Signal · reference

Signal, to look up

The files the package ships and every example. Each example runs in this page, on the package version shown in the bar above.

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README.md DOCS.md DESIGN.md CHANGELOG.md

API

The package’s exports: createSignal (the client), defineTool (a tool definition), SignalError (the error class) and providerRegistry (the providers known by name).

createSignal defineTool SignalError providerRegistry

Methods

The methods of a signal, the client createSignal returns. A method that sets an option returns a new signal and leaves the one it was called on unchanged.

signal.complete signal.schema signal.stream signal.history signal.describe signal.count signal.embed signal.decide

Structured output

How a schema is sent to the provider, by provider capability: as a JSON Schema response_format, as JSON mode with the schema in a system message, or as the system message alone. The response is validated against the Zod schema in every case.

JSON mode fallback Structured output with tools

Validation and retries

How a response is validated against the schema: JSON extraction, retries with the validation error, and the error when retries run out.

JSON extraction from prose Retry on validation failure (onRetry)Retries exhausted (E_VALIDATION_FAILED)

Tool calling

Functions the model can call. Signal runs the tool call loop: it validates the arguments, runs the function and sends the tool result to the model, and a tool call that fails is reported to the model as its tool result.

Tool call loop Invalid tool arguments Iteration limit (E_MAX_ITERATIONS)