Show and tell: Codex as supervisor, Reasonix as a sandboxed executor via MCP

[rixzkiye]

I built codex-reasonix-mcp, an external MCP bridge for a specific agent-to-agent pattern:

Codex supervisor -> MCP bridge -> Reasonix ACP Goal session -> Codex review and finalization

This is not a built-in Reasonix MCP server and it does not replace the Reasonix UI or direct CLI. It uses the ACP surface and the supervisor extensions merged in PR #7097 so Reasonix can report effective planner, work mode, collaboration mode, sandbox, phase, readiness, and usage state without exposing reasoning text.

Each delegated task is bound to an immutable contract, isolated branch and worktree, and one ACP session. Reasonix implements in Delivery plus Goal mode with the planner forced off. Codex can inspect bounded evidence, steer, request up to two repair rounds, and trigger final verification. The bridge owns permission policy, scope enforcement, secret scanning, explicit staging, and the final atomic commit. Reasonix never commits, pushes, or merges.

This is closely related to issue #6031. It demonstrates one external implementation using persistent ACP sessions rather than adding a built-in HTTP or MCP server to Reasonix, so I do not consider that issue fully resolved by this project.

Current status: codex-reasonix-mcp 0.1.0-rc.3 is a prerelease. Until the ACP supervisor capability is included in an official Reasonix release, users need a local build from current main-v2.

Install the bridge:

npm install codex-reasonix-mcp@next

Or register it directly in Codex with a local Reasonix binary:

codex mcp add reasonix-worker --env REASONIX_BIN=/absolute/path/to/reasonix -- npx -y codex-reasonix-mcp@0.1.0-rc.3

Then run the no-model compatibility check:

REASONIX_BIN=/absolute/path/to/reasonix npx -y codex-reasonix-mcp@0.1.0-rc.3 doctor

Links:

• Source and architecture
• npm package
• v0.1.0-rc.3 release

I would appreciate feedback from Reasonix maintainers and users on the ACP lifecycle, recovery semantics, usage telemetry, and whether this pattern should influence future first-party agent-to-agent surfaces.

Disclosure: I maintain the linked bridge and npm package.

[esengine]

Thanks for building and sharing this! The ACP supervisor status from #7097 has shipped in stable releases since 1.19.x (merged 2026-08-01), so users can now point the bridge at an official build (latest 1.39.0) instead of a local main-v2 build.

[Linearl]

我是reasonix做主开发会话，zcode开发，mcp打通
glm的150%额度和晚上免费太香了