or cannot be verified, they skip capture and injection.
Interactive sessions with verified CLI headers continue normally. Threads on the
Codex app-server (the TUI since 0.160, the VS Code extension and the desktop app)
count as interactive only when their originator is one of those three clients;
other app-server clients are treated like exec and need the same opt-in. Older frozen
runtimes must first be updated with setup; config prints the exact command.
To stop prompt recall while keeping automatic capture, run
npx @cairn-ink/memory prompt-recall-off --client codex.
Use prompt-recall-on --client codex to enable it again. This does not change MCP.
Codex defaults to 200 automatic captures per day; reruns keep an existing cap.
Change it with setup --codex-daily-cap N or config --codex-daily-cap N.
Status shows today's count and cap. Unscoped pause and resume select installed
Codex, and pause both tools when paired. Uninstall preserves keys and memories.
status reads local state without testing remote service or hooks. --verbose
shows technical diagnostics. Review and allow the four Cairn entries in Codex
/hooks after installation. --client claude|codex restricts the run.
--no-browser allows sign-in on another device. Legacy MCP removal requires
confirmation. Unqualified Codex alone may offer manual MCP tools.
Setup options and credential handling · chichi's release checklist
Manual fallback: from your terminal, run:
Or use the slash-command form inside Claude Code:
Create a personal access token at https://cairn.ink/settings/tokens, then run
/plugin configure cairn-memory@cairn-memory in Claude Code and enter it there.
Start a new session after installation.
/cairn-memory:status reads content-free credential observations written by the
hooks, because Claude Code's Bash tool does not inherit sensitive plugin options.
configured (verified <time>) reports the last accepted authenticated request;
rejected links to the configured endpoint's token page. configured (not verified yet) or configured (unreachable <time>; not verified) does not claim
successful authentication; server answered: busy/error reports an HTTP refusal.
SessionStart clears the old verdict so token rotation requires new verification.
not seen yet asks you to restart Claude Code and
send one message; missing means a hook actually observed no configured token.
Status makes no network request and never reads the token from secure storage.
Agents: ask the user before installing. The hosted plugin captures allowlisted conversation text by default, and the user creates and enters the token themselves. See the hosted plugin privacy contract.
For local development:
Hosted explicit MCP for Claude Code
For explicit memory tools without automatic capture, add the remote MCP server:
Then sign in from /mcp in Claude Code using browser OAuth.
Connect from Codex (explicit MCP memory)
Codex connects through the hosted MCP tools. Keep the token in your shell or secret manager, not in a repository or committed config file:
Restart Codex, then use /mcp or codex mcp list to confirm the connection.
The hosted tools support explicit remember, recall and forget operations.
Automatic Codex lifecycle integration remains under development; the
Codex building blocks are disabled by default.
Hosted plugin loop
The bundled MCP connection also exposes explicit remember_memory, recall_memory, and forget_memory tools. Clients without lifecycle hooks can use those tools manually; passive capture is never claimed where the host does not expose a hook.
Hosted plugin privacy contract
- Installation is explicit. Automatic capture begins only after installation and is on by default.
- Only textual user and assistant message blocks are allowlisted.
- Tool-result and tool-use blocks are excluded; the plugin does not read arbitrary project files. Ordinary user/assistant text can still contain pasted file contents, terminal output, paths, or repository names and is eligible for processing.
- Supported credential shapes are replaced with
[REDACTED]locally in both capture text and automatic recall queries before transmission. Redaction is best-effort, not a guarantee that every secret is recognized. The hosted service redacts again as defense in depth. - Automatic recall sends a redacted, bounded version of the current prompt to the configured service. This occurs before capture and is a separate processing path.
- Prompt recall sends the host conversation id when it matches the 1–200 character
ASCII allowlist (
A–Z,a–z,0–9,.,_,:,-). Trusted hooks supply it, never model text; the server stores only an owner-scoped SHA-256 hash. An older strict server gets one exact-schema retry without the optional field. - Project scope is a keyed opaque identifier. Its derivation key never leaves the device and is separate from the anonymous telemetry id.
- Automatically inferred memories remain personal or project-private. They cannot publish into a team or community.
- Product telemetry is content-free, defaults on, and can be disabled. Its schema accepts only lifecycle event, client version, platform, and a random installation id.
- Hooks fail open: Cairn outages and timeouts do not block normal Claude Code work.
- Capture workers are detached so headless
claude -psessions cannot cancel them during teardown; the allowlisted handoff is piped directly to the worker and is not written to a queue file.
Use /cairn-memory:pause, /cairn-memory:resume, and /cairn-memory:status to control capture and recall.
Paused text is not automatically backfilled. After resume, each session's first capture hook skips its current unprocessed history (including any early resumed text); later complete messages are captured. Requests already started before pause may finish. See the detailed pause boundaries in the privacy guide.
Read the full privacy and threat model. Security reports belong in the private channel described in SECURITY.md, not a public issue.
What is open
This repository is the source of truth for:
- the Claude Code plugin and marketplace manifest;
- local transcript filtering, redaction, and project identity derivation;
- the public HTTP/MCP wire contract and JSON Schemas;
- a local SQLite core with receipts, namespace isolation, capture orchestration, MOC organization, model-guided recall, correction and deletion suppression;
- an optional OpenAI adapter, thin local MCP host and inspected install artifact;
- conformance tests and self-host implementation guidance.
The Cairn.ink hosted extraction service, user database, auth, billing, abuse controls, and production operations live in a separate private repository. See Architecture and Self-hosting for the public service boundary.
Status
The released hosted plugin and local developer preview have different readiness levels. The local install lifecycle is verified, but source-support quality still fails; broad promotion is not yet cleared. No first-ten-user result or star target is presented as achieved. See Known limitations, ROADMAP.md and the proposed adoption experiment.
Star the repository to follow the local preview and upcoming integrations.
Development
The dependency-free plugin runtime and test suite require Node.js 20 or newer. Maintainer-only Claude plugin validation requires Node.js 22 and is isolated under tools/plugin-validation so it is never installed with the plugin.
For the local store on Node >=22.16 (no dependency installation required):
Contributions are welcome after reading CONTRIBUTING.md and the privacy invariants in docs/protocol.md.
Source: README.md at commit 35a29c1
Tools
0Version history
1- v0.1.0LatestSep 25, 2026
Score
85% of the applicable checks met
How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.
- Reached in the last 30 daysRequired25 pts
- Auth declaredRequired10 pts
- Tools listed15 pts
Answer tools/list without a credential, or ship a package that starts in a sandbox without one.
- DescriptionRequired15 pts
- Logo10 pts
- Documentation15 pts
- License10 pts
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