Add `codex mcp enable|disable <server>` CLI subcommands

Problem

Toggling an MCP server on or off currently requires manually editing ~/.codex/config.toml (or .codex/config.toml) to set enabled = true|false, or passing -c 'mcp_servers.<name>.enabled=false' on every invocation — which is verbose and has known issues (#16045).

The codex mcp subcommand already supports add and remove, but there is no middle ground: you either have a server configured or you don't. Temporarily disabling a server without losing its configuration (URL, args, env, tool approvals) should be a first-class operation.

Existing proposals and how this differs

| Issue | Approach | Scope |
|-------|----------|-------|
| #11765 | General request for enable/disable UX | No concrete API proposed |
| #12197 | Interactive TUI toggle inside a running session (/mcp) | In-session only, not scriptable |

This proposal focuses on a non-interactive CLI command that works outside of a Codex session. It complements the TUI approach (#12197) rather than replacing it — both address the same need on different Codex surfaces. A CLI primitive could also serve as a foundation for IDE extensions that want to toggle MCP servers programmatically.

Proposed behavior

codex mcp enable <server>   # sets enabled = true
codex mcp disable <server>  # sets enabled = false

Scope flag:

--scope global    # ~/.codex/config.toml (default)
--scope project   # .codex/config.toml in the current project

This mirrors how config already works: project-level overrides global, closest to cwd wins.

Examples:

# Disable a noisy MCP server globally
codex mcp disable context7

# Enable an MCP server only for this project
codex mcp enable atlassian --scope project

# Re-enable globally
codex mcp enable context7

Edge cases:

• If <server> is not defined in the target scope, the command should error with a suggestion (e.g., "server 'foo' is not configured in project scope; did you mean --scope global?").
• codex mcp list could show the effective enabled state per server (already shows status, but making enabled/disabled explicit would help).

Why this matters

• Scriptable — useful in CI, dotfiles, project setup scripts, Makefile targets
• Fast — single command vs opening TUI → /mcp → navigate → toggle → confirm
• Consistent — follows the existing codex mcp {add|remove|list|get} pattern
• Cross-surface — a CLI primitive that complements the TUI toggle and can be consumed by IDE extensions

Observations on feasibility

The enabled boolean field already exists in RawMcpServerConfig (see codex-rs/core/config.schema.json), and the codex mcp add command already reads/writes config.toml — so the building blocks appear to be in place. That said, the team is best positioned to decide on the right approach and scope.

Related

• #11765 — Manage MCP servers UX (general request)
• #12197 — TUI toggle for /mcp (in-session)
• #13056 — Per-project MCP server configuration
• #16045 — Bug with -c dot-notation overrides for MCP