Houston: one window, one main process Diagram

What keeps pages out

Browser tabs are sandboxed, get only the extension-API and ad-block preloads and are denied every permission but fullscreen, pointer lock and clipboard writes
Every IPC channel refuses any sender but the shell view
acc:// pages (documents, Cronsole runs, Git diffs, dev server logs) run no scripts; only documents may link to documents, the rest open from the app only

What an agent can do

Look with no click: list_tabs, read_tab, sidebar_search, recent, list_terminals, terminal_read, run_status, cron_tasks
Navigate: open_tab, and open_file by Hub node id (VS Code or Explorer, never the default app)
Act only after Run: terminal_run starts a managed run in its own PowerShell, whose exit code is the result; cron_run asks Cronsole's run_task

Who reaches the MCP server

Claude Code in an app terminal: ACC_MCP_URL and ACC_MCP_TOKEN are in every terminal's environment
The chat panel, through the same server and token, so its calls are logged and confirmed like any client's
Every call, refused ones too, goes to the sidebar's MCP tab and logs/mcp.log, with the connecting client named

Optional parts

Without Project Hub the browser and terminals still work; Files and Bookmarks offer Retry
The chat needs ACC_CHAT_API_KEY and ACC_CHAT_MODEL; there is no default model
Cronsole starts only when ACC_CRONSOLE_MCP names its server script
Dev servers and the Git tab need a workspace folder; git and npm are found on PATH