agentcairn: memory tool for Hermes Agent

Cross-project Markdown memory for coding agents, with an Obsidian vault and a DuckDB index

What agentcairn does

agentcairn captures durable context from the coding agents you use, stores it as inspectable Markdown with provenance, and recalls only the most relevant pieces when another agent needs them. The Markdown vault is the canonical memory. DuckDB is a derived retrieval cache that can be deleted or rebuilt without losing the vault. Supported hosts share the same configured vault, so memory is not split per tool.

History is non-lossy: superseded and expired facts stay inspectable and are demoted rather than hidden, and a fact edited by hand is honored on the next reconciled read. The plugin bundles an MCP server, a memory skill and host-specific hooks, and launches through uvx. The README documents Claude Code and Codex installs, with Claude Code getting commands such as /agentcairn:recall and /agentcairn:remember. The default vault is ~/agentcairn, a separate Obsidian companion exposes provenance and links, and the README says it sends no telemetry.

Key features

Markdown vault as canonical memory, with notes, frontmatter and wikilinks
DuckDB retrieval cache that can be rebuilt without touching the vault
One vault shared across supported coding agents
Non-lossy history: superseded and expired facts are demoted, not deleted
Bundled MCP server, memory skill and ambient hooks in a plugin
Claude Code commands for recall, remember, memory, savings and ingest

When to use it

Carrying decisions and project context from one coding agent session to the next
Sharing one memory between Claude Code and Codex
Reading or hand-editing agent memory in Obsidian

Who it is for: Developers who use more than one coding agent and want a local, human-readable memory that they own.

How it fits with Hermes Agent

Supports Hermes among other agents: the repository is tagged hermes, hermes-agent and hermes-plugin on GitHub, while the opening part of the README documents Claude Code and Codex installs.

How to install agentcairn

These commands are copied from the project's README. Check the repository for the latest steps before you run them.

npx skills add ccf/agentcairn --skill agentcairn-setup -g

Requirements: uv, because the plugin launches through uvx

FAQ

What is agentcairn?

agentcairn is a long-term, cross-project memory for AI coding agents. It keeps memory as Markdown notes in a vault and uses DuckDB as a replaceable retrieval cache.

Does agentcairn work with Hermes Agent?

It is tagged hermes-agent and hermes-plugin on GitHub, but the opening part of the README documents Claude Code and Codex installs. Check the repository for the current Hermes setup steps.

Is agentcairn free and open source?

Yes. agentcairn is open source under the Apache-2.0 license.