Why a Zed MCP knowledge base sits outside the editor
Zed is excellent at reading the open file and threading edits across it. It is not designed to read the design doc in someone's Notion, the runbook a teammate keeps in Apple Notes, or the decision buried in a Linear comment. Hjarni is one place all of that can land, with MCP search built in.
The assistant's planning step is the highest-leverage moment to inject context. If it starts with the wrong assumptions, the diff is wrong. Folder-level AI instructions in Hjarni let you steer the assistant per project: 'in the Payments folder, never propose schema changes without an ADR'.
Zed is one editor. Engineers use more than one. Hjarni stays put while editors change underneath it, so the notes you write today are still useful when you switch editors next year or when a new teammate joins.
ACP connects Zed to the external agent. MCP gives that agent access to Hjarni. Zed can forward its configured MCP servers to external agents; the agent may also load its own MCP configuration. A connection working in Zed's native agent does not by itself verify the external-agent setup.
If Hjarni tools are missing, check the MCP server status, the selected external agent, and its native MCP configuration. Use 'dev: open acp logs' in Zed's command palette to inspect the connection. Check the logs for credentials or private note content before sharing them.
Setup references: Zed external agents and MCP connections in Zed.