9fd321043f
MCP tools (send/check_inbox/peek_inbox/list_mailboxes) now accept the caller's mailbox name as an explicit argument (from/name), falling back to the X-Mailbox header for legacy single-session HTTP setups. This unblocks multi-session coordination through a shared .mcp.json — each Claude session passes its own session-derived name on every call, instead of relying on a single transport header that all sessions would share. The plugin now ships .mcp.json (no header), and the SessionStart announcement spells out the exact args to pass to each mcp__mailbox__* tool so Claude wires it up automatically.
@kuns/claude-mailbox
Standalone MCP mail server that lets parallel Claude sessions coordinate with each other. TypeScript / Node port of the .NET claude-mailbox daemon — wire-compatible (same port, same X-Mailbox header, same MCP tool names, same SQLite schema).
Install
One-time per machine:
npm config set @kuns:registry=https://git.kuns.dev/api/packages/releases/npm/
npm install -g @kuns/claude-mailbox
Then:
claude-mailbox install-autostart # registers per-OS autostart, no admin needed by default
See the repository README for the full architecture, MCP tool reference, and .mcp.json snippet.
Claude Code hook (auto-check inbox)
Register a UserPromptSubmit hook so Claude pulls pending mailbox messages before every prompt:
claude-mailbox install-hook --name alice # patches ~/.claude/settings.json
claude-mailbox install-hook --name alice --project # patches <cwd>/.claude/settings.json
claude-mailbox uninstall-hook # remove again
The hook is idempotent (running install-hook twice does nothing the second time) and only touches the UserPromptSubmit block — other hooks and settings are preserved.
Under the hood the hook runs claude-mailbox check --name <mailbox> --hook, which:
- prints unread messages in a Claude-friendly format,
- silently exits 0 if the inbox is empty or the daemon is unreachable (no context noise),
- marks the messages delivered so they aren't injected again next prompt.
Cost: one local HTTP round-trip plus Node coldstart per prompt (~100ms on Windows).
Troubleshooting
npm installreturns401 Unauthorized- The Gitea registry usually serves the
releasesscope publicly, but if your instance requires auth you'll need a read token:npm config set //git.kuns.dev/api/packages/releases/npm/:_authToken=<token> gyp ERR! find VSon Windows during installbetter-sqlite3ships prebuilt binaries for current Node LTS versions. If yours isn't covered, npm falls back to building from source and needs the Visual Studio Build Tools. Either install them or pin to a Node version with a matching prebuild.