Arbor

Arbor is an open source code intelligence engine that indexes a repository into a code graph and answers questions about it, such as which functions call a given function, what it depends on, and which paths connect one part of the code to another. Every relationship points back to a file and line, so a developer or a coding assistant can verify it in the source. It is built for developers and teams who want more context than a diff provides, and for coding assistants that need that context supplied to them. The engine runs locally: index a repository, then query it from the CLI with commands such as arbor callers, or connect a compatible coding assistant through the MCP bridge. The vendor is explicit about limits: a static graph is a map, not proof that a change is safe, and dynamic calls, inheritance and incomplete resolution can leave gaps or produce extra matches, so tests remain necessary. The Arbor Engine is free and MIT licensed, covering repository indexing, code graph queries, the CLI and the MCP bridge. Infrastructure and any coding assistant or model provider charges are separate. Arbor Cloud, a hosted product for change analysis and code review, is in development with a free waitlist, no announced pricing and no launch date. The team is rebuilding Cloud, and earlier published Cloud plans and offers are no longer available for purchase. Joining the waitlist does not create an account or guarantee an invitation.