diff --git a/src/create-ai-chain.ts b/src/create-ai-chain.ts
index cf31d98..adda7c2 100644
--- a/src/create-ai-chain.ts
+++ b/src/create-ai-chain.ts
@@ -1,4 +1,5 @@
 import type { SetOptional } from 'type-fest'
+import type { z } from 'zod'
 import pMap from 'p-map'
 
 import type * as types from './types.js'
@@ -8,6 +9,19 @@ import { Msg } from './message.js'
 import { asSchema, augmentSystemMessageWithJsonSchema } from './schema.js'
 import { getErrorMessage } from './utils.js'
 
+export type AIChainParams<Result extends types.AIChainResult = string> = {
+  chatFn: types.ChatFn
+  params?: types.Simplify<
+    Partial<Omit<types.ChatParams, 'tools' | 'functions'>>
+  >
+  tools?: types.AIFunctionLike[]
+  schema?: z.ZodType<Result> | types.Schema<Result>
+  maxCalls?: number
+  maxRetries?: number
+  toolCallConcurrency?: number
+  injectSchemaIntoSystemMessage?: boolean
+}
+
 /**
  * Creates a chain of chat completion calls that can be invoked as a single
  * function. It is meant to simplify the process of resolving tool calls
@@ -32,7 +46,7 @@ export function createAIChain<Result extends types.AIChainResult = string>({
   maxRetries = 2,
   toolCallConcurrency = 8,
   injectSchemaIntoSystemMessage = true
-}: types.AIChainParams<Result>): types.AIChain<Result> {
+}: AIChainParams<Result>): types.AIChain<Result> {
   const functionSet = new AIFunctionSet(tools)
   const defaultParams: Partial<types.ChatParams> | undefined =
     rawSchema && !functionSet.size
diff --git a/src/extract-object.ts b/src/extract-object.ts
index 458cc64..484ccd0 100644
--- a/src/extract-object.ts
+++ b/src/extract-object.ts
@@ -1,8 +1,18 @@
 import type * as types from './types.js'
-import { createAIChain } from './create-ai-chain.js'
+import { type AIChainParams, createAIChain } from './create-ai-chain.js'
+
+export type ExtractObjectParams<Result extends types.AIChainResult = string> =
+  types.Simplify<
+    types.SetRequired<
+      Omit<AIChainParams<Result>, 'tools' | 'toolCallConcurrency' | 'params'>,
+      'schema'
+    > & {
+      params: types.SetRequired<Partial<types.ChatParams>, 'messages'>
+    }
+  >
 
 export function extractObject<Result extends types.AIChainResult = string>(
-  args: types.ExtractObjectParams<Result>
+  args: ExtractObjectParams<Result>
 ): Promise<Result> {
   const chain = createAIChain(args)
   return chain()
diff --git a/src/fns.ts b/src/fns.ts
index 7f420da..ac0e9ac 100644
--- a/src/fns.ts
+++ b/src/fns.ts
@@ -39,7 +39,10 @@ export abstract class AIFunctionsProvider {
   get functions(): AIFunctionSet {
     if (!this._functions) {
       const metadata = this.constructor[Symbol.metadata]
-      assert(metadata)
+      assert(
+        metadata,
+        'Your runtime does not appear to support ES decorator metadata: https://github.com/tc39/proposal-decorator-metadata/issues/14'
+      )
       const invocables =
         (metadata?.invocables as PrivateAIFunctionMetadata[]) ?? []
       // console.log({ metadata, invocables })
diff --git a/src/services/jina-client.ts b/src/services/jina-client.ts
index e2408c8..507f3de 100644
--- a/src/services/jina-client.ts
+++ b/src/services/jina-client.ts
@@ -75,6 +75,12 @@ export namespace jina {
     }
   }
 
+  export interface ReaderResponseHtml extends JinaResponse {
+    data: {
+      html: string
+    }
+  }
+
   export interface SearchResponse extends JinaResponse {
     data: ReaderData[]
   }
@@ -159,7 +165,9 @@ export class JinaClient extends AIFunctionsProvider {
         ? T['json'] extends true
           ? T['returnFormat'] extends 'screenshot'
             ? jina.ReaderResponseScreenshot
-            : jina.ReaderResponse
+            : T['returnFormat'] extends 'html'
+              ? jina.ReaderResponseHtml
+              : jina.ReaderResponse
           : T['returnFormat'] extends 'screenshot'
             ? ArrayBuffer
             : string
diff --git a/src/types.ts b/src/types.ts
index ecf0226..f865667 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,16 +1,15 @@
-import type { Jsonifiable, SetOptional, SetRequired, Simplify } from 'type-fest'
+import type { Jsonifiable, SetOptional, Simplify } from 'type-fest'
 import type { z } from 'zod'
 
 import type { AIFunctionSet } from './ai-function-set.js'
 import type { AIFunctionsProvider } from './fns.js'
 import type { Msg } from './message.js'
-import type { Schema } from './schema.js'
 
 export type { Msg } from './message.js'
 export type { Schema } from './schema.js'
 export type { KyInstance } from 'ky'
 export type { ThrottledFunction } from 'p-throttle'
-export type { Simplify } from 'type-fest'
+export type { SetRequired, Simplify } from 'type-fest'
 
 export type Nullable<T> = T | null
 
@@ -136,24 +135,3 @@ export type SafeParseResult<TData> =
     }
 
 export type ValidatorFn<TData> = (value: unknown) => SafeParseResult<TData>
-
-export type AIChainParams<Result extends AIChainResult = string> = {
-  chatFn: ChatFn
-  params?: Simplify<Partial<Omit<ChatParams, 'tools' | 'functions'>>>
-  tools?: AIFunctionLike[]
-  schema?: z.ZodType<Result> | Schema<Result>
-  maxCalls?: number
-  maxRetries?: number
-  toolCallConcurrency?: number
-  injectSchemaIntoSystemMessage?: boolean
-}
-
-export type ExtractObjectParams<Result extends AIChainResult = string> =
-  Simplify<
-    SetRequired<
-      Omit<AIChainParams<Result>, 'tools' | 'toolCallConcurrency' | 'params'>,
-      'schema'
-    > & {
-      params: SetRequired<Partial<ChatParams>, 'messages'>
-    }
-  >