ADR-236 follow-up: productionize Codex brain MCP, hooks, and bridge

[ruvnet]

Context

ADR-236 documents the local Codex integration that was completed on 2026-07-08:

• ruvultra-mcp is built and registered as Codex MCP server ruvultra-brain.
• The local personal plugin metaharness-brain@personal is installed and validates.
• Brain MCP smoke test passed (ruv_brain_health returned local sqlite status OK).
• The hook script is packaged, but plugin manifest validation currently rejects a manifest-level hooks field.
• metallm-dev-bridge is present but intentionally not enabled because COGNITUM_DEV_KEY is not available in the Codex process environment.
• The documented mcp-serve entrypoint for metaharness is not wired because this checkout does not currently ship a real stdio server entrypoint by that name.

ADR: docs/adrs/ADR-236-codex-local-brain-mcp-and-hooks.md

Work items

• Add a tested metaharness mcp-serve or equivalent stdio MCP server for generator authoring tools.
• Decide the supported Codex hook activation path and make packaged hooks schema-valid or install them through the documented runtime path.
• Add a Secret Manager or shell wrapper path that exports COGNITUM_DEV_KEY into Codex before enabling metallm-dev-bridge.
• Add smoke tests for the personal plugin .mcp.json, brain MCP tool list, and post-write safety hook.
• Document the mutation-tool operating rule: explicit user intent, local-only, summarize writes, and never silently change brain behavior.

Acceptance criteria

• codex can start with the configured MCP servers and no startup failures.
• ruvultra-brain tools list includes brain health/info/search/memory/RVF/checkpoint/export tools.
• Hook activation path is documented and verified, not just packaged as an inert asset.
• metallm-dev-bridge remains disabled by default unless credentials are present and healthcheck passes.
• MetaHarness generator MCP serving is backed by an actual stdio server and regression tests.