import { Effect, JsonSchema, Schema } from "effect" import type { ToolCallPart, ToolDefinition as ToolDefinitionClass } from "./schema" import { ToolDefinition, ToolFailure } from "./schema" /** * Schema constraint for tool parameters / success values: no decoding or * encoding services are allowed. Tools should be self-contained — anything * beyond pure data conversion belongs in the handler closure. */ export type ToolSchema = Schema.Codec export interface ToolExecuteContext { readonly id: ToolCallPart["id"] readonly name: ToolCallPart["name"] } export type ToolExecute, Success extends ToolSchema> = ( params: Schema.Schema.Type, context?: ToolExecuteContext, ) => Effect.Effect, ToolFailure> /** * A type-safe LLM tool. Each tool bundles its own description, parameter * Schema and success Schema. The execute handler is optional: omit it when you * only want to expose a tool schema to the model and handle tool calls outside * this package. * * Errors must be expressed as `ToolFailure`. Unmapped errors and defects fail * the stream. * * Internally each tool also carries memoized codecs and a precomputed * `ToolDefinition` so the runtime doesn't rebuild them per invocation. */ export interface Tool, Success extends ToolSchema> { readonly description: string readonly parameters: Parameters readonly success: Success readonly execute?: ToolExecute /** @internal */ readonly _decode: (input: unknown) => Effect.Effect, Schema.SchemaError> /** @internal */ readonly _encode: (value: Schema.Schema.Type) => Effect.Effect /** @internal */ readonly _definition: ToolDefinitionClass } export type AnyTool = Tool, ToolSchema> export type ExecutableTool, Success extends ToolSchema> = Tool< Parameters, Success > & { readonly execute: ToolExecute } export type AnyExecutableTool = ExecutableTool, ToolSchema> export type ExecutableTools = Record type TypedToolConfig = { readonly description: string readonly parameters: ToolSchema readonly success: ToolSchema readonly execute?: ToolExecute, ToolSchema> } type DynamicToolConfig = { readonly description: string readonly jsonSchema: JsonSchema.JsonSchema readonly execute?: (params: unknown, context?: ToolExecuteContext) => Effect.Effect } /** * Constructs a tool. Two input modes: * * 1. **Typed** — pass Effect `parameters` and `success` Schemas; inputs and * outputs are statically typed and decoded/encoded automatically. * * ```ts * Tool.make({ * description: "Get current weather", * parameters: Schema.Struct({ city: Schema.String }), * success: Schema.Struct({ temperature: Schema.Number }), * execute: ({ city }) => Effect.succeed({ temperature: 22 }), * }) * ``` * * 2. **Dynamic** — pass raw JSON Schema as `jsonSchema`. Use this when the * schema comes from an external source (MCP server, plugin manifest, * dynamic config) and is not known at compile time. Inputs are typed as * `unknown`; the handler is responsible for any validation it needs. * * ```ts * Tool.make({ * description: "Look something up", * jsonSchema: { type: "object", properties: { ... } }, * execute: (params) => Effect.succeed(...), * }) * ``` * * In both modes the produced tool flows through `toDefinitions(...)` and the * runtime identically. */ export function make, Success extends ToolSchema>(config: { readonly description: string readonly parameters: Parameters readonly success: Success readonly execute: ToolExecute }): ExecutableTool export function make, Success extends ToolSchema>(config: { readonly description: string readonly parameters: Parameters readonly success: Success readonly execute?: undefined }): Tool export function make(config: { readonly description: string readonly jsonSchema: JsonSchema.JsonSchema readonly execute: (params: unknown, context?: ToolExecuteContext) => Effect.Effect }): AnyExecutableTool export function make(config: { readonly description: string readonly jsonSchema: JsonSchema.JsonSchema readonly execute?: undefined }): AnyTool export function make(config: TypedToolConfig | DynamicToolConfig): AnyTool { if ("jsonSchema" in config) { return { description: config.description, parameters: Schema.Unknown as ToolSchema, success: Schema.Unknown as ToolSchema, execute: config.execute, _decode: Effect.succeed, _encode: Effect.succeed, _definition: new ToolDefinition({ name: "", description: config.description, inputSchema: config.jsonSchema, }), } } return { description: config.description, parameters: config.parameters, success: config.success, execute: config.execute, _decode: Schema.decodeUnknownEffect(config.parameters), _encode: Schema.encodeEffect(config.success), _definition: new ToolDefinition({ name: "", description: config.description, inputSchema: toJsonSchema(config.parameters), }), } } export const tool = make /** * A record of named tools. The record key becomes the tool name on the wire. */ export type Tools = Record /** * Convert a tools record into the `ToolDefinition[]` shape that * `LLMRequest.tools` expects. The runtime calls this internally; consumers * that build `LLMRequest` themselves can use it too. * * Tool names come from the record keys, so the per-tool cached * `_definition` is rebuilt with the correct name here. The JSON Schema body * is reused. */ export const toDefinitions = (tools: Tools): ReadonlyArray => Object.entries(tools).map( ([name, item]) => new ToolDefinition({ name, description: item._definition.description, inputSchema: item._definition.inputSchema, }), ) const toJsonSchema = (schema: Schema.Top): JsonSchema.JsonSchema => { const document = Schema.toJsonSchemaDocument(schema) if (Object.keys(document.definitions).length === 0) return document.schema return { ...document.schema, $defs: document.definitions } } export { ToolFailure } export * as Tool from "./tool"