Agentcairn MCP Server

Local-first agent memory: an Obsidian markdown vault as source of truth, with a rebuildable DuckDB index.

Remote serverstreamable-httpPython

What is the Agentcairn MCP server?

Most knowledge and memory work still happens through a UI a human drives. Agentcairn MCP server moves it into the conversation instead. Local-first agent memory: an Obsidian markdown vault as source of truth, with a rebuildable DuckDB index.

The short version

One durable memory across supported coding agents.

The tools it exposes

The server publishes 13 tools. What each one is for:

  • Capture — ** host hooks improve immediacy; cairn sweep reads supported transcript stores out-of-band as the durable backstop. AgentCairn redacts recognized
  • Reconcile — ** the first read transactionally brings the vault-scoped index in sync with Markdown. A failed rebuild preserves the last good cache and the durable
  • Recall — ** BM25 and semantic vectors are fused with Reciprocal Rank Fusion, then optionally reranked. Model/provider failures visibly fall back to BM25 with
  • Remember — ** the MCP tool atomically writes a Markdown note and updates the index under one writer lock, making a successful save immediately recallable
  • Time — aware corrections.** valid_from, valid_until, and superseded_by keep old evidence visible while making current facts rank first
  • Project — aware recall.** The current project is boosted by default; cross-project results remain available and are labeled. Automatic recall is project-scoped
  • Promise — What it means in practice
  • Host — Integration
  • Codex — Plugin + MCP + skill
  • Cursor — MCP + skill + ingest
  • OpenCode — Plugin + MCP + ingest
  • Antigravity — Plugin + ingest

Getting it running

Because this one is hosted, setup is mostly authentication — you point your client at the endpoint and approve access. Nothing runs on your machine, so there is no runtime to keep patched.

How it compares

This sits in the knowledge and memory group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Agentcairn's toolset — Capture, Reconcile, Recall and 10 more — is a fair guide to whether it matches your workflow.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Things to watch

  • Your data travels to the provider's service, so the usual questions apply about what you send and what they retain.
  • With 13 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Agentcairn.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

Available tools

ToolWhat it does
Capture** host hooks improve immediacy; cairn sweep reads supported transcript stores out-of-band as the durable backstop. AgentCairn redacts recognized credentials, deduplicates, importance-gates, and distills before its autom
Reconcile** the first read transactionally brings the vault-scoped index in sync with Markdown. A failed rebuild preserves the last good cache and the durable files remain untouched.
Recall** BM25 and semantic vectors are fused with Reciprocal Rank Fusion, then optionally reranked. Model/provider failures visibly fall back to BM25 with diagnostics instead of returning incompatible vectors.
Remember** the MCP tool atomically writes a Markdown note and updates the index under one writer lock, making a successful save immediately recallable.
Timeaware corrections.** valid_from, valid_until, and superseded_by keep old evidence visible while making current facts rank first.
Projectaware recall.** The current project is boosted by default; cross-project results remain available and are labeled. Automatic recall is project-scoped unless you explicitly opt into all projects.
PromiseWhat it means in practice
HostIntegration
CodexPlugin + MCP + skill
CursorMCP + skill + ingest
OpenCodePlugin + MCP + ingest
AntigravityPlugin + ingest
DatasetMean full history

How to install the Agentcairn MCP server

{
  "mcpServers": {
    "agentcairn": {
      "command": "npx",
      "args": ["-y", "skills"]
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Example prompts to try

  • Use Agentcairn to Capture.
  • Use Agentcairn to Reconcile.
  • Use Agentcairn to Recall.

Frequently asked questions

It connects Agentcairn to MCP-compatible AI assistants such as Claude and Cursor, exposing 13 tools (Capture, Reconcile, Recall, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Agentcairn directly.