WebAssembly API Reference

WebAssembly API Reference v1.16.0

Functions

createClient()

Create a new LLM client with simple scalar configuration.

This is the primary binding entry-point. All parameters except api_key are optional — omitting them uses the same defaults as ClientConfigBuilder.

Errors:

Returns LiterLlmError if the underlying HTTP client cannot be constructed, or if the resolved provider configuration is invalid.

Signature:

function createClient(apiKey: string, baseUrl?: string, timeoutSecs?: number, maxRetries?: number, modelHint?: string): DefaultClient

Example:

const result = createClient("value", "value", 42, 42, "value");

Parameters:

Name	Type	Required	Description
apiKey	string	Yes	The api key
baseUrl	string | null	No	The base url
timeoutSecs	number | null	No	The timeout secs
maxRetries	number | null	No	The max retries
modelHint	string | null	No	The model hint

Returns: DefaultClient

Errors: Throws Error with a descriptive message.

---

createClientFromJson()

Create a new LLM client from a JSON string.

The JSON object accepts the same fields as liter-llm.toml (snake_case).

Errors:

Returns LiterLlmError.BadRequest if json is not valid JSON or contains unknown fields.

Signature:

function createClientFromJson(json: string): DefaultClient

Example:

const result = createClientFromJson("value");

Parameters:

Name	Type	Required	Description
json	string	Yes	The json

Returns: DefaultClient

Errors: Throws Error with a descriptive message.

---

encodeDataUrl()

Encode bytes as a base64 data URL: data:<mime>;base64,<b64>.

mime defaults to IMAGE_PNG when null.

Signature:

function encodeDataUrl(bytes: Buffer, mime?: string): string

Example:

const result = encodeDataUrl(new Uint8Array([100, 97, 116, 97]), "value");

Parameters:

Name	Type	Required	Description
bytes	Buffer	Yes	The bytes
mime	string | null	No	The mime

Returns: string

---

decodeDataUrl()

Decode a base64 data URL into DecodedDataUrl.

Returns null for:

• Non-data URLs (strings that do not start with "data:").
• Malformed prefixes (missing ";base64," marker).
• Invalid base64 payloads.

The returned MIME string is extracted verbatim from the URL prefix — it is not validated or normalised.

Signature:

function decodeDataUrl(url: string): DecodedDataUrl | null

Example:

const result = decodeDataUrl("value");

Parameters:

Name	Type	Required	Description
url	string	Yes	The URL to fetch

Returns: DecodedDataUrl | null

---

registerCustomProvider()

Register a custom provider in the global runtime registry.

The provider will be checked before all built-in providers during model detection. If a provider with the same name already exists it is replaced.

Errors:

Returns an error if the config is invalid (empty name, empty base_url, or no model prefixes).

Signature:

function registerCustomProvider(config: CustomProviderConfig): void

Example:

registerCustomProvider(new CustomProviderConfig());

Parameters:

Name	Type	Required	Description
config	CustomProviderConfig	Yes	The configuration options

Returns: No return value.

Errors: Throws Error with a descriptive message.

---

unregisterCustomProvider()

Remove a previously registered custom provider by name.

Returns true if a provider with the given name was found and removed, false if no such provider existed.

Errors:

Returns an error if the custom-provider registry cannot be updated.

Signature:

function unregisterCustomProvider(name: string): boolean

Example:

const result = unregisterCustomProvider("value");

Parameters:

Name	Type	Required	Description
name	string	Yes	The name

Returns: boolean

Errors: Throws Error with a descriptive message.

---

capabilities()

Return the capability flags for a named provider.

Performs an O(n) linear scan over the embedded registry (165 entries). Returns an owned value so bindings can pass capability data without borrowing registry internals.

For unknown provider_name values the function returns an all-false sentinel so callers never need to handle Option.

Signature:

function capabilities(providerName: string): ProviderCapabilities

Example:

const result = capabilities("value");

Parameters:

Name	Type	Required	Description
providerName	string	Yes	The provider name

Returns: ProviderCapabilities

---

allProviders()

Return all provider configs from the registry.

Useful for tooling, documentation generation, or runtime enumeration. Returns the public ProviderConfig slice (without capability flags). To query capability flags for a specific provider use capabilities.

Signature:

function allProviders(): Array<ProviderConfig>

Example:

const result = allProviders();

Returns: Array<ProviderConfig>

Errors: Throws Error with a descriptive message.

---

complexProviderNames()

Return the set of complex provider names.

Complex providers require custom auth/routing logic beyond simple bearer tokens (e.g. AWS Bedrock SigV4, Vertex AI OAuth2).

The returned reference points into the static registry — no allocation.

Signature:

function complexProviderNames(): Array<string>

Example:

const result = complexProviderNames();

Returns: Array<string>

Errors: Throws Error with a descriptive message.

---

completionCost()

Calculate the estimated cost of a completion given a model name and token counts.

Returns null if the model is not present in the embedded pricing registry. Returns Some(cost_usd) otherwise, where the value is in US dollars.

When an exact model name match is not found, progressively shorter prefixes are tried by stripping from the last - or . separator. For example, gpt-4-0613 will match gpt-4 if no gpt-4-0613 entry exists.

Signature:

function completionCost(model: string, promptTokens: number, completionTokens: number): number | null

Example:

const result = completionCost("value", 42, 42);

Parameters:

Name	Type	Required	Description
model	string	Yes	The model
promptTokens	number	Yes	The prompt tokens
completionTokens	number	Yes	The completion tokens

Returns: number | null

---

completionCostWithCache()

Calculate the estimated cost of a completion, accounting for cached (cache-hit) prompt tokens billed at the provider’s discounted rate.

cached_tokens is the count of prompt tokens served from the provider’s prompt cache. It must be <= prompt_tokens (cached tokens are a subset of the prompt). The non-cached portion is billed at input_cost_per_token and the cached portion at cache_read_input_token_cost when the model has cache pricing; otherwise the entire prompt is billed at the regular input rate.

Returns null if the model is not present in the embedded pricing registry, mirroring completion_cost.

When the model has ModelPricing.tiers, the tier whose min_context_tokens is the highest value <= prompt_tokens supplies the input/output/cache rates for the whole call; models without tiers (or when prompt_tokens is below every tier threshold) use the base rates unchanged, matching the original flat-rate behaviour.

Signature:

function completionCostWithCache(model: string, promptTokens: number, cachedTokens: number, completionTokens: number): number | null

Example:

const result = completionCostWithCache("value", 42, 42, 42);

Parameters:

Name	Type	Required	Description
model	string	Yes	The model
promptTokens	number	Yes	The prompt tokens
cachedTokens	number	Yes	The cached tokens
completionTokens	number	Yes	The completion tokens

Returns: number | null

---

modelInfo()

Look up FFI-friendly pricing and capability metadata for a model.

Returns null if the model is not present in the active pricing registry. Uses the same exact-match-then-prefix-fallback resolution as model_pricing; unlike model_pricing, the result is an owned ModelInfo value safe to hand across the FFI boundary.

When a runtime catalog refresh has succeeded, this reflects the refreshed (overlay) catalog; otherwise it reflects the embedded catalog. See model_pricing for the embedded-only alternative.

Signature:

function modelInfo(model: string): ModelInfo | null

Example:

const result = modelInfo("value");

Parameters:

Name	Type	Required	Description
model	string	Yes	The model

Returns: ModelInfo | null

---

clear()

Remove all guardrails from the global registry.

Primarily useful in tests to reset state between test cases.

Panics:

Panics if the global registry lock is poisoned.

Signature:

function clear(): void

Example:

clear();

Returns: No return value.

---

checkBound()

Assert that current_len + incoming does not exceed limit.

Call this before appending incoming bytes to any buffer that must stay below limit. Returns Err(LiterLlmError.Streaming) on overflow and emits a tracing.warn! with context.

Signature:

function checkBound(context: string, currentLen: number, incoming: number, limit: number): void

Example:

checkBound("value", 42, 42, 42);

Parameters:

Name	Type	Required	Description
context	string	Yes	The context
currentLen	number	Yes	The current len
incoming	number	Yes	The incoming
limit	number	Yes	The limit

Returns: No return value.

Errors: Throws Error with a descriptive message.

---

installCatalogOverlayFromStr()

Install the overlay registry from a raw catalog JSON string, bypassing the network and disk cache entirely.

Parses and flattens catalog_json with the same registry_from_catalog_str logic used for the embedded catalog and the network refresh path, then atomically swaps it in as the active overlay. A parse failure returns CatalogRefreshError.Parse and leaves any existing overlay untouched.

This is primarily a testable seam: it lets tests exercise overlay installation and the embedded/overlay fallback behavior in completion_cost / model_info without a real network call.

Signature:

function installCatalogOverlayFromStr(catalogJson: string): void

Example:

installCatalogOverlayFromStr("value");

Parameters:

Name	Type	Required	Description
catalogJson	string	Yes	The catalog json

Returns: No return value.

Errors: Throws Error with a descriptive message.

---

clearCatalogOverlay()

Clear the overlay registry, reverting completion_cost, completion_cost_with_cache, and model_info to the embedded catalog.

Primarily a test seam (see install_catalog_overlay_from_str); also usable by long-running processes that want to abandon a runtime refresh.

Signature:

function clearCatalogOverlay(): void

Example:

clearCatalogOverlay();

Returns: No return value.

---

refreshCatalog()

Refresh the runtime catalog overlay per config.

• config.enabled == false: returns Ok(RefreshOutcome.Disabled) immediately. No network, filesystem, or overlay activity.

• A fresh on-disk cache (age < config.ttl_seconds) exists at the resolved cache path (config.cache_path, or a default under std.env.temp_dir()): read + flatten it and install the overlay, returning Ok(RefreshOutcome.FromCache). No network request is made.

• Otherwise: validate config.source_url uses https (CatalogRefreshError.InsecureUrl otherwise), fetch it, flatten it, install the overlay, best-effort write the raw JSON to the cache path (a cache write failure does not fail the refresh), and return Ok(RefreshOutcome.Fetched).

On any error return, the overlay is left untouched: the previously active registry (a prior successful overlay, or the embedded catalog if none was ever installed) remains in effect. This is what makes the feature air-gap-safe — an unreachable or invalid source_url never degrades completion_cost / model_info below embedded-catalog availability.

Signature:

function refreshCatalog(config: CatalogRefreshConfig): Promise<RefreshOutcome>

Example:

const result = await refreshCatalog(new CatalogRefreshConfig());

Parameters:

Name	Type	Required	Description
config	CatalogRefreshConfig	Yes	The configuration options

Returns: RefreshOutcome

Errors: Throws Error with a descriptive message.

---

Types

AssistantMessage

Assistant’s response to a user message.

Field	Type	Default	Description
content	AssistantContent | null	null	The assistant’s response: plain text, structured parts, or absent. null is valid when the model replies with tool calls only.
name	string | null	null	Optional name for the assistant.
toolCalls	Array<ToolCall> | null	\[\]	Tool calls the model wants to execute, if any.
refusal	string | null	null	Refusal reason, if the model declined to respond per safety policies.
functionCall	FunctionCall | null	null	Deprecated legacy function_call field; retained for API compatibility.
reasoningContent	string | null	null	Reasoning/thinking tokens returned by the provider, if any (e.g. DeepSeek R1, Qwen reasoning_content, or Anthropic extended thinking).

Methods

text()

Return the assistant’s textual response, concatenating all Text parts if the content is structured.

Returns null for Refusal-only or OutputImage-only responses.

Signature:

text(): string | null

Example:

const result = instance.text();

Returns: string | null

refusalText()

Return the refusal message, if the model declined to respond.

Checks both the top-level refusal field and any Refusal parts inside a structured content.

Signature:

refusalText(): string | null

Example:

const result = instance.refusalText();

Returns: string | null

reasoningText()

Return the model’s reasoning/thinking tokens, if the provider returned any.

Signature:

reasoningText(): string | null

Example:

const result = instance.reasoningText();

Returns: string | null

outputImages()

Return all AssistantPart.OutputImage parts in the response.

Signature:

outputImages(): Array<ImageUrl>

Example:

const result = instance.outputImages();

Returns: Array<ImageUrl>

outputAudio()

Return all AssistantPart.OutputAudio parts in the response.

Signature:

outputAudio(): Array<AudioContent>

Example:

const result = instance.outputAudio();

Returns: Array<AudioContent>

---

AudioContent

Audio content part for speech-capable models.

Field	Type	Default	Description
data	string	—	Base64-encoded audio data.
format	string	—	Audio format (e.g., “wav”, “mp3”, “ogg”).

---

AuthConfig

Auth configuration block.

Field	Type	Default	Description
authType	AuthType	—	Auth scheme classification.
envVar	string | null	null	Name of the environment variable that holds the API key (e.g. "OPENAI_API_KEY"). Holds the variable name, never the secret value.

---

BatchListQuery

Query parameters for listing batches.

Field	Type	Default	Description
limit	number | null	null	Maximum number of results to return. Defaults to 20.
after	string | null	null	Pagination cursor: return results after this batch ID.

---

BatchListResponse

Response from listing batches.

Field	Type	Default	Description
object	string	—	Object type (always "list").
data	Array<BatchObject>	\[\]	List of batch objects.
hasMore	boolean | null	null	Whether more results are available.
firstId	string | null	null	First batch ID in the result set (for pagination).
lastId	string | null	null	Last batch ID in the result set (for pagination).

---

BatchObject

A batch job object.

Field	Type	Default	Description
id	string	—	Unique batch ID.
object	string	—	Object type (always "batch").
endpoint	string	—	API endpoint (e.g., "/v1/chat/completions").
inputFileId	string	—	ID of the input file.
completionWindow	string	—	Completion window (e.g., "24h").
status	BatchStatus	BatchStatus.Validating	Current job status.
outputFileId	string | null	null	ID of the output file (present when completed).
errorFileId	string | null	null	ID of the error file (present if some requests failed).
createdAt	number	—	Unix timestamp of batch creation.
completedAt	number | null	null	Unix timestamp of completion (if completed).
failedAt	number | null	null	Unix timestamp of failure (if failed).
expiredAt	number | null	null	Unix timestamp of expiration (if expired).
requestCounts	BatchRequestCounts | null	null	Request processing counts.
metadata	unknown | null	null	Metadata attached to the batch.

---

BatchRequestCounts

Request processing counts for a batch.

Field	Type	Default	Description
total	number	—	Total requests in the batch.
completed	number	—	Completed requests.
failed	number	—	Failed requests.

---

BedrockConfig

AWS Bedrock configuration.

All fields are optional; anything left unset falls back to the standard AWS environment variables (AWS_DEFAULT_REGION / AWS_REGION, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN, BEDROCK_CROSS_REGION).

Field	Type	Default	Description
region	string | null	null	AWS region (e.g. "us-east-1").
crossRegionPrefix	string | null	null	Cross-region inference profile prefix (e.g. "us").
accessKeyId	string | null	null	Explicit AWS access key ID.
secretAccessKey	string | null	null	Explicit AWS secret access key.
sessionToken	string | null	null	Explicit AWS session token (temporary credentials).

---

CatalogRefreshConfig

Plain-data configuration for refresh_catalog.

Deliberately FFI/binding-friendly: no Duration or PathBuf, just primitives that translate directly across language boundaries.

Field	Type	Default	Description
enabled	boolean	false	Runtime catalog refresh is entirely opt-in: when false, refresh_catalog is a no-op that returns Ok(RefreshOutcome.Disabled) without touching the network, the filesystem, or the overlay registry.
sourceUrl	string	—	Source URL to fetch catalog.json from. Must be https. Defaults to DEFAULT_CATALOG_URL; configurable so self-hosted mirrors work.
ttlSeconds	number	86400	How long a cached catalog.json remains valid before a network refetch is attempted, in seconds.
cachePath	string | null	null	Filesystem path for the on-disk cache. null uses a default path under std.env.temp_dir().

Methods

default()

Signature:

static default(): CatalogRefreshConfig

Example:

const result = CatalogRefreshConfig.default();

Returns: CatalogRefreshConfig

---

ChatCompletionChunk

A streamed chunk of a chat completion response.

Field	Type	Default	Description
id	string	—	Unique identifier for this stream.
object	string	—	Always "chat.completion.chunk" from OpenAI-compatible APIs. Stored as a plain String so non-standard provider values do not fail parsing.
created	number	—	Unix timestamp of chunk creation.
model	string	—	Model used to generate the chunk.
choices	Array<StreamChoice>	\[\]	Streaming choices (delta updates).
usage	Usage | null	null	Token usage (typically only in the final chunk).
systemFingerprint	string | null	null	Fingerprint of the system configuration (OpenAI-specific).
serviceTier	string | null	null	Service tier used (OpenAI-specific).

---

ChatCompletionRequest

Chat completion request (compatible with OpenAI and similar APIs).

Field	Type	Default	Description
model	string	—	Model ID (e.g., "gpt-4o-mini", "claude-3-5-sonnet").
messages	Array<Message>	\[\]	Conversation history from oldest to newest.
temperature	number | null	null	Sampling temperature in \[0.0, 2.0\]. Higher increases randomness. Defaults to 1.0.
topP	number | null	null	Nucleus sampling parameter in \[0.0, 1.0\]. Lower is more focused.
n	number | null	null	Number of chat completions to generate. Defaults to 1.
stream	boolean | null	null	Whether to stream the response. Managed by the client layer — do not set directly.
stop	StopSequence | null	null	Stop sequence(s) that halt token generation.
maxTokens	number | null	null	Max output tokens. Different from max_completion_tokens in some providers.
presencePenalty	number | null	null	Presence penalty in \[-2.0, 2.0\]. Positive discourages repeated topics.
frequencyPenalty	number | null	null	Frequency penalty in \[-2.0, 2.0\]. Positive discourages repeated tokens.
logitBias	Record<string, number> | null	{}	Token bias map. Uses BTreeMap (sorted keys) for deterministic serialization order — important when hashing or signing requests.
user	string | null	null	User identifier for request tracking and abuse detection.
tools	Array<ChatCompletionTool> | null	\[\]	Tools the model can invoke.
toolChoice	ToolChoice | null	null	Tool usage mode (auto, required, none, or specific tool).
parallelToolCalls	boolean | null	null	Whether the model can call multiple tools in parallel. Defaults to true.
responseFormat	ResponseFormat | null	null	Output format constraint (text, JSON, JSON schema).
streamOptions	StreamOptions | null	null	Streaming options (e.g., include_usage).
seed	number | null	null	Random seed for reproducible outputs. Provider support varies.
reasoningEffort	ReasoningEffort | null	null	Reasoning effort level (minimal, low, medium, high, max) for extended-thinking models.
modalities	Array<Modality> | null	\[\]	Output modalities to request from the model. For OpenAI audio models, pass \["text", "audio"\]. Vertex AI / Gemini translates these to generationConfig.responseModalities (uppercase).
extraBody	unknown | null	null	Provider-specific extra parameters merged into the request body. Use for guardrails, safety settings, grounding config, etc.

---

ChatCompletionResponse

Chat completion response from the API.

Field	Type	Default	Description
id	string	—	Unique identifier for this response.
object	string	—	Always "chat.completion" from OpenAI-compatible APIs. Stored as a plain String so non-standard provider values do not break deserialization.
created	number	—	Unix timestamp of response creation.
model	string	—	Model used to generate the response.
choices	Array<Choice>	\[\]	List of completion choices.
usage	Usage | null	null	Token usage statistics.
systemFingerprint	string | null	null	Fingerprint of the system configuration (OpenAI-specific).
serviceTier	string | null	null	Service tier used (OpenAI-specific).

---

ChatCompletionTool

A tool the model can invoke (currently, all tools are functions).

Field	Type	Default	Description
toolType	ToolType	—	Tool type (always “function” in OpenAI spec).
function	FunctionDefinition	—	Function definition with name, description, and JSON schema parameters.

---

Choice

A single completion choice.

Field	Type	Default	Description
index	number	—	Index of this choice in the choices array.
message	AssistantMessage	—	The assistant’s message response.
finishReason	FinishReason | null	null	Why the model stopped generating (stop, length, tool_calls, content_filter, etc.).

---

ChunkMiddleware

A per-chunk transformation in the StreamPipeline.

Each middleware receives a typed chunk and returns Ok(Some(chunk)) to pass it through (optionally modified), Ok(None) to drop the chunk, or Err(e) to propagate a stream error.

The trait is object-safe so multiple middleware implementations can be chained inside StreamPipeline.

Methods

process()

Process a single chunk.

• Ok(Some(chunk)) — emit (possibly transformed) chunk.
• Ok(None) — drop this chunk silently.
• Err(e) — propagate as a stream error.

Signature:

process(chunk: ChatCompletionChunk): ChatCompletionChunk | null

Example:

const result = instance.process(new ChatCompletionChunk());

Parameters:

Name	Type	Required	Description
chunk	ChatCompletionChunk	Yes	The chat completion chunk

Returns: ChatCompletionChunk | null

Errors: Throws Error with a descriptive message.

---

CreateBatchRequest

Request to create a batch job.

Field	Type	Default	Description
inputFileId	string	—	ID of the uploaded input file (JSONL format).
endpoint	string	—	API endpoint (e.g., "/v1/chat/completions").
completionWindow	string	—	Completion window (e.g., "24h").
metadata	unknown | null	null	Optional metadata to attach to the batch.

---

CreateFileRequest

Request to upload a file.

Field	Type	Default	Description
file	string	—	Base64-encoded file data.
purpose	FilePurpose	FilePurpose.Assistants	Purpose for the file.
filename	string | null	null	Optional filename to associate with the upload.

---

CreateImageRequest

Request to create images from a text prompt.

Field	Type	Default	Description
prompt	string	—	Text description of the image to generate.
model	string | null	null	Model ID (e.g., "dall-e-3"). Optional; API may use default if unset.
n	number | null	null	Number of images to generate. Defaults to 1.
size	string | null	null	Image size (e.g., "1024x1024", "1792x1024").
quality	string | null	null	Image quality: "standard" or "hd".
style	string | null	null	Style: "natural" or "vivid" (DALL-E 3 only).
responseFormat	string | null	null	Response format: "url" or "b64_json".
user	string | null	null	User identifier for request tracking.

---

CreateResponseRequest

Request to create a structured response.

Field	Type	Default	Description
model	string	—	Model ID.
input	unknown	—	Input data to process (e.g., a document to extract from).
instructions	string | null	null	Instructions for processing the input.
tools	Array<ResponseTool> | null	\[\]	Available tools the model can use.
temperature	number | null	null	Sampling temperature in \[0.0, 2.0\]. Defaults to 1.0.
maxOutputTokens	number | null	null	Maximum output tokens.
metadata	unknown | null	null	Optional metadata.
stream	boolean | null	null	Whether to stream the response. Managed by the client layer — do not set directly.

---

CreateSpeechRequest

Request to generate speech audio from text.

Field	Type	Default	Description
model	string	—	Model ID (e.g., "tts-1", "tts-1-hd").
input	string	—	Text to synthesize into speech.
voice	string	—	Voice name (e.g., "alloy", "echo", "fable", "onyx", "nova", "shimmer").
responseFormat	string | null	null	Audio format (e.g., "mp3", "opus", "aac", "flac", "wav", "pcm").
speed	number | null	null	Playback speed in \[0.25, 4.0\]. Defaults to 1.0.

---

CreateTranscriptionRequest

Request to transcribe audio into text.

Field	Type	Default	Description
model	string	—	Model ID (e.g., "whisper-1").
file	string	—	Base64-encoded audio file data.
language	string | null	null	Language ISO-639-1 code (e.g., "en", "fr", "de"). Optional; model auto-detects.
prompt	string | null	null	Optional text to guide the model (improves accuracy for domain-specific terms).
responseFormat	string | null	null	Output format (e.g., "json", "text", "vtt", "srt", "verbose_json").
temperature	number | null	null	Sampling temperature in \[0.0, 1.0\]. Higher increases variability. Defaults to 0.

---

CustomProviderConfig

Configuration for registering a custom LLM provider at runtime.

Field	Type	Default	Description
name	string	—	Unique name for this provider (e.g., “my-provider”).
baseUrl	string	—	Base URL for the provider’s API (e.g., <https://api.my-provider.com/v1>).
authHeader	AuthHeaderFormat	—	Authentication header format.
modelPrefixes	Array<string>	—	Model name prefixes that route to this provider (e.g., \["my-"\]).

---

DecodedDataUrl

Result of decoding a data: URL — MIME type and the decoded byte payload.

Named struct (rather than a tuple) so polyglot bindings can extract decode_data_url with a typed return rather than a sanitized scalar.

Field	Type	Default	Description
mime	string	—	MIME type extracted from the URL prefix (verbatim, not normalised).
data	Buffer	—	Decoded base64 payload.

---

DefaultClient

Default client implementation backed by reqwest.

Sends requests to 165 LLM providers with automatic provider detection and per-request routing. The provider is resolved at construction time from model_hint (or defaults to OpenAI), but individual requests can override the provider via model name prefix (e.g. "anthropic/claude-3-5-sonnet" routes to Anthropic regardless of construction-time setting).

When the model prefix does not match any known provider, the construction-time provider is used as the fallback. This enables seamless migration between providers by changing only the model name.

The provider is stored behind an Arc so it can be shared cheaply into async closures and streaming tasks. Pre-computed auth headers and extra headers are cached at construction to avoid redundant encoding on every request.

Methods

fetchBatchForPolling()

Signature:

fetchBatchForPolling(batchId: string): Promise<BatchObject>

Example:

const result = await instance.fetchBatchForPolling("value");

Parameters:

Name	Type	Required	Description
batchId	string	Yes	The batch id

Returns: BatchObject

Errors: Throws Error with a descriptive message.

waitForBatch()

Poll a batch until it reaches a terminal status (Completed, Failed, Expired, Cancelled).

Uses exponential backoff with configurable initial interval, maximum interval, and backoff multiplier. Optionally supports a timeout that aborts polling if exceeded.

Errors:

Returns BatchWaitError.Failed if the batch reaches a failure terminal status. Returns BatchWaitError.Timeout if the configured timeout is exceeded. Returns BatchWaitError.Client for underlying client errors.

Signature:

waitForBatch(batchId: string, config: WaitForBatchConfig): Promise<BatchObject>

Example:

const result = await instance.waitForBatch("value", new WaitForBatchConfig());

Parameters:

Name	Type	Required	Description
batchId	string	Yes	The batch id
config	WaitForBatchConfig	Yes	The configuration options

Returns: BatchObject

Errors: Throws Error with a descriptive message.

---

DeleteResponse

Response from a delete operation.

Field	Type	Default	Description
id	string	—	ID of the deleted resource.
object	string	—	Object type.
deleted	boolean	—	Confirmation that the resource was deleted.

---

DeveloperMessage

Developer message (system-like message for Claude models).

Field	Type	Default	Description
content	string	—	Developer-specific instructions or context.
name	string | null	null	Optional name for the developer message source.

---

DocumentContent

PDF/document content part for vision-capable models.

Field	Type	Default	Description
data	string	—	Base64-encoded document data or URL.
mediaType	string	—	MIME type (e.g., “application/pdf”, “text/csv”).

---

EmbeddingObject

A single embedding vector.

Field	Type	Default	Description
object	string	—	Always "embedding" from OpenAI-compatible APIs. Stored as a plain String so non-standard provider values do not break deserialization.
embedding	Array<number>	—	The embedding vector. Providers may return this as a JSON float array or, when encoding_format: "base64" was requested, as a base64 string of little-endian f32 bytes. Base64 responses are decoded on read; this field always serializes back out as a JSON float array.
index	number	—	Index in the batch (corresponds to input order).

---

EmbeddingRequest

Embedding request.

Field	Type	Default	Description
model	string	—	Model ID (e.g., "text-embedding-3-small").
input	EmbeddingInput	EmbeddingInput.Single	Text or texts to embed.
encodingFormat	EmbeddingFormat | null	null	Output format: float (native) or base64.
dimensions	number | null	null	Requested embedding dimensions (if supported by the model).
user	string | null	null	User identifier for request tracking.

---

EmbeddingResponse

Embedding response.

Field	Type	Default	Description
object	string	—	Always "list" from OpenAI-compatible APIs. Stored as a plain String so non-standard provider values do not break deserialization.
data	Array<EmbeddingObject>	—	List of embeddings.
model	string	—	Model used to generate embeddings.
usage	Usage | null	/* serde(default) */	Token usage (input tokens only; embeddings have zero output tokens).

---

FileListQuery

Query parameters for listing files.

Field	Type	Default	Description
purpose	string | null	null	Filter by file purpose (e.g., "batch", "fine-tune").
limit	number | null	null	Maximum number of results to return. Defaults to 20.
after	string | null	null	Pagination cursor: return results after this file ID.

---

FileListResponse

Response from listing files.

Field	Type	Default	Description
object	string	—	Object type (always "list").
data	Array<FileObject>	\[\]	List of file objects.
hasMore	boolean | null	null	Whether more results are available.

---

FileObject

An uploaded file object.

Field	Type	Default	Description
id	string	—	Unique file ID.
object	string	—	Object type (always "file").
bytes	number	—	File size in bytes.
createdAt	number	—	Unix timestamp of file creation.
filename	string	—	Filename.
purpose	string	—	File purpose.
status	string | null	null	Processing status (e.g., "uploaded", "processed").

---

FunctionCall

Function call details.

Field	Type	Default	Description
name	string	—	Function name.
arguments	string	—	Arguments as a JSON string (parse with serde_json.from_str).

---

FunctionDefinition

Function definition exposed to the model.

Field	Type	Default	Description
name	string	—	Name of the function. Required and must be alphanumeric + underscores.
description	string | null	/* serde(default) */	Human-readable description explaining what the function does.
parameters	unknown | null	/* serde(default) */	JSON Schema defining the function’s parameters.
strict	boolean | null	/* serde(default) */	If true, enforce strict JSON schema validation for arguments.

---

FunctionMessage

Deprecated legacy function-role message body.

Field	Type	Default	Description
content	string	—	The extracted text content
name	string	—	The name

---

HealthChecker

Abstraction over a health probe strategy.

Implementors issue a lightweight probe against upstream (typically a provider base URL or named identifier) and report HealthStatus.

Methods

check()

Probe upstream and return its current HealthStatus.

The parameter is taken by value (String) so that implementations can move it into the returned future without a clone, making the 'static + Send bound on the future trivially satisfiable.

Signature:

check(upstream: string): Promise<HealthStatus>

Example:

const result = await instance.check("value");

Parameters:

Name	Type	Required	Description
upstream	string	Yes	The upstream

Returns: HealthStatus

---

Image

A single generated image, returned as either a URL or base64 data.

Field	Type	Default	Description
url	string | null	null	Image URL (if response_format was “url”).
b64Json	string | null	null	Base64-encoded image data (if response_format was “b64_json”).
revisedPrompt	string | null	null	The final prompt used to generate the image (DALL-E 3).

---

ImageUrl

An image URL reference with optional detail level for processing.

Field	Type	Default	Description
url	string	—	URL of the image (data URI or HTTP/HTTPS URL).
detail	ImageDetail | null	null	Detail level: low (512x512), high (2x2 tiles), or auto (model-selected).

---

ImagesResponse

Response containing generated images.

Field	Type	Default	Description
created	number	—	Unix timestamp of image creation.
data	Array<Image>	\[\]	List of generated images.

---

JsonSchemaFormat

JSON Schema specification for constrained output.

Field	Type	Default	Description
name	string	—	Name of the schema (must be unique in the request).
description	string | null	null	Description of what the schema represents.
schema	unknown	—	JSON Schema object defining the output structure.
strict	boolean | null	null	If true, enforce strict schema validation.

---

LlmBudgetConfig

Budget enforcement configuration.

Field	Type	Default	Description
globalLimit	number | null	null	Global spend limit in USD.
modelLimits	Record<string, number> | null	{}	Per-model spend limits in USD, keyed by model name.
enforcement	string | null	null	Enforcement mode: "hard" (reject over-budget requests) or "soft" (log only).

---

LlmCacheConfig

Response cache configuration.

Field	Type	Default	Description
maxEntries	number | null	null	Maximum number of cached entries.
ttlSeconds	number | null	null	Cache entry time-to-live, in seconds.
backend	string | null	null	Cache backend name (e.g. "memory", or an opendal scheme).
backendConfig	Record<string, string> | null	{}	Backend-specific configuration key/value pairs.

---

LlmConfig

Canonical configuration for an LLM client.

All fields except model are optional so that partially-specified configs (e.g. from environment-driven defaults) round-trip cleanly. Convert to a runtime client configuration via LlmConfig.into_client_builder.

temperature and max_tokens are request-time parameters rather than client-level settings; they are carried on this struct for callers to read when building individual requests, and are intentionally not mapped by LlmConfig.into_client_builder.

Field	Type	Default	Description
model	string	—	Model identifier (e.g. "gpt-4o", "bedrock/anthropic.claude-3-sonnet-20240229-v1:0").
apiKey	string | null	null	API key for authentication.
baseUrl	string | null	null	Override base URL. When set, all requests go here and provider auto-detection is skipped.
timeoutSecs	number | null	null	Request timeout, in seconds.
maxRetries	number | null	null	Maximum number of retries on 429 / 5xx responses.
temperature	number | null	null	Sampling temperature for requests built from this config.
maxTokens	number | null	null	Maximum number of tokens to generate for requests built from this config.
loadEnv	boolean | null	null	Automatically load the API key from the provider’s environment variable when no explicit key is provided (default: true).
headers	Record<string, string> | null	{}	Extra headers sent on every request.
providers	Array<LlmProviderConfig> | null	\[\]	Custom provider configurations, in addition to the built-in providers.
cache	LlmCacheConfig | null	null	Response cache configuration.
budget	LlmBudgetConfig | null	null	Budget enforcement configuration.
rateLimit	LlmRateLimitConfig | null	null	Per-model rate limiting configuration.
costTracking	boolean | null	null	Enable per-request cost tracking.
tracing	boolean | null	null	Enable OpenTelemetry-compatible tracing spans.
cooldownSecs	number | null	null	Cooldown duration after transient errors, in seconds.
healthCheckSecs	number | null	null	Background health check interval, in seconds.
bedrock	BedrockConfig | null	null	AWS Bedrock configuration (region, credentials, cross-region routing).

Methods

providers()

Get the custom provider configurations from this config.

Signature:

providers(): Array<LlmProviderConfig>

Example:

const result = instance.providers();

Returns: Array<LlmProviderConfig>

---

LlmProviderConfig

A custom provider configuration entry.

Field	Type	Default	Description
name	string	—	Provider name, used to key model prefix matching.
baseUrl	string	—	Base URL for the provider’s OpenAI-compatible API.
authHeader	string | null	null	Header name used to carry the API key (defaults to Authorization when unset).
modelPrefixes	Array<string>	\[\]	Model name prefixes routed to this provider (e.g. \["my-provider/"\]).

---

LlmRateLimitConfig

Per-model rate limiting configuration.

Field	Type	Default	Description
rpm	number | null	null	Requests per minute limit.
tpm	number | null	null	Tokens per minute limit.
windowSeconds	number | null	null	Rate limit window, in seconds.

---

ModelInfo

Public, FFI-friendly snapshot of a model’s pricing and capability metadata, projected from ModelPricing.

Unlike ModelPricing (which is excluded from binding generation), ModelInfo is an owned plain-data DTO safe to hand across the FFI boundary — see model_info.

Field	Type	Default	Description
inputCostPerToken	number	—	Cost in USD per input (prompt) token.
outputCostPerToken	number	—	Cost in USD per output (completion) token.
cacheReadInputTokenCost	number | null	null	Cost in USD per cached input token (cache hit / read).
cacheCreationInputTokenCost	number | null	null	Cost in USD per token written to the prompt cache.
inputCostPerAudioToken	number | null	null	Cost in USD per input audio token.
outputCostPerAudioToken	number | null	null	Cost in USD per output audio token.
outputCostPerReasoningToken	number | null	null	Cost in USD per reasoning (extended-thinking) output token.
maxTokens	number | null	null	Total context window size in tokens (input + output).
maxInputTokens	number | null	null	Maximum input (prompt) tokens accepted.
maxOutputTokens	number | null	null	Maximum output (completion) tokens the model can generate.
mode	string | null	null	Best-effort operating mode, e.g. "chat", "embedding".
supportsVision	boolean | null	null	The model accepts image input.
supportsFunctionCalling	boolean | null	null	The model supports tool / function calling.
supportsReasoning	boolean | null	null	The model supports extended-thinking / reasoning tokens.
supportsStructuredOutput	boolean | null	null	The model supports JSON-mode or response_format structured output.
supportsAudioInput	boolean | null	null	The model accepts audio input.
supportsAudioOutput	boolean | null	null	The model can generate audio output.
supportsPromptCaching	boolean | null	null	The model supports prompt caching.
tiers	Array<ModelTier>	\[\]	Context-tiered pricing overrides, sorted by ascending min_context_tokens. Empty when the model has flat pricing.

---

ModelObject

A model available from the API.

Field	Type	Default	Description
id	string	—	Model ID (e.g., "gpt-4o", "claude-3-5-sonnet").
object	string	—	Always "model" from OpenAI-compatible APIs. Stored as a plain String so non-standard provider values do not break deserialization. Defaults to empty when a provider omits the field.
created	number	—	Unix timestamp of model creation (or release date). Defaults to 0 when a provider omits it — DeepSeek and some other OpenAI-compatible providers do not return created from /v1/models.
ownedBy	string	—	Organization or entity that owns the model. Defaults to empty when a provider omits the field.

---

ModelTier

Public, FFI-friendly snapshot of a single context-window pricing tier, projected from PricingTier.

Field	Type	Default	Description
minContextTokens	number	—	The tier applies when the prompt/context token count is at least this value.
inputCostPerToken	number	—	Cost in USD per input (prompt) token within this tier.
outputCostPerToken	number	—	Cost in USD per output (completion) token within this tier.
cacheReadInputTokenCost	number | null	null	Cost in USD per cached input token within this tier.
cacheCreationInputTokenCost	number | null	null	Cost in USD per cache-write token within this tier.
inputCostPerAudioToken	number | null	null	Cost in USD per input audio token within this tier.
outputCostPerAudioToken	number | null	null	Cost in USD per output audio token within this tier.
outputCostPerReasoningToken	number | null	null	Cost in USD per reasoning output token within this tier.

---

ModelsListResponse

Response listing available models.

Field	Type	Default	Description
object	string	—	Always "list" from OpenAI-compatible APIs. Stored as a plain String so non-standard provider values do not break deserialization. Defaults to empty when a provider omits the field.
data	Array<ModelObject>	\[\]	List of available models.

---

ModerationCategories

Boolean flags for each moderation category.

Field	Type	Default	Description
sexual	boolean	—	Sexual content.
hate	boolean	—	Hate speech.
harassment	boolean	—	Harassment.
selfHarm	boolean	—	Self-harm content.
sexualMinors	boolean	—	Sexual content involving minors.
hateThreatening	boolean	—	Hate speech that threatens violence.
violenceGraphic	boolean	—	Graphic violence.
selfHarmIntent	boolean	—	Intent to self-harm.
selfHarmInstructions	boolean	—	Instructions for self-harm.
harassmentThreatening	boolean	—	Harassment that threatens violence.
violence	boolean	—	Non-graphic violence.

---

ModerationCategoryScores

Confidence scores for each moderation category.

Field	Type	Default	Description
sexual	number	—	Sexual content score.
hate	number	—	Hate speech score.
harassment	number	—	Harassment score.
selfHarm	number	—	Self-harm content score.
sexualMinors	number	—	Sexual content involving minors score.
hateThreatening	number	—	Hate speech that threatens violence score.
violenceGraphic	number	—	Graphic violence score.
selfHarmIntent	number	—	Intent to self-harm score.
selfHarmInstructions	number	—	Instructions for self-harm score.
harassmentThreatening	number	—	Harassment that threatens violence score.
violence	number	—	Non-graphic violence score.

---

ModerationRequest

Request to classify content for policy violations.

Field	Type	Default	Description
input	ModerationInput	ModerationInput.Single	Text or texts to check.
model	string | null	null	Model ID (e.g., "text-moderation-latest"). Optional; API uses default if unset.

---

ModerationResponse

Response from the moderation endpoint.

Field	Type	Default	Description
id	string	—	Unique identifier for this moderation request.
model	string	—	Model used for classification.
results	Array<ModerationResult>	—	Results for each input string.

---

ModerationResult

A single moderation classification result.

Field	Type	Default	Description
flagged	boolean	—	True if any category was flagged.
categories	ModerationCategories	—	Boolean flags for each moderation category.
categoryScores	ModerationCategoryScores	—	Confidence scores for each category.

---

OcrImage

An image extracted from an OCR page.

Field	Type	Default	Description
id	string	—	Unique image identifier within the document.
imageBase64	string | null	/* serde(default) */	Base64-encoded image data (if include_image_base64 was true).

---

OcrPage

A single page of OCR output.

Field	Type	Default	Description
index	number	—	Page index (0-based).
markdown	string	—	Extracted page content as Markdown.
images	Array<OcrImage> | null	/* serde(default) */	Embedded images extracted from the page (if include_image_base64 was true).
dimensions	PageDimensions | null	/* serde(default) */	Page dimensions in pixels, if available.

---

OcrRequest

An OCR request.

Field	Type	Default	Description
model	string	—	The model/provider to use (e.g. "mistral/mistral-ocr-latest").
document	OcrDocument	OcrDocument.Url	The document to process (URL or base64).
pages	Array<number> | null	\[\]	Specific pages to process (1-indexed). null means all pages.
includeImageBase64	boolean | null	null	Whether to include base64-encoded images of each processed page.

---

OcrResponse

An OCR response.

Field	Type	Default	Description
pages	Array<OcrPage>	—	Extracted pages in order.
model	string	—	Model/provider used for OCR.
usage	Usage | null	/* serde(default) */	Token usage, if reported by the provider.

---

PageDimensions

Page dimensions in pixels.

Field	Type	Default	Description
width	number	—	Width in pixels.
height	number	—	Height in pixels.

---

PromptTokensDetails

Breakdown of tokens used in the prompt portion of a request.

cached_tokens is included in Usage.prompt_tokens — it is not an additional charge on top of the prompt token count. When pricing supports a cache_read_input_token_cost, the cached portion is billed at the discounted rate and the remainder at the regular input rate.

Field	Type	Default	Description
cachedTokens	number	—	Cached tokens present in the prompt. Defaults to 0 when absent.
audioTokens	number	—	Audio input tokens present in the prompt. Defaults to 0 when absent.

---

ProviderCapabilities

Static capability flags for a provider.

Each flag indicates whether the provider’s models generally support that feature. For providers that aggregate many underlying models (e.g. Bedrock, OpenRouter, vLLM) the flags reflect the superset of available model capabilities — a flag being true means at least one model supports the feature, not every model.

All flags default to false so that newly added providers are safe.

Access via the crate-level capabilities function:

Field	Type	Default	Description
vision	boolean	—	The provider accepts image input in chat messages.
reasoning	boolean	—	The provider supports extended-thinking / reasoning tokens.
structuredOutput	boolean	—	The provider supports JSON-mode or response_format structured output.
functionCalling	boolean	—	The provider supports tool / function calling.
audioIn	boolean	—	The provider accepts audio as input.
audioOut	boolean	—	The provider can generate audio / TTS output.
videoIn	boolean	—	The provider accepts video as input.

---

ProviderConfig

Static configuration for a single provider entry in providers.json.

This struct deliberately does not include capability flags or streaming format, which are accessed via the capabilities function.

Field	Type	Default	Description
name	string	—	Provider identifier (matches the entry key in providers.json).
displayName	string | null	null	Human-readable provider name shown in UIs.
baseUrl	string | null	null	Base URL used as the default for this provider’s HTTP client.
auth	AuthConfig | null	null	Authentication scheme metadata (auth type + env var holding the key).
endpoints	Array<string> | null	null	Supported endpoint kinds (e.g. chat, embeddings).
modelPrefixes	Array<string> | null	null	Model-name prefixes claimed by this provider (e.g. \["gpt-", "o1-"\]).
paramMappings	Record<string, string> | null	null	Parameter key renaming for this provider. Each entry maps an OpenAI-spec field name (e.g. "max_completion_tokens") to the name this provider expects (e.g. "max_tokens"). Applied automatically by ConfigDrivenProvider.transform_request.

---

RerankRequest

Request to rerank documents by relevance to a query.

Field	Type	Default	Description
model	string	—	Model ID (e.g., "cohere/rerank-english-v3.0").
query	string	—	The search query.
documents	Array<RerankDocument>	\[\]	Documents to rerank.
topN	number | null	null	Return only the top N results. Optional.
returnDocuments	boolean | null	null	Include the document content in results. Defaults to false.

---

RerankResponse

Response from the rerank endpoint.

Field	Type	Default	Description
id	string | null	null	Unique identifier for this rerank request.
results	Array<RerankResult>	—	Reranked documents in order of relevance.
meta	unknown | null	/* serde(default) */	Optional metadata about the reranking operation.

---

RerankResult

A single reranked document with its relevance score.

Field	Type	Default	Description
index	number	—	Original document index in the input list.
relevanceScore	number	—	Relevance score in \[0, 1\]. Higher indicates more relevant.
document	RerankResultDocument | null	/* serde(default) */	Original document content (if return_documents was true).

---

RerankResultDocument

The text content of a reranked document, returned when return_documents is true.

Field	Type	Default	Description
text	string	—	Document text.

---

ResponseObject

Response from a structured response request.

Field	Type	Default	Description
id	string	—	Unique response ID.
object	string	—	Object type (e.g., "response").
createdAt	number	—	Unix timestamp of response creation.
model	string	—	Model used to generate the response.
status	string	—	Status (e.g., "succeeded", "failed").
output	Array<ResponseOutputItem>	\[\]	Output items from the response.
usage	ResponseUsage | null	null	Token usage.
error	unknown | null	null	Error details (if status is “failed”).

---

ResponseOutputItem

A single output item from the response.

Field	Type	Default	Description
itemType	string	—	Output type (e.g., "text", "object", "error").
content	unknown	—	Output content (flattened into the object).

---

ResponseTool

A tool available for the response request.

Field	Type	Default	Description
toolType	string	—	Tool type (e.g., “extractor”, “search”).
config	unknown	—	Tool configuration (flattened into the object).

---

ResponseUsage

Token usage for a response.

Field	Type	Default	Description
inputTokens	number	—	Input tokens used.
outputTokens	number	—	Output tokens used.
totalTokens	number	—	Total tokens used.

---

SearchRequest

A search request.

Field	Type	Default	Description
model	string	—	The model/provider to use (e.g. "brave/web-search", "tavily/search").
query	string	—	The search query string.
maxResults	number | null	null	Maximum number of results to return.
searchDomainFilter	Array<string> | null	\[\]	Domain filter — restrict results to specific domains.
country	string | null	null	Country code for localized results (ISO 3166-1 alpha-2, e.g., "US", "FR").

---

SearchResponse

A search response.

Field	Type	Default	Description
results	Array<SearchResult>	—	List of search results.
model	string	—	Model/provider that performed the search.

---

SearchResult

An individual search result.

Field	Type	Default	Description
title	string	—	Result title.
url	string	—	Result URL.
snippet	string	—	Text snippet or excerpt from the page.
date	string | null	/* serde(default) */	Publication or last-updated date, if available.

---

SpecificFunction

Name of the specific function to invoke.

Field	Type	Default	Description
name	string	—	Function name.

---

SpecificToolChoice

Directive to call a specific tool.

Field	Type	Default	Description
choiceType	ToolType	ToolType.Function	Tool type (always “function”).
function	SpecificFunction	—	The specific function to invoke.

---

StreamChoice

A streaming choice with incremental delta.

Field	Type	Default	Description
index	number	—	Index of this choice in the choices array.
delta	StreamDelta	—	Incremental update to the message (content, tool calls, etc.).
finishReason	FinishReason | null	null	Why the stream ended (present only in final chunk).

---

StreamDelta

Incremental delta in a stream chunk.

Field	Type	Default	Description
role	string | null	null	Role (typically present only in the first chunk).
content	string | null	null	Partial content chunk (e.g., a few words of the response).
toolCalls	Array<StreamToolCall> | null	\[\]	Partial tool calls being streamed.
functionCall	StreamFunctionCall | null	null	Deprecated legacy function_call delta; retained for API compatibility.
refusal	string | null	null	Partial refusal message.
reasoningContent	string | null	null	Partial reasoning/thinking tokens (OpenAI-compatible extension used by DeepSeek R1, Qwen, etc.).

---

StreamFunctionCall

Partial function call details in a stream.

Field	Type	Default	Description
name	string | null	null	Function name (typically in the first chunk).
arguments	string | null	null	Partial JSON arguments chunk.

---

StreamOptions

Options for streaming responses.

Field	Type	Default	Description
includeUsage	boolean | null	null	If true, include token usage in the final stream chunk.

---

StreamToolCall

A streaming tool call being built incrementally.

Field	Type	Default	Description
index	number	—	Index of this tool call in the tool_calls array.
id	string | null	null	Tool call ID (typically in the first chunk for this call).
callType	ToolType | null	null	Tool type (typically “function”).
function	StreamFunctionCall | null	null	Partial function name and arguments.

---

SystemMessage

System message guiding model behavior for the entire conversation.

Field	Type	Default	Description
content	UserContent	UserContent.Text	Instructions or context that apply throughout the conversation. Accepts either a plain text string or an array of content parts, mirroring UserContent so that Message.system_with_parts works.
name	string | null	null	Optional name for the system message source.

---

ToolCall

A tool call the model wants to execute.

Field	Type	Default	Description
id	string	—	Unique ID for this call, used to reference in tool result messages.
callType	ToolType	—	Tool type (always “function”).
function	FunctionCall	—	Function name and arguments.

---

ToolMessage

Tool execution result returned to the model.

Field	Type	Default	Description
content	UserContent	UserContent.Text	Result of the tool execution as plain text or an array of content parts (text, images, documents, audio), mirroring UserMessage.content. #\[serde(untagged)\] on UserContent means a bare JSON string still deserialises into Text, so tool results persisted before this field carried structured content continue to round-trip.
toolCallId	string	—	ID of the tool call this result responds to.
name	string | null	null	Optional tool/function name.

---

TranscriptionResponse

Response from a transcription request.

Field	Type	Default	Description
text	string	—	The transcribed text.
language	string | null	null	Detected language (ISO-639-1 code).
duration	number | null	null	Total audio duration in seconds.
segments	Array<TranscriptionSegment> | null	\[\]	Detailed segment-level transcription (if response_format is “verbose_json”).

---

TranscriptionSegment

A segment of transcribed audio with timing information.

Field	Type	Default	Description
id	number	—	Segment index (0-based).
start	number	—	Start time in seconds.
end	number	—	End time in seconds.
text	string	—	Transcribed text for this segment.

---

Usage

Token-usage accounting returned by the provider on each completion / embedding call.

Field	Type	Default	Description
promptTokens	number	—	Prompt tokens used. Defaults to 0 when absent (some providers omit this).
completionTokens	number	—	Completion tokens used. Defaults to 0 when absent (e.g. embedding responses).
totalTokens	number	—	Total tokens used. Defaults to 0 when absent (some providers omit this).
promptTokensDetails	PromptTokensDetails | null	null	Breakdown of tokens used in the prompt, including cached tokens served at the provider’s discounted cache-read rate. Absent when the provider does not return prompt-token details.

---

UserMessage

User message in the conversation.

Field	Type	Default	Description
content	UserContent	UserContent.Text	Message content as plain text or array of content parts (text, images, documents, audio).
name	string | null	null	Optional name for the user.

---

WaitForBatchConfig

Configuration for polling a batch until terminal status.

All time values are in seconds as f64 so the struct bridges across FFI boundaries without requiring a Duration shim.

Field	Type	Default	Description
initialIntervalSecs	number	5	Initial interval between polls, in seconds.
maxIntervalSecs	number	60	Maximum interval between polls (backoff plateau), in seconds.
backoffMultiplier	number	1.5	Exponential backoff multiplier (e.g., 1.5 increases delay by 50% each poll).
timeoutSecs	number | null	null	Optional timeout in seconds — polling fails if this duration is exceeded.

Methods

default()

Signature:

static default(): WaitForBatchConfig

Example:

const result = WaitForBatchConfig.default();

Returns: WaitForBatchConfig

---

Enums

Message

A chat message in a conversation.

Value	Description
System	System — Fields: 0: SystemMessage
User	User — Fields: 0: UserMessage
Assistant	Assistant — Fields: 0: AssistantMessage
Tool	Tool — Fields: 0: ToolMessage
Developer	Developer — Fields: 0: DeveloperMessage
Function	Deprecated legacy function-role message; retained for API compatibility. — Fields: 0: FunctionMessage

---

UserContent

User message content as either plain text or a list of multimodal parts.

Value	Description
Text	Plain text content. — Fields: 0: string
Parts	Array of content parts (text, images, documents, audio). — Fields: 0: Array<ContentPart>

---

ContentPart

A single content part in a user message — text, image, document, or audio.

Value	Description
Text	Plain text. — Fields: text: string
ImageUrl	Image identified by URL (with optional detail level). — Fields: imageUrl: ImageUrl
Document	Document file (PDF, CSV, etc.) as base64 or URL. — Fields: document: DocumentContent
InputAudio	Audio input as base64. — Fields: inputAudio: AudioContent

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ImageDetail

Image detail level controlling token cost and processing.

Value	Description
Low	Low detail: scales image to 512x512, uses fewer tokens.
High	High detail: processes up to 2x2 grid of tiles, higher token cost.
Auto	Auto: model chooses low or high based on image dimensions.

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AssistantContent

Content shape for assistant messages.

#[serde(untagged)] means providers returning a plain scalar string for the content field still deserialise correctly into AssistantContent.Text(_). Providers returning an array of typed parts (e.g. after an image-generation or audio-synthesis request) deserialise into AssistantContent.Parts(_).

Value	Description
Text	Plain text response (the common case for text-only models). — Fields: 0: string
Parts	Structured parts — text, refusals, output images, output audio. — Fields: 0: Array<AssistantPart>

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AssistantPart

One part of a structured assistant response.

#[serde(tag = "type", rename_all = "snake_case")] matches OpenAI’s parts-spec discriminator ("type": "text", "type": "output_image", …).

Value	Description
Text	A text segment of the response. — Fields: text: string
Refusal	A refusal — the model declined to respond. — Fields: refusal: string
OutputImage	An image produced by the model (e.g. gpt-image-1, Gemini Imagen). — Fields: imageUrl: ImageUrl
OutputAudio	Audio produced by the model (e.g. gpt-4o-audio-preview). — Fields: audio: AudioContent

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ToolType

The type discriminator for tool/tool-call objects.

Per the OpenAI spec this is always "function". Using an enum enforces that constraint at the type level and rejects any other value on deserialization.

Value	Description
Function	Function

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ToolChoice

Tool usage mode or a specific tool to call.

Value	Description
Mode	Predefined mode: auto, required, or none. — Fields: 0: ToolChoiceMode
Specific	Force a specific tool to be called. — Fields: 0: SpecificToolChoice

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ToolChoiceMode

Tool choice mode.

Value	Description
Auto	Model may or may not call tools; default behavior.
Required	Model must call at least one tool.
None	Model must not call any tools.

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ResponseFormat

Wire format for the chat completions response_format field.

Provider mapping

• OpenAI (and OpenAI-compatible providers): emitted verbatim as {"type": "json_schema", "json_schema": {...}} per the chat-completions spec.

• Gemini / Vertex AI: translated to generationConfig.responseMimeType = "application/json" and generationConfig.responseSchema = <schema>. The name, description, and strict fields are dropped — Gemini’s structured-output API does not consume them.

• Anthropic: no native JSON mode. A system instruction is prepended asking the model to respond with valid JSON. strict is advisory only; callers should still validate the returned JSON if the schema is load-bearing.

Value	Description
Text	Plain text output (default).
JsonObject	Output must be valid JSON object (no schema validation).
JsonSchema	Output must conform to the specified JSON schema. — Fields: jsonSchema: JsonSchemaFormat

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StopSequence

Stop sequence(s) that cause the model to stop generating.

Value	Description
Single	Single stop sequence. — Fields: 0: string
Multiple	Multiple stop sequences. — Fields: 0: Array<string>

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Modality

Output modality requested from the model.

Passed as modalities: ["text", "audio"] (OpenAI) or translated to generationConfig.responseModalities (Gemini / Vertex AI).

Value	Description
Text	Text output (the default for all providers).
Audio	Audio / speech output.
Image	Image output (Gemini Imagen, gpt-image-1).

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FinishReason

Why a choice stopped generating tokens.

Value	Description
Stop	Stop
Length	Length
ToolCalls	Tool calls
ContentFilter	Content filter
FunctionCall	Deprecated legacy finish reason; retained for API compatibility.
Other	Catch-all for unknown finish reasons returned by non-OpenAI providers. Note: this intentionally does not carry the original string (e.g. Other(String)). Using #\[serde(other)\] requires a unit variant, and switching to #\[serde(untagged)\] would change deserialization semantics for all variants. The original value can be recovered by inspecting the raw JSON if needed.

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ReasoningEffort

Controls how much reasoning effort the model should use.

Value	Description
Low	Low
Medium	Medium
High	High
Minimal	Minimal
Max	Max

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EmbeddingFormat

The format in which the embedding vectors are returned.

Value	Description
Float	32-bit floating-point numbers (default).
Base64	Base64-encoded string representation of the floats.

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EmbeddingInput

Text or texts to embed.

Value	Description
Single	Single text string. — Fields: 0: string
Multiple	Multiple text strings (batch embedding). — Fields: 0: Array<string>

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ModerationInput

Input to the moderation endpoint — a single string or multiple strings.

Value	Description
Single	Single text string. — Fields: 0: string
Multiple	Multiple text strings (batch moderation). — Fields: 0: Array<string>

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RerankDocument

A document to be reranked — either a plain string or an object with a text field.

Value	Description
Text	Plain text document content. — Fields: 0: string
Object	Document with explicit text field (may include metadata). — Fields: text: string

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OcrDocument

Document input for OCR — either a URL or inline base64 data.

Value	Description
Url	A publicly accessible document URL. — Fields: url: string
Base64	Inline base64-encoded document data. — Fields: data: string, mediaType: string

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FilePurpose

Purpose of an uploaded file.

Value	Description
Assistants	File for use with Assistants API.
Batch	File for batch processing.
FineTune	File for fine-tuning.
Vision	File for vision/image tasks.

---

BatchStatus

Status of a batch job.

Value	Description
Validating	Validating the input file.
Failed	Job failed.
InProgress	Job is running.
Finalizing	Finalizing results.
Completed	Job completed successfully.
Expired	Job expired before completion.
Cancelling	Job is being cancelled.
Cancelled	Job has been cancelled.

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AuthHeaderFormat

How the API key is sent in the HTTP request.

Value	Description
Bearer	Bearer token: Authorization: Bearer <key>
ApiKey	Custom header: e.g., X-Api-Key: <key> — Fields: 0: string
None	No authentication required.

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StreamFormat

The streaming wire format a provider uses for its response stream.

Most providers use standard Server-Sent Events (SSE). AWS Bedrock uses a proprietary binary EventStream framing.

Deserialized from the streaming_format JSON field via serde.

Value	Description
Sse	Standard Server-Sent Events (text/event-stream).
AwsEventStream	AWS EventStream binary framing (application/vnd.amazon.eventstream).

---

AuthType

Auth scheme used by a provider.

Value	Description
Bearer	Standard Authorization: Bearer <key> header.
ApiKey	x-api-key: <key> header (also handles "header" and "x-api-key" aliases).
None	No authentication header required.
Unknown	Unrecognised auth scheme — falls back to bearer.

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RefreshOutcome

Result of a refresh_catalog call.

Value	Description
Disabled	config.enabled was false; no network, filesystem, or overlay activity occurred.
FromCache	The on-disk cache was fresh (age < ttl_seconds); the overlay was installed from the cached file without a network request.
Fetched	The catalog was fetched over the network, the cache file was (best-effort) refreshed, and the overlay was installed from the fetched catalog.

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Errors

LiterLlmError

All errors that can occur when using liter-llm.

Errors are thrown as plain Error objects with descriptive messages.

Variant	Description
Authentication	status preserves the exact HTTP status code received (401 or 403).
RateLimited	rate limited: {message}
BadRequest	status preserves the exact HTTP status code received (400, 405, 413, 422, …).
ContextWindowExceeded	context window exceeded: {message}
ContentPolicy	content policy violation: {message}
NotFound	not found: {message}
ServerError	status preserves the exact HTTP status code received (500, or other 5xx not covered by ServiceUnavailable).
ServiceUnavailable	status preserves the exact HTTP status code received (502, 503, or 504).
Timeout	request timeout
Streaming	A catch-all for errors that occur during streaming response processing. This variant covers multiple sub-conditions including UTF-8 decoding failures, CRC/checksum mismatches (AWS EventStream), JSON parse errors in individual SSE chunks, and buffer overflow conditions. The message field contains a human-readable description of the specific failure.
EndpointNotSupported	provider {provider} does not support {endpoint}
InvalidHeader	invalid header {name:?}: {reason}
Serialization	serialization error: {0}
BudgetExceeded	budget exceeded: {message}
HookRejected	hook rejected: {message}
InternalError	An internal logic error (e.g. unexpected Tower response variant). This should never surface in normal operation — if it does, it indicates a bug in the library.
OutboundForbidden	An outbound request was blocked by the active OutboundPolicy. Returned when register_custom_provider is called with a base_url that violates the policy (e.g. a private-range IP under DenyPrivate), or when the per-connection DNS resolver detects a forbidden address at connect time.
IdempotencyConflict	A different request body was submitted for an existing Idempotency-Key. Per the OpenAI Idempotency-Key convention, once a key is used with a particular request body, subsequent requests using the same key must carry an identical body. A body mismatch is a hard error (not retryable). HTTP equivalent: 409 Conflict.
IdempotencyInFlight	The same Idempotency-Key is already in-flight (another request with the same key is currently being processed). The caller should wait briefly and retry. The response is not yet available, and this request has been short-circuited to avoid running the operation twice. HTTP equivalent: 409 Conflict (retryable after a brief delay).

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CatalogRefreshError

Errors from refresh_catalog and install_catalog_overlay_from_str.

On every variant, the overlay registry is left untouched: a previously installed overlay (or the embedded catalog, if none was ever installed) remains active. This is the air-gap-safety contract — a failed refresh never degrades pricing/model-info availability.

Errors are thrown as plain Error objects with descriptive messages.

Variant	Description
Disabled	Runtime catalog refresh was not enabled. refresh_catalog itself never returns this — it returns Ok(RefreshOutcome.Disabled) instead — but the variant is part of the public error surface for callers that want to treat “disabled” as a hard error.
InsecureUrl	source_url did not use the https scheme, or failed to parse as a URL at all. There is no host allowlist: the URL is user-configurable for self-hosted catalog mirrors, so only the scheme is enforced.
Fetch	The network fetch failed, timed out, or returned a non-success status.
Parse	The fetched or cached catalog JSON failed to parse.
Cache	A cache file read failed on an otherwise-fresh cache file. Cache write failures are best-effort and never surface as this error (see refresh_catalog).

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