| .. | ||
| tests | ||
| index.ts | ||
| README.md | ||
| state.ts | ||
OpenAI Codex fast mode
Adds /fast for Pi's openai-codex provider and openai-codex-responses API.
When enabled, the extension adds service_tier: "priority" to matching requests.
It keeps the selected model, reasoning level, tools, and conversation input.
Usage
/fasttoggles fast mode./fast onrequests priority service. Usage may increase./fast offstops this extension's override and restores provider defaults./fast statusreports the setting without changing it.
New sessions start with fast mode off. Changes are stored as custom session entries, outside model context. Resume and reload restore the active branch's setting. Forks inherit only settings before the fork point. Switching to another provider makes the setting inactive; switching back to Codex reactivates it. Changes require an idle session. Status reports remain available during a turn.
The footer shows Codex fast: priority while this extension requests priority
service. This shows the requested tier, not confirmation from OpenAI.
Availability and usage
OpenAI controls priority access for each model and account. Priority service can increase subscription usage or cost. The extension does not change reasoning settings, query Codex's model catalog, verify account eligibility, or guarantee faster responses. Unlike the Codex CLI, it does not hide the command for models without an advertised fast tier. API failures use Pi's normal error handling; the extension does not silently retry with another tier.
Other providers are untouched, including openai, OpenRouter, and providers
that reuse the Codex API under another name. While enabled, this extension
replaces any existing service_tier value with priority. Disabling it leaves
native request settings and other extensions' overrides unchanged.
Your openai-server-compaction extension can remain enabled. Both request
patches preserve unrelated fields. Fast mode applies to normal session requests,
not the compaction extension's separate HTTP compaction or summary calls.
Installation
Home Manager deploys this directory through rsydn.aiTools.piExtensions along
with the other extensions. Apply your usual dotfiles rebuild, then run /reload.
To test before deploying:
pi -e ./pi/extensions/openai-codex-fast/index.ts
Codex implementation reference
Reviewed OpenAI Codex commit
1a69ad3237fc.
- Service-tier UI toggles the model's advertised Fast tier and persists the selection.
- Model catalog
identifies Fast with the request value
priority. - Request builder
sends the selected tier in
service_tier.
Pi's before_provider_request hook changes the native payload. No provider
replacement, custom transport, or additional runtime dependency is required.
Tests
Requires Node.js 22.19 or newer and an installed pi executable. Tested with
Pi 1.1.0.
node --experimental-strip-types --test \
pi/extensions/openai-codex-fast/tests/*.test.ts \
pi/extensions/openai-codex-fast/tests/*.test.cjs
Unit tests cover scope, payload preservation, branch state, and both compaction patch orders. The runtime test uses Pi's real loader and native providers with a local HTTP fixture. It checks outgoing payloads, commands, the idle guard, provider switching, resume, and forks. It sends no requests to OpenAI and uses no real credentials.