Document MCP workflow prompt research

[deverman]

Researches #94; does not close it because the five-participant discovery gate and live client tests remain outstanding.

Impact

docs

Acceptance journey

An OmniFocus user opens a supporting MCP client workflow picker, recognizes inbox processing without knowing its exact command, invokes it, and receives a compact guided workflow that asks for approval before writes.

Findings

• MCP 2025-06-18 and pinned Swift SDK 0.12.1 support capability advertisement, prompts/list, prompts/get, arguments, and prompt messages.
• Current FocusRelay baseline advertises no prompt capability; prompt methods return -32601; the public catalog remains nine tools.
• Claude Code documents MCP prompt command discovery.
• Current OpenCode and Codex documentation covers MCP tools but does not establish server-prompt discovery, so both require versioned live tests.
• Recommend an instruction-first process_inbox prototype with no eager OmniFocus data in prompts/get.

The document defines the comparison variant, byte/latency/tool-call measurements, privacy rules, exact technical regression assertions, and Gate 1 participant criteria. No participant outcomes are fabricated.

Validation

• swift run focusrelay-dev validate --impact docs — passed whitespace and local Markdown links.
• git diff --check — passed.

Remaining #94 gates

• Five independent participant sessions.
• Versioned Claude Code, OpenCode, and Codex live compatibility probes.
• Instruction-first versus bounded data-backed prototype comparison.
• Research-supported prompt implementation and end-to-end UAT.