feat(scrybe-tui): live MCP surface — mcp open drives the TUI via ~/.scrybe/sock

[hartsock]

Subscribe to ~/.scrybe/sock so mcp open drives the TUI exactly like the desktop app — the MCP keystone extended to the terminal. Part of #154 (re-scoped). Rides the MCP platform (#122).

[hartsock]

Design sketch (wave close-out, 2026-07-22) — the TUI as a live agent-drivable surface. Since this was filed, the ground shifted in our favor: the socket contract is FROZEN and typed (docs/rpc-contract-0.6.md), and the app side already serves reply-correlated methods. Proposed shape: the TUI grows an OPTIONAL --serve mode that binds the SAME socket contract (or a scoped subset: open/read/reload/state/quit) at a DISTINCT path (~/.scrybe/tui.sock — never contending with the app's socket), reusing scrybe-rpc's server-side types. An agent then drives the terminal viewer exactly as it drives the GUI: SCRYBE_SOCK=~/.scrybe/tui.sock scrybe-mcp-server stdio gives MCP-over-the-TUI for free — zero new tool surface, the 22-tool contract just points at a different living surface. Read-only tools (read/find/section/state/list_tabs) map naturally; mutating ones (edit/save) need the TUI to own a buffer, which it currently doesn't — v1 scope: the read-only subset + open/reload/quit, honestly advertised (isError on unsupported). Effort: mostly server-loop plumbing inside scrybe-tui + a capability flag in the contract. Blocked on nothing; sized medium.

[hartsock]

Re-scope — 2026-07-29 backlog scrub. The body's "subscribe to ~/.scrybe/sock" sketch is stale; the 2026-07-22 design comment on this issue is the real spec. Current scope:

Add an optional --serve mode to scrybe-tui that binds the frozen 0.6 socket contract (reusing scrybe-rpc's typed Request/Reply structs) at the distinct path ~/.scrybe/tui.sock, serving read/find/section/state/list_tabs plus open/reload/quit and returning isError for unsupported mutating methods. Agents then drive the terminal viewer with SCRYBE_SOCK=~/.scrybe/tui.sock scrybe-mcp-server stdio — the existing MCP contract pointed at a different living surface, zero new tools.

Audit: full-workflow backlog scrub vs the adopted-renderer reality; ROADMAP re-compaction PR follows.