pi-inferhub

A Pi extension that registers the InferHub inference provider with Pi, exposing your InferHub combos as selectable chat models.

InferHub pools AI subscriptions behind one OpenAI-compatible endpoint. Combos are its server-side routed bundles — failover, cache-sticky, billed in USDC — and they are the primary consumption surface. This extension exposes combos only: each combo on your account appears as exactly one model named combo/<slug>. Upstream prefix/model entries, bare-name aliases, and free-tier models from InferHub's model list are intentionally not exposed.

Install

Add the package to your Pi settings:

// ~/.pi/agent/settings.json
{
	"packages": ["npm:pi-inferhub"]
}

or run pi install npm:pi-inferhub.

For local development against a checkout:

pi -e /path/to/pi-inferhub

Auth

Either:

• set INFERHUB_API_KEY in your environment (sk-airo-…), or
• run /login inferhub and paste the key at the prompt.

/login inferhub prompts for the key (input is masked), validates it against GET https://inferhub.dev/api/me, and only then hands it to Pi's credential store (auth.json). A rejected key (HTTP 401) notifies you and re-prompts; after three failed attempts the login aborts without storing anything.

When both exist, the stored credential wins; INFERHUB_API_KEY is the fallback when nothing is stored.

/inferhub-login reports whether the provider is currently configured and points you to /login inferhub if not.

Model selection

Send /model and filter by provider name inferhub or by combo/. Each model id is combo/<slug> — the routable inference name on https://api.inferhub.dev/v1.

Catalog derivation

On refresh the extension makes two authenticated GETs — GET https://inferhub.dev/api/combos (the account's combos) and GET https://api.inferhub.dev/v1/models (per-model metadata) — and maps each combo to one model:

• Context/output limits — minimum across resolvable members (input_token_limit / max_output_tokens), so a combo is only as large as its smallest member. When no resolvable member supplies limits, conservative fallbacks apply: 128k context / 8k max output.
• Image input — offered (text + image) only when every resolvable member's modality includes image; otherwise text-only.
• Reasoning — the combo is marked reasoning-capable when any resolvable member advertises reasoning_levels; Pi's thinking levels map onto the advertised ladder (levels a combo doesn't advertise are unavailable).
• Cost — per-direction minimum of resolvable members' official rates (see below). cacheRead/cacheWrite are shown as 0: the catalog carries no per-combo cache pricing, and none is fabricated.

Combos whose members are all unresolvable aliases get safe defaults: text-only, reasoning-capable, 0 cost, and the fallback limits.

Refresh semantics

The catalog is fetched on demand via the provider's fetchModels; the extension keeps no snapshot of its own. Every refresh hits both endpoints live, so combos added, removed, or changed server-side appear on the next refresh instead of being served stale. When no credential is configured the refresh is a no-op returning an empty list — no unauthenticated upstream call and no silent fake catalog.

[!NOTE] Pi refreshes provider model catalogs in TUI and RPC modes; other non-interactive modes use the latest persisted catalog. Open the TUI to discover new combos.

Cost estimates

The per-model cost is an upper-bound estimate: the cheapest resolvable member's official list rates (official_in / official_out) per direction. InferHub's marketplace bills below list, so the real usage.cost reported per request comes in at or under the displayed estimate.

Design rationale

The full design — why combos only, why /v1/models supplies member metadata instead of the management /catalog endpoint, why the OpenAI completions surface, and the conservative-defaults philosophy — is in the design spec.

Development

npm install
npm test          # vitest
npm run typecheck

License

MIT