docs: add Phase 8C MCP design-only plan

[ProfRandom92]

Summary

Adds a docs-only Phase 8C MCP design plan for the CompText / Codex operating layer.

This PR defines review-gated MCP concepts only. It does not activate MCP, install plugins, enable hooks, register global skills, run provider/model calls, or mutate runtime/source artifacts.

Scope

Added:

• docs/PHASE8C_MCP_DESIGN_ONLY.md

Covers:

• MCP trust boundary
• read-only Git topology/diff/history MCP concept
• read-only docs/RAG MCP concept
• read-only CI/log MCP concept
• local Context Pack MCP concept
• proposal review MCP concept
• denied initial operations
• interaction with Phase 8A draft skills
• interaction with Phase 8B plugin scaffold
• claim hygiene
• artifact hygiene
• promotion gates before .mcp.json or .codex/** changes

Explicit non-goals

This PR does not:

• create .mcp.json
• edit .codex/**
• edit .agent/skills/**
• edit AGENTS.md
• edit README.md
• edit source code
• edit reports or artifacts
• install packages
• register MCP servers
• activate plugins
• activate hooks
• install global skills
• run provider/model calls
• use Computer Use
• deploy, release, merge, or rebase

Validation

Local:

• git diff --check origin/main...HEAD
• git diff --stat origin/main...HEAD
• branch status clean before push

Expected diff:

• one docs-only file
• no source/runtime/config activation

Review status

Draft PR. Keep draft until review confirms:

• MCP concepts remain read-only/design-only
• denied operations are explicit enough
• promotion gates are sufficient before any future .mcp.json, .codex/**, plugin, hook, skill, or automation activation

[gemini-code-assist]

Code Review

This pull request introduces a design-only document, docs/PHASE8C_MCP_DESIGN_ONLY.md, which outlines candidate Model Context Protocol (MCP) concepts for future CompText and sparkctl operating-layer work. The feedback identifies several hallucinated URLs pointing to developers.openai.com/codex/... and suggests replacing them with correct official sources, such as modelcontextprotocol.io and Anthropic's documentation, or internal references.

Important

The consumer version of Gemini Code Assist on GitHub is being sunset. Starting June 18, 2026, new organization installations will be blocked, and all code review activity will officially cease on July 17, 2026.
For more details on the timeline and next steps, please review the Help Documentation.

[gemini-code-assist]

The listed URLs point to https://developers.openai.com/codex/..., which appears to be a hallucinated domain/path structure. Model Context Protocol (MCP) is an open standard created by Anthropic, and its official documentation is hosted at https://modelcontextprotocol.io. Similarly, concepts like 'Computer Use' are Anthropic-specific features (typically documented under docs.anthropic.com).

If 'Codex' refers to a local/proprietary desktop application or internal tool, these links should point to the internal repository documentation or the correct internal domain rather than openai.com. Please update these references to point to their actual official or internal sources.

Suggested change

	- `https://developers.openai.com/codex/app`
	- `https://developers.openai.com/codex/app/worktrees`
	- `https://developers.openai.com/codex/app/local-environments`
	- `https://developers.openai.com/codex/app/review`
	- `https://developers.openai.com/codex/app/automations`
	- `https://developers.openai.com/codex/app/computer-use`
	- `https://developers.openai.com/codex/app/commands`
	- `https://developers.openai.com/codex/app/windows`
	- `https://developers.openai.com/codex/permissions`
	- `https://developers.openai.com/codex/rules`
	- `https://developers.openai.com/codex/hooks`
	- `https://developers.openai.com/codex/guides/agents-md`
	- `https://developers.openai.com/codex/mcp`
	- `https://developers.openai.com/codex/plugins`
	- `https://developers.openai.com/codex/skills`
	- `https://developers.openai.com/codex/concepts/subagents`
	- https://modelcontextprotocol.io
	- https://docs.anthropic.com/en/docs/build-with-claude/computer-use
	- Internal Codex App Reference (docs/placeholder.md)