pi-openai-service-tier

Cost-correct OpenAI service tier / fast mode for pi.

Most fast-mode extensions only patch the outgoing JSON payload:

{ service_tier: "priority" }

That can route the request correctly, but Pi's displayed cost accounting uses its internal provider option named serviceTier. This extension wraps Pi's built-in OpenAI provider calls and passes:

{ ...options, serviceTier: "priority" }

So Pi gets both the OpenAI request field and the matching Pi-side service-tier cost multiplier.

Features

• /fast toggles cost-correct priority tier.
• /openai-tier selects priority, flex, default, auto, or scale.
• Works with Pi's OpenAI Responses and OpenAI Codex Responses providers.
• Avoids sending tiers that a provider does not support.
• Includes gpt-5.4 and gpt-5.5 OpenAI/Codex models by default.
• Does not change model, reasoning level, prompts, tools, or text.verbosity.
• Does not make network calls of its own.
• Stores simple JSON config with project-over-global precedence.

Install

pi install npm:pi-openai-service-tier

GitHub install also works:

pi install https://github.com/anirudhmehra/pi-openai-service-tier

Then start Pi normally:

pi --provider openai-codex --model gpt-5.5

Enable priority tier at startup:

pi --provider openai-codex --model gpt-5.5 --fast

Try without installing:

pi -e npm:pi-openai-service-tier --provider openai-codex --model gpt-5.5 --fast

Commands

Fast mode

/fast
/fast on
/fast off
/fast status

/fast toggles priority service tier on/off.

Explicit service tier

/openai-tier priority
/openai-tier flex
/openai-tier default
/openai-tier auto
/openai-tier scale
/openai-tier off
/openai-tier status

/openai-tier <tier> enables that tier for supported models.

Configuration

The extension uses project-over-global config:

<repo>/.pi/extensions/pi-openai-service-tier.json
~/.pi/agent/extensions/pi-openai-service-tier.json

If neither file exists, the extension creates this global default on session start:

{
  "persistState": true,
  "active": false,
  "serviceTier": "priority",
  "supportedModels": [
    "openai/gpt-5.4",
    "openai/gpt-5.5",
    "openai-codex/gpt-5.4",
    "openai-codex/gpt-5.5"
  ]
}

Config fields

Field	Type	Default	Description
persistState	boolean	true	Whether /fast and /openai-tier persist state across sessions.
active	boolean	false	Whether a service tier is active.
serviceTier	priority | flex | default | auto | scale	priority	Service tier passed to Pi's OpenAI provider option when supported by the current provider.
supportedModels	string[]	see above	Allow-list of provider/model-id pairs that should receive serviceTier.

Add/remove allow-listed models by editing supportedModels.

Supported providers/APIs

The extension applies tiers only when all of these are true:

1. the model appears in supportedModels,
2. the model uses one of these Pi APIs:
   • openai-responses
   • openai-codex-responses, and
3. the selected tier is supported by that API.

Provider-specific tier support:

Pi API	Supported tiers
openai-responses	priority, flex, default, auto, scale
openai-codex-responses	priority

If a tier is configured but unsupported by the current model/provider, the extension leaves serviceTier unset for that request instead of sending an invalid value.

Compatibility notes

This extension overrides Pi's API stream handlers for:

• openai-responses
• openai-codex-responses

It delegates back to Pi's built-in OpenAI implementations, adding serviceTier only for configured/supported OpenAI models. If another extension also overrides those API handlers, whichever extension loads last wins.

Requires Pi / @mariozechner/pi-ai >=0.72.1 and Node.js >=22.

Updating

For npm installs:

pi update npm:pi-openai-service-tier

For git installs, re-run:

pi install https://github.com/anirudhmehra/pi-openai-service-tier

Uninstall

pi remove npm:pi-openai-service-tier

or, if installed from git:

pi remove https://github.com/anirudhmehra/pi-openai-service-tier

If desired, remove config files manually:

rm -f ~/.pi/agent/extensions/pi-openai-service-tier.json
rm -f .pi/extensions/pi-openai-service-tier.json

Development

git clone https://github.com/anirudhmehra/pi-openai-service-tier.git
cd pi-openai-service-tier
npm install
npm run check

Local Pi smoke test:

pi -e ./index.ts --list-models
pi -e ./index.ts --provider openai-codex --model gpt-5.5 --fast

Security

Pi extensions run with your local user permissions. This extension only reads/writes its config JSON files and delegates LLM calls to Pi's built-in OpenAI providers; it does not perform independent network requests.

License

MIT