@ghostpaw/codex

Local, evidence-backed memory for AI agents. One SQLite file, zero runtime dependencies.

Codex stores what an agent believes as claims with a source, a certainty, evidence counts, decay and an honest revision history. Agents search before they remember, confirm or correct instead of appending, and see which beliefs are stale, fading or weakly evidenced. It runs as a TypeScript library, an MCP server, a CLI and an Agent Skill, all generated from the same seven tools.

Website: ghostpaw.anonyfox.com/codex

Requires Node.js 24+ (uses the built-in node:sqlite).

30-second quickstart

MCP server

Every client below starts the same stdio server: npx -y @ghostpaw/codex mcp. Beliefs live in ~/.ghostpaw/codex.db unless the GHOSTPAW_CODEX_DB environment variable (absolute path) or --db <path> says otherwise.

Claude Code

claude mcp add ghostpaw-codex -- npx -y @ghostpaw/codex mcp

or as a plugin, which also installs the skill:

/plugin marketplace add GhostPawJS/codex
/plugin install ghostpaw-codex@ghostpaw-codex

Codex CLI (~/.codex/config.toml)

[mcp_servers.ghostpaw-codex]
command = "npx"
args = ["-y", "@ghostpaw/codex", "mcp"]

Cursor (.cursor/mcp.json), Claude Desktop (claude_desktop_config.json) or a project .mcp.json:

{
  "mcpServers": {
    "ghostpaw-codex": {
      "command": "npx",
      "args": ["-y", "@ghostpaw/codex", "mcp"]
    }
  }
}

Claude Desktop users can also install server.mcpb from the latest GitHub release. A Dockerfile is included for container hosts: docker build -t ghostpaw-codex . && docker run -i --rm -v codex:/data ghostpaw-codex.

The server speaks MCP 2026-07-28 (stateless, server/discover) and the initialize-based revisions 2025-11-25, 2025-06-18, 2025-03-26 and 2024-11-05.

CLI

npx -y @ghostpaw/codex remember_belief --claim "Deploys go out on Tuesdays" --source explicit --category procedure
npx -y @ghostpaw/codex search_codex --query "when do we deploy"
npx -y @ghostpaw/codex tools              # list tools
npx -y @ghostpaw/codex describe revise_belief

Install globally for the ghostpaw-codex binary: npm i -g @ghostpaw/codex. ghostpaw-codex mcp starts the stdio server.

Agent Skill

SKILL.md (repo root) and skills/codex/SKILL.md follow the Agent Skills format and ship in the npm package. Copy skills/codex/ into your agent's skills folder, or print it:

npx -y @ghostpaw/codex skill > SKILL.md

Library

npm install @ghostpaw/codex

import { DatabaseSync } from 'node:sqlite';
import { initCodexTables, read, write } from '@ghostpaw/codex';

const db = new DatabaseSync('codex.db');
initCodexTables(db);

const { id } = write.remember(db, {
  claim: 'The API uses GraphQL with a REST fallback.',
  source: 'explicit',
  category: 'fact',
});
write.confirmBelief(db, id);
write.correctBelief(db, id, {
  claim: 'The API uses GraphQL exclusively; REST was retired.',
  source: 'observed',
  category: 'fact',
});

read.recall(db, 'graphql api'); // ranked, lineage-aware
read.listFlags(db);             // stale, fading, low-trust, single-evidence

Wire the same tools into any LLM SDK. Each tool carries a JSON Schema:

import { tools } from '@ghostpaw/codex';

for (const tool of tools.codexTools) {
  // tool.name, tool.description, tool.inputSchema, tool.handler(db, input)
}

Or embed the MCP server in your own process:

import { createCodexMcpServer } from '@ghostpaw/codex/mcp';
const server = createCodexMcpServer({ dbPath: './codex.db' });

Related MCP server: alaya

Why not MEMORY.md?

A markdown memory file works until it doesn't:

• It only grows. Agents append, rarely delete, and the file ends up in every prompt. Codex returns the few beliefs that match a query (FTS5 plus local embeddings, fused by rank).

• Contradictions pile up. "We use REST" and "REST was retired" sit side by side. Codex detects near-duplicates on every write, and corrections supersede the old belief while keeping the lineage.

• Everything looks equally true. A guess and a confirmed fact read the same in prose. Codex tracks source (explicit, observed, distilled, inferred), certainty and evidence count, and flags what is stale or weakly supported.

• No time. Codex decays freshness, so old beliefs surface for review instead of quietly steering behaviour.

• Concurrent edits. Two agents writing one file clobber each other. Codex is a SQLite database in WAL mode.

It stays local: one file you can copy, back up or inspect with any SQLite tool. No server, no API key, no network.

Tools

Results are structured (outcome: success | no_op | needs_clarification | error) with entities, next-step hints and recovery advice. The MCP server, CLI, SKILL.md and plugin manifests are generated from this registry (npm run surfaces) and drift-checked in CI.

Performance

Measured with npm run bench on Node 24.14.0, Linux, Intel Xeon (shared cloud vCPU), 10,000 beliefs in a file-backed database:

Cold start (process spawn to first response, median): --version 29 ms, MCP server/discover 26 ms, first search against the 10,000-belief file 57 ms. Seeding 10,000 beliefs takes 2.2 s on disk.

Gzip sizes and cold-start medians are budgeted in budgets.json and enforced by npm run check.

The model

State is derived, never toggled: freshness, strength, review priority and flags are computed at read time.

Package surface

ESM and CommonJS, with type declarations for both.

Documentation

Development

npm install
npm run check   # types, lint, zero-deps, tests, build, surfaces, size, API, consumer, startup, ratchet
npm run bench   # hot-path benchmarks at 10,000 beliefs
npm run surfaces  # regenerate SKILL.md, plugin manifests, server.json, mcpb manifest

npm run check is the single gate, locally and in CI. Size budgets (budgets.json) and the public API snapshot (api-surface.json) can only grow with an explicit approval tag in the commit message. The repo is pinned to Node 24.14.0 via .nvmrc.

Support

If this package helps your project, consider sponsoring its maintenance:

Anonyfox • MIT License