Sibyl
Give your coding agents persistent memory across every session.
Quick answer
Sibyl — Give your coding agents persistent memory across every session. It's free. Best for restoring project context automatically when starting a new AI-assisted coding session.
Sibyl is a free, open-source, self-hosted knowledge-graph and persistent memory layer designed to give AI coding agents long-term recall of project context. Developers who work with tools like Claude Code, Codex, Cursor, Aider, or Cline often lose valuable context between sessions, forcing them to re-explain project structure, conventions, and decisions every time. Sibyl solves this by maintaining a structured knowledge graph that any supported shell-running coding agent can query at the start of a session, instantly restoring the context that would otherwise be lost. It is particularly useful for solo developers and engineering teams managing complex, long-lived codebases where consistent context is critical to productivity. Because Sibyl is self-hosted and open-source, all project data stays on your own infrastructure, making it a strong choice for privacy-conscious developers or those working on proprietary codebases. The tool acts as a shared memory backbone that multiple agents can read from and write to, enabling a more cohesive and intelligent development workflow without relying on any third-party cloud service.
Key features
- Persistent knowledge graph stores project context across coding sessions
- Cross-agent memory compatibility with Claude Code, Codex, Cursor, Aider, and Cline
- Self-hosted deployment keeps all data on your own infrastructure
- Shell-based integration allows any supported agent to query memory at session start
Pros & cons
- +Completely free and open-source with no subscription or usage fees
- +Self-hosted design ensures full data privacy and ownership
- +Compatible with multiple popular AI coding agents out of the box
- −Requires self-hosting setup which may be a barrier for non-technical users
- −Limited to environments where shell access is available for agent integration
Pricing
Fully free and open-source, self-hosted with no usage limits
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Who is it for
- →Restoring project context automatically when starting a new AI-assisted coding session
- →Maintaining consistent coding conventions and architectural decisions across multiple agents
- →Managing long-lived codebases where accumulated project knowledge improves AI-assisted development
Frequently asked questions
Is Sibyl free?
Yes, Sibyl is completely free. It is an open-source project with no paid tiers, subscriptions, or usage limits. You host it yourself on your own infrastructure.
What is Sibyl best used for?
Sibyl is best used for giving AI coding agents persistent memory of your project's context, conventions, and decisions across multiple sessions. It is ideal for developers working on complex or long-lived codebases who use tools like Claude Code, Cursor, or Aider.
What are the best alternatives to Sibyl?
Alternatives include MemGPT for persistent LLM memory, Graphiti for knowledge-graph-based agent memory, and custom context injection scripts. Some coding IDEs also offer limited built-in context persistence, though few match Sibyl's cross-agent flexibility.
Is Sibyl safe to use?
Yes. Because Sibyl is self-hosted and open-source, your project data never leaves your own infrastructure. You have full visibility into the codebase and full control over where data is stored, making it a privacy-respecting choice for sensitive projects.
How much does Sibyl cost?
Sibyl costs nothing. It is a fully open-source tool that you run on your own hardware or server. There are no licensing fees, no cloud subscription costs, and no per-usage charges.
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