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Vayl

Official registry AI and agents

Reconciling memory for AI agents: a changed fact retires the old value, with history and approval.

Source code Website Documentation

What can you do with Vayl?

  • Reconciles changes. A new value supersedes the old one, and "we stopped X" retracts X. A retired fact is never returned as current.
  • Keeps history. Ask what is true now or what was true before. Every change goes on a signed, tamper-evident audit chain.
  • Human approval where it matters. Mark slots such as medications as confirm-required, and changes wait in a queue. check_before_act blocks an action that depends on a disputed, stale or just-changed fact.
  • Small and local. SQLite by default, Postgres for teams. One model call to store a fact and one to answer. Any OpenAI-compatible model, Anthropic, Groq or a local Ollama model.
  • Built-in presets for clinical, support, finance, sales, coding and assistant memory.

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 vayl-mcp
Claude Code 
claude mcp add vayl -e 'OPENAI_API_KEY=<your openai_api_key>' -e 'VAYL_DB=<VAYL_DB>' -- uvx vayl-mcp==0.10.0
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "vayl": {
            "command": "uvx",
            "args": [
                "vayl-mcp==0.10.0"
            ],
            "env": {
                "OPENAI_API_KEY": "<your openai_api_key>",
                "VAYL_DB": "<VAYL_DB>"
            }
        }
    }
}

Environment variables

  • OPENAI_API_KEY secret OpenAI key for extraction and embeddings. Leave unset to use a local Ollama model.
  • VAYL_DB Absolute path of the SQLite memory database.

Documentation

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

Contents
  1. Vayl
  2. Features
  3. Install
  4. Use it from code
  5. Integrations
  6. Documentation
  7. Contributing
  8. Security
  9. License

Vayl

The reconciling memory layer for AI agents.

When a fact changes, most agent memory keeps both versions and lets the model guess which is current. Vayl replaces the old value, keeps it in history, and can hold high-stakes changes until a person approves them. It runs locally on SQLite and works with any MCP client: Claude Code, Cursor, Claude Desktop, or your own agent.

A real run with gpt-6-luna and the clinical preset. The patient is fictional. Script: assets/demo/clinical_demo.py

Features

  • Reconciles changes. A new value supersedes the old one, and "we stopped X" retracts X. A retired fact is never returned as current.
  • Keeps history. Ask what is true now or what was true before. Every change goes on a signed, tamper-evident audit chain.
  • Human approval where it matters. Mark slots such as medications as confirm-required, and changes wait in a queue. check_before_act blocks an action that depends on a disputed, stale or just-changed fact.
  • Small and local. SQLite by default, Postgres for teams. One model call to store a fact and one to answer. Any OpenAI-compatible model, Anthropic, Groq or a local Ollama model.
  • Built-in presets for clinical, support, finance, sales, coding and assistant memory.

Install

pip install vayl-mcp

Add it to Claude Code:

claude mcp add vayl -e LLM_PROVIDER=openai -e OPENAI_API_KEY=sk-... -e VAYL_DB=$HOME/.vayl/vayl.db -- vayl-mcp

For Cursor, Claude Desktop and other clients, see the quickstart. Run vayl-demo to try reconciliation with no API key.

Use it from code

from vayl import Vayl

with Vayl(user_id="cust_5521") as m:
    m.remember("Acme's invoice bounced. Account suspended until payment clears.")
    print(m.recall("Is Acme's account in good standing?"))
    # No. Acme's account is suspended until payment clears.

Integrations

Agent frameworks. Backends plug into the framework's own memory, so facts are stored and recalled on every turn. Tool adapters give the agent memory tools to call.

FrameworkInstallUse
Google ADKpip install 'vayl-mcp[adk]'from vayl.integrations.adk import VaylMemoryService (memory backend)
LlamaIndexpip install 'vayl-mcp[llamaindex]'from vayl.integrations.llamaindex import VaylMemory (memory block)
AutoGenpip install 'vayl-mcp[autogen]'from vayl.integrations.autogen import VaylMemory (memory backend)
LangGraph / LangChainpip install 'vayl-mcp[langgraph]'from vayl.integrations.langgraph import VaylMemory (tools)
OpenAI Agents SDKpip install 'vayl-mcp[openai-agents]'from vayl.integrations.openai_agents import VaylMemory (tools)
CrewAIpip install 'vayl-mcp[crewai]'from vayl.integrations.crewai import VaylMemory (tools)
Pydantic AIpip install vayl-mcp 'pydantic-ai-slim[openai,mcp]'MCPToolset over MCP, no adapter
Agnopip install vayl-mcp agno openaiMCPTools over MCP, no adapter
Vercel AI SDKnpm i @vayl.dev/client ai zodimport { vaylTools } from "@vayl.dev/client/vercel"
Mastranpm i @vayl.dev/client @mastra/core zodimport { vaylTools } from "@vayl.dev/client/mastra"

Examples for each are in Agent frameworks.

MCP clients. Install vayl-mcp, then add it to your client: Claude Code · Cursor · VS Code · Windsurf · Zed · Cline · Continue · Codex CLI · Gemini CLI. For a shared team memory, run vayl-server and call it over MCP or REST.

Documentation
QuickstartInstall and connect a client
How Vayl worksExtraction, reconciliation and retrieval
Tutorial: a hospital medication assistantClinical preset, critical facts and approval
Tutorial: a customer-support assistantAccount state and safety checks
MCP toolsAll 30+ tools
Deploying vayl-serverTeam server, auth, Docker, Postgres
BenchmarksStale-value and retraction results against Mem0 and Graphiti

Contributing

See CONTRIBUTING.md. The unit tests run offline, with no API key. Good starting points are labeled good first issue.

Security

Data is encrypted at rest by default, and Vayl sends nothing anywhere except to the model endpoints you configure. Vayl is not certified for clinical use and has not been audited by a third party. Report vulnerabilities as described in SECURITY.md.

License

Apache-2.0 </content> </invoke>

Frequently asked questions

What is Vayl?

Reconciling memory for AI agents: a changed fact retires the old value, with history and approval.

How do I install Vayl?

It runs on your machine. In Claude Code: claude mcp add vayl -e 'OPENAI_API_KEY=<your openai_api_key>' -e 'VAYL_DB=<VAYL_DB>' -- uvx vayl-mcp==0.10.0. For other clients, paste the JSON configuration from this page into their MCP settings.

Does Vayl need an API key?

Yes. It expects OPENAI_API_KEY, which you set in its configuration.

Is Vayl open source?

Yes. Its code is on GitHub under the Apache-2.0 license.

Who maintains Vayl?

It is published by ac12644. AI.tn lists it but does not maintain or endorse it.

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