Feature request: expose native composer suggestion hooks/API for local plugins

Summary

Codex local plugins can currently package skills, apps, MCP servers, and install-surface metadata, but there does not appear to be a public plugin API for intercepting native composer typing events and rendering realtime suggestion UI inside the desktop app's input box.

This blocks a class of plugins that are specifically about in-composer guidance, autocomplete, prompt coaching, and adaptive keyword suggestion.

Concrete use case

I built a local Codex plugin called oh-oh-oh that helps users choose better Codex keywords from natural-language prompts.

The plugin already supports:

• local installation through marketplace + plugin cache
• skill-based invocation
• local personalization based on accepted keyword history
• realtime keyword recommendation logic in the plugin runtime

What I cannot do with the current public surface is the most important part of the UX:

• detect when the user pauses while typing in the native Codex desktop composer
• show a ranked suggestion deck directly under the input box
• let the user click a suggestion to prepend it to the prompt
• hide suggestions that were already accepted

Why this matters

This is especially useful for newer users who do not know professional Codex keywords or prompt prefixes yet.

Example:

• User types: 鎴戞兂鐪嬬湅浠ｇ爜鏈夊摢浜涘啑浣欑殑
• Plugin should be able to suggest something like code review or another appropriate built-in keyword/prefix
• If the user accepts it, Codex should insert that prefix at the beginning of the prompt

Without a native composer suggestion API, plugin authors can only approximate this via:

• explicit skill invocation
• external prototype UIs
• separate helper commands

Those workarounds are useful, but they do not solve the real in-context onboarding problem.

Current limitation observed

From the currently published Codex docs, local plugins appear to support:

• skills
• apps/connectors
• MCP servers
• install and discovery metadata such as defaultPrompt, composerIcon, and logo

However, I could not find a public API for:

• composer input change events
• pause/debounce hooks for the native input field
• plugin-owned suggestion rows under the composer
• accepting a suggestion and programmatically rewriting the current draft

features.codex_hooks also appears to be about lifecycle hooks and is marked as under development, not as a composer extension API.

Requested capability

Please expose a supported plugin API for native composer augmentation in Codex desktop, for example:

1. Read-only access to the current draft text in the composer
2. Debounced onInputChanged or onPause events
3. A way for plugins to return ranked suggestion items with labels, descriptions, and insertion behavior
4. A safe API to prepend, replace, or insert suggestion text into the current draft
5. A way to hide or invalidate suggestions after acceptance
6. Optional telemetry hooks so plugins can learn from accepted suggestions locally

Suggested design constraints

• Keep this API local-first so plugins do not need to exfiltrate draft text
• Make suggestion rendering clearly attributed to the plugin
• Provide user controls to disable a plugin's composer suggestions
• Limit mutation scope so plugins can only edit the active draft, not arbitrary thread history
• Consider rate limits / debounce guidance to avoid noisy or expensive suggestion loops

Impact

Opening this API would unlock an important category of Codex-native productivity plugins:

• prompt keyword coaches
• onboarding assistants
• repo-aware command recommenders
• code-review prompt helpers
• test/debug prompt suggestions
• adaptive workflow hints for new users

Right now, plugin authors can package the recommendation logic, but not the UX surface where that logic is most valuable.

Environment used while investigating

• Codex desktop on Windows
• local plugin installed and enabled through ~/.agents/plugins/marketplace.json
• plugin enabled in ~/.codex/config.toml
• plugin loaded from ~/.codex/plugins/cache/.../local

The plugin installation itself works correctly. The missing piece is the public native composer extension surface.