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factstore

Official registry Data and databases

A fact store for AI agents, on Postgres: registered attributes, every write citing its evidence.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

PYPI package factstore
Claude Code 
claude mcp add factstore -e 'FACTSTORE_DSN=<your factstore_dsn>' -e 'FACTSTORE_EXCISE_DSN=<your factstore_excise_dsn>' -- uvx factstore==0.1.0 mcp
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "factstore": {
            "command": "uvx",
            "args": [
                "factstore==0.1.0",
                "mcp"
            ],
            "env": {
                "FACTSTORE_DSN": "<your factstore_dsn>",
                "FACTSTORE_EXCISE_DSN": "<your factstore_excise_dsn>"
            }
        }
    }
}

Environment variables

  • FACTSTORE_DSN required secret The credential `factstore actor STORE NAME` prints: a Postgres connection string for one actor of one store.
  • FACTSTORE_EXCISE_DSN secret An excision credential (`factstore actor --excise`). Only then is the excise tool listed.

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. factstore
  2. Install
  3. What's here
  4. Status

factstore

A fact store for AI agents, on Postgres. Agents record what a company's systems and documents say as facts: a value for a registered attribute, in a transaction stamped with who wrote it and the document it came from. Nothing is overwritten, so the store can say what it knew on any date.

Skills that ship with it index a company's systems from their exports, and read documents and mail into facts. They leave people's personal details in the source. MIT-licensed.

Install

pip install factstore

In Claude Code, the plugin brings the MCP server and the skills:

/plugin marketplace add Victor-EU/factstore
/plugin install factstore@factstore

factstore/README.md walks through Postgres, a first store and connecting an agent.

What's here
factstore/The kernel, the MCP server, the Python SDK and the CLI
packages/Vocabulary packages: core, and ecom-ops and ecom-index for an online brand
factstore-skills/The catalogue, ontology and ingestion skills
evals/What it was tested on: a synthetic brand, and five public datasets from real companies
factstore-design.mdThe design, and what testing changed in it
factstore-build-plan.mdThe milestones, and where each stands

Status

0.1.0, alpha. The kernel's code held unchanged through every test, up to 3.2 million facts in one store. The skills passed every round on public data: product lists, a million order lines, a marketplace's duplicate customers, 100 suppliers' forms and a trader's mailbox. No company has run it on its own data yet.

Frequently asked questions

What is factstore?

A fact store for AI agents, on Postgres: registered attributes, every write citing its evidence.

How do I install factstore?

It runs on your machine. In Claude Code: claude mcp add factstore -e 'FACTSTORE_DSN=<your factstore_dsn>' -e 'FACTSTORE_EXCISE_DSN=<your factstore_excise_dsn>' -- uvx factstore==0.1.0 mcp. For other clients, paste the JSON configuration from this page into their MCP settings.

Does factstore need an API key?

Yes. It expects FACTSTORE_DSN, FACTSTORE_EXCISE_DSN, which you set in its configuration.

Is factstore open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains factstore?

It is published by Victor-EU. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.