FallbackSpec

Defined in: core/src/fallback.ts:64

A fallback named by PRESET id rather than hand-built: the endpoint, auth style, effort dialect and every measured quirk come from the presets table, so a consumer writes neither a baseUrl nor a model-spelling rule. A hand-built Provider is still accepted wherever a spec is.

Extends

PresetProviderConfig

Properties

apiKey

apiKey: string;

Defined in: core/src/providers/factory.ts:40

The credential: an API key for key/bearer presets, an ACCESS TOKEN for oauth ones. @providerkit/core/auth signs in and renews it.

Inherited from

PresetProviderConfig.apiKey

baseUrl?

optional baseUrl?: string;

Defined in: core/src/providers/factory.ts:50

Replaces the preset’s API root. For a vendor that gives each account its own host (Copilot: credential.baseUrl from the sign-in).

Inherited from

PresetProviderConfig.baseUrl

dataCollection?

optional dataCollection?: "allow" | "deny";

Defined in: core/src/providers/factory.ts:91

OpenRouter-only: provider.data_collection. "deny" keeps the request on hosts that don’t train on the prompt. Not zero retention: that is OpenRouter’s separate zdr. Absent = the account’s own setting. Never sent to another host.

Inherited from

PresetProviderConfig.dataCollection

effort?

optional effort?: "none" | "low" | "medium" | "high" | "max";

Defined in: core/src/providers/factory.ts:51

Inherited from

PresetProviderConfig.effort

fallbackOptions?

optional fallbackOptions?: FallbackOptions<Provider>;

Defined in: core/src/fallback.ts:94

Custom cooldown or telemetry options for the fallback pool.

Inherited from

PresetProviderConfig.fallbackOptions

fallbacks?

optional fallbacks?: readonly FallbackCandidate[];

Defined in: core/src/fallback.ts:88

Secondary and tertiary providers to try if this provider fails/exhausts: hand-built Providers, preset-id FallbackSpecs, or both.

Inherited from

PresetProviderConfig.fallbacks

fetchImpl?

optional fetchImpl?: (input, init?) => Promise<Response>;

Defined in: core/src/providers/factory.ts:95

MDN Reference

Parameters

Parameter	Type
`input`	`RequestInfo` \| `URL`
`init?`	`RequestInit`

Returns

Promise<Response>

Inherited from

PresetProviderConfig.fetchImpl

headers?

optional headers?: Record<string, string>;

Defined in: core/src/providers/factory.ts:56

Per-request headers (request ids, ChatGPT-Account-Id) on top of the preset’s static protocol headers.

Inherited from

PresetProviderConfig.headers

instanceSessionId?

optional instanceSessionId?: string;

Defined in: core/src/providers/factory.ts:67

The session id for a call without StreamOptions.sessionId, on a preset that sends one (opencode-go, opencode-zen, chatgpt). Absent, the provider mints its own when it is built. Pass one when you build the provider per attempt (withKeyPool, withToken): each build would mint a new id, and a gateway that pins a session to one upstream host then treats every call as a new session, re-routes it and misses its prompt cache. Every model in a chain sends the same one. A preset without a session header has nowhere to put it and ignores it.

Inherited from

PresetProviderConfig.instanceSessionId

maxTokens?

optional maxTokens?: number;

Defined in: core/src/providers/factory.ts:53

Output ceiling. The Anthropic shape requires one; adapters default it.

Inherited from

PresetProviderConfig.maxTokens

model?

optional model?: string;

Defined in: core/src/providers/factory.ts:43

Which model to run. Absent = the preset’s defaultModel; a preset without either throws rather than sending a request nobody chose.

Inherited from

PresetProviderConfig.model

models?

optional models?: readonly string[];

Defined in: core/src/providers/factory.ts:47

A model chain on this one endpoint and key: the first answers, the rest take over in order when it fails (quota, rate, outage). Wins over model and the preset’s rotation; fallbacks still run after the chain.

Inherited from

PresetProviderConfig.models

preset

preset:
  | "anthropic"
  | "openai"
  | "google"
  | "google-openai"
  | "deepseek"
  | "openrouter"
  | "groq"
  | "mistral"
  | "xai"
  | "together"
  | "fireworks"
  | "cerebras"
  | "moonshot"
  | "zhipu"
  | "minimax"
  | "minimax-openai"
  | "nvidia"
  | "perplexity"
  | "deepinfra"
  | "nebius"
  | "novita"
  | "chutes"
  | "siliconflow"
  | "volcengine"
  | "stepfun"
  | "digitalocean"
  | "crusoe"
  | "baseten"
  | "huggingface"
  | "zai"
  | "zai-openai"
  | "opencode-go"
  | "qwen"
  | "opencode-zen"
  | "kimi"
  | "kimi-openai"
  | "alibaba-coding-plan"
  | "qwen-token-plan-openai"
  | "alibaba"
  | "qwen-api"
  | "ollama"
  | "lmstudio"
  | "vllm"
  | "claude"
  | "chatgpt"
  | "grok"
  | "kimi-plan"
  | "github-copilot"
  | "antigravity";

Defined in: core/src/fallback.ts:65

projectId?

optional projectId?: string;

Defined in: core/src/providers/factory.ts:69

Google Antigravity (Cloud Code Assist) project id for the request envelope.

Inherited from

PresetProviderConfig.projectId

providerOrder?

optional providerOrder?: string[];

Defined in: core/src/providers/factory.ts:86

OpenRouter-only: preferred upstream hosts, in order. OpenRouter’s cache lives on the upstream host’s account and default routing hops hosts between rounds. Pinning keeps a conversation’s rounds (and their cache) on one host. Empty/absent = default routing.

Inherited from

PresetProviderConfig.providerOrder

serviceTier?

optional serviceTier?: ServiceTier;

Defined in: core/src/providers/factory.ts:94

Default service_tier for every call on the OpenAI and Responses shapes; StreamOptions.serviceTier wins. Anthropic and Gemini presets refuse it.

Inherited from

PresetProviderConfig.serviceTier

siteName?

optional siteName?: string;

Defined in: core/src/providers/factory.ts:81

App name for OpenRouter’s rankings, sent as X-Title. See siteUrl.

Inherited from

PresetProviderConfig.siteName

siteUrl?

optional siteUrl?: string;

Defined in: core/src/providers/factory.ts:77

App attribution for OpenRouter’s rankings. The site URL rides as HTTP-Referer, the app name as X-Title. Public, not secret. Sent on the OpenAI-compatible and Anthropic shapes (OpenRouter reads them for app attribution); the Gemini and Responses shapes ignore them. An explicit entry in headers always wins.

Inherited from

PresetProviderConfig.siteUrl

watchdog?

optional watchdog?: WatchdogOptions;

Defined in: core/src/fallback.ts:92

Watch every candidate separately. A silent candidate then times out and rotates; wrapping the completed pool would abort the whole chain instead. Fallback specs inherit this unless they set their own watchdog.

Inherited from

PresetProviderConfig.watchdog